application of nanotechnologies in the energy sector€¦ · the fossil fuels coal, crude oil and...

Ministry of Economics, Energy, Transport and Regional Development – State of Hessen

www.hessen-nanotech.de

Application of Nanotechnologiesin the Energy Sector

Hessen Nanotech

Hessen – there’s no way around us.

Application of Nanotechnologies in the Energy Sector

Volume 9 of the Technologielinie Hessen-Nanotech Publication Series

Imprint

Application of Nanotechnologies in the Energy Sector

Volume 9 of the Technologielinie Hessen-Nanotech Publication Series of the Ministryof Economics, Energy, Transport and Regional Development – State of Hessen

Created by:

VDI Technologiezentrum GmbH,

Innovationsbegleitung und Innovationsberatung

VDI-Platz 1, 40468 Düsseldorf, Germany

Authors:

Dr. Wolfgang Luther, Dr. Heinz Eickenbusch, Oliver S. Kaiser, Dr. Leif Brand

Translated by:

A.C.T. Fachübersetzungen GmbH, Mönchengladbach

Editorial team:

Sebastian Hummel (Ministry of Economics, Energy, Transport and Regional

Development – State of Hessen)

Dr. David Eckensberger (Hessen Trade & Invest GmbH, Hessen-Nanotech)

Publisher:

Hessen Trade & Invest GmbH

Konradinerallee 9, 65189 Wiesbaden, Germany

Phone +49 611 95017-8326

Fax +49 611 95017-8620

www.htai.de

The publisher does not accept any responsibility for the correctness, the accuracy and

completeness of the information or for the observance of private rights of third parties. The

views and opinions expressed in the publication are not necessarily those of the publisher.

© Ministry of Economics, Energy, Transport

and Regional Development – State of Hessen

Kaiser-Friedrich-Ring 75

65185 Wiesbaden, Germany

www.wirtschaft.hessen.de

Duplication and reprinting – even as excerpts – only after prior written permission.

Layout: Theißen-Design, Lohfelden

Pictures on cover: Petair | Fotolia.com (top); Fraunhofer IWM (bottom left);

U.I. Lapp (bottom center); DLR (CC-BY 3.0) (bottom right)

Print: A&M Service GmbH, Elz


1st edition, May 2008

2nd, completely revised edition, December 2015

Contents

Preface ......................................................................................................................................................... 1

1 Energy Supply Perspectives in the 21st Century ....................................................................... 2

2 Nanotechnology Innovation Potentials in the Energy Sector ........................................... 7

3 Utilising Renewable Energy Sources and Energy Conversion ...................................... 12

4 Energy Storage ..................................................................................................................................... 39

5 Energy Distribution ............................................................................................................................. 47

6 Energy Efficiency in Industrial Applications ........................................................................... 50

7 Success Stories in Hessen ................................................................................................................ 54

8 Further Information ............................................................................................................................. 62

Publication Series ................................................................................................................................ 68

1

The energy sector faces enormous challenges requiring innovative solutions:

completing the nuclear power phase-out, substituting fossil fuels, reducing carbon

dioxide emissions. All this affects the generation of energy as well as its efficient

use. Gradually, fossil fuels are being replaced by new technologies – not least due

to nanotechnological innovations. Here, companies and research institutions in

Hessen are at the forefront.

For example, the Marburg-based NAsP III/V GmbH has developed concentrators

that double the efficiency of silicon or gallium arsenide based solar cells. This

enables highly efficient and miniaturised solar cells. The Hanau operation of the

technology group Umicore provides nanostructured catalysts for efficient mem-

brane fuel cells. And scientists of the RheinMain University of Applied Sciences in

Rüsselsheim investigate the hydrogen storage and its detection in nanoporous

powder materials – fundamental research to develop safer hydrogen storage

systems for fuel cell vehicles.

Obviously, nanotechnological innovations have already found their way into the

energy sector. And lots more wait to be developed. The completely revised edition

of our brochure provides an up-to-date overview of success stories and develop-

ment potentials. I wish you enjoyable and stimulating reading.

Preface

Tarek Al-WazirMinister of Economics, Energy, Transport and Regional Development – State of Hessen

1. Energy Supply Perspectivesin the 21st Century

Energy drives our lives. It guarantees pleasant temper-atures and ensures our living and working environ-ments are sufficiently bright; it feeds production facil-ities, urban infrastructure and the army of routine elec-tronic assistants, and allows almost unlimited mobilityaround the globe. Global energy demand continuesto grow and, according to International EnergyAgency forecasts, will increase from approximately 13billion tonnes crude oil equivalent at the moment toprobably 15 to 17 billion tonnes crude oil equivalentby 2030 (IEA 2014). The primary driver for this largeincrease in energy consumption, and with it the asso-ciated global carbon dioxide emissions, is the backlogdemand of emerging economies such as China andIndia, whose energy consumption is increasinglyapproaching that of the industrialised nations, gener-ally utilising fossil fuels. The largest proportion ofglobal energy consumption is used by the industrialsector, followed by the transport sector, householdsand other commercial operations (services, retailing,etc.). However, there are pronounced regional differ-ences in terms of energy consumption and develop-ments in the individual sectors. For example, inadvanced industrial nations such as Germany, energyconsumption is highest in the transport sector and alsodisplays the greatest growth rates there, while energyconsumption in the industrial sector has been fallingin recent years.

At a global level, however, an increase in energy con-sumption is forecast for all sectors, with the greatestrates of increase being anticipated in non-OECDcountries such as China and India. It is obvious that inorder to meet this growing energy demand in the longterm a fundamental renewal of the energy sector isnecessary, away from the previously dominating fossilfuels and towards the increased use of renewableenergy sources. Climate change, which forces us toreduce carbon dioxide emissions, and the foreseeablescarcity of fossil fuels leave us with no other choicethan to continue to drive forward the urgently requiredinnovations in the energy sector. This not only appliesto the increased development of renewable energysources but to the entire value chain, from the produc-tion of energy carriers from primary energy sources tothe conversion, storage, distribution and utilisation ofenergy.

2

1.1 Energy Supply and Global Energy Demand

The fossil fuels coal, crude oil and natural gas coverthe largest proportion of today’s global energydemand at around 80 percent. Current scenarios forthe development of future energy demand assumethat the proportion of fossil fuels in global supplies willremain at the same high level until 2035 (BP 2015).This trend can only be countered by massive globalefforts and investments in the fields of renewableenergy and energy-saving measures. The EuropeanUnion assumes a pioneering role here and has com-mitted to some ambitious targets, for example with a mandatory proportion of 20 percent renewableenergy sources in overall EU energy consumption by2020, a 20-percent reduction in EU-wide greenhousegases and a 20-percent increase in energy efficiency.

The global proportion of renewable energy forms inenergy consumption is currently less than 20 percent.Energy recovery from biomass contributes half of this,followed by hydropower and geothermal energy,while wind and solar energy together contribute justover one percent. In terms of the generation of elec-trical energy, renewable energy forms, includinghydropower, produce around 22 percent globally.

3

1.2 Available Primary Energy Source Potentials

2.6 %Nuclear power

All renewables

19.1 %

Fossil fuels

78.3 %

Percentage of fossil fuels:Crude oil 29.7 %Coal 27.2 %Gas 21.5 %(Total 78.3 %)

Modern renewables

10.1 %

Traditional biomass

9.0 %0.8 %Biofuels

1.3 %Wind/solar/

biomass/geothermal

power

Biomass/geothermal/solar heat

4.1 %

Hydropower

3.9 %

Percentages of energy sources in global energy consumption in 2013. (Source: REN21 2015)

Today’s proven reserves of technically recoverable fos-sil fuels are sufficient to meet global energy demandfor a few more decades. Availability estimates aregreater than 50 years for crude oil and natural gas andgreater than 100 years for coal (WEC 2013). These fig-ures are constantly changing in line with develop-

ments in global consumption and advances in explo-ration and production technologies. With regard tocrude oil, non-conventional sources such as heavy oilor oil shale, the use of which is associated with majorenvironmental pollution, are being increasinglyexploited.

Large regional differences exist in the use of renew-able energy sources. In Germany, the proportion ofrenewable energy sources relative to total energy con-sumption is currently around ten percent and thusbelow the global average. This is primarily due to thelesser use of biomass in the energy supply comparedto less industrialised nations. However, the trend touse renewable energy sources has greatly increasedin Germany in recent years, in particular in electricitysupplies. Due to highly dynamic developments thewind energy sector’s share of the total electricity sup-ply in Germany is now over 14 percent (FHG ISE 2015).In photovoltaics, too, very high growth rates areachieved, so that this technology now accounts forapproximately seven percent of total electricity gen-eration.

Together with electricity from biomass andhydropower, one third of electricity is produced fromrenewable energy sources. The aim of the FederalGovernment is to increase the proportion of renew-able energy sources in total energy consumption to 60percent by 2050. It is intended to increase the propor-tion of renewable energy sources in the electricity sup-ply to 80 percent by 2050. Objectives such as thesewill only be achievable through the use of newapproaches and technological breakthroughs, whichwill further increase the cost-effectiveness of providingrenewable energy sources and contribute to develop-ing significant efficiency potentials along the entireenergy sector value chain.

4

Fossil fuels and nuclear

77.2 %.2 %

Renewableelectricity

22.8 %

Wind 3.1 %

Bio-power 1.8 %

Solar PV 0.9 %Geothermal, CSP, and ocean 0.4 %

Hydropower

16.6 %

Estimated percentages of renewable energy sources in global electricity generation in 2014. (Source: REN21 2015)

1.3 Using Renewable Energy Sources

The global potential of renewable energy sources iscurrently barely developed. Global energy demandcould be met many times over by direct utilisation ofthe radiation energy of the sun. Wind and tidal energyalso offer considerable potentials. However, fromtoday’s perspective, the technically and economicallyexploitable percentage is extremely small, in particulardue to the low energy density and the limited numberof economically exploitable sites. For example, theenergy input of the solar radiation impinging on thesurface of the Earth in central Europe is limited to amaximum of approximately 1,000 watts per squaremetre. Other barriers to the use of renewable energysources include the discontinuous energy input as afunction of environmental influences, low energy con-version efficiencies and the cost-intensive manufactur-ing methods and materials.

A prerequisite for significant growth in energy sup-plies from renewable energy sources is the substantialreductions of costs, for example through economiesof scale in the further development of renewableenergy sources, the development of more cost-effec-tive manufacturing methods and efficiency improve-ments through technological innovations. In the longterm, there will be no alternative but to optimise thedevelopment of renewable energy source potentials.The utilisation of solar energy using solar cells andsolar thermal power plants, in particular, will play a keyrole here. Long-term scenarios forecast that the utili-sation of solar energy will cover more than 50 percentof the global energy demand by the year 2100.Whether or not additional options will be available, forexample, the technically and economically achievableuse of nuclear fusion, remains conjecture at the pres-ent time.

5

Net electricity generation in the public power supply in Germany in 2014 (TWh: terawatt hours). (Source: FHG ISE 2015)

0Nuclear power Lignite Black coal Gas

Year 2014

Wind Solar Biomass Hydropower

91.8 TWh

140.9 TWh

99.0 TWh

33.2 TWh51.4 TWh

32.8 TWh53.9 TWh

18.5 TWh40

80

120

150

TWh

In order to safeguard global energy supplies in thelong term, it is not enough to merely develop the avail-able energy source as efficiently and environmentallycompatible as possible. The energy losses en routefrom the source to the end consumer must also beminimised, the provision and distribution of energymust be made as flexible and efficient as possible forthe respective purpose, and the energy demand inindustry, infrastructure and private households mustbe reduced.

Optimisation potentials, which can also be exploitedwith the use of nanotechnologies, exist in every sec-tion of the value chain. As enabling technologies, nan-otechnologies generally take hold relatively early inthe value chain, because they optimise componentsand intermediate products. However, the implemen-tation of nanotechnological innovations not onlydepends on technical and economic criteria, but alsoheavily on the political and socio-economic environ-ment and framework conditions, especially in theenergy sector. Which technological development willultimately prevail is therefore primarily determined byeconomic constraints, as well as by political and socialaspects, in addition to technological feasibility.

6

Primary energyexploitation

Energy conversion

Energy distribution

Energy storage

Energy utilisation

Framework conditions

Energy supply chain

Policy • Legislation (renewable energies,

thermal insulation, nuclear power, competition law, emission control ...)

• Taxes, subsidies (petrol, coal, bio, solar ...) • International climate protection agreements • Research funding

(solar, fuel cells, fusion ...)

Industry and commerce• Energy/commodity prices • Competitive structure

(formation of cartels/monopolies)• Corporate investments/depreciations • Capital market (VC, base rate level)• Economic performance• International competition

Environment/society• Climate change • Protecting ecosystems • Clean air/protection

from radiation • Acceptance of

Social technology • Employment developments

Value chain and framework conditions in the energy sector. (Source: VDI TZ)

1.4 The Energy Value Chain

2. Nanotechnology Innovation Potentials in the Energy Sector

The term nanotechnologies has been established formore than two decades as a keyword in the researchand innovation strategies of leading industrial nations.Around the world, nanotechnologies are viewed askey technologies for innovation and growth in modernindustrial societies. By virtue of their innovative prop-erties, from a technical perspective, nanotechnologiesprimarily mean nanostructured materials, the proper-ties of which differ from the properties of individualatoms, molecules and bulk materials, and which canbe used for enhanced materials, applications and sys-tems.

The term nanotechnologies bundles a multitude of dif-ferent technology and application fields, dealing withthe technical utilisation of structures and material com-ponents in the nano-size range. It is therefore difficultto conclusively define nanotechnologies and to clearlydistinguish them from other fields of technology. Inpractice, nanotechnologies are often addressed assubsectors of traditional technological disciplinessuch as materials engineering, electronics, optics orbiotechnologies, and doubtlessly the interdisciplinaryinteractions have an important role to play. Nanotech-nological methods are not even always entirely newbut often rather developments of tried-and-testedproduction and analysis techniques. Nanoeffects wereeven sporadically used during the middle ages, forexample in colouring church windows red due tofinely distributed gold colloids or in hardening theDamascene steel of sword blades using carbon nan-otubes, without even being conscious of the physico-chemical principles. The essence of nanotechnologiesis therefore the controlled use of nano-scale struc-tures, an understanding of the laws governing them atthe molecular level and targeted technologicalimprovements in both materials and componentsderived from this.

In recent years, the international standardisationorganisation ISO has compiled a basis for definitionsand standards relating to nanotechnologies. In it, nan-otechnology denotes the application of scientificinsights for controlling and utilising material compo-nents in the nano size range (approximately one to100 nanometres; one nanometre equals 10-9 metres),where special properties and phenomena relative tothe size or structure may occur (ISO 2010).

However, the subject of nanotechnologies is bestapproached less by formal definitions than by adescription of principles and research approaches,which play a considerable role in this context. Thereare two fundamental approaches for technical utilisa-tion of the nanocosmos. One is the principle of con-struction using the elementary units of animate andinanimate nature, atoms and molecules, comparableto building with a Lego set (bottom-up approach). Theaim here is to manufacture complex components andproducts, based on nature’s model, through the self-organisation of material components and without theuse of energy- and resource-intensive technicalprocesses. In addition to these approaches, predomi-nantly still in the realm of basic research, the nanocos-mos is exploited by the miniaturisation of structuresdown to sizes of only a few nanometres. This top-downapproach allows an increasing number of structuresand functions to be implemented in as small a spaceas possible and thus to further increase the perform-ance of technical components. A classic example ofthis approach is the five decades of advancing minia-turisation of semiconductor structures in electronics,which have now shrunk to as little as ten nanometres.Such nanotechnologies drive the development of eversmaller and more powerful electronic chips as motorsfor the progressing digital revolution in industry andsociety.

7

2.1 Importance and Definition of Nanotechnologies

In power engineering, a whole range of products onlymade possible by nanotechnologies is already in theprototype stage or available on the market. The follow-ing products are offered, for example: nanoporousantireflection coated solar glass, nanostructured LEDs,nano-additives for engine lubricants, nanoelectrodesfor lithium-ion batteries, nanocrystalline magneticmaterials for power electronics and nanoporous

hydrogen storage materials, as well as nanocatalystsin fuel cells and industrial chemical productionprocesses. The success stories from Hessen given inSection 7 also demonstrate that nanotechnology isalready being implemented by companies in theirproducts. But this nowhere near exhausts the potentialapplications of nanotechnology in power engineering.

8

2.2 Application of Nanotechnologies in the Energy Value Chain

Optical

a Optimised light absorption properties of solarcells facilitated by quantum dots and nanolayersin stacked cells.

a Antireflection properties for solar cells toincrease the energy yield in photovoltaics andsolar thermal applications.

a Light-emitting polymers for manufacturing moreenergy-efficient organic light-emitting diodes.

Electronic

a Optimised electrical conductivity facilitated bynanostructured superconductors.

a Electrical isolators facilitated by nanostructuredfillers in high-voltage line components.

a Improved thermoelectric materials facilitated by nanostructured layer systems for efficient electricity generation from heat.

Thermal

a Nanostructured thermal protection layers for turbine blades in gas and aircraft turbines.

a Improved thermal conductivity thanks to the useof nanomaterials for optimised heat exchangers.

a Optimised heat storage based on nanoporousmaterials (zeolites) or microencapsulated phasechange storage.

a Nanofoams as superinsulating systems for industrial and building technology applications.

Chemical

a More efficient catalysts in fuel cells and for thechemical conversion of fuels facilitated byenlarged surfaces and specific catalyst designs.

a More powerful batteries, accumulators andsupercapacitors facilitated by enlarged specificelectrode surfaces.

a Optimised polymer electrolyte membranes withenhanced temperature and corrosion resistancefor applications in fuel cells or separators inlithium-ion batteries.

a Nanoporous materials for storing hydrogen, for example metal hydrides or metal-organiccompounds.

a Optimised separation efficiency of gas membranes for separating carbon dioxide fromcoal-fired power plants.

Mechanical

a Improved stiffness of construction materials for wind turbine rotor blades.

a Wear-resistant nanolayers for drill heads, transmissions and motor components.

a Nanostructured silicate compounds as lubricantadditives for improving wear protection and lowering energy consumption in motors andtransmissions.

Examples of nanobased property changes and their potential

applications in the energy sector. (Source: VDI TZ)

This is because nanotechnologies present numerousadditional opportunities for innovative, intelligentmaterial design, in which the desired material proper-ties can be combined and specifically adapted tomeet the needs of the respective technical application.

Here, a broad spectrum of chemical, optical, electronicand thermal material properties that are of interest forapplications in the energy sector are addressed.

9

Exploiting renewable energy sources

Energy conversion

Energy distribution

Energy storage

Energy utilisation

Gas turbines

Heat and corrosion protectionfor turbine blades (e.g., ceramic, intermetallic coatings)for more efficient power plants and propulsion units

Nanocatalysts for optimised production of chemical energysources (hydrogen, biofuels, crude oil processing, coal liquefaction)

Chemical transformation

Nanooptimised membranes and electrodes for more efficient fuel cells (vehicle and mobile electronics applications)

Fuel cell

Nanostructured semiconductormaterials (boundary layer design, nanowires) for more efficient thermoelectric electricity generation (among others, utilisation of waste heat from vehicles and bodies for mobile electronics)

Thermoelectrics

Combustion enginesWear/corrosion protection of engine components, diesel injectors (composites, coatings, particle additives)

Electric motorsNanocomposites for super-conductors and magnetic materials

Conducting electricity

Supraconducting: Optimised superconductors facilitated by nanostructuring and boundary layer design for loss-free power conductors

CNT cables: Superconducting cables based on carbon nanotubes envisaged in the long term

Cordless transmission: Power transmission by laser, microwaves, electromagnetic resonance possible in the long term with partial solutions from nanooptimised components

High-voltage transmission: Nanofillers for electrical insulation systems and transformers, power semi-conductors for low-loss voltage conversion

Intelligent power gridsNanosensors and power electronics for controllable grids with load and fault management for heavily decentralised energy input

Heat transmissionHeat input and output facilitated by nanooptimised heat exchangers/pipes (for example based on nano-carbons) in industry and private households

Electrical energy

Batteries/rechargeable batteries: Optimised lithium ion batteries facilitated by nanostructured electrodes and flexible, ceramic separators, used in electronics, in the mid term, in automobiles or for load regulation in power grids

Supercapacitors: Nanomaterials for electrodes (carbon aerogels, graphenes, metal (oxides) and electrolytes for higher energy densities

Chemical energyHydrogen storage: Nanoporous materials (organometals, metal hydrides)for applications in mobile electronics, in the long term in automobiles

Fuel tanks: Gas-tight polymer nanocomposites for reducing emissions from automobile fuel tanks

Thermal energyPhase change storage: Microencapsulated PCMs for air conditioning in buildings and more efficient solar heat energy.

Nanoporous materials (e.g. zeolites) for thermal adsorption storage units in heaters

Thermal insulation

Nanoporous foams and gels for thermal insulation in buildings (aerogels, polymer foams) or thermostatically controlling technical processes

Air conditioningLight and heat flow control in buildings facilitated by switchable windows (electrochemistry), micromirror systems or infrared reflectors

Lightweight constructionLightweight construction materials based on nano-materials and composites (carbon nanotubes, metal-matrix composites, nanocoatedlightweight metals, polymer composites, ultra-high strength concrete)

Industrial productionReplacement of energy-intensive processes utilising nanotechnological process innovations (among others, optimised catalysts), self-organising processes

LightingEnergy-saving lighting thanks to inorganic and organic light-emitting diodes (use of nanomaterials and nano-coatings, e.g. quantum dots)

Creation of biofuels from renewable resources facilitated by nanooptimised catalysts and methods

Biomass

Nanocoatings for enhanced energy input (antireflection, light absorption, nanooptimisedheat exchangers)

Solar heat

Nanomaterials for lighter and more stable rotor blades, wear and corrosion protection for bearings and transmissions

Wind energy

Nanocoatings and materials for wear resistant drill heads

Geothermal energy

Nanocoatings as corrosion protection, nanomaterials for wave power and reverse osmotic power plants (nanomembranes, electroactivepolymers)

Marine energy

Photovoltaics

Nanomaterials for solar cells (fullerenes, quantum dots, titanium dioxide nanoparticles, organic semiconductors), nanocoatings (for example, antireflection)

Examples of potential nanotechnology applications along the energy sector value chain (Source: VDI TZ)

Thanks to improved materials and methods, nanotech-nologies can contribute to utilising renewable energysources in a considerably more cost-efficient way andthus help smooth the way to a broad-based economicbreakthrough. Here, nanotechnological innovationsplay a role in all sections of the energy sector valuechain, from the development of renewable energysources to the conversion and storage of energy andon to its utilisation in industry and in private house-holds. Nanotechnological solutions offer substantialenergy-saving potentials across all branches of indus-try thanks to more efficient energy utilisation and opti-mised production technologies. In the long term, theyraise hope for of important contributions to sustain-able energy supplies and the success of global climateprotection policies.

10

Scenario with examples of future application options for

nanotechnologies in the energy sector.

Image: VDI TZ

Image sources (clockwise from top left): BASF; Skeleton Technol -

ogies; Fraunhofer IWS; Fraunhofer IPA; Heliatek/Tim Deussen,

Berlin; Fraunhofer ISE; Universität Duisburg-Essen; Novaled;

REWITEC; BINE Informationsdienst/Anna Durst; MAGNETEC; ZBT

GmbH – Zentrum für BrennstoffzellenTechnik; Helmholtz-Zentrum

Geesthacht; TU Darmstadt, Institut für Werkstoffkunde

Magnetic materials

Nanoporous hydrogen storagefor mobile fuel cellapplications

Nanocrystallinemagnetic materialsfor efficient powersupply components(among others,transformers,meters etc.)

Nano-thermal protection layers for gas turbines

Nanomembranesseparating carbondioxide in combustion power plants

Hydrogen storage

Conventional power plants

Nanooptimised fuel cells for auto-mobiles and transport vehicles

Fuel cell

Nanostructured,high-temperaturesuperconductors for power cables,current limiters andgenerators

Superconductivity

Nanoparticles as lubricant additives improveenergy efficiency and reduce wear in mechanical components (for example, motors,transmissions, vehicle and machine bearings)

Wear protection

11

Nanomaterials improve theefficiency of thermoelectricgenerators for wearableelectronics and waste heatutilisation in industry andautomotive engineering

Nanooptimised polymersolar cells for large scalesolar facades and integra-tion in everyday items

Nanomaterial-based, dye-sensitised solar cells asdecorative facade elementsfor electricity generation

Thermoelectrics

Photovoltaics

Carbon nanotube-based,heatable coatings for ice-free wind turbinerotor blades

Wind energyElectricity storage

Organic light-emitting diodes forlarge-scale displaysand lighting objects

Lighting

Nanocomposites aselectrode material forhigh-performance batteries in stationaryand mobile applications

Graphene-based supercapacitors for electromobility applications

Photovoltaics market and economic relevance

The global photovoltaics market has displayed dou-ble-digit growth rates in recent years, in particular inJapan, China and the USA. According to the ‘GlobalSolar Power Market’ report by the market researchcompany Frost & Sullivan, the global market for solarenergy will more than double from its current approx-imately 60 billion US dollars by 2020 (to approximately137 billion US dollars). A European Photovoltaic Indus-try Association study predicts that photovoltaics maycover up to 15 percent of the European Union’s elec-trical energy demand in 2030 (EPIA 2015). Around 177gigawatts of PV capacity were installed globally at theend of 2014. Of this, Germany produces the largestproportion at 38.2 gigawatts, followed by China (28.2 gigawatts), Japan (23.3 gigawatts), Italy (18.5gigawatts) and the USA (18.3 gigawatts). In addition tothese five largest photovoltaic electricity producingcountries, France, Spain, the United Kingdom, Aus-tralia and Belgium also belong in the top ten.

Despite the global growth in the photovoltaics indus-try, a noticeable decline has been registered in Ger-many in recent years, especially in cell and moduleproduction. The cause of this is, on the one hand, theerosion of prices for solar modules, in particular as aresult of Chinese competition, and, on the other hand,a substantial drop in newly installed photovoltaiccapacity as a consequence of the altered feed-in con-ditions brought about by the revised RenewableEnergy Sources Act (German: Erneuerbare-Energien-Gesetz) in force since 2014. Despite the decliningnumber of solar cell and solar module manufacturersthe industry continues to be very important economi-cally in Germany. According to the German SolarAssociation (German: Bundesverband Solarwirtschaft)data, there are currently around 50,000 peopleemployed in approximately 10,000 German solarcompanies, including suppliers, distributors andinstallers providing installation and servicing, in addi-tion to cell, module and inverter manufacturers (BSWSolar 2015).

12

3. Utilising Renewable Energy Sources and Energy Conversion

3.1 Photovoltaics

20

0

60

80

120

160

180

2006200420022000 2008 2010

Gigawatt peak

2012 2014

IEA PVPS Countries Non IEA PVPS Countries

40

100

140

Development of global photovoltaic installations with time. Gigawatt peak: electrical capacity in gigawatt at standardized test conditions.

(Source: International Energy Agency – Photovoltaic Power Systems (IEA PVPS))

Additional efficiency improvements and especiallylower prices will be decisive for the future course ofphotovoltaics. The broad commercial breakthrough ofphotovoltaics is to be expected only as soon as itbecomes possible to cover large areas with solar cellswithout recourse to state subsidies. What is neededhere, among other things, is further efficiencyimprovements and, even more importantly, more cost-effective materials and manufacturing methods, withdevelopment activities focusing on a variety of solarcell types.

Development status and applications of a variety of solar cell types

Wafer-based mono and multicrystalline silicon solartechnology continues to dominate the market with ashare of around 90 percent in photovoltaics. However,further cost reductions in this field resulting from tech-nical improvements and mass production are limited.Alternative cell types, offering material savings poten-tials and substantially more cost-effective manufac-turing methods, appear more promising here. Theyinclude thin-film solar cells and organic solar cells(dye-sensitised solar cells or polymer solar cells).

13

Different solar cell types and efficiencies achieved to date. (Source: NREL 2013)

Compared to conventional silicon wafer technology,inorganic and organic thin-film solar cells offer sub-stantial cost reduction potentials in terms of solar cellproduction as a result of material savings, low temper-ature processes, integrated cell circuitry and a highdegree of automation in series production. An addi-tional advantage is that flexible substrates areadopted as carrier materials, allowing a new range ofenergy supply applications to be developed, forexample, by integrating solar cells in textiles andeveryday items. Thin-film solar cells, for instance, canbe used as a mobile power supply for entertainmentelectronics and small devices, allowing mobile tele-phones and notebooks to be charged even in remoteand rural regions without electricity grids. Even thedecentralised power supply for electrical plants and

devices is possible, independent of a main power sup-ply. Solar modules integrated in solar vehicle roofsmay provide not only the on-board power supply, butalso support battery charging in hybrid vehicles. Inbuildings, for example in house roofs and walls, glassfacades, skylights, sunroofs or display boards, trans-parent organic solar cells can be used to generate anduse energy and to feed into the grid.

Nanotechnology application opportunities

Nanotechnologies have a key role to play in furtheradvancing the development of photovoltaics throughcost savings and efficiency improvements based onnew materials, nanolayers and solar cell types, as wellas by adopting simpler production processes.

14

Wafer-based solar cells

Efficiency

Materials

Structure

Solar cell type

Multi-stacked cellsIII/V compound semiconductors

46 % with concentrator38 % without concentrator

Ge

Ga 0.97In 0.03As

Ga 0.51In 0.49P

Crystalline silicon

25 %

Thin-filmsolar cells

Silicon (amporphous or crystalline), CIGS, cadmium telluride,

III/V compound semi-conductors, perovskite

21 %

Dye-sensitised solar cells

Nanoporous titanium dioxide,

organic dye complexes

14 %

Polymer solar cells

Fullerenes (C60), conjugated polymers

11 %

Structure and materials of different solar cell types as well as efficiency based on current state of the art.

(Source: altered after Hahn-Meitner-Institut, Helmholtz-Zentrum Berlin, HMI 2007)

Inorganic thin-film solar cells

With regard to inorganic thin-film solar cells, nano-technological expertise is primarily required in termsof coating technology for optimised cell design. Inaddition to the photoactive layer, only a few microme-tres thick, a typical thin-film solar cell design also com-prises nanoscaled layers, which act as adhesion pro-moters and buffer zones for contact to the substrate,the metallic back contact and the transparent frontelectrode. In addition to crystalline and amorphous sil-icon, other material combinations such as copper,indium, gallium, sulphur and selenium (CIGS cells),cadmium telluride/selenide, perovskite or III/V com-pound semiconductors (for example, gallium nitride,gallium arsenide, gallium indium phosphide) are alsoused for inorganic thin-film solar cells. Moderate effi-ciencies of more than 20 percent can be achievedusing thin-film solar cells.

In addition to the already established thin-film solarcell nanotechnologies, by utilising nanocrystals, offerpotentials for replacing complex vacuum coatingprocesses with more cost-effective liquid phaseprocesses or for substituting environment-pollutingmaterials such as the lead in perovskite solar cells withalternative substances such as tin, for example.

15

III/V compound semiconductors are semiconduc-tors consisting of material combinations of chemicalelements in the main groups III and V. Compared to silicon, III/V compound semiconductors have theadvantage that their electronic properties can beoptimised to meet specific application require-ments (for example, solar cells or light-emittingdiodes) by altering the composition of the material.

Info box: III/V compound semiconductors

CdS – 150 nm

SnO2 – 30 nm

metallic backcontact – 250nm

glass substrate

ITO – 240 nm

Te – 20 nm

CdTe – 8 µm

Electron microscope image (left) and diagram (right)

of a cadmium telluride thin-film solar cell.

(Source: TU Darmstadt)

Dye-sensitised solar cells

Dye-sensitised solar cells utilise dye molecule-dopedtitanium oxide nanoparticles (for example, variousruthenium complexes) for charge separation. Lightabsorption in the dye molecules leads to the releaseof electrons, which are then accepted by titaniumdioxide particles and transferred to the electrode viaa redox electrolyte. The advantages of dye-sensitisedsolar cells include cost-effective manufacturing meth-ods using screen printing, applications using even dif-fuse incident light (for example, in interior applica-tions), and the transparency and colour design optionsof the cells, opening up interesting architectural appli-cation opportunities. Disadvantages include thechemically reactive liquid electrolytes used, which mayleak into the environment, the still relatively low effi-ciencies up to twelve percent and the limited long-term stability. Initial prototype applications have beenimplemented by Fraunhofer Institute for Solar EnergySystems ISE.

Polymer solar cells

Polymer solar cells use organic semiconductors forenergy conversion. Conjugated polymers are used aslight absorbing electron donors and fullerene deriva-tives as electron acceptors. Both components are inte-grated as 100 to 300 nanometre thick composite lay-ers between charge transfer layers and electrodes inthe sandwich-like cell structure. Merck, based in Darm-stadt, is a leading manufacturer of materials fororganic photovoltaics and is running numerous proj-ects in order to participate in the new growth market.In cooperative research with the American start-upNano-C, Merck has developed new fullerene deriva-tives for the organic photovoltaics (OPV) field, whichdisplay substantial improvements in service lifetimeand thermal durability compared to traditional sub-stances. Formulations comprising these fullerene com-pounds can be processed as the active layer using avariety of industrial coating technologies (Merck2015).

16

Currently the world’s largest dye-sensitised solar cell

(60 x 100 centimetres), manufactured by Fraunhofer ISE

in Freiburg. (Source: Fraunhofer ISE)

The advantages of organic solar cells include cost-effective materials and manufacturing methods, andthe flexibility of the modules, which can adapt toalmost any object and product shapes and contours.The objective is to achieve the mass production oflarge-scale modules in a traditional roll-to-roll printingprocess. In the mid term, efficiencies of approximatelyten percent and durabilities extending to several yearsare aimed for with the aid of material and cell designoptimisation. In Germany, research into polymer solarcells is driven by numerous Federal Ministry for Edu-cation and Research funding programmes.

For example, Merck coordinates the funded collabo-rative project ‘Development of new materials anddevice structures for competitive mass productionmethods and applications in organic photovoltaics’(German: ‘Entwicklung neuer Materialien und Devices-trukturen für konkurrenzfähige Massenproduk-tionsverfahren und Anwendungen der organischenPhotovoltaik’ (‘POPUP’). The collaboration partnershave set themselves the target of developing cost-effective industrial solar modules using more efficientmaterials and coating methods.

17

Left: The German pavilion’s ‘solar tree’, based on polymer solar cells, at the 2015 Milan Expo. (Source: U.I. Lapp)

Right: Special inks for printing the solar cells are produced by Merck. (Source: U.I. Lapp)

Left: Thin and mechanically flexible organic solar foils for novel applications. (Source: Heliatek /Tim Deussen, Berlin)

Right: Printed solar cells as reels. (Source: pmTUC/Bystrek Trenovec)

Band gap optimisation for highest conversion efficiencies

In traditional photovoltaics, non-conducting electronsin a semiconductor are excited into movement by theabsorption of sunlight and can be used as a source ofelectricity. Light that exactly corresponds to the energydifference between the non-conducting and the con-ducting electrons is required to excite the electrons.This energy difference, referred to as the band gap, isa specific material property for every semiconductor.One photovoltaics development objective is to opti-mise the band gap of a semiconductor by combiningvarious materials such that as large a fraction of thesunlight as possible is used to excite the free electronsand thus the efficiency of the solar cells is increased.The world record, at up to 46 percent conversion effi-ciency, is held by wafer-based stacked cells made ofIII-V semiconductor systems. In these solar cells, nanoto micrometre thin, semiconductor material layer sys-tems with differing band gaps are combined such thatthe solar spectrum is exploited as efficiently as possi-ble to convert light to electricity (see the NAsP III/Vsuccess story, Section 7.2). However, due to the com-plex manufacturing process these cells are often stilltoo cost-intensive. Their use is more economical if thesunlight is concentrated through relatively cost-effec-

tive optics and thus the cell efficiency increased. Suchconcentrator modules are commercially available andthere are realistic chances of substantially reducingcosts by further system optimisation and by economiceffects of scale in production. Another approach forreducing the cost of these solar cells is to use them incombination with cheaper silicon substrates.

Approaches for utilising quantum dots to increase theefficiency of solar cells are still in the basic researchstage. Quantum dots are nanoscaled clusters of semi-conductor compounds with unusual optoelectronicproperties which can be modified using quantumphysics effects as a function of the size of the cluster.Applications in solar cells are of interest because, onthe one hand, several electron-hole pairs can be gen-erated for each photon by using quantum dots and,on the other hand, the absorption bands can be opti-mally adapted to the wavelengths of the incident light.At the laboratory scale, three-dimensional quantumdot meshes or other structures, which may be interest-ing for solar cell applications, can be produced usingnanowires. Cells such as these make theoretical con-version efficiencies of more than 60 percent possible.However, current research is still a long way from thisobjective and no functioning, experimental model ofa quantum dot solar cell has yet been demonstrated.

18

0

200

400

600

800

1000

1200

1400

1600

500 1000 1500 2000 2500

Power density [W/m2µm]

Wavelength [nm]

Am 1.5 spectrum GalnP (1.70 eV)GalnAS (1.18 eV) Ge (0.67 eV)

Decreasing band gap

Ge

Ga 0.97In 0.03As

Ga 0.51In 0.49P

Absorption spectra of semiconductor materials

used in stacked solar cells to optimise the

quantum efficiency. Stacked cells consist of a

series of layers of compound semiconductors

with different band gaps.

(Source: Fraunhofer ISE)

Nanostructures for optimising energy yield

Regardless of the type of material used and the celltype, nanotechnological approaches to solutions areadopted in order to further optimise solar cell effi-ciency. For example, efficiency increases can beachieved using nanostructured antireflection layers,which allow better light exploitation. One develop-ment that is ready to market is antireflection layers forplate glass, based on a nanoporous coating of silicondioxide. The layers are generated based on a sol-gelprocess and subsequent immersion coating. Theporosity allows the effective refractive index of theglass to approach that of the surrounding air, therebyreducing the reflective losses of the glass plates fromthe usual eight percent to two percent. Such antireflec-tion glasses for solar modules have been commer-cially marketed by the Darmstadt company Merck forseveral years and display good growth rates in photo-voltaics and in solar thermal applications.

An alternative approach is based on nanotextured,transparent, conductive oxide layers, used as frontelectrodes to minimise light scatter and reflectionlosses. In organic solar cells, the large-scale periodicsurface structures created with the aid of holographicexposure methods can be transferred to the solar cellpolymer layer using a cost-effective embossingmethod. In addition to this, work is being carried outon improving the back reflectors in order to furtherincrease light exploitation in the substrate. To achievethis, photonic crystals or non-metallic nanolayer sys-tems, offering the potential for additional efficiencyimprovements, are used instead of conventional metallayers such as, for example, silver.

Research is also being carried out into coating struc-tures with which solar spectrum frequencies are con-verted into light quanta with higher (up-conversion) orlower energy (down-conversion), in order to optimisethem for the absorption properties of the adoptedsolar cell material. A promising option seems to beavailable in rare earth metal nanoclusters embeddedin glass ceramics, with which infrared and ultravioletlight can be converted into visible light that is utilis-able in photovoltaics.

19

Glass ceramics doped with rare earth metals

for up and down-conversion.

(Source: Fraunhofer IWM)

Solar thermal energy will play a greater role in utilisingsolar energy in the future, because it can cost-effec-tively provide both power and heat. The provision ofsolar thermal heating in buildings is decentralisedusing roof-mounted solar collectors, which convertsolar energy to heat with efficiencies of approximately60 to 70 percent. The solar thermal potential here ishuge, because approximately 50 percent of the totalfinal energy consumption in Germany is caused byheat applications. However, solar thermal energy isalso used at an industrial scale for electricity genera-tion in solar power plants. Globally, solar thermalpower plants with a capacity of around 2.5 gigawattsare installed and around 1.5 additional gigawatts areunder construction. The world’s largest facilities arelocated in Spain at 150 megawatts capacity (Andasolfacility with three power plant blocks of 50 megawattseach), in Abu Dhabi (100 megawatt Shams 1 facility)and the USA (Solar One in Nevada with a rated capac-ity of 64 megawatts). Of the solar thermal powerplants, the parabolic trough power plants, in whichsunlight is concentrated using parabolic mirrors andconverted to heat in what are called ‘receiver tubes’,

then subsequently exploited to generate steam andelectricity, dominate with a market share of approxi-mately 95 percent.

Research is also being carried out on solar updrafttowers, which use the thermal flow of heated air layersto generate electricity. The European market for solarthermal power plants is currently being displacedfrom Spain to Italy, where fourteen solar thermalpower plant projects with a total of approximately 400megawatts are being developed and will probably goonline by 2017 (EurObserv’ER 2014). German industryis predominantly involved in the export of key compo-nents such as absorbers, collectors and mirrors, usedaround the world in solar thermal power plants. Inprinciple, solar thermal power plants at sites withintense insolation represent an economical alternativeto electricity generated from fossil fuels. However,improvements in terms of efficiency, lower servicingintensity and a longer service life of the individualcomponents still need to be achieved here.

20

3.2 Solar Thermal Energy

Diagram of a solar thermal parabolic trough power plant. Inside vacuum tubes, a heat transfer medium, such as thermal oil, is heated

to around 400 degrees Celsius by concentrating sunlight using movable parabolic mirrors. The heat produced generates the steam for

a downstream steam power plant. (Source: FRIATEC AG Division Rheinhütte Pumpen: www.exposegmbh.de)


In contrast to photovoltaics, the nanotechnologiesused for solar thermal applications are not required tooptimise electronic band gaps and photoelectric con-version efficiencies. However, solar thermal energy isused to exploit the energy in sunlight as efficiently aspossible, that is, to convert it to heat. Just like in solarcells, nanooptimised anti reflection coatings in solarthermal receivers ensure that sunlight reflection lossesare kept as low as possible. In addition to this, coatingsolutions are used to minimise heat energy radiationlosses due to what are referred to as low-e layers andthus to improve the absorption properties of thereceiver. These coatings, usually produced using phys-ical vacuum methods, must also be stable undermechanical loads and corrosion, as well as be heat-resistant. This applies in particular to solar thermal par-abolic trough power plants in which the receiver tubesneed to withstand working temperatures up to 450degrees Celsius over extended periods. Nanotechno-logical coating expertise allows the various propertiesrequired to be integrated in an optimised layerdesign.

21

Solar thermal power plant in the Negev Desert, Israel. (Source: iStock.com/byllwill)

Nanocoated receiver tubes for solar thermal power plants.

(Source: Fraunhofer ISE)

Thermoelectrics are used to directly convert a heatflow to electrical energy, utilising the Seebeck effect.The Seebeck effect describes the occurrence of elec-trical voltages between two points of an electrical con-ductor of different temperatures. The greater the tem-perature differential, the more energy can be pro-duced by thermoelectric generators. Desirable ther-moelectric material properties include low thermalconductivity in conjunction with good electrical con-ductivity, which directly affect the thermoelectric effi-ciency determined by the dimensionless parameter ZT(figure of merit).

Different semiconducting solid state compounds areused, depending on the temperature range. At a tem-perature gradient of 700 degrees Celsius an efficiencybetween five and ten percent can be achieved usingconventional silicon/germanium alloys. Due to theirrelatively low efficiencies, thermoelectric converterscan currently only be economically employed in nicheapplications. However, in the mid to long term the util-isation of waste heat from automobiles presents a highenergy-saving potential, because approximately two-thirds of the energy input into an automobile are lostas waste heat. In Germany alone, the theoreticalenergy-saving potential of thermogenerators is tenterawatt hours per year if all cars were fitted with one-kilowatt thermogenerators. Automobile manufacturerssuch as BMW or Daimler are driving pilot and proto-type development.

As a result of stability problems during continuousoperation, use in series applications is not anticipatedbefore 2020. However, the market research companyIDTechEx reckons with strong thermogenerator marketgrowth. The company forecasts a global turnover of950 million US dollars in 2024 (IDTechEx 2014). In thelong term, industrial and power plant applications arealso anticipated through the development of thermo-electric generators.

22

3.3 Thermoelectrics – Power from Heat

Heat source

p n

Us

RLI

Heat sink

Diagram of a thermoelectric energy converter utilising

the Seebeck effect. In an n-doped, that is, electron-rich,

material, more electrons are raised from the valence to

the conduction band and are available as charge carriers

in the warm zone; correspondingly, in a p-doped, that is,

electron-poor, material, more electron holes are available.

This potential difference generates a flow of electric

current. (Source: VDI TZ)


Nanotechnology innovations, demonstrated in recentresearch work, may provide thermoelectrics with newimpulses thanks to substantially improved efficiency.Nanostructured thermoelectric materials areextremely interesting because the electrical and ther-mal properties of the material can be specifically influ-enced by the structure sizes. Nanostructured materialswith a much higher proportion of grain boundariescan be generated using new manufacturing methods.The grain boundaries lead to a reduction in heat trans-port as a result of lattice vibrations in the solid body,while the electrical conductivity is not affected or onlyslightly impaired. This is a principal requirement forincreasing the quality of the thermoelectric material.By characterising the relationship between structure,composition and properties at the nanolevel, it may bepossible in the future to design materials with thedesired properties. Nanostructures investigated in thecontext of thermoelectric materials comprise, amongothers, nanostructured surfaces, quantum dots orquantum wires. Bismuth telluride or antimony telluridequantum dot super lattices or nanostructured silicon,silicon/germanium, skutterudite (cobalt/arsenic sul-phides) or clathrate compounds* have proven to behighly efficient thermoelectric materials.

Such efficiency improvements using nanostructuredsemiconductors with optimised boundary layer designmay pave the way for the widespread use of thermo-electric materials in utilising waste heat, for example,in automobiles or even human body heat, for mobileelectronics in textiles.

* Inclusion compounds of two materials, where a guest molecule

is included in a lattice consisting of host molecules.

23

Silicon thermogenerator. (Source: Universität Duisburg-Essen)

Semiconductor nanowires offer potentials for efficient

thermoelectric generators. (Source: Universität Hamburg)

Fuel cells convert the chemical energy of an energysource into an electrical current with high efficiency. Inaddition to pure hydrogen, natural gas, methanol,petrol or biogas can be used, from which the hydro-gen necessary to operate the fuel cell can be pro-duced in a reforming process. Depending on the fieldof application, different fuel cell types with differentworking temperatures, from room temperature up to1,000 degrees Celsius, based on various material sys-tems, are used. Here, high-temperature fuel cells suchas MCFC (Molten Carbonate Fuel Cell) or SOFC (SolidOxide Fuel Cell) are particularly attractive becausethey allow combined heat and power (CHP) systemswith high efficiencies to be implemented. Polymerelectrolyte membrane fuel cells are best suited to pro-viding the power supply of electric motors in fuel cellvehicles. This is a low-temperature fuel cell, operatedin a continuous mode at approximately 80 degreesCelsius.

Fuel cell market and application potentials

The potential spectrum of fuel cell applications rangesfrom power supplies for electronic equipment,through electric vehicle drives and heat and powersupplies for buildings, to power plants. The current,approximately two billion US dollar global market isprimarily dominated by stationary fuel cells, in partic-ular for domestic power and emergency electricitysupplies. An important field of application is uninter-rupted power supplies, for example, in informationand communications technology or applications inluxury goods such as yachts or mobile homes, wherethe additional costs caused by the fuel cell are lessimportant.

24

3.4 Fuel Cells

Direct current

Electron

Anode Electrolyte Cathode

Hydrogen H² Oxygen O²

Warm waterH²O

Direct current

Right: PEM fuel cell-based domestic energy centre, capable of covering the electricity

and heat demand base loads for a single-family home.

Bottom: Diagram of a fuel cell. Gaseous hydrogen or a hydrogen containing process

gas is electrochemically converted to water at an electrolyte/electrode assembly using

atmospheric oxygen, producing electricity and heat.

(Source: Viessmann)

Mobile applications also offer large potentials. In Ger-many, fuel cell vehicles have been demonstrated in arange of applications. Their suitability for everydayapplications is tested in company vehicle fleets, forexample. Rhein-Main Transport Association (German:Verkehrsverbund Rhein-Main) plans to use fuel celldrives in rail vehicles, and fuel cell-driven fork lifts arebeing tested in logistics operations. Two fuel cell-driveDaimler vehicles have also been in use for severalyears in the Industriepark Höchst. Furthermore, a fuel

cell bus by Van Hool will operate on internal bus linesof the industrial park from the beginning of 2016.Tofacilitate the broad use of fuel cells in automobiles, itis necessary to create a suitable framework to makethese vehicles economically competitive compared tothose with combustion engines (total cost of owner-ship, or TOC), as well as to develop an adequate infra-structure such as sufficient capacity to generate ‘greenhydrogen’, that is, CO2-neutral hydrogen, and a net-work of filling stations. In Germany, several projectswere started in 2012 as part of the national hydrogenand fuel cell technology innovation programme, withthe aim of building around 50 hydrogen filling stationsby mid-2015. The H2 Mobility joint venture plans tobuild and operate 400 filling stations in Germany by2023 as the next phase of filling station networkexpansion.

Hyundai in 2013 and Toyota in 2015 were the firstmanufacturers to introduce a series-production carwith fuel cells to the German market. The Germanautomobile manufacturers Daimler, BMW and VW(including Audi), who have also developed fuel cellsystems for vehicles to series maturity during recentdecades, have also announced their intention to enterthe market with their first series vehicles in 2017(Daimler) and 2020, respectively.

25

Series-production fuel cell car Toyota Mirai. (Source: Toyota Deutschland GmbH)

Fuel cell drives in fork lift trucks, tested in an information

campaign funded by the Hessian Ministry of the Environment,

Climate Protection, Agriculture and Consumer Protection

(Hessisches Ministerium für Umwelt, Klimaschutz, Landwirtschaft

und Verbraucherschutz).

(Source: Hessen Agentur /H2BZ-Initiative Hessen)

The use of miniaturised fuel cells for operating mobileelectronic devices, which can be operated usingmethanol, for example, appears more promising in theshort term and on a broader base. For example, thecompany eZelleron has developed a microtubular,portable SOFC fuel cell product to series maturity.

The fuel cells can be operated with traditional andavailable gases such as propane/butane and hydro-gen. The mini fuel cells are suitable as power suppliesfor mobile electronic devices, for instance, for charg-ing emergency batteries in sensors for weather sta-tions, smartphones, tablets or notebooks.

26

Mini fuel cell ‘Kraftwerk’ (power plant), for example for recharging a smartphone. (Source: eZelleron)

Fuel cell stack for mobile applications.

(Source: ZBT GmbH/Nadine van der Schoot)


Nanotechnologies open up innovation and optimisa-tion potentials for all common fuel cell systems. Opti-mised electrodes, electrolytes, catalysts and mem-branes, in particular, facilitate increases in power yieldsin the conversion of chemical energy. In SOFC-typesolid oxide fuel cells, for example, the ion conductivitycan be improved by using ceramic nanopowderbased on yttrium-stabilised zirconium. In terms ofmembrane fuel cells, the optimisation approaches pri-marily affect the polymer membrane, where the aim isto enhance its temperature stability by employinginorganic-organic nanocomposites, among otherthings. Here, the functionalised polymers are modifiedby inorganic nanoparticles using sol-gel processes.Higher operating temperatures mean that better effi-ciencies can be achieved and that the sensitivity of thecatalyst to carbon monoxide, formed when producinghydrogen from methanol in the reforming process, isreduced. Moreover, nanostructuring of the electrodematerials, which enlarges the active surface, has animportant role to play. This allows the highest possibleefficiency in electrochemical hydrogen/oxygen con-version or in hydrogen generation to be achieved byconverting natural gas or methanol (in the directmethanol fuel cell), for the lowest possible use ofcostly precious metal catalysts.

Using nanomaterials, membranes can be structuredand functionalised by targeted design in order toachieve higher conductivities and higher temperatureand corrosion resistance for applications in polymerelectrolyte membrane fuel cells (PEM fuel cells).

SolviCore, based in Hanau and taken over by theJapanese chemicals company Toray Industries in2015, manufactures so-called membrane-electrodeassemblies (MEA) for safe and more cost-efficienthigh-temperature membrane fuel cells. The MEA usessolid, non-extractable polymer electrolytes in theplace of phosphoric acid-doped polymer membranes.A further development of MEA was achieved in thePSUMEA research project, where the membranes weremanufactured from highly sulfonated polyphenylenesulfones. Here, so-called multiblock copolymers werestructured such that a specially arranged nanomor-phology was created. This nanostructuring allowedchemically and mechanically stable, high-temperaturePEM fuel cells with very high proton conductivity to bedeveloped.

27

Nanomorphology of a membrane

for PEM fuel cells.

(Source: Max-Planck-Institut für

Festkörperforschung)

0

1000

1500

Wind energy in Hessen

500

0

200

300

New

constructio

n (MW

)To

tal i

nsta

lled

cap

acity

(MW

)

100

2000 2002 2004 2006 2008 2010 2012 2014

Total installed capacity (MW) New construction (MW)

Installed capacity and new construction of wind turbines in Hessen (MW: megawatt). All figures are based on Deutsche Windenergie

Institut (DEWI) and Deutsche WindGuard surveys. (BWE 2015)

28

The global wind energy market is estimated at approx-imately 99 billion US dollars. 25 percent growth is fore-cast for the next five years (Bloomberg 2014). Windenergy has become established in Germany as animportant branch of industry, providing approximately138,000 jobs and a turnover of twelve billion euros(Strom-Report 2015). Wind energy in Germany isalready economically competitive today; that is, thepower generation costs are of a similar magnitude asthose of conventional power plants. For the futureexpansion of wind energy in Germany, the problem ismore one of the choice of suitable and sufficientlywindy locations, now increasingly shifted offshore.


Nanotechnologies can make a considerable contribu-tion to optimising wind energy exploitation with high-strength lightweight materials for rotor blades, basedon nanocomposites, low-friction and wear protectionlayers for bearings and transmissions, and resource-saving magnets.

Replacing expensive magnetic materials withnanomaterials

Some of the generators commonly installed in windturbines use large permanent magnets. The magnetscontain metals of the so-called rare earths, which pri-marily need to be imported from China and are expen-sive. The aim of research work at TU Darmstadt istherefore to reduce the rare earth content in magnets.One approach, for example, is to not distribute theparticularly problematic dysprosium homogeneouslyin alloyed materials, but instead, to apply it to the crys-tal boundary layers, where it is required for the high-temperature stability of the magnets. In this way, thedysprosium content could be reduced from, in somecases, eight percent by weight to less than two percentby weight (TU Darmstadt 2014).

Moreover, with nanotechnology it may be possible todispense with dysprosium in general by reducing thegrain sizes of the other metal constituents to thenanometre range and ‘bonding’ them to form com-posites.

3.5 Wind Energy

0

6000

8000

10000

Installed wind energy capacity in Germany

4000

2000

0

50000

40000

30000

20000

Cum

ulated (M

W)

Ad

ded

cap

acity

(MW

)

10000

2000 2002 2004 2006 2008 2010 2012 2014

Added capacity (MW) Cumulated (MW)

4,750 megawatt (MW) new wind capacity was installed in 2014. The total installed wind energy capacity is therefore 38,115 megawatts.

(BWE 2015; data source: Deutsche WindGuard)

Longer service life of wind turbines thanks to nanolubricants

The service life of transmissions can be increased bysurface coatings on gear wheel and bearings usingnanomaterials. REWITEC, based in Lahnau, Hessen,has developed a nanocoating that can revitalise wornmetal surfaces and protects against wear even underunfavourable conditions. The technology is based ontargeted modifications to the surface structure of therubbing materials, allowing a new metal silicate layerto form with a surface roughness of only a fewnanometres. The active component is a mixture of var-ious synthetic silicate compounds, which are added tothe existing lubricant and react with the metal surfacesas a result of the high temperatures and pressures. Themetal-metal friction pairs are thereby modified tometal silicate-metal silicate friction pairs with reducedfriction.

Carbon nanotubes for lightweight materials andanti-freezing protection of wind turbine rotor blades

A wind turbine’s rotor blades determine the maximumenergy yield that can be extracted from the wind. Inparticular in offshore facilities with rotor diameters ofup to 200 metres and blade weights of 50 tonnes andmore, glass fibre-reinforced plastic (GFP) based rotorblades have long since reached their limits. Here, car-bon fibre-reinforced plastics (CFP) offer an alternative.Innovative material systems for rotor blade materialsmay also become important, such as new, lightweightand stable nanocomposites consisting of carbon andglass fibre-reinforced epoxides, where carbon nano-tubes (CNT) are added to the resin matrix as stabilisingcomponents.

29

Carbon nanotubes also offer potentials for protectingthe wind turbine rotor blades against icing up. Ice cov-ered rotor blades lose their original aerodynamics andgenerate less energy. These capacity losses are esti-mated to be as much as 20 percent. In order to avoidthis problem, researchers have developed an intelli-gent rotor blade heating system coating solutionbased on carbon nanotubes. A carbon nanotube layera few micrometres thick is applied by spraying onto aself-adhesive polymer film.

Any size of wind turbine rotor blade can be thustreated, with the blades being subdivided into severalheating sections. By integrating ice detectors in theheating sections, only those sections specificallyaffected by ice formation can be heated. In this way,the ice can be thawed in only a few seconds and veryenergy-efficiently because the complete rotor bladedoes not need to be heated.

30

Left:Wind turbine rotor blade icing can lead to considerable capacity losses in wind turbines. (Photo: iStock.com/kaspan)

Right: A new energy-efficient heating system can melt ice on wind turbines within seconds. The carbon nanotube coating heats up

defined areas of the rotor blade as soon as integrated sensors detect icing. (Photo: Fraunhofer IPA)

In the course of developing renewable energysources, global efforts to produce clean energy fromthe oceans have increased. In principle, the world’soceans may be regarded as a practically inexhaustibleenergy reservoir. Their energy resources are estimatedto be more than 10,000 terawatt hours per year by theInternational Energy Agency (IEA) and thus corre-spond to many times the annual global electricity

demand. The technological approaches for exploitingthis energy are manifold and range from current andtidal power plants, through harvesting wave energy,to exploiting temperature or salt concentration differ-entials. The majority of these approaches are at thebasic research stage or in demonstration projects andare still far removed from economic usefulness.

31

3.6 Marine Energy

Elastomer GeneratorsEnergy production by dielectric elastomer converters.

Floater is elevated by the wave. Elastomer layers are compressed.

Electrode

Elastomer

Electrode

In the wave trough, the elastomer relaxes, thus increasing the distance between the electrodes. Hence the electric voltage increases. This energy is harvested.

One electrode is positively charged, the other one negatively. The applied voltage is low.

Elastomer generators for wave power plants. (Source: Bosch)


The use of nanotechnologies as such is not in thefocus of marine energy research. However, certainnanomaterials are increasingly important at variouspoints in energy production.

They assume a more passive or conserving role in pro-tecting components from the aggressive-corrosiveand degrading effect of seawater as well as from foul-ing processes, and in reducing friction. Depending ontheir purpose, nanoscaled and nanostructured protec-tive coatings and lubricants are highly water resistant(super hydrophobic), anti-microbial, frost protecting,friction reducing, anti-corrosive, etc., and contributesubstantially to material preservation.

Electroactive polymers, for example, play an activerole in terms of producing electricity from waves.These are plastics that change shape when subject toan electric voltage. They are also occasionally referredto as artificial muscles. In contrast, an imposed positiveor negative external strain generates an electrical volt-age, which may be used for power generation givensuitable technical provisions. The thinner an electroac-tive polymer film is, the stronger is the relationshipbetween shape change and voltage generation. Avariety of research projects are testing the use of elec-troactive polymer components for generating waveenergy. In Germany, the EPoSil (Electroactive Silicon-based Polymers for Energy Generation; German: elek-troaktive Polymere auf Silikonbasis zur Energiegewin-nung) research network, in which TU Darmstadt par-ticipates, is working to develop stacks of thousands ofthin polymer films. They are covered with electrodesand amalgamated to form a generator. Attached tobuoys on the surface of the water, they are constantlydeformed as a result of wave action. The electrical volt-age generated is collected by the electrodes. Otherresearch approaches focus on nanoscaled polymerthreads, placed between flexible electrodes.

An additional approach to energy generation from thesea is based on exploiting differences in the water’ssalt concentration. These gradients are particularlylarge in river estuaries. In the pressure osmosisapproach, a net water flow in the direction of the saltwater reservoir results when semipermeable mem-branes are installed between the fresh water and thesalt water containers. The osmotic pressure can beused to drive a turbine. In reverse electrodialysis, alter-nating series of cathode and anode exchange mem-branes are placed in series, each being respectivelypermeable to potassium or chloride ions and separat-ing salt and fresh water reservoirs from each other. Thechemical potential difference between neighbouringchambers generates an electrical voltage at eachmembrane. The membranes are of decisive impor-tance in both approaches. Nanotechnological innova-tions make substantial contributions to membrane effi-ciency optimisation in terms of pore structure, surfacestructure and material composition. Small demonstra-tion power plants exist for both methods in Norwayand the Netherlands.

32

Demonstrator of elastomer generators. (Source: Bosch)

Generating chemical energy sources from renewableenergy resources plays a key role in implementing the‘energy revolution’. The highly fluctuating power gen-erated by renewable energy sources requires the useof long-term energy storage systems to cope with thecontinuous balancing of power supply and demand.Those systems also need to be capable of being effi-ciently and cost-effectively stored, transported andconverted back to electricity. Chemical energy sourcessuch as hydrogen and hydrocarbons are particularlyimportant in this context. The replacement of fossilfuels by regeneratively produced energy sources formobile applications is also being studied. In additionto hydrogen, this predominantly affects biofuels pro-duced from plant materials.

3.7.1 Hydrogen Production

In the long term, there are high hopes for hydrogen asan environmentally friendly energy source, because itproduces no pollutants on combustion. However, interms of its use as an energy source, currently existingobstacles regarding the market entry of the technol-ogy are to be overcome. Only by regulatory changeswith respect to the energy system and governmentsupport that reduce production costs by rising quan-tities, its economically viable use will be succeeded.Besides investments in hydrogen generation, amend-ments to the existing supply infrastructure for distrib-uting hydrogen (especially hydrogen fuel stations withhigh pressure compressors) are necessary. Technolo-gies for efficient production and storage are a basicrequirement for the widespread use of hydrogen as afuture energy source.


Electrolytic hydrogen generation

The efficiency of precious metal catalysts in the elec-trolytic separation of water can be increased by nano-structuring. In addition, optimisation potentials exist inthe high-temperature electrolysis of water, where elec-trolysis occurs at around 1,000 degrees Celsius andhigh conversion efficiencies of greater than 90 percentare achieved. Here, ceramic materials are used as oxy-gen ion conducting solid electrolytes. By using nano-materials, they can be improved in terms of ion con-ductivity and temperature-resistance. In addition, theyare coated with micro- and nanoporous electrodes, onthe large surfaces of which the passing steam is sepa-rated into its molecular constituents hydrogen andoxygen. In principle, high-temperature electrolysis isthe reverse of the high-temperature fuel cell and assuch is a subject of hydrogen research.

33

3.7 Generating Chemical Energy Sources

Membrane electrode assemblies (MEA) of electrolysers can be

operated with low degradation rates at high current densities

using innovative catalytic coatings (picture above: electrolyser

stack with MEAs by ITM Power, Sheffield/UK). The electrolyser

generates hydrogen with high power density and increased gas

pressure at an efficiency factor of 77 percent because of the

compact design. (Source: ITM Power)

Photoelectrolytic hydrogen production

A very promising approach is photoelectrolytic watersplitting. Here, the absorption of light at photoelec-trodes in a photocell results in the photochemical sep-aration of water, whereby oxygen oxidises at theanode and hydrogen atoms are reduced to elemen-tary hydrogen at the cathode. These processes cur-rently display only low conversion efficiencies. Greatefforts go into pursuing efficiency optimisation.Nanostructuring and the selection of suitable materialsystems play a decisive role here.

Important criteria for the selection of semiconductormaterials for photoelectrodes include their stability inaqueous solutions and the conversion efficiencyresulting from band gaps optimally coordinated withthe redox potentials of water. III/V semiconductorstacked cells display promising conversion efficien-cies, but are generally unstable in aqueous media andexpensive to manufacture. One alternative is cost-effective metal oxides, for example of the elementstitanium, manganese, iron or tin as electrode materi-als. By using nanostructuring and nanocrystalline sub-stances, further optimisation is possible. Non-metallicmaterials also appear promising. For example, goodconversion efficiencies of around ten percent in thevisible light range were achieved with carbon quan-tum dot and carbon nitride nanocomposites (Liu et al.2015). However, photoelectrolytic water splittingprocesses are still at the research stage. Large scaleeconomic applications are not currently envisaged.

3.7.2 Biofuels

Against the backdrop of climate protection, reducingthe carbon dioxide input into the atmosphere is oneof our most important social challenges. The EU’srenewable energy directives stipulate that the propor-tion of renewable energy in the transport sector mustbe increased to ten percent by 2020. The gradualreplacement of mineral fuels by biofuels, producedfrom renewable resources or biomass, will make a sub-stantial contribution to this. However, the energy utili-sation of biofuels is not uncontroversial in terms of cli-mate policy, because it is associated with high landuse and may be in competition with foodstuff produc-tion. The most important liquid biofuels are bioethanoland biodiesel, but biokerosene, biomethanol and cer-tain vegetable oils also play a role.

First, second and third generation biofuels are oftendifferentiated. In first generation fuels, only the fruit isutilised. Second generation fuels utilise the entire cropmass. Their production processes are often charac-terised by the designation BtL (Biomass-to-Liquid).Fuels from algae cultures, in particular, are referred toas third generation fuels. Compared to other energycrops, they display much greater productivity per unitarea.

34

h · ν

OxidationH2O + 2h+ p ½ O2 + 2H+

Reduction2H+ + 2e– p H2

n-d

op

ed s

emic

ond

ucto

r

Met

al e

lect

rod

eH2O

O2 H2

Diagram of photoelectrolytic

hydrogen production. Electron

hole pairs are created in the

semiconductor by the absorption

of light energy.

If a semiconductor is in contact

with a metal auxiliary electrode,

a photovoltage results, leading

to splitting of the aqueous

electrolyte into hydrogen and

oxygen. (Source: ODB-Tec)


A variety of processes for the production of biofuelsare now established. Intense research into the optimi-sation of numerous process steps and the develop-ment of new second generation methods, in particular,is ongoing. Nanotechnologies deliver optimisationcontributions in monitoring process technology usingsensors and, especially, in conversion methods.Numerous process paths are aimed at generating syn-thesis gas from the thermochemical gasification ofbiomass. Liquid fuels can be synthesised (also referredto as the Fischer-Tropsch process) from the gas mix-ture consisting of hydrogen, carbon gases, sulphurand nitrogen compounds. Nanostructured catalysts,such as zeolites, for example, are often used toincrease the efficiency of the synthesis reaction.

3.7.3 Power-to-Gas

The term power-to-gas describes a process that usesexcess electricity for the large-scale generation ofhydrogen gas by electrolysis as the fundamentalprocess step (also known as power-to-hydrogen, PtH).Optionally, methane is produced in a subsequentstep. If necessary, the hydrogen or the methane canbe reconverted using fuel cells or gas turbines.

Intense work is being carried out on testing and opti-mising power-to-gas processes and a number ofdemonstration facilities have been commissioned. Forexample, the Hessian Ministry of Economics, funds thejoint demonstration project involving SolviCore,RheinMain University of Applied Sciences, Mainovaand the Hanau municipal utility company (German:Stadtwerke Hanau), in which hydrogen is generatedfrom renewable electricity in Wolfgang Industrial Park.Among other things PEM electrolysis technology(PEM: Proton Exchange Membrane) is tested. In addi-tion to conversion efficiency, the focus is on thedynamic operation of electrolysis under fluctuatingconditions, as given by the irregular supply of windand solar power. The EKOLYSER project, as part of theFederal Government’s energy storage systems fund-ing initiative and involving SolviCore, researches newand cost-effective materials for PEM electrolysis. Forexample, the aim is to develop new membrane mate-rials and reduce the proportion of expensive preciousmetals in the catalyst.

Another power-to-gas concept demonstration facilityin Hessen is located in Frankfurt am Main. Under theleadership of Mainova it analyses the technical feasi-bility of converting electricity from renewable energyforms to hydrogen and feeding in hydrogen to munic-ipal gas networks (DENA 2015).

The hydrogen produced using the power-to-gasprocess can be utilised directly or stored in pres-surised reservoirs or in the natural gas network. Up tofive percent hydrogen may be introduced into thepublic gas network. Extrapolated to the entire Germannatural gas network, this corresponds to a hugeamount of hydrogen.

Methanisation

In order to integrate power-based hydrogen in the gassector beyond the direct feeding-in of hydrogen, it ispossible to chemically convert the hydrogen gas tomethane by adding concentrated carbon dioxide gasas accumulated in coal-fired power plants or industrialplants like cement production or biogas plants, and tothen feed it in to the natural gas network. The methani-sation reaction has to be performed by microorgan-isms or initiated by using catalysts. In the latter case,the efficiency of the catalytic process depends on thematerial and the surface characteristics. Nickel cata-lysts are primarily used; among others, ruthenium isalso being tested. Catalyst efficiency optimisation canbe achieved by nanostructuring. This allows the sur-face accessible to the reactants to be increased. How-ever, methanisation goes hand in hand with a reduc-tion in the overall efficiency and with additional costs,but allows less problematic feed-in to the natural gasnetwork than does hydrogen.

The achievable efficiencies for hydrogen productionare currently around 64 percent. If the methanisationstage is downstream, the overall efficiency is reducedfurther to around 50 percent (Krause and Müller-Syring 2011). For comparison: for direct electricitytransport and energy storage in a pumped storagepower plant, the efficiency is greater than 70 percent.However, the storage capacity of pumped storage inGermany is very limited.

35

Work on the development and optimisation of elec-trolysis methods to improve the efficiency of thepower-to-gas process is intense. Efficiencies of 90 per-cent appear achievable in the foreseeable future.Other development objectives are to make electroly-sers more flexible in terms of a fluctuating electricitysupply and frequent load changes, and the upscalingof production processes. Nanotechnologies play a keyrole here in terms of the further development of elec-trolysis (see Section 3.7.1).

Process engineering and the methanisation stage arealso being developed further. For example, a currentFraunhofer Institute for Wind Energy and Energy Sys-tems Technology IWES research project utilises thecarbon dioxide contained in biogas as a CO2 sourcewithout previous separation or complex scrubbingstages. The gas produced using this direct methanisa-tion is therefore of 100 percent renewable origin. Cor-responding demonstration facilities are located at theHessische Biogas-Forschungszentrum (HBFZ) (HessenBiogas Research Centre) in Bad Hersfeld and at theViessman factory in Allendorf (Eder).

Power-to-Liquid

In a process related to methane production by power-to-gas processes, so-called power-to-liquid processesare being researched, which produce liquid fuelsinstead of gases from electrical energy, water and car-bon dioxide (CO2). These approaches are based onthe production of synthesis gas, a mixture of carbonmonoxide and hydrogen, whereby the carbon monox-ide is chemically reduced from CO2. Liquid hydrocar-bons such as diesel, petrol, etc., can be specificallysynthesised from this synthesis gas. In Germany,power-to-liquid is being addressed with the aid ofextensive funding by the Federal Ministry for Educa-tion and Research, among others. The aim is todevelop the technology to industrial scale. However,compared to power-to-gas processes, power-to-liquidis still at an early research stage.

36

Power-to-gas plant in Allendorf (Eder), Hessen, which was realised as part of a project funded by the Federal Ministry for Economic Affairs

and Energy. (Source: Viessmann Werke)

Despite growing efforts to develop renewable energysources, the conversion of fossil fuels to power andheat still represent the backbone of today’s globalenergy supply. To save resources and reduce carbondioxide emissions, conversion processes that are asefficient as possible are required. Optimisation poten-tials are available in coal-fired power plants, in partic-ular, because they represent a large percentage ofglobal power generation. The world’s operationalblack coal power plants have an average efficiency ofaround 30 percent, while new plants exhibit efficien-cies of more than 45 percent. Gas turbine powerplants achieve efficiencies of around 60 percent. Bycompletely replacing the world’s operational blackcoal power plants with modern plants, carbon dioxideemissions from firing black coal for power could bereduced by 35 percent (DECHEMA 2007).

Optimisation by further increasing power plant effi-ciency would require higher working temperatureswhile simultaneously retaining the fundamental powerplant processes. One prerequisite for achieving theseefficiency improvements and CO2 savings potentialsis the availability of new, extremely heat resistant mate-rials. Other approaches for reducing CO2 emissionsare available in the separation and storage of carbondioxide in underground reservoirs (CCS: carbon cap-ture and storage) or otherwise utilising the separatedcarbon dioxide. In addition to coal-fired power gener-ation, CCS technologies could also be employed inother high CO2 industries such as in steel, aluminiumand cement production, for example. Currently, morethan 20 large CCS projects are operating globally.Once initial pilot projects had run their course, CCSresearch activities in Germany have generally beendiscontinued as a result of current structural changesand falling profits in the energy sector. The energygroup Vattenfall aims to exploit the insights gained inits ‘Schwarze Pumpe’ oxyfuel CCS pilot plant inCanada. Generally speaking, CCS technologies areassociated with significant costs for the power plantoperator, assuming 85 to 100 percent carbon dioxidecapture, depending on the type of process, and over-all efficiency losses of around ten percent. However, inthe long term, the separation of carbon dioxide frompower plant processes is regarded as an importantbaseline technology for converting to a climatefriendly energy system on a global level.

37

3.8 Power Generation by Fossil Fuel-Fired Power Plants

Structure of thermal insulation layers produced by means of electron beam physical vapour deposition.

(Source: TU Darmstadt, Institut für Werkstoffkunde)

Adhesion promoting layer (e.g.: MCrAlY)

Turbine parent material

E B -PVDThermal insulation layer (TIL)

Yttrium stabilised zirconium oxide

Gas turbine. (Source: industrieblick /Fotolia.com )


Nanostructured thermal insulation layers for gas turbines

Thermal insulation layers are indispensable for pro-tecting gas turbine blades against heat. At 1,500degrees Celsius, the gas temperatures at the turbineinlet are substantially higher than the melting point ofthe turbine materials used. The principal demands onthermal insulation layers include low thermal conduc-tivity and thermal expansion properties suited to thesubstrate, in order to minimise stresses and crack for-mation in the material. Modern, multi-source plasmacoating methods allow complex thermal insulationsystems, consisting of active, adhesion and barrier lay-ers, to be manufactured with nanoscale precision anda variety of material combinations. This creates addi-tional optimisation potentials, for example to furtherreduce the thermal conductivity of the layers, increasethe durability of the turbine components and thus tofacilitate higher operating temperatures. The efficiencyof gas turbines can thus be further enhanced, leadingto considerable cost and carbon dioxide emission sav-ings.

Nanostructured membranes for carbon dioxideseparation

The separation of carbon dioxide from coal-firedpower plant flue gas is currently one of the mostintensely driven technological developments forachieving CO2-neutral coal-fired power plants orrespectively the use of carbon dioxide as a raw mate-rial. Nanotechnologies may contribute to the develop-ment of methods for selective separation of carbondioxide using specific membranes, for example, by theuse of nanostructured polymer membranes coatedwith catalysts, which convert the carbon dioxide tohydrogen carbonate in the presence of water. Thesolid hydrogen carbonate can then be easily sepa-rated from the remaining flue gas constituents.

Another possible option is the development ofceramic nanotubes, facilitating the highly efficient sep-aration of oxygen from the air. If this pure oxygen wasused for the combustion of fossil fuels, the flue gaswould almost exclusively consist of carbon dioxide,which could then be easily separated and utilised.

Anti-adhesive coatings for boilers and heatexchangers in coal-fired power plants

One of the problems in operating coal-fired powerplants or waste incineration power plants are encrus-tations of combustion residues in the boiler and heatexchangers, which must be expensively serviced atregular intervals. Ceramic anti-adhesive coatingsbased on nanoparticle coating materials substantiallyreduce encrustations, thereby increasing the servicelife of heat exchanger tubes and extending servicingintervals.

38

Nanostructured membranes play a key role in selective gas

separation. (Source: Helmholtz-Zentrum Geesthacht)

Residues on electrostatic filter funnels in power plants or waste

incineration plants can be avoided by using ceramic nanocoat-

ings. The coating ensures that dust can run off and does not

lead to adherence or plugging in the funnel.

(Source: CeraNovis GmbH)

Regenerative sources such as solar, wind andhydropower increasingly contribute to power suppliesin Germany. The Federal Government’s energy strat-egy aims for a 35 percent share of power generationfrom renewable sources in gross power consumptionby 2020. It aims to increase this share further to 50 per-cent by 2030. However, because renewable powergeneration is closely linked to weather conditions, thedevelopment and use of high capacity energy storagesystems play a critical role. With their aid, it is possibleto adapt the daily and annually fluctuating energy sup-ply to demand. Moreover, they can contribute tomains power grid stabilisation by providing energy atshort notice.

Energy can be stored in a number of formats: The stor-age options range from mechanical flywheels, throughbatteries, compressed air and pumped storage sys-tems, and on to gas storage in pressurised tanks, gasnetworks and cavern storage systems. The natural gasnetwork possesses the most extensive storage capac-ity and simultaneously offers the longest storage dura-tion. In principle, this makes seasonal buffering in therange of several months possible.

Particularly relevant to these applications are electro-chemical storage systems, chemical energy storagesystems (for example for hydrogen and methane ornatural gas) and thermal storage systems.

39

Flyw

heel

Hydro

gen

Methane

Batteries Compressed air storage

Pumped

storage

1 kWh 1 MWh102

10–3

10–2

10–1

100

101

102

103

104

104 108 1010

1 GWh

Storage capacity in kWh

Sto

rag

e d

urat

ion

in h

1 TWh 100 TWh

Energy storage technologies compared (kWh: kilowatt hours). (Source: DLR)

4. Energy Storage

Electrical power is a universally utilisable energysource. Systems that allow the direct storage of elec-tricity without conversion to other types of energy aretherefore particularly relevant.

The range of applications of electrochemical energystorage systems is wide. It can be initially divided intomobile and stationary applications. In terms of mobileapplications, the fields of electromobility and portablesmall electronics such as smartphones, tablets, etc.,are differentiated. Stationary applications can be dif-ferentiated into large-scale storage and decentralisedsystems.

The availability of high capacity energy storage sys-tems with high efficiencies, energy and power densi-ties are critically important for all of these applications.The primary drivers of innovation in Germany are theenergy revolution and the precise shape of futuremobility concepts. For example, one of the FederalGovernment's objectives is to see one million electricvehicles on the roads by 2020. Parallel to this, hybridvehicle drives are becoming more widespread. Localpublic transport also offers additional potential.

In the field of stationary decentralised storage, theexpansion of internal consumption plays an increasingrole. The feed-in tariffs for domestic solar power instal-lations will continue to fall in line with the requirementsof the Renewable Energy Sources Act. Installation ofthese systems now often only pays off for home own-ers with optimised self-use of the generated energy.Greater internal consumption necessitates suitablestorage systems. Complete systems consisting of solarpower installation, storage battery and the correspon-ding energy management system are increasinglyavailable commercially.

In view of the expansion of renewable energy forms,large scale storage systems for the mains power gridsare also becoming increasingly relevant. They can pro-vide a buffer between fluctuating power generationand power demand. Moreover, they can compensatefor fluctuating renewable energy sources and con-tribute to stabilising municipal and regional grids. Ashare of fluctuating power sources greater than 15percent can cause instabilities in local grids. Given astorage potential of four hours, this threshold valuecan be increased from 60 to 70 percent (H2BZ 2013).

In an emergency, large batteries can even bridgeshort-term power failures and provide an uninter-rupted power supply. The potentials of an extensiveelectric vehicle fleet are also discussed in this context.It may be possible to also utilise their batteries forenergy storage, accepting excess power from the gridand feeding it back in as necessary.

Supercapacitors

Supercapacitors are electrochemical double-layercapacitors characterised by a high power density. Theyconsist of two flat electrodes, are surrounded by anelectrolyte and kept apart by a separator. The chargecarriers accumulate at the electrodes and are storedthere. Because the storage capacity is a function of thesurface area of the electrode, nanostructuring and theassociated increase in surface area can achieve a substantial increase in the performance of super-capacitors.

40

4.1 Electrochemical Storage Systems

(Source: Petair / Fotolia.com)

Supercapacitors with energy densities in excess of tenwatt hours per kilogram are now being marketed. Sub-stantially higher values are already being achieved inthe laboratory (Zhang et al. 2013). However, comparedto batteries, only small amounts of energy can bestored. The storage capacity of modern lithium ionbatteries, for example, is more than ten times greater.The advantage, however, lies in the high power den-sity of supercapacitors. Typically, and in contrast tobatteries, energy storage is not facilitated by creatingchemical bonds. This means that supercapacitors havegreater cyclic stability (number of charging and dis-charging cycles), and charging and discharging arenot limited by slow chemical reactions. The powerdensity determines not only the amount of energystored but also the speed of charging and discharg-ing. Supercapacitors are therefore especially suitablefor the rapid acceptance and delivery of electricalenergy (so-called peak power). Their range coversmobile applications, in which large amounts of energymust be delivered or accepted in a short time (forexample, when recuperating the braking energy inelectric cars, or during acceleration).

Batteries

In batteries, chemical energy is stored at the molecularlevel in certain material systems consisting of elec-trodes and electrolytes. The chemical energy can beconverted to electrical energy in electrochemical reac-tions. Rechargeable batteries, also known as accumu-lators, are particularly important with regard to futureenergy, mobility, Internet and communications chal-lenges. With them, the conversion of chemical to elec-trical energy is reversible. They can be charged anddischarged many times. The governing parametersare the achievable storage capacity/energy density,the charging and discharging speed (power density),the cyclic stability or service life, and the size, weightand manufacturing costs. A wide range of differentmaterial systems are used in batteries.

During the last ten years, lithium ion technology hascome to the fore wherever size and weight are partic-ularly important. It is used in rechargeable batteries forportable electronics, as well as in traction batteries inthe electromobility field. Stationary power storage isanother growing application field.

Lithium systems are regarded as one of the mostpromising future power storage options. Compared totraditional batteries such as lead-acid batteries, forexample, they deliver considerably higher cell volt-ages and energy densities. Technologies based onlithium, cobalt, lithium-nickel or lithium-manganeseare now well established. More recent developmentssuch as lithium-phosphate and lithium-titanate sys-tems are now also matured and available on the mar-ket. The achievable energy densities in series produc-tion are up to 200 watt hours per kilogram.

41

Lithium ion battery for electric cars. (Source: iStock.com/zorazhuang)

Despite these high values for batteries, a comparisonwith the 11,000 watt hours per kilogram energy con-tent of mineral oil is modest. In particular against thebackdrop of the desired expansion of electromobility,much energy is currently being expended in batteryresearch to increase energy density.

Lithium-sulphur (LiS) based systems are regarded ashaving a large potential. LiS batteries are viewed asbeing particularly favourable and promise an increasein energy storage capacity by a factor of three or fourcompared to conventional lithium ion technology.However, market maturity is not anticipated for aroundten to fifteen years. Research into lithium-sulphur sys-tems is global and German research institutions arealso intensely occupied with this technology.

The development of so-called metal-air battery con-cepts, in which the ambient air, or more exactly, theoxygen it contains, replaces the cathode, is evenlonger term. The lithium-oxygen system, presentingthe possibility of energy densities greater than 1,000watt hours per kilogram, is especially promising. However, market maturity is not anticipated for at leastfifteen to twenty years.


The use of nanotechnologies is increasingly seen as a prerequisite for powerful batteries and supercapac-itors. In terms of the demands on the various applica-tions, a wide range of criteria need to be optimised,among others, the energy and power densities, serv-ice life, fast reaction times, large operating tempera-ture range, robust safety and high efficiency. Develop-ment objectives include electrodes with high charg-ing/discharging capacity, for example, usingnanoporous carbon materials (for example, carbonaerogel, carbon nanotubes, graphene, etc.), highercell voltages facilitated by using mixed oxides, thesubstitution of organic liquid electrolytes with polymerelectrolytes, or the use of nanomaterial-based ceramicfilms as separators.

42

Graphene-based

supercapacitor SkelCap 4500F.

(Source: Skeleton Technologies)

Scanning electron microscope photo of a fibre-reinforced carbon-aerogel that is

used as an electrode material in supercapacitors. (Source: ZAE)

As nanoporous substances, carbon aerogels are emi-nently suitable as graphitic electrode materials insupercapacitors, because of their extremely largeinternal surfaces, adjustable pore distribution andpore diameters. Other electrode designs are based onnanocrystalline graphite, carbon nanotubes and other,generally carbon-based, materials.

Innovative developments utilise the surface propertieson monolayered carbon, known as graphene. Embed-ding lithium ions in the electrodes has proven benefi-cial. With these lithium supercapacitors the begin-nings of mass production and initial commercial marketing can already be recognised.

In a future energy system, chemical energy sourcesgained from regenerative sources, in particular hydro-gen, will play an increasingly important role. In addi-tion to the necessary infrastructure adaptations, theefficient storage of hydrogen is regarded as one of thecritical success factors on the road to a possible hydro-gen economy. This is especially the case for mobileapplications, in which the hydrogen is stored in a com-pressed form. In addition to the traditional high-pres-sure or liquefied gas storage, the industry uses chem-ical hydrogen storage systems consisting of metalhydride compounds, in particular. However, the cur-rently available storage methods still display a numberof disadvantages, which rule out broad economic use.

High-pressure storage systems are very heavy; lique-fied gas storage is expensive because it must behighly insulated to keep losses from hydrogen evapo-ration as low as possible. Metal hydride storage sys-tems are also associated with high costs and are relatively heavy. Moreover, the materials currentlyemployed for chemical storage do not correspond tothe technical and economical requirements asdemanded by the automotive industry, for example, interms of a hydrogen storage capacity of up to ten per-cent by weight.

43

Left: Nanostructured carbon as substrate for sulphur cathodes. (Source: Fraunhofer IWS)

Right: Free-standing carbon/sulphur nanocomposite electrodes. (Source: Fraunhofer IWS)

4.2 Hydrogen Storage Systems


Research in recent years has demonstrated that nano-materials offer promising development potentials ashydrogen storage systems for operating fuel cells invehicles and in mobile electronics. Research is beingcarried out on a variety of nanostructured solid statestorage systems, capable of efficiently binding anddischarging hydrogen, either chemically or by adsorp-tion. Highly porous materials or complex hydrides, inwhich hydrogen is chemically reversibly stored in thelattice structure, appear promising here. Complexhydrides are compounds similar to salt consisting ofhydrogen and light alloy mixtures, such as the alkalimetal hydrides, for example lithium borohydride,which contain gravimetric hydrogen densities up to 20percent. However, only part of this can be used as areversible hydrogen storage system; in addition, thehigh temperatures required to liberate the hydrogenagain are problematic, for both practical and eco-nomic reasons.

Porous metal borohydrides such as magnesium boro-hydride, which, as a light alloy hydride, also possessesa highly porous metal organic skeleton structure (33percent pore volume), are more advantageous. Suchmaterials can not only store large weight percentages

of hydrogen (14.9 to 17.4 percent) but can also liber-ate the hydrogen again at relatively low temperatures(approximately 300 degrees Celsius). In the EU-funded research project BOR4STORE – Developmentof solid state hydrogen storage from fundamentals toapplication, a number of borohydride materials arebeing investigated and developed to achieve efficienthydrogen storage.

Another approach is based on nanoporous metal-organic compounds (so-called metal-organic frame-works, or MOFs), which provide very high specific sur-faces of greater than 6,000 square metres per gram.This means that one gram of this compound has a sur-face area corresponding to the area of a football field.The material structure consists of metallic clusters (forexample copper, chromium, zinc) and organic bridg-ing molecules. However, the currently achievable stor-age capacities are still relatively far removed from anypossible use as hydrogen storage systems in automo-biles. The first cost-effective applications are thereforeanticipated more for operating fuel cells in mobileelectronics. In general terms, however, much remainsto be researched in the development of solid statestorage systems.

44

*Calculated for 500km range.

Various hydrogen storage systems compared.

(Image: VDI TZ; data sources: Prof. Dr. Stefan Kaskel, TU Dresden, and Prof. Dr. Birgit Scheppat, RheinMain University of Applied Sciences)

Hydrogen storage system overviewStorage medium Temperature

or pressureWeight* orvolume*

Storage capacity

+ Advantages/– disadvantages

Liquid hydrogen –270 °C 140 kg, 86 l 7.5% by weight

+ low space demand– highly elaborate insulation– energy loss due to gas liquefaction– gas escape during storage

Gaseous hydrogen 700 bar 125 kg, 260 l 6% by weight

+ small technical investment– large space required for cylindrical high-pressure tank

– high storage pressure represents safety risk

Nanoscaled metal hydrides(for example MgH2)

> 300 °C, 8 bar

175 kg, 73 l 4–7%by weight

+ little space required– high weight– very high temperatures required

Nanoporous metal-organicmaterials (MOFs) (for example MOF-177)

< –210 °C, > 50 bar

86 kg, 160 l 7,5%by weight

+ low weight– low temperature– large space required

There are a variety of technical options available forstoring thermal energy and liberating it again whenneeded. So-called latent heat storage systems arealready widespread. They consist of phase changematerials, or PCMs, which can absorb heat in areversible phase transition in the operating tempera-ture range and liberate it into the environment again.The storage substances are salt hydrates or organiccompounds, such as paraffins and sugar alcohols.Phase change storage systems are used for thermo-static control in buildings, for example. Phase changematerials are also being developed by automobilemanufacturers to store waste exhaust heat, which canthen be used to reduce energy consumption, amongother things, to quickly warm the engine on cold starts.Phase change storage system products developed forthis purpose by Merck, for example, are available onthe market.

Other thermal storage system concepts are based onthe use of so-called adsorption storage systems, usingzeolites or silica gels, for example. These storage sys-tems can dry out when heat is added (charged) andliberate heat again by passing moist air through them(discharged). Adsorption storage system applicationsinclude zeolite heating systems for residential build-ings, for example, heating systems from Viessmannand Vaillant, or a zeolite dishwasher offered bySiemens.

When heating buildings using solar thermal collectors,in particular, high-capacity thermal storage systemsare necessary to increase the solar proportion in theannual useful heat, by making available in winter thesolar heat stored during the summer months.

45

Sodium aluminium hydride /hydrogen storage tank.

(Source: Helmholtz-Zentrum Geesthacht /Christian Schmid)

Metal-organic skeleton structure materials with pore sizes up to

three by three nanometres, which allow extremely high storage

capacities for gaseous hydrogen. (Source: Fraunhofer ICT)

4.3 Thermal Storage Systems


Nanotechnologies play an important role in the devel-opment of efficient thermal storage systems. Forexample, in zeolites, nanometre-sized pores are delib-erately configured such that the bonding strength ofthe water molecules to be incorporated, or the energydensity, are increased. Moreover, the heat and sub-stance transport in adsorption thermal storage sys-tems can be improved by using nanofluids.

Phase change storage systems based on nanoencap-sulation and nanocomposites such as nanographite orcarbon nanotube phase change composite materialsare also being developed in order to enhance thethermal conductivity and heat transport within thestorage systems.

46

Condenser

CompressorDesorber

Evaporator

Boiler heat

Useful heat

Check valve

Check valve

Condenser

CompressorAdsorber

Evaporator

Check valve

Useful heat

Ambient

heat

Check valve

(1) (2)

Diagram of a periodic adsorption heat pump consisting of a sorber heat exchanger, operating as desorber (1) or adsorber (2),

depending on the operating phase. The condensation and latent heat of the water vapour in the zeolite structures is delivered

as useful heat to the heating loop. (Source: Viessmann)

Various materials like ceramic beads, liquid salts, different types of concrete and natural stones are investigated

with respect to their potential as heat-storage systems. (Source: DLR (CC-BY 3.0))

The growing deployment of renewable energysources to generate electricity increasingly necessi-tates transporting power over large distances from thepoint of generation to the final consumer. The expan-sion and conversion of power distribution grids there-fore represent a central aspect of the energy revolu-tion. In this context, technologies transmitting highpower output with only minor losses have a role toplay. These predominantly comprise the superconduc-tors and new transmission technologies such as high-voltage direct current transmission.

Low-loss power supply using nanostructuredsuperconductors

Superconductors will increasingly assume a role inpower engineering in loss-free cable-based powertransmission, in coil windings and the bearings of elec-tric motors, and in ground current limiters in high-volt-age grids. The world’s longest superconducting cable,at 1,000 metres in length, has been installed in Essencity centre since 2014, where it connects two trans-former stations. It saves the space for routing and atransformer because a lower voltage than usual is suf-ficient due to the transmission without losses. For rea-sons of cost the high-temperature superconductorsare more interesting, which use high-tech materialsbased on oxide ceramics.

Processing the brittle metal ceramics to technicallyutilisable components such as flexible wires andcables is a particular technical challenge. Control ofthe material at the nanoscale plays a decisive role inthe manufacture of high-temperature superconduc-tors using flat wires produced from a powder-filledtube or thin-film techniques. Sufficient current carryingcapacity in the high-temperature superconductors isonly achieved by highly homogeneous ceramicsnanostructuring. In wire manufacturing from tubes, theceramics are initially in powder form. This powder con-tains both coarse particles (grain sizes greater thantwo micrometres) and an approximately ten percentproportion of nanoparticles. The nano proportion isthe key to the quality and performance of the materialbecause during sintering, this is what bonds the grainssuch that their current carrying capacity becomes amacroscopically exploitable property. When usingthin-film coatings, so-called nanodots, that is, extrinsicphases such as yttrium oxide, are generated or addedon a nanometre scale (approximately 35 nanometres,finely distributed) in order to contribute to perform-ance enhancement.

47

5. Energy Distribution

5.1 Low-Loss Power Supply and Conversion

Considerable advances have been made in recentyears in the development of high-temperature super-conductors thanks to the manufacturing of yttrium-barium-copper oxide (YBCO) on metallic substrates(so-called coated conductors), which have substan-tially extended the processability and usability of thismaterial class. The greatest challenge is manufacturingall deposited coatings (superconductor and bufferprotection coatings) by chemical means from low-costprecursors, in order to decrease costs to an economi-cally attractive range. In the long term, other nanoma-terials such as carbon nanotube composites, repre-senting highly efficient conductors, may offer an alter-native for low-loss electricity transmission. However,this requires substantial advances in terms of econom-ical processes and technologies for manufacturinglonger, homogeneous carbon nanotube fibres.

Nanostructured insulation materials for high-voltage lines

The efficiency of power transmission in high-voltagelines increases with increasing voltage. In Europe,power is generally transmitted at approximately 400kilovolts, while in large countries such as China andIndia, 1,500 kilovolts are aimed for. The electrical andmechanical loads on high-voltage lines grow withincreased voltages and the multiple feed-in points ofdecentralised power generators, as well as by supply-ing large conurbations. One of the central roles ofhigh-voltage engineering is therefore to develop elec-trical insulation systems, for example by using nano-materials. The material design at the nano scale allowsthe electrical insulation properties, such as the break-down voltage, to be optimised, for example, by usingnanostructured metal oxide powder in varistors to pro-tect against overvoltages in power lines. Multifunc-tional, non-linear and auto-adaptive insulation systemsare currently being developed, whose electrical andmechanical properties change with the field strength,the temperature or the mechanical load, and whichadapt optimally to the performance demands.

48

Structure of the superconductor cable beneath Essen city centre: the

superconductor cable is provided with central nitrogen feed (1) for

nitrogen cooling. Three superconductor layers (2) alternate with polypro-

pylene coated paper insulation (3). This is followed by copper screening

(4) and a nitrogen return (5). All layers are amalgamated in what is known

as the cryostat (6), a double-skinned, corrugated stainless steel, super-

insulated vacuum enclosure. The outside of the double-skinned, super-

insulated cryostats is protected by a polyethylene casing.

(Source: BINE Informationsdienst /Anna Durst)

1

2

3

2

3

2

3

4

5

6

The globally advancing liberalisation of the powermarkets and further decentralisation of productionnoticeably increase the demands on the flexibility ofthe power grids. Any trans-European power tradingsystem requires efficient power distribution, even overlarge distances, flexible adaptation to occasionallyheavily fluctuating demands, as well as rapid controlof the load flow, in order to limit the extent of grid per-turbations and the risk of widespread blackouts. Interms of the growing decentralised power feed-infrom fluctuating regenerative power sources, the exist-ing power distribution grid is also increasingly reach-ing its limits. Efficient power distribution demandspower grids that allow dynamic load and fault man-agement, and demand-driven power supply with flex-ible price mechanisms. Nanotechnologies could pro-vide valuable contributions to achieving this vision, forexample by using nanosensory and power electronicscomponents, which are capable of managing theextremely complex control and monitoring of thesetypes of power grid.

Nanooptimised power electronics and sensors

Transforming and controlling strong current-usingpower electronics components will increase in rele-vance in the future. Power electronics guarantees low-loss power transformation en route to the final con-sumer and also plays a central role in transmittingpower through long submarine cables. Similarly,decentrally generated photovoltaic electricity can onlybe utilised after power electronics transformation ininverters. Further development of power semiconduc-tors using materials with large band gaps, such as sil-icon carbide, facilitates applications for high voltages(transmission grids and railways) or high temperatures(for example for controlling electric motors in automo-biles). The development of power electronics canprofit greatly from nanotechnologies, for example, bythe optimisation of the coating design in so-calledwide band gap semiconductors or the use of carbonnanotubes as connecting wires for high current flowsand minimal heat development.

Miniaturised, magnetoresistive sensors based on mag-netic nanocoatings offer the potential of facilitatingthe complete online measurement of current and volt-age parameters in the power grid. One example ofthis is a wireless sensor network for monitoring over-head transmission cables, which can increase thetransmission capacities of high- and extra high-voltagelines. The energy autarkic microsensors determine theprevalent current flow at 500 metre intervals, the cabletemperature, the sag and the wind movement, andtransmit these data to a receiving station. Here, usingthe recorded data, grid capacities can be quicklyincreased because reserves are utilised that resultfrom the difference between the weather forecast andthe true condition of the cables. The Fraunhofer Insti-tute for Electronic Nanosystems ENAS has imple-mented this technology in the ASTROSE (Autarkic Sen-sor Network for Power Engineering Monitoring; Ger-man: Autarkes Sensornetzwerk zum Monitoring in derEnergietechnik) project, which started pilot operationsat the end of 2014.

Nanocrystalline soft magnet materials for intelligent power grids

Due to properties such as high permeability and tem-perature stability, nanocrystalline soft magnet materi-als, which can be manufactured by rapid solidificationprocesses applied to iron alloys, for example, are emi-nently suitable for power engineering applications.These materials are employed in low-loss transform-ers, such as, for example, electronic power meters,residual current operated circuit-breakers or powerelectronics components. Companies in Hessen suchas Vakuumtechnik in Hanau or MAGNETEC in Lan-genselbold (see success story in Section 7.7) areglobal market leaders in marketing these nanocrys-talline magnetic materials as toroidal cores for diverseelectrotechnical applications.

49

5.2 Smart Grids

In the short term, nanotechnologies will primarily havethe greatest impact in efficient energy utilisation interms of reducing resource use and carbon dioxideemissions in the energy sector. In almost all branchesof industry and in the private sector, nanotechnologi-cally optimised products and production facilitiespresent considerable energy-saving potentials.

Numerous examples of applications in the respectivebranches can be found in the series of brochures pub-lished by Hessen-Nanotech (for example, automotive,civil engineering, bionics, optics, production technol-ogy). Some examples of the most relevant applicationsare described below.

Around ten to fifteen percent of the fuel consumptionof car combustion engines is determined by friction inthe engine. By coating the moving engine compo-nents such as the cylinders, pistons and valves withnanocrystalline composite materials, friction and wear

can be reduced and thus fuel saved. Nanocrystallinepiezomaterials and nano wear protection coatingsbased on DLC (diamond-like carbon) allow the effi-ciency and precision of diesel injectors to be opti-mised.

50

6. Energy Efficiency in Industrial Applications

6.1 Friction Reduction in Machines and Vehicles

Long-term stress tests of rolling-element bearings demonstrate the reduction in wear due to REWITEC additives

compared to untreated lubricants. (Source: REWITEC)

Microscopy of rolling-element bearing, Castrol X320 with 0,2% REWITEC®

Microscopy of rolling-element bearing, Castrol X320 without REWITEC®

In the transport sector in particular, highly stable light-weight construction materials can contribute substan-tially to energy savings. Nanomaterials offer numerouspotentials for achieving weight savings and combiningvarious material properties, for example:

a extremely favourable strength to weight ratiosa enhanced hardness, toughness and wear resistance

a improved thermal capacity and corrosion resistance

Nanostructured metal-matrix composites (MMC) orpolymer nanocomposites, for example, offer light-weight construction potentials. Metal-matrix compos-ites are metallic materials, the mechanical and thermalproperties of which are improved by introducing areinforcing phase (primarily ceramics and carboncompounds). Light metal materials/alloys, predomi-nantly with aluminium, and more rarely with magne-sium and titanium, are used as a matrix. Metal-matrixcomposites are predominantly used in applications inwhich high mechanical (for example the ratio ofstrength to weight or the toughness) or thermaldemands (such as high conductivity or low thermalexpansion) are made.

Applications here are primarily in the aerospace sectorand the automotive or electronics industries. Metal-matrix composites unify metallic properties such asformability and toughness with the hardness and ten-sile strength of ceramic materials. A developmenttrend of recent years is the use of nanoscaled fibresand particles as a reinforcing phase, with which abroad spectrum of material properties can be opti-mised to match the demands of the respective indi-vidual applications.

Nanobased protective coatings will expand the use ofmagnesium alloys in automotive engineering. Com-pared to conventional chrome coatings, environmen-tally friendly, silicon dioxide based coatings, which canbe manufactured using physical vapour deposition orsol-gel processes, offer improved abrasion and corro-sion protection for magnesium materials. Polymercomposites reinforced by nanoparticle or carbon nan-otubes also have the potential to form ultra-light, high-strength construction materials. However, for practicalapplications, a number of technical problems in termsof alignment and integration in the polymer matrix, aswell as further cost reductions in material manufactur-ing, must be addressed.

51

6.2 Lightweight Construction Using Nanocomposites

REWITEC, in Lahnau, has developed an innovativecoating technology, which ceramises the surfaces ofmetallic components in engines, transmissions, etc.,using nanoparticles, thus protecting them from wear.The nanoparticles react with the metal surfaces at thepressures and temperatures caused by the frictioncontact to form hard ceramic compounds. This notonly prevents new damage to the components, but

previous mechanical damage can even be compen-sated for and repaired. In addition to its use in com-bustion engines, the process can also be applied tonumerous mechanical components such as transmis-sions, bearings or pumps, and leads to substantialenergy savings and extended periods of use (seeREWITEC success story, Section 7.3).

Building technology offers large energy-saving poten-tials, for example in lighting, heat supply, air condition-ing and ventilation. Modern technologies mean thatenergy savings between 25 and 70 percent can bemade compared to conventional solutions.

Substantial cost benefits may be achieved for compa-nies, private households and public budgets throughthe use of new technologies. Around ten percent ofelectrical power in Germany is used for lighting alone.This corresponds to around 50 billion kilowatt hours(AG Energiebilanzen 2013). Of the total power costsof a commercial operation, lighting may reach morethan 50 percent; in some wholesale and retail compa-nies this may even be as much as 70 percent.

Nanotechnology applications in lighting engineeringprimarily concern the development and use of energy-efficient light-emitting diodes (LEDs) based on inor-ganic and organic semiconductor materials. Due to itscompact construction, the variety of colours and thehigh energy yield, LED technology has already cap-tured large market potentials in display, building andautomobile lighting. Organic light-emitting diodes(OLEDs) have the potential to provide large lightedareas and screens on flexible substrates, which can beintegrated in numerous areas in interior design. Pointsof contact for nanotechnology are provided by further

optimisation of LEDs using quantum dots, for exam-ple, which allow the energy efficiency and light yieldto be increased further. Moreover, LED scatter effectscan be minimised and thus the light yield increased byusing nanoscaled light-emitting particles. It is neces-sary to coat the particles in order to increase their sta-bility.

The further development of OLEDs will also dependon nanotechnological innovations, which involve,among other things, optimisation of substrates, thesequence and thickness of coatings, the use ofdopants and the purity of the materials used. An OLEDconsists of a glass or flexible film substrate to which atransparent electrode, one or more layers of semicon-ducting organic materials, each a few nanometresthick, and an auxiliary electrode are attached. If anelectric voltage is applied, positive and negativecharges in the organic semiconductor produce anexcited state from which light is subsequently emitted.As flat light sources, OLEDs can open new applicationdimensions for lighting, such as integrated lightsources on walls and wallpapers, or in furniture andfabrics. OLED features include high energy efficiencyand flat, glare-free light with natural colour reproduc-tion.

52

6.3 Intelligent, Energy-Efficient Building Technology

Save energy and costs in industry and commerceEnergy efficiency potentials in cross-sector multidisciplinary technologies in percent

70 %

Lighting

50 %

Compressed air

bar

30 %

Pump systems

30 %

Refrigeration and cooling water plants

30 %

Heat supply

25 %

Ventilation systems

More information at www.industrie-energieeffizienz.de

Energy-saving potentials as a result of innovative building services

engineering. (Source: Initiative Energieeffizienz)

Organic light-emitting diodes for ultra-thin large-scale displays

and lighting objects. (Source: Novaled)

Another field for nanotechnology is adaptive windowand facade elements, where nanotechnological solu-tions can make significant contributions to energy sav-ings. These include, for example, responsive shadingsystems (smart glazing), which present an alternativeto conventional mechanical sun/glare protection sys-tems (blinds, shades, etc.) and permanently colouredsun shield glazing. Annual growth rates for smart glassof 20 percent, up to 5.81 billion US dollars in 2020, areanticipated (Marketsandmarkets.com 2014). The tech-nological basis for smart glass is provided by layersintroduced into the glazing system, which can bereversibly coloured as a function of their chemical andphysical variables, and in this way modify the opacityand heat conductivity of the glass. In addition to activesystems, there are also passive systems, which altertheir opacity automatically as a function of the lightingconditions. These include special liquid crystal mix-tures with inclusions of tailor-made dyes, developedby Merck, which either allow light to pass or block itby absorption. In the first case, the panes are transpar-ent, in the second, they are darkened. The requiredelectricity is generated within the window itself, inde-pendent of external power sources. The special dye-

doped liquid crystal mixture transfers the solar energyto the photovoltaic cells integrated in the windowframe, where it is then converted to electricity. The firstpilot projects are already running in the Netherlands(Merck 2014).

53

Electrically controllable colouring of electrochromic window

panes. (Source: EControl-Glas)

Technical processes in industry, in particular in primarychemical products or metal production, are oftenassociated with high energy inputs and contribute sig-nificantly to operating costs. The energy saving poten-tial provided by using nanotechnologies is predomi-nantly given by replacing or optimising energy-inten-sive reaction stages, for example, by employingnanostructured catalysts or thermal insulation materi-als. The catalytic process plays a role in more than 80percent of all products produced by the chemicalsindustry. Because of their increased active surfacearea, nanostructured catalysts allow improved reactionyields or even, in some cases, new, energetically morefavourable synthesis routes. One example is the use offullerenes as catalysts in the industrially relevantstyrene synthesis process, which can significantlyincrease reaction yields and reduce process tempera-tures.

6.4 Energy Efficiency of Production Processes

Iron oxide catalyst (Fe2O3) encased in fullerene-like carbon

layers for optimising styrene synthesis.

(Source: Fritz-Haber-Institut)

54

7. Success Stories in Hessen

Platinum nanoparticles on carbon black substrate as electro-

catalysts for fuel cells. (Source: Umicore)

7.1 Umicore: Nanostructured catalysts for efficient membrane fuel cells

Umicore is a global leader in the manufacture of carexhaust catalytic converters and numerous productscontaining precious metals. In many cases, these prod-ucts considerably contribute to facilitating environ-mentally friendly processes or to reducing theirenergy consumption.

The company’s research primarily focuses on thedevelopment and production of electrocatalysts as thekey components for membrane fuel cells (PEMFCs,proton exchange membrane fuel cells), which areregarded as an environmentally friendly and highlyefficient energy conversion technology. Nitrogenoxides or other pollutants generally produced in tra-ditional combustion do not occur in PEMFCs. The useof PEMFCs in automobiles, domestic power supplysystems and even for portable power supplies (forexample in laptops and mobile telephones) hasalready been successfully demonstrated. In Japan,several tens of thousands of domestic fuel cell powersystems have already been deployed and the Asiancar manufacturers Toyota and Hyundai have initiatedseries production of fuel cell-powered vehicles.

The nanofine distribution of the precious metal and itsstable union with the catalyst substrate are decisive forthe use of the electrocatalysts developed by Umicorein membrane fuel cells. This increases the catalyticeffect per gram of precious metal used and thus con-tributes to the conservation of resources in terms ofvaluable input substances and to reducing costs.

Umicore is a globally operating materials technologiesgroup with headquarters in Brussels, Belgium. In 2014,the company had a turnover of 8.8 billion euros (2.4billion euros without precious metals) and is globallyactive with 14,000 employees at 86 locations. Activi-ties are concentrated on the business sectors recy-cling, energy & surface technologies and catalysis.

In Hessen, the group operates a site at WolfgangIndustrial Park in Hanau. Here, around 1,000 employ-ees work in a total of seven business sectors.

Contact:Umicore AG & Co. KGRodenbacher Chaussee 463457 Hanau-Wolfgang, Germany

Dr. Ralf ZuberTelephone: +49 (0)6181 59-6627E-Mail: [email protected]

55

7.2 NAsP III /V: Small is beautiful – miniaturised solar cells offer thehighest conversion efficiency for concentrating photovoltaic systems

Concentrating solar cells with 1,000-fold light concentration.

(Source: Isofoton)

Solar cell wafers in a chemical process box.

(Source: NAsP III/V)

In 2004, NAsP III/V was spun off as a stand-alone com-pany from the materials sciences centre of Philipps-Uni-versität Marburg. The main business sector is the devel-opment and marketing of new materials and technolo-gies for integrating optical and photonic functions withsilicon-based micro and nanoelectronics for high powerlasers and highly efficient solar cells, based on innova-tive III/V compound semiconductors with the appropri-ate nanostructures.

Together with domestic and international university,research and industry partners, NAsP III/V is working ondeveloping the next generation of highly efficient mul-tiple solar cell structures, to be used in concentratingphotovoltaics (CPV) with conversion efficiencies ofgreater than 50 percent in the CPV solar cells. This proj-ect objective demands integration of an innovativesolar cell material, such as the complex III-V solid solu-tion system (GaIn)(NAs) with a suitable energy gap ofapproximately one electron volt in the multiple solarcell stack.

NAsP III/V’s development work on manufacturing theseinnovative materials were performed on state-of-the-artmultiwafer production facilities in order to guaranteefast and efficient transfer to industrial applications. Thenewly developed production method is characterisedby the use of special chemicals that can be exploited ina radically more efficient way and are less environmen-tally hazardous.

In addition, NAsP III/V is pursuing a recycling conceptin order to ensure that the high purity chemicals andother input materials are reused as efficiently as possi-ble. This sustainable production method and enhancedconversion efficiency guarantee an additional signifi-cant improvement in the cost/benefit ratio for CPVapplications.

Contact:NAsP III / V GmbHAm Knechtacker 1935041 Marburg, Germany

Dr. Wolfgang StolzTelephone: +49 (0)6421 2825696E-Mail: [email protected]

Multiwafer production

facilities.

(Source: Aixtron)

High availability, lowwear, long runningtimes and low operat-ing costs are crucialaspects for decisionmakers, engineersand service techni-cians in industrialcompanies and powergenerators, as well asfor the shipping andautomotive industries– regardless ofwhether extensiveproduction lines, cost-intensive building andplant engineering orthe more mundanecommercial vehiclesare involved.

The medium sizedcompany REWITEC,

which globally develops and sells innovative nano-and microparticle-based lubricant additives, providesa comprehensive solution. The tried and testedREWITEC technology is used in tribological systemssuch as transmissions or bearings, and permanentlyenhances their surfaces. In this way the original mate-rial properties are optimised: friction can be reducedby up to 33 percent, the temperature by up to 20 per-cent and the surface roughness by up to 50 percent(scientifically proven in lubricant tests at MannheimUniversity of Applied Sciences Kompetenzzentrum Tri-bologie (Tribology Competence Centre), 10/2012).

‘Our technologies are literally additives, that is, addi-tions to engine and transmission oils and to greasesconsisting of a combination of up to seven differentraw materials’, explains REWITEC CEO Stefan Bill.However, the modus operandi of the lubricant addi-tives cannot be compared to more traditional addi-tives: the synthetic and mineral-based silicate com-pounds use the lubricant as a transport agent onlyand, in this way, reach the relevant surfaces in the so-called tribosystem.

At operating temperatures, the coating particles reactwith the metallic surface in a chemical process and therubbing metal surfaces are ceramised. Thanks to themetal-ceramic surface, the original material propertiesare considerably enhanced with regard to friction andwear, and the lubricant properties, in contrast, remainunaltered.

Against this backdrop, the product series of this cen-tral Hessen company are not only deployed by servic-ing companies and so-called technical operationsmanagers in the wind energy field but also by numer-ous global players around the world. With regard tolubricant additives for wind turbines, REWITEC hasgrown into a market leader. Despite, or perhapsbecause of, the enormous demands on wind turbinesin terms of engineering and materials, years of practi-cal experience have shown that the consistent use ofREWITEC products leads to extended running times,reduced servicing needs and spare parts require-ments, and to less downtime. ‘The relevance of sub-stantially enhanced performance of wind turbines isobvious and represents a considerable positivechange in return on investment for the operator’, CEOStefan Bill adds. ‘This experience can be transferred tonumerous other applications where engines, transmis-sions and bearings are in use. By the way, we have alsoreceived positive feedback on our technology and ourproducts from the field of motorsports.’

Contact:REWITEC GmbHDr.-Hans-Wilhelmi-Weg 1Gewerbepark Lahnau35633 Lahnau, Germany

Stefan BillTelephone: +49 (0)6441 44599-0E-Mail: [email protected]

56

7.3 REWITEC: Higher performance for engines, transmissions and bearings

View through the laser microscope: the lower

gearwheel surface displays considerably less

wear thanks to optimisation of the material

properties using REWITEC technology.

(Source: REWITEC)

Hydrogen is regarded as the ‘greenest’ of all energysources, because it can be easily produced by elec-trolysis anywhere with sufficient sunlight and water.When burned safely and noiselessly in fuel cells, elec-tricity is produced directly and on demand, with onlywater being liberated as a combustion product. At firstglance, even hydrogen storage does not appear topresent problems. However, in the usual compressedgas bottles, the energy storage density of 0.77 kilowatthours per litre at 350 bar is only one twelfth of the stor-age density of petrol. If hydrogen is liquefied beforestorage, the storage density is substantially increased,but temperatures below minus 252 degrees Celsiusare needed to achieve this, which requires extremelylarge amounts of energy.

However, a group of crystalline chemical compoundsare available for numerous applications: the metalhydrides. They can take up hydrogen in their relativelyloose crystal lattice like a sponge with nanometre finepores and absorb it safely and securely. If these metalhydrides are ground to a micrometre fine powder,they acquire an extremely large surface area, whichmakes the absorption of hydrogen gas even easier.Hydrogen absorption takes place under pressure,while desorption (liberation) occurs simply by warm-ing. Here, the desorption temperature is substantiallyreduced and the desorption speed increased byadding catalysts.

However, a reliable fill level indicator is required foreach tank, especially for mobility applications, whereit must be possible to estimate the range of the vehiclewith respect to the next filling station. This representsa particular challenge for the metal hydride-hydrogentank. At the RheinMain University of Applied Sciences,

a double measuring method was developed allowingthe infrared spectrum and the weight change of apowder sample of only 0.5 grams to be simultane-ously determined during desorption. The infraredspectrum changes considerably during desorptionbecause the crystal structure of the powder and thestoichiometric composition change when hydrogen isliberated. The spectral data can now be related to thequantity of liberated hydrogen. That is, it would thenbe possible to develop a calibrated optical sensor thatwould display the amount of hydrogen remaining inthe tank. In addition, this method is suitable for inves-tigating the desorption kinetics of other hydrogenstoring substances: for example, the liberation ratesand activation energies can be measured. It wouldalso be interesting to investigate their relationship tothe degree of grinding or the powder porositybecause the thermal conductivity of the bulk and therelease of hydrogen from the powder tank depend onthese factors. Moreover, other solid state reactions inwhich gaseous substances are liberated from powderscan be investigated.

Contact:Hochschule RheinMainUniversity of Applied SciencesAm Brückweg 2665428 Rüsselsheim, Germany

Labor für Wasserstofftechnologie (Hydrogen Technology Lab)Prof. Dr. Birgit ScheppatTelephone: +49 (0)6142 898-4512E-Mail: [email protected]/en/

57

7.4 Hochschule RheinMain – University of Applied Sciences:Hydrogen storage in nanoporous powder materials

Fuel cell vehicles powered by hydrogen: (1) Buggy. (2) Pedelec. (3) Setup to measure infrared spectra

of a metal hydride sample while simultaneously measuring its weight. (4) IR-spectral changes of a

metal hydride sample during hydrogen desorption.

(Source: Hochschule RheinMain – University of Applied Sciences)

Institut für Mikrotechnologien(Microtechnologies Institute) Prof. Dr. Hans-Dieter BauerTelephone: +49 (0)6142 898-0E-Mail: [email protected]/en/

(1) (2) (3)

(4)

The objective of materials research in TU DarmstadtEnergy Center is to secure a sustainable energy tech-nology for the future by researching the necessarymaterial science fundamentals for producing compet-itive elements at all technological levels (primaryenergy collection, energy conversion, storage, trans-port). The research and development work and theexisting expertise present in the different departmentsat Technische Universität Darmstadt, spanning abridge between the natural and the engineering sci-ences, are brought together and coordinated suchthat academic education, research, opportunities man-agement and public relations all contribute to the suc-cessful implementation of the energy revolution. Theinstitutionalised cooperation between the university,industry, government and the public forms an integralcomponent of the concept of addressing the manifoldrelationships between energy and environmentalquestions, but also the technological, economic andsocial implications of a sustainable energy future.

Many innovative energy systems are based on nano-technology and the combination of different materialswith properties adapted at the atomic scale. A numberof research topics at Technische Universität Darmstadtuse new materials and material combinations at thenanometre scale to develop innovative energy sys-tems. Examples include:

a Optimisation of thin-film solar cells for low-costdirect generation of electricity from sunlight. Here, inorganic or organic thin-film absorbermaterials or composites are particularly interest-ing. The efficiency is determined by the structureand the electronic properties of the homoge-neous and heterogeneous phase boundaries insubmono layers down to the micrometre range.Thin-film solar cells can now achieve efficienciesgreater than 20 percent, but often consist of rareor ecologically worrisome materials (cadmium telluride, copper-indium-gallium selenide (CIGS)or perovskite cells), so new, but ecologically safe,substitute materials would be of interest. Moreover, new absorbers with large band gapsaround two electron volts are an option for thin-film tandem structures for third generation solarcells with drastically enhanced efficiencies.

58

7.5 TU Darmstadt Energy Center: Nanotechnology in energy research

solar cell cathode

cathode

U / I

Ag:Ptsolar cell

a-Si:H/µc-Si:Hor

a-Si:H/a-Si:H

anodeRuO2

O2H2

anodeelectrolyte

Representation of a photoelectrochemical cell for splitting water. (Source: TU Darmstadt)

a Innovative photovoltaic converters for directlyconverting sunlight in chemical storage systems,in particular hydrogen. To achieve this, adaptedphotovoltaic tandem structures must be devel-oped, which can split water into hydrogen andoxygen with high efficiency, similar to solar cells.Challenges are adapted surfaces and catalysislayers on the nanometre scale. Efficiencies of ten percent solar-to-hydrogen were achieved in cooperation with Research Centre Jülich. However, the materials used still need to be stabilised and further improved.

a Identification and development of new, highly efficient catalysts for converting hydrogen andcarbon dioxide or biomass into hydrocarbons toform liquid or gaseous fuels, or of electrocatalystsfor electrolysis, or in fuel cells consisting of metallic nanoparticles on porous oxide graphiticsubstrate materials. The aim is to substitute expensive catalysts containing precious metalswith more economical, but more specifically effective catalysts.

a Improved energy storage systems such aslithium ion batteries are manufactured from composite structures of interconnected, electronically conducting carbon nanotubes with active nanocrystals that store and liberatelithium. Innovative cathode materials based onolivines, a group of silicate-based minerals, butalso thin-film batteries, are being researched.

a Ceramic nanometre-thick protective coatingsserve to increase the temperature stability of turbine materials and therefore also their effi-ciency. Beginning with specific synthesis andprocessing methods yet to be developed, therequired functional properties must first beresearched, characterised and optimised bymeans of a variety of feedback processes beforethe specific required elements and systems canbe developed for practical applications.

The necessary research and development chainsextend across the spectrum from the atomic naturalscience fundamentals to engineering implementation,and including the social implications. Only with thisholistic TU Darmstadt Energy Center approach, will itbe possible to ensure the social conditions and securethe approval of the population for the energy revolu-tion.

Contact: TU Darmstadt Energy CenterFranziska-Braun-Strasse 764287 Darmstadt, Germany

Prof. Dr. Wolfram JaegermannTelephone: +49 (0)6151 16-6304E-Mail: jaegermann@surface.tu-darmstadt.dewww.energycenter.tu-darmstadt.de

59

Glass

Au

Aue–

Pt

LiPON Li+

LiCoO2

Representation of a thin-film lithium ion battery.

(Source: TU Darmstadt)

The working groups at theInstitute of Physical Chem-istry at Justus Liebig Univer-sity (JLU) work intensely andin close cooperation withother university institutes onresearch into new materialconcepts for energy storagesystems and energy conver-sion technologies. Some ofthese activities have, since2013, been extensivelyfunded by the State of Hes-sen as part of the LOEWE(Hessian initiative to createexcellence in science andeconomy; German: Landes-Offensive zur EntwicklungWissenschaftlich-ökonomi-scher Exzellenz) priority pro-gramme STORE-E. The aimof the research work inGiessen is to develop newmaterials for use in batteriesand fuel cells. It will alsoinvestigate the stability ofthe materials under real life

conditions. The application fields of the projects cov-ered by the LOEWE priority programme and coordi-nated by both Jürgen Janek and Joachim Sann consistof innovative thin-film batteries and electrochromiccells, supercapacitors and storage catalysts. In addi-tion, new analytic methods for materials and computersimulations also play an important role.

A key topic of the work in Giessen are boundary layers(both surfaces and internal boundary layers) in elec-trochemical systems. The governing electrochemicalreactions occur at the boundary layers, and the struc-ture and morphology of the boundary layers governthe properties of the system as a whole. Accordingly,the boundary layer form, for example, in the shape ofelectrodes for batteries or other electrochemical cells,plays a very important role. This is particularly appar-ent in the example of thin-film batteries, in which sev-eral layers of functional materials must be combined

and structures at the nanometre scale are critical to thebattery properties. By using efficient coating deposi-tion methods and highly advanced analytical methods,the optimal materials can be identified and their prop-erties characterised.

Nanostructured, electrochemical functional materialsalso play an important role in electrochromic cells.Here, an electrochromic coating is coloured by apply-ing an electrical potential. Electrochromic coatings of nanostructured materials possess particularlyfavourable properties and are therefore also subjectto intense investigation in STORE-E.

The Institute of Physical Chemistry is excellentlyequipped for almost all types of research in the fieldof solid state chemistry and electrochemistry. Anextensive range of analytical methods guarantees thatwork takes place at the highest international level. Cur-rent work includes projects investigating lithium ionbatteries and solid state batteries, new materials foruse in high-temperature electrochemistry, but alsospecifically prepared, porous solid state systems. Targeted nanostructuring is often an inherent part ofresearch work.

Contact: Justus Liebig University GiessenInstitute of Physical ChemistryHeinrich-Buff-Ring 58, 35392 Gießen, Germany

Dr. Joachim SannTelephone: +49 (0)641 99-34512E-Mail: [email protected]/cms/fbz/fb08/Inst/physchem/janek

60

7.6 Justus Liebig University Giessen: Electrochemical and solid stateionics – materials research for electrochemical energy technologies

Top: Complex analysis techniques

in an ultra-high vacuum, such as

secondary ion mass spectrometry

or photoelectron spectroscopy, are

used to analyse energy storage

materials.

Bottom: Battery cells with new cell

chemistries are tested at laboratory

scale.

(Source: Universität Giessen)

Defined nanoscaled pore structures

allow the electrochemical proper-

ties of known materials to be modi-

fied and used for completely new

purposes.

(Source: Universität Giessen)

In the renewable production and processing of elec-trical energy, as practised by the wind and solar powerindustries, for example, the focus is on the efficiencyof the process in order to minimise the losses in theenergy supply chain to the final consumer. In the elec-tronic energy conversion circuits, high-performancecomponents are therefore increasingly employedbecause particularly in these applications investmentin the highest quality also makes sense from an eco-nomic perspective.

MAGNETEC in Langenselbold has manufactured highquality inductive elements for more than 30 years. Pro-duction of toroid cores using the at the time novelnanocrystalline material NANOPERM® began approx-imately 15 years ago. This soft magnetic material, pro-duced using the so-called rapid solidification processas a 15 to 20 micrometre thick strip or as a film, initiallyhas an amorphous internal structure and is magneti-cally neutral. During a specially designed heat treat-ment under a shield gas, and with precisely definedmagnetic fields, an inner, fine nanocrystalline structureis created, producing soft magnetic properties thatwere barely conceivable around 15 years ago.

This means that magnetic cores, shunt reactors andtransformers can not only be designed smaller by sev-eral factors, for example, but they also facilitateextremely low-loss operations at high switching fre-quencies (typically 100 kilohertz). These advances gohand in hand with the long-term trend in the semicon-ductor industry of achieving the envisaged efficiencyimprovements by adopting ever increasing transistorswitching frequencies. This increases the efficiency of

devices and facilities while simultaneously reducingthe dimensions and weight. A new semiconductorgeneration based on silicon carbide is currently in thestarting blocks.

In recent years, the applications of NANOPERM® have expanded from the field of installation engineer-ing/personal safety (residual current operated circuitbreakers) to include electromagnetic compatibility(EMC filters), bearing protection on large motors andgenerators (wind turbines), modernelectrical energy meters (smartmeters) and, more recently, burgeon-ing electromobility, where operatingtemperatures up to 180 degrees Cel-sius are generally required.

MAGNETEC employs around 400 staffand has previously been awarded aninnovation prize for its products by Initiative Mittelstand.

Contact:MAGNETEC GmbHIndustriestrasse 763505 Langenselbold, Germany

Dr. Martin FerchTelephone: +49 (0)6184 9202-27E-Mail: [email protected]

61

7.7 MAGNETEC: Highly efficient and compact energy conversionusing nanocrystalline toroid cores

Forms of supply of inductive elements with

nanocrystalline toroid cores. (Source: Magnetec)

NANOPERM® parent

material for nanocrys-

talline toroids.

(Source: Magnetec)

Current compensated

noise suppression

chokes for EMC filters.

(Source: Magnetec)

Top: Single conductor

shunt cores for genera-

tor bearing protection in

wind turbines.

Bottom: Forms of supply

of inductive elements

with nanocrystalline

toroid cores.

(Source: Magnetec)

Bruker HTS GmbHEhrichstrasse 1063450 Hanau, GermanyTelephone: +49 (0)6181 4384-4100www.bruker.com/best.html

Relevant products/research:Nanooptimised high-temperaturesuperconductors for power engineering;energy transport /distribution p

Dockweiler Chemicals GmbHEmil-von-Behring-Strasse 7635041 Marburg, GermanyTelephone: +49 (0)6421 396380www.dockchemicals.com

Relevant products/research:Specialised chemicals and precursors for semiconductor layers on thin-film solar cells and LEDs pp

Heraeus Deutschland GmbH & Co. KGHeraeusstrasse 12–1463450 Hanau, GermanyTelephone: +49 (0)6181 35-0www.heraeus.de

Relevant products/research:Nanostructured precious metal powdersfor fuel cell catalysts, sputter targets for functional coatings on thin-film solar cells, solar receivers and functional glasses pp

Hollingsworth & Vose GmbH & Co. KGBerleburger Strasse 7135116 Hatzfeld (Eder), GermanyTelephone: +49 (0)6467 801-0www.hollingsworth-vose.com

Relevant products/research:Nanostructured, high porosity, oxidation resistant fibres for separators in batteries p

MAGNETEC GmbHIndustriestrasse 763505 Langenselbold, GermanyTelephone: +49 (0)6184 920210www.magnetec.de

Relevant products/research:Nanocrystalline, magnetic toroids for inductive elements in power and electronics engineering p

Merck KGaAPerformance MaterialsFrankfurter Strasse 25064293 Darmstadt, GermanyTelephone: +49 (0)6151 72-0www.merck-performance-materials.de

Relevant products/research:Semiconductors and special dyes for organic photovoltaics and organic light-emitting diodes;coating materials for antireflection layers on solarcells and electrode membrane units in fuel cells;liquid crystals for energy saving, responsive windows pp

62

8. Further Information

8.1 Expertise and Addresses of Actors in Hessen

Colour key:

p Energy conversion renewable p Energy conversion conventional

p Energy storage p Energy transport/distribution p Energy efficiency

Companies

NAsP III/V GmbHHans-Meerwein-Strasse35032 Marburg, GermanyTelephone: +49 (0)6421 2825696www.nasp.de

Relevant products/research:Highly efficient III-V semiconductor solar cells p

REWITEC GmbHDr.-Hans-Wilhelmi-Weg 135633 Lahnau, GermanyTelephone: +49 (0)6441 44599-0www.rewitec.com

Relevant products/research:Nanoadditives for lubricants providing wear protection and energy savings in motor and transmission components (wind turbine rotors,mobility) p

Schunk Kohlenstofftechnik GmbHRodheimer Strasse 5935452 Heuchelheim, GermanyTelephone: +49 (0)641 608-1460www.schunk-group.com

Relevant products/research:Nanooptimised components of carbon, graphite,carbon fibre reinforced carbon (CFC), siliconcarbide for applications in power engineering pp

SGL Carbon AGRheingaustrasse 18265203 Wiesbaden, GermanyTelephone: +49 (0)8271 83-2458www.sglcarbon.de

Relevant products/research:Nanostructured carbon materials as electrodematerials for energy storage systems p

SolviCore GmbH & Co. KGRodenbacher Chaussee 463457 Hanau, GermanyTelephone: +49 (0)6181 59-5432www.solvicore.de

Relevant products/research:Membrane electrode units for fuel cells andelectrolysis of water p

Umicore AG & Co. KGRodenbacher Chaussee 463457 Hanau, GermanyTelephone: +49 (0)6181 59-6627www.umicore.de

Relevant products/research:Nanostructured catalysts for membrane fuel cells p

Vacuumschmelze GmbH & Co. KGGrüner Weg 3763450 Hanau, GermanyTelephone: +49 (0)6181 38-0www.vacuumschmelze.de

Relevant products/research:Nanocrystalline, magnetic alloys, for example for toroids for inductive elements in power andelectronics engineering p

Viessmann Werke GmbH & Co. KGViessmann Strasse 135107 Allendorf (Eder), GermanyTelephone: +49 (0)6452 70-3410www.viessmann.de

Relevant products/research:Nano-CHP with fuel cells and zeolite adsorption heat pumps for highly efficient heating devices p

63

DECHEMA-ForschungsinstitutTheodor-Heuss-Allee 2560486 Frankfurt am Main, GermanyTelephone: +49 (0)69 7564-337www.dechema-dfi.de

Relevant research activity:Electrochemical energy storage systems and converters such as fuel cells and metal-air batteries pp

Fraunhofer Institute for Wind Energy and Energy System TechnologyKönigstor 5934119 Kassel, GermanyTelephone: +49 (0)561 7294-0www.energiesystemtechnik.iwes.fraunhofer.de

Relevant research activity:Intelligente Stromnetze, Integration regenerativer Energiequellen p

Hochschule RheinMain – University of Applied SciencesRüsselsheim CampusInstitut für MikrotechnologienAm Brückweg 2665428 Rüsselsheim, GermanyTelephone: +49 (0)6142 898-521www.hs-rm.de/en/

Relevant research activity:Nanostructured thermoelectric materials, optical metrology for charging hydrogen storage systems p

Hochschule RheinMain – University of Applied SciencesRüsselsheim CampusLabor für WasserstofftechnologieAm Brückweg 2665428 Rüsselsheim, GermanyTelephone: +49 (0)6142 898-512www.wasserstofflabor.de

Relevant research activity:Fuel cells, hydrogen storage systems, electrolysis pp

Justus Liebig University GiessenInstitut für Angewandte Physik(Institute of Applied Physics) Heinrich-Buff-Ring 1635392 Giessen, GermanyTelephone: +49 (0)641 99-33401www.uni-giessen.de/cms/fbz/fb07/fachgebiete/physik/einrichtungen/institut-fur-angewandte-physik/agschlett

Relevant research activity:Dye-sensitised solar cells, electrochemical energy storage systems pp

Justus Liebig University GiessenInstitute of Physical Chemistry Heinrich-Buff-Ring 5835392 Giessen, Germany Telephone: +49 (0)641 99–34500 oder -34501www.uni-giessen.de/cms/fbz/fb08/Inst/physchem

Relevant research activity:New materials for energy storage systems (hydrogen storage systems, batteries), electrochemistry p

Philipps-Universität Marburg Wissenschaftliches Zentrum für MaterialwissenschaftenHans-Meerwein-Strasse35032 Marburg, GermanyTelephone: +49 (0)641 99-25696www.uni-marburg.de/wzmw

Relevant research activity:Gas phase epitaxy and structural analysis of compound semiconductors, among other things, for solar cells p

Technische Universität DarmstadtEnergy CenterFranziska-Braun-Strasse 764287 Darmstadt, GermanyTelephone: +49 (0)6151 16-6304www.tu-darmstadt.de/fb/ms/fg/ofl/index.tud

Relevant research activity:Thin film solar cells, photovoltaic hydrogen production, improved lithium ion batteries, catalysts for producing fuels from biomass and CO2 pp

64

Research institutions

http://www.uni-giessen.de/fbz/fb07/fachgebiete/physik/einrichtungen/institut-fur-angewandte-physik/agschlett

Technische Universität DarmstadtFachgebiet MaterialwissenschaftenAlarich-Weiss-Strasse 264287 Darmstadt, GermanyTelephone: +49 (0)6151 16-5377www.mawi.tu-darmstadt.de

Relevant research activity:Nanomaterials for solid oxide fuel cells (SOFC), batteries, hydrogen storage systems, gas separation membranes pp

Technische Universität DarmstadtCenter for Engineering Materials, State Materials Testing Institute Darmstadt (MPA), Chair and Institute for Materials Technology (IfW)Grafenstrasse 2, 64283 Darmstadt, Germany Telephone: +49 (0)6151 16-3351www.mpa-ifw.tu-darmstadt.de

Relevant research activity:Nanostructured thermal protection coatings for turbine blades p

University of KasselFachbereich MaschinenbauMönchebergstrasse 3, 34125 Kassel, GermanyTelephone: +49 (0)561 804-2830www.uni-kassel.de/maschinenbau/institute/iaf/lmt0/startseite.html

Relevant research activity:Tribological nanolayers, wear protection p

University of KasselInstitute of Nanostructure Technologies and AnalyticsHeinrich-Plett-Strasse 4034132 Kassel, GermanyTelephone: +49 (0)561 804-4485www.te.ina-kassel.de

Relevant research activity:Innovative light guidance systems based on micromirror arrays, among other things, for concentrating light in photovoltaics p

The ForschungsCampus FC3 NachhaltigeMobilität offers information regarding energyfor sustainable mobility at www.forschungs-campus-hessen.de (German only).

65

8.2 References

a AG Energiebilanzen 2013: „Anwendungsbilanzenfür die Endenergiesektoren in Deutschland in denJahren 2011 und 2012 mit Zeitreihen von 2008bis 2012“, November 2013, (www.ag-energiebi-lanzen.de/index.php?article_id=29&fileName=ageb_endbericht_anwendungsbilanzen_2011-2012_endg.pdf, accessed September 2015)

a BINE 2013: „Solarthermische Kraftwerke“ Themeninfo II / 2013(www.bine.info/themen/erneuerbare-energien/publikation/solarthermische-kraftwerke-2/, accessed September 2015)

a Bloomberg 2014: “Rebound in clean energyinvestment in 2014 beats expectations”, press release dated 9/1/2015,(http://about.bnef.com/press-releases/ rebound-clean-energy-investment-2014-beats-expectations, accessed September 2015)

a BP 2015: “Energy Outlook 2035”, February 2015(www.bp.com/content/dam/bp/excel/Energy-Economics/energy-outlook-2015/BP-Energy-Outlook-2035-Summary-Tables-2015.xls, accessedSeptember 2015)

a BSW Solar 2015: „Statistische Zahlen der deutschen Solarstrombranche“ Bundesverband Solarwirtschaft, 5 March 2015

a BWE 2015: „Installierte Windenergieleistung inDeutschland /Hessen“ (www.wind-energie.de/themen/statistiken/deutschland, accessed Sep-tember 2015)

a DECHEMA 2007: „Positionspapier: Energieversor-gung der Zukunft – der Beitrag der Chemie, 2007“(www.gecats.de/dechema_media/Energie_Positionspapier_final-p-2555-view_image-1-called_by-gecats-original_site-gecats-original_page-17.pdf, accessed September 2015)

a DENA 2015: „Strom zu Gas – Demonstrations -anlage der Thüga-Gruppe“, StrategieplattformPower to Gas (www.powertogas.info/roadmap/pilotprojekte-im-ueberblick/thuega, accessedSeptember 2015)

a EPIA 2015: “Global Market Outlook for Photo -voltaics 2014–2018”, European Photovoltaic Industry Association 2014

a EurObserv’ER 2014: „Markt der solarthermischenKraftwerke verschiebt sich, europäischer Solar-wärme-Markt schrumpft“, press release dated17/6/2014, (www.solarserver.de/solar-magazin/nachrichten/archiv-2014/2014/kw25/eurobserver-markt-der-solarthermischen-kraftwerke-verschiebt-sich-europaeischer-solarwaerme-markt-schrumpft.html, accessed September 2015)

a FHG ISE 2015: „Stromerzeugung aus Solar- undWindenergie im Jahr 2014. Fraunhofer-Institut fürSolare Energiesysteme ISE“, presentation in Frei-burg on 7/1/2015(www.ise.fraunhofer.de/de/downloads/pdf-files/data-nivc-/stromproduktion-aus-solar-und-wind-energie-2014.pdf, accessed September 2015)

a HMI 2007: Ergebnisse des Workshops „Nano-technologie für eine nachhaltige Energieversor-gung“, 29–30/11/2007, Helmholtz Zentrum Berlin

a H2BZ 2013: „Energiespeicherung mit Batterieund Wasserstoff“; conference proceedings6/3/2013; H2BZ-Initiative Hessen e.V.

a IDTechEx 2014: “Thermoelectric Energy Harves-ting 2014-2024: Devices, Applications, Oppor -tunities”, (www.idtechex.com/research/reports/thermoelectric-energy-harvesting-2014-2024-devices-applications-opportunities-000392.asp,accessed September 2015)

a IEA 2014: “Key World Energy Statistics 2014”,International Energy Agency 2014 (www.iea.org,accessed September 2015)

66

a ISO 2010: ISO/TS 80004-1:2010, Nanotechno -logies – Vocabulary, International Organizationfor Standardization (www.iso.org, accessed September 2015)

a Krause and Müller-Syring 2011: „Wasserstoff ausWindstrom als chemischer Energiespeicher imErdgasnetz und die Rolle der Brennstoffzellen zurRückverstromung“, Kooperationsforum – Techno-logien stationärer Stromspeicher, Freiberg, 1 December 2011

a Liu, J. et al. 2015: „Metal-free efficient photo -catalyst for stable visible water splitting via a twoelectron pathway“; Science Vol. 347, p. 970 (2015)

aMarketsandmarkets.com 2014: “Smart Glass Market worth $5814 Million by 2020”, press release(www.marketsandmarkets.com/PressReleases/smart-glass.asp, accessed September 2015)

aMerck 2014: “Merck – Living Innovation”, corporate brochure 2014 (www.merck.de/company.merck.de/de/images/Innovation_Flyer_Merck_Chemicals_DE_2014_03_04_tcm1613_121642.pdf, accessed September 2015)

aMerck 2015: „Merck und Nano-C präsentierenoptimierte Materialien für die organische Photo-voltaik“, Merck press release dated 3/8/2015

a NREL 2013: “All solar efficiency records in onechart”, American National Renewable Energy Lab(www.solarplaza.com/channels/archive/11202/1975-2013-all-solar-efficiency-records-in-one-char/, accessed September 2015)

a REN21 2015: “Renewables 2015 Global StatusReport”, Renewable Energy Policy Network for the 21st Century REN21 (www.ren21.net/status-of-renewables/global-status-report, accessed September 2015)

a Strom-Report 2015: (http://strom-report.de/windenergie/#arbeitsplaetze-windenergie, accessed September 2015)

a TU Darmstadt 2014: „Nachhaltige Magnete“(www.tu-darmstadt.de/vorbeischauen/aktuell/archiv_2/2014/einzelansicht_86080.de.jsp, accessed September 2015)

aWEC 2013: “World Energy Resources, 2013 Survey”WORLD ENERGY COUNCIL, 10 /2013(www.worldenergy.org/publications/2013/world-energy-resources-2013-survey/, accessed September 2015)

a Zhang L, et al. 2013: Porous 3D graphene-basedbulk materials with exceptional high surface areaand excellent conductivity for supercapacitors.Sci Rep. 2013;3:1408

67

a Atlas: Competence and Infrastructure Atlas Nanotechnologies in Hessen

a Atlas: Competence Atlas Photonics in Hessen

a Vol. 1: Uses of Nanotechnology in Environmental Technology in HessenInnovation potentials for companies

a Vol. 2: NanomedizinInnovationspotenziale in Hessen für Medizintechnik und Pharmazeutische Industrie

a Vol. 3: Nanotechnologies in AutomobilesInnovation Potentials in Hesse for the AutomotiveIndustry and its Subcontractors

a Vol. 4: NanoKommunikationLeitfaden zur Kommunikation von Chancen undRisiken der Nanotechnologien für kleine undmittelständische Unternehmen in Hessen

a Vol. 5: Nanotechnologien für die optischeIndustrie Grundlage für zukünftige Innovationenin Hessen

a Vol. 6: NanoProduktionInnovationspotenziale für hessische Unternehmendurch Nanotechnologien im Produktionsprozess

a Vol. 7: Einsatz von Nanotechnologienin Architektur und Bauwesen

a Vol. 8: NanoNormungNormung im Bereich der Nanotechnologienals Chance für hessische Unternehmen

a Vol. 9: Application of Nanotechnologies in the Energy Sector

a Vol. 10: Werkstoffinnovationen aus HessenPotenziale für Unternehmen

a Vol. 11: Sichere Verwendung von Nanomaterialien in der Lack- und FarbenbrancheEin Betriebsleitfaden

a Vol. 12: Nanotech-KooperationenErfolgreiche Kooperationen für kleine undmittlere Nanotechnologie-Unternehmen

a Vol. 13: Mikro-Nano-IntegrationEinsatz von Nanotechnologie in derMikrosystemtechnik

a Vol. 14: Materialeffizienzdurch den Einsatz von Nanotechnologienund neuen Materialien

a Vol. 15: Nanotechnologie in KunststoffInnovationsmotor für Kunststoffe, ihre Verarbeitung und Anwendung

a Vol. 16: NanoAnalytikAnwendung in Forschung und Praxis

a Vol. 17: Nanotechnology for Disaster Relief and Development Cooperation

a Vol. 18: Materials shape ProductsIncrease Innovation and Market Opportunitieswith the Help of Creative Professionals

a Vol. 19: Patentieren von Nanotechnologien

a Vol. 20: Nanotechnologie in der Natur –Bionik im Betrieb

a Vol. 21: Smart Energy MaterialsWerkstoffinnovationen für die Energiewende

a Vol. 22: Competence Atlas Biomimetics in Hessen

a Vol. 23: Nanotech in HessenProfil und Status des Forschungs- und Innovationsstandorts

a Vol. 24: Nanotech Ideas in Science-Fiction-Literature

a Vol. 25: Additive ManufacturingThe path toward individual production

a Vol. 26: Nanotechnologie und MedizinEine Schlüsseltechnologie kommt an

a Vol. 27: Nano- und materialtechnologische Lösun-gen für Oberflächen

Information /Download /Orders:www.hessen-nanotech.de/veroeffentlichungen

Publication Series

68

The Technologielinie Hessen-Nanotech of theMinistry of Economics, Energy, Transport and RegionalDevelopment – State of Hessen, is managed by

The Technologielinie Hessen-Nanotech is co-fundedby the European Union.


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