alternative ways of biomethane production - green gas grids · page 7 of 19 swot analysis has been...
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The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the EACI nor the European Commission are responsible for any use that may be made of the information contained therein.
Alternative ways of biomethane production - a SWOT analysis
May 2014
Page 2 of 19
Authors: Sabine Strauch, Tim Schulzke, Oliver Jochum
Contact: Fraunhofer UMSICHT
Research Group »Biogas Technology«
Osterfelder Strasse 3
46047 Oberhausen, Germany
www.umsicht.fraunhofer.de
Note on legal topics
All legal topics published in this report exclusively serve the purpose of general
information and do not refer to individual legal concerns. The authors and other
parties involved assume no liability regarding the correctness, timelines,
completeness or usability of the information made available. The assertion of claims
of any kind is excluded.
Page 3 of 19
The Biomethane Guide for Decision Makers has been created within the project
GreenGasGrids supported by the Intelligent Energy - Europe programme (contract
number IEE/10/235/S12.591589).
Webpage: www.greengasgrids.eu
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THE GREEN GAS GRIDS PROJECT PARTNERS
German Energy Agency - dena (Germany)
Fraunhofer UMSICHT (Germany)
Austrian Energy Agency (Austria)
Energetski Institut Hrvoje Požar -EIHP (Croatia)
Agence de l’Environnement et de la Maîtrise de
l’Energie - ADEME (France)
Renewable Energy Agency – REA (UK)
University Szeged (Hungary)
European Biogas Association
Consorzio Italiano Biogas (Italy)
Agentschap NL (The Netherlands)
Krajowa Agencja Poszanowania Energii – KAPE
(Poland)
Slovenská Inovacná Energetická Agentúra - SIEA
(Slovakia)
Natural Gas Vehicle Association - NGVA
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TABLE OF CONTENTS
INTRODUCTION ............................................................................................. 6
Alternative ways of producing biomethane ...................................................... 6
What is a SWOT analysis? ............................................................................. 6
Synthetic Natural Gas production from biomass (BioSNG) ................................... 8
The technical process ................................................................................... 8
Plants in operation – examples ...................................................................... 9
SWOT analysis .......................................................................................... 11
Power to bioGas – biological methanation of renewable hydrogen ....................... 12
The technical process ................................................................................. 12
Plants in operation – examples .................................................................... 14
SWOT analysis .......................................................................................... 15
Comparative analysis and conclusion .............................................................. 16
LITERATURE ................................................................................................ 18
ABBREVIATIONS .......................................................................................... 19
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INTRODUCTION Alternative ways of producing biomethane
Biomethane is a gas mixture obtained from cleaning and upgrading biogas. As its
name suggests, its main component is methane (CH4); in this context biomethane
is defined here as a renewable gas that is either sourced from biogenic materials
(organic matter) or is generated through biological processes. Due to its high
methane content and its gas condition biomethane is appropriate to substitute
natural gas.
Conventionally, biomethane results from the anaerobic digestion of organic matter
such as manure, bio-waste or energy crops. During this process wet biomass is
biologically digested to some residuals full of nutrients (digestate) and a gas
mixture known as biogas, which will be subsequently upgraded to biomethane.
Apart from this production way, biomethane can be obtained from other processes
that work under different circumstances and with different sources.
The main two alternative processes to obtain biomethane are
� the production of Synthetic Natural Gas from biomass (BioSNG) from
woody biomass by thermo-chemical conversion, and
� the Power to BioGas process on the basis of biological methanation of
renewable hydrogen and carbon dioxid.
This document is based on our general experience and knowledge at the time of
publishing this report. It is intended to give information about biomethane and its
sources to decision makers in policy and business and to provide a rough overview
on the characteristics of the single technologies.
What is a SWOT analysis?
SWOT is a flexible concept that can be used in various scenarios from assessing
projects or business ventures, making decisions, solving problems to strategy
formulation. In the Green Gas Grids project we use it to analyse the state of
development and the capability of biomethane production pathways.
Concept of the SWOT analysis, which is presented on the graphic below, contains
four sections,
� Strengths,
� Weaknesses,
� Opportunities,
� Threats,
which describe positive or negative, internal or external characteristics of the
respective biomethane production technology.
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SWOT analysis has been chosen to serve as an initial assessment of technical and
economical risks for biomethane production technologies. The analysis aims to
identify internal strengths and weaknesses of the production pathways BioSNG
production and Power to BioGas as well as examining the external opportunities
and threats which can endanger the feasibility of a biomethane project.
Strengths
Opportunities Threats
Weaknesses
SWOT SWOT
Figure 1: Principle of a SWOT analysis
Page 8 of 19
Synthetic Natural Gas production from biomass (BioSNG) SNG is referred to as Synthetic Natural Gas and is a substitute for natural gas that
can be derived either from fossil coal (brown coal, black coal), municipal solid waste
or from renewable biomass. In this report only renewable SNG sourced from
biomass is considered which is also referred to as BioSNG. In contrast to anaerobic
digestion, the BioSNG production requires organic matter with low water content
and with woody characteristic (lignocellulosic material). The large amount of
appropriate biomass, ranging from e.g. agricultural and forest residues,
lignocellulosic content of energy crops or municipal paper waste, is a reason why
this production pathway is considered to be able to contribute significantly to green
the natural gas grid. The resource potential of biomass that is accessible for BioSNG
production in the EU27 has been estimated by Thrän to exceed 2500 PJ per year
[1].
The technical process
BioSNG production is based on the gasification of biomass. Gasification is a partial
oxidation process in which biomass is transformed into carbon monoxide (CO),
hydrogen (H2) and carbon dioxide (CO2) using high temperatures. This mixture of
gases will at a later stage be upgraded to a high quality natural gas substitute:
BioSNG.
BioSNG production process consists mainly on five steps (Figure 2) which will be
described in the following.
Figure 2: BioSNG production process
Drying: During this step biomass has to be dried to remove water and
lower the moisture content; this allows a reduction of energy
input at elevated temperature during the gasification process and
increases its efficiency. The most widely applied drying
techniques are steam drying, flue gas drying and low
temperature air drying.
Gasification: Once the biomass is dried, it is ready to be gasified. The solid
material is converted to a gaseous phase and gasification is
achieved due to partial oxidation at temperatures of around
700-900°C. The usable technologies depend on the biomass to
be fed in; the most common technologies are fixed bed, fluidised
bed and entrained flow gasification. In contrast to gasification
plants with direct CHP utilisation which are often using air as
gasification agent, BioSNG production suffers from the input of
inert gases such as N2 due to its negative effect on the heating
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value of the product gas. For this reason, biomass is gasified by
using gasifying agents such as pure oxygen or water steam.
Gas cleaning: The product of gasification is a gas containing mainly CO, H2,
CO2, CH4 , higher carbons and some impurities (e.g. dust, tars);
reason for which this gas must be cleaned. To achieve the
desired gas quality and composition, cyclones, fabric filters and
scrubbing separators are used.
Methanation: During the methanation step CO2 and CO are converted to CH4
according to the following reactions
��� + 4�� → ��� + 2���
�� + 3�� → ��� + ���
The methanation process requires a catalyst while most often
nickel catalysts are used. Fixed bed reactor can be considered as
the state of the art technology. However, there are other
technologies using fluidised bed or slurry reactors as well.
Gas upgrade: The received product gas is to be upgraded by CO2 and CO
removal. Depending on the grid specification and the product gas
quality H2 is to be separated and moisture is to be reduced by an
appropriate drying technology.
The comprehensive gas treatment technology, which is required when producing
BioSNG, results in high investment costs. These costs contribute significantly to
BioSNG production costs whereas plants with high gas production capacity benefit
from scaling effects. Urban estimated BioSNG production costs for a 60 MW plant
(fuel capacity) and resulted in roughly 58 €/MWhHi,N considering investment
conversion and fuel costs1 [2],. Recent publications result in a cost estimation for
production costs for a plant capacity of 100 MWth to be 63 €/MWhHi,N for BioSNG
production with steam reforming and 68 €/MWhHi,N with oxygen reforming [3].
Plants in operation – examples
Gasification plants representing a pre-stage and pre-requisite of BioSNG production
have been implemented in several projects all over Europe. Especially Austria is one
of the very active countries (Table 1).
BioSNG production itself is considered to be in demonstration status. There are only
a few BioSNG projects in planning or in inauguration stage [4], [5]. In 2008 at the
European Center for Renewable Energy in Güssing, Austria the first methanation
plant in the world (1 MW) was built in Güssing. This project successfully
demonstrated the methanation of gas sourced from woody biomass. It transformed
the wood gas from the neighbouring biomass power plant into synthetic natural gas
and produced 300 Nm³ of wood gas from 360 kg of wood, which was converted into
120 Nm³ natural gas at the methanation step. As a first step, a small part of the
synthesis gas stream obtained from the fluidised bed gasification was taken from
1 year of commissioning 2010, 70€/t of wood
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the Güssing plant. In the second step, methane was synthesised from this synthesis
gas. The methanation reactor was a stationary fluidised bed, which was operated in
a pressure range from 1 to 10 bar [6]. The project has been supported by the 6th
RTD Framework Programme in the time from 2006 to 2009. After sucessful
demonstration the plant has been taken out of operation [7], [8].
The project GoBiGas is the first demonstration project for SNG production at
industrial scale. It is located in Göteborg, Sweden, and the owner of the plant, the
Swedish energy company Göteborg Energie, celebrated the inauguration of the
plant in March 2014. The gas production capacity is 20 MW at its first scale. A
second phase with a capacity of 80 MW is planned [9].
An additional Swedish project for BioSNG production at industrial scale (200 MW) is
announced by E.on [8].
In France 11 partners investigate together the production of BioSNG under the
umbrella of the R&D project Gaya. The project aims at demonstrating the vehicle
fuel production from lignocellulosic biomass by thermo-chemical conversion [10].
Table 1: Location and status of gasification plants in Europe, no
claim to be complete [source: [5], [7], [9], own research]
LOCATION UTILISATION/
PRODUCT
FUEL/PRODUCT
[MW]
START OF
OPERATION
STATUS EQUIPMENT
SUPPLIER
Austria
Güssing Gas engine 8.0fuel / 2.0el 2002 Operating AE&E / Repotec
Güssing BioSNG 1methane 2008 Out of operation Repotec
Oberwart Gas engine/ORC 8.5fuel / 2.8el 2008 Operating Ortner Anlagenbau
Villach Gas engine 15fuel / 3.7el 2010 Out of operation Ortner Anlagenbau
Klagenfurt Gas engine 25fuel / 5.5el 2013 Stopped
Vienna Hydrogen 50fuel / 30hydrogen 2015 Planning Repotec
Germany
Neu-Ulm Gas engine/ORC 14fuel / 5el 2013 Commissioning Repotec
Sweden
Göteborg BioSNG 33fuel / 20methane 2014 Operating
(gasifier) /
Commissioning
(methanation)
Metso / Repotec /
Haldor Topsoe
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SWOT analysis
POSITIVE
NEGATIVE
STRENGTHS WEAKNESSES
IN
TER
NA
L
• Large resources of lignin containing biomass are available.
• Very good space-time-yield compared to conventional biomethane plants
• Small spatial footprint • Small amounts of residues and
wastes
• High technical effort and challenging process conditions in terms of process temperature and pressure
• Comprehensive gas cleaning is necessary for several process steps and has impact on plant availability
• Nutrient recycling is only possible to a very limited extent (e.g. ash extraction)
EX
TER
NA
L
OPPORTUNITIES
• Large scale plants offer the possibility of an increase in energy efficiency
• The used biomass resource is not in conflict with food production.
THREATS
• Further research is required e.g. to increase plant availability
• Under the current market conditions, BioSNG production costs are not competitive with fossil gas. Support schemes are required.
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Power to BioGas – biological methanation of renewable hydrogen
Efficient concepts for storage of electric power are crucial for the success of the
energy transition in addition to the expansion of renewable energies. The energy
storage concept “power to gas” converts the excess electrical power into hydrogen
or methane. In this way on sunny and windy days renewable electricity from PV or
wind can be stored and later used in times when they are needed.
Integrating the natural gas grid and its cavern storages, the concept of power to
gas has the greatest capacity among all other storage technologies and is today
considered as the only option to store electricity in order of several TWh over a long
period of time (Figure 3) [11].
Figure 3: Demand for storage solutions will rise with the increase
of fluctuating renewable energies. The natural gas grid offers
interesting options via biomethane and PtG solutions. (source ZSW
2009)
The technical process
The conversion of carbon dioxide (CO2) and hydrogen (H2) into methane (CH4) and
water (H2O) is described by the following reaction:
��� + 4�� → ��� + 2���
This conversion can take place by means of thermo-chemical or biological
processes. In thermo-chemical processes, metal catalysts are used to enable the
chemical reaction of CO2 and H2. Most often nickel catalysts are used which requires
highly pure starting gas streams.
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This thermo-chemical conversion runs at temperatures of about 340-500 °C and
pressure conditions in the range of 10 bars. Due to the strong exothermic nature of
the reaction cooling is essential to ensure proper operating.
The option that is discussed in this report is the conversion of CO2 to methane via
the biological pathway, called “Power to BioGas”. In contrast to the thermo-
chemical process, the metabolic reactions of biological methanation occur naturally
when specialised microorganisms are present. Methanogenic archaea use hydrogen
and carbon dioxide as source for their metabolism – as a product methane is
produced.
photovoltaic and windenergy
maize
electrolysis biological methanation
O2
biogas upgrade
CO2
H2
biogasbiomassbiogas plant
excesselectr.current
CHP
H O2H O2
O2
manure
electr. current
heat energy
O2
H O2 CO2
natural gas vehicle
mobility
H O2 CO2
gas grid
CH4
CH4
Figure 4: Power to gas concept with biological methanation
(source: Fraunhofer UMSICHT 2013)
These are the same microorganisms that are responsible for the methane-forming
step in biogas, landfill gas and sewage gas production. Power to BioGas is at a
development stage, however, from the current point of view it offers certain
benefits such as described in the following:
� Mild process conditions with low temperature and pressure conditions
(35-70 °C; reaction already at ambient pressure) ease the engineering and
operation. These conditions are very similar to the ones in biogas plants.
� Cost-effectively because of the use of microorganisms from freely available
by-and waste products such active biomass from digestate from biogas
plants
� High tolerance against contaminants. Hydrogen sulfide as a nutrient source
is even beneficial to the process; therefore in contrast to the thermo-
chemical pathway the biological methanation does not require
comprehensive gas treatment.
� High reactivity results in fast start and stop operation [13].
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� High selectivity of the microorganisms which means that methane is
produced without intermediate products.
Whereas the implementation of biological methanation into an existing biogas plant
is not expected to involve extraordinary financial efforts, the production of
renewable hydrogen is considered to be the most important economical challenge.
The high investment costs for an electrolyser of 800 to 1500 €/kW 2 [12] make up
a significant part of the production costs. The exploitation of the biological
methanation technology will therefore strongly depend on the development of
electrolysis technology for low costs. Production costs are estimated to range from
ca. 80 to 150 €/MWhHs, provided excess electricity is delivered without charge3.
An additional challenge will be to optimise the conversion rate of biological
methanation. The conversion rate is strongly linked to the accessibility of the feed
to the bacteria which is limited by the solubility of the feed gases. More research is
needed to further investigate and optimise the process of biological methanation
before it reaches maturity for being realized at industrial scale.
Plants in operation – examples
Biological methanation is considered to be at development stage and there has
been little experience with larger scale applications. There are some pilot projects in
operation (Table 2), whereby the largest pilot plants have been set up by
Electrochaea in Foulum, Denmark [14], and another one by Microbenergy in
Schwandorf, Germany [16]. A new project aiming at scaling up to a capacity of 1
MW has been recently announced by Electrochaea [14].
Table 2: Location and status of plants for biological methanation in
Europe (no claim to be complete) [source: [14], [16], own
research]
2 only alkaline electrolysers are considered here, since invest costs for PEM electrolysers are
even higher
3 further assumptions: 2000 operation hours, capital costs 12% p.a.
LOCATION FERMENTER SIZE
[CUBIC METER]
BEGINNING OF
OPERATION
SCALE OPERATOR
Germany
Allendorf 2012 pilot Microbenergy
Schwandorf 100 2012 pilot Microbenergy
Oberhausen 0,005 2012 laboritory Fraunhofer UMSICHT
Denmark
Foulum 10 2012 pilot Electrochaea
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SWOT analysis
POSITIVE
NEGATIVE
STRENGTHS WEAKNESSES
IN
TER
NA
L
• Mild process conditions regarding required temperature, pressure and purity of the educt gas streams
• Easy switch on and off behaviour of the process has been reported.
• Easy integrating into biogas / biomethane plant concepts is possible without major hurdles.
• The process is still at research and pilot plant stage
• Still high investment costs for electrolysis facility ca. 1000 €/kW]
• Rate of conversion is strongly linked to the solubility of hydrogen in water.
• The handling of hydrogen bears some challenges (e.g. security, technical leak tightness)
EX
TER
NA
L
OPPORTUNITIES
• Renewable storage for renewables.
• Biogas / biomethane plants are able to offer the levelling of excess electricity as a service and therefore take a new role in the energy supply and grid stabilisation
• Increasing economical feasibility if costs for electrolysis can be lowered.
• Countries with high percentage of fluctuating RES can benefit from this technology.
THREATS
• Further research is required e.g. to investigate and optimise the process
• Under the current market conditions not competitive with fossil gas. Support schemes are required.
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Comparative analysis and conclusion The analysis shows that there are several ways available for producing biomethane.
A large range of biomass substrates can be used to generate biomethane, and even
excess electricity and appropriate CO2 sources can be converted via the Power to
BioGas technology.
Concerning stage of development, it can be stated that biomethane from AD is the
most developed pathway. More than 230 plants are in operation, almost all of them
produce renewable gas at industrial scale. Compared to that state, the other two
presented options Power to BioGas and BioSNG production are regarded to be at
demonstration status. Trials at laboratory and pilot stage have been carried out to
investigate the process and technical feasibility has been proven. The first real
industrial scale BioSNG project has just recently been commissioned. One large
scale Power to BioGas project is already in the pipeline.
The three pathways have their specific characteristics concerning the appropriate
technical and economical scale. BioSNG production is considered to be appropriate
for large scale projects due to issues such as availability of substrates and cost
degradation effects; Biomethane from AD projects in practise experienced that
plant size is driven by the fermentation unit and the availability of appropriate
substrates. Specific production costs benefit from scale-up effects up to a plant size
of 2000 Nm³/h. Larger plants are most often built in parallel production lines [14].
Due to the connection of Power to BioGas projects with biogas plants, their scale
are expected to be linked to the size of Biomethane from AD projects.
The costs for biomethane production range from 53 – 63 €/MWhHs for BioSNG [5],
over 65-83 €/MWhHs for biomethane from AD [15] and even higher for biomethane
received from Power to BioGas processes. Under the current economical conditions
(e.g. low natural gas price of ca. 24 €/MWhHs) these renewable gases can only
compete with fossil natural gas, if appropriate support mechanisms are available.
These schemes should value the benefits of biomethane – its renewable nature and
the fact that it can be stored and can be flexibly used for climate protection.
To sum up, the comparison shows that each biomethane production pathway has
its specific strengths. Due to the flexibility in production and utilisation biomethane
is worth to be considered in a lot more energy concepts.
Page 18 of 19
LITERATURE
[1] Thrän D, Müller-Langer F (2011): Potenziale in Deutschland und Europa; In: Biogas: Erzeugung, Aufbereitung, Einspeisung; Oldenbourg Industrieverlag, München; pp 17 – 40; Graf F, Bajohr S (editor)
[2] Urban W et al (2009): Abschlussbericht BMBF-Verbundprojekt Biogaseinspeisung, Band 3; www.biogaseinspeisung.de
[3] Simell P et al (2014): Techno-economic study on bio-SNG and hydrogen production and recent advances in high temperature gas cleaning. In: Regatec 2014, Conference Proceedings; pp 39; Held J (editor)
[4] Kopyscinski J et al (2010): Production of synthetic natural gas (SNG) from coal and dry biomass – a technology review from 1950-2009; Fuel 89 pp1763-1783
[5] Webpage of European Biofuels Technology Platform http://www.biofuelstp.eu/bio-sng.html (accessed 15 of May 2014)
[6] Webpage of the European Centre for Renewable Energy http://www.eee-info.net/cms/EN/
[7] Seiffert M et al (2009): Final report: Bio-SNG – Demonstration of the Production and Utilisation of Synthetic Natural Gas (SNG) from Solid Biofuels
[8] Webpage of Transport Research and innovation Portal: http://www.transport-research.info/web/programmes/programme_details.cfm?ID=35788 (accessed 15th of May 2014)
[9] Webpage of GoBiGas project http://gobigas.goteborgenergi.se (accessed 20th of May 2014)
[10] Webpage of the Gaya project www.projectgaya.com (accessed 20th of May 2014)
[11] Specht M et al (2009): Speicherung erneuerbarer Energien im Erdgasnetz
[12] Dena (2013): Power to Gas. Eine innovative Systemlösung auf dem Weg zur Marktreife. (Brochure)
[13] Krajete A et al (2013): Benefits of biological methanation. Presentation at DBI http://www.dbi-gti.de/fileadmin/downloads/5_Veroeffentlichungen/Tagungen_Workshops/2013/H2-Fachforum/14_Krajete_KrajeteGmbH.pdf (accessed 20th of May 2014)
[14] Hofstetter D (2013): Biomethane Production via Power-to-Gas In: UK Biomethane Day 2013 http://www.r-e-a.net/images/upload/events_133_10_-_Dominic_Hoffstetter_-_Power-to-Gas_-_UK_Biomethane_Day_2013.pdf (accessed 20th of May 2014)
[15] Beil M et al. (2014): Final project report BIOMON
[16] Albrecht U et al. (2013): Analyse der Kosten Erneuerbarer Gase, BEE Plattform Systemtransformation