2012 tus lecture 3

Nanoscience and Energy Lecture 3

Energy and Nanotechnology

Lecture 3. Energy and Nanotechnology Review of Alternate Energy

Sources

Review of Electronic Properties of

Solids:

Free- electron Fermi gas

Energy bands in Solids

Semiconductors and doping

pn junctions

Amorphous semiconductors

0

5

10

15

20

25

30

30 40 50 60 70 80 90 0 10 20

Gb/yr

Year

Middle East

USA

E-Europe/Asia

W-Europe

Rest of World

John A. Woollam, PV talk UNL 2007

World oil discovery rates declined since early 1960s; oil is consumed ~ 4 X greater rate than discovery rate.

Societal Drivers - Fossil Fuel Depletion D.E.Carlson, BP Solar

John A. Woollam, PV talk UNL 2007

Laherrere (2001): world oil production peaks ~ 2010.

Natural gas by ~ 2030.

Societal Drivers - Fossil Fuel Depletion D.E.Carlson, BP Solar

BioMass

• In 2003 — and for the fourth year in a row — biomass was the leading source of renewable energy in the United States, providing 2.9 Quadrillion Btu of energy. Biomass was the source for 47% of all renewable energy or 4% of the total energy produced in the United States). Agriculture and forestry residues, and in particular residues from paper mills, are the most common biomass resources used for generating electricity, and industrial process heat and steam and for a variety of biobased products. These are the organic byproducts of food, fiber, and forest production. In fact, 48% or 1.1 Quad Btu of biomass energy was consumed by the pulp and paper industry, solely using black liquor. Current biomass consumption in the United States is dominated by industrial use, largely derived from wood. Use of liquid transportation fuels such as ethanol and biodiesel, however, currently derived primarily from agricultural crops, is increasing dramatically. In 2003 ethanol produced from corn reached 2.81 billion gallons.

Hydropower

With 80,000 megawatts of generating

capacity, hydropower is the nation's largest renewable electricity source. Working with industry, the Wind and Hydropower Technologies Program pursues R&D to develop more environmentally friendly technologies to maintain the nation's existing hydropower capacity.

6.6.06 - 8.6.06 Clemson Summer School

Dr. Karl Molter / FH Trier / molter@fh-trier.de

23

Solar irradiation in the USA

Shown is the average radiation received on a horizontal surface across the continental United States in the month of June. Units are in kWh/m2

6.6.06 - 8.6.06 Clemson Summer School

Dr. Karl Molter / FH Trier / molter@fh-trier.de

24

Solar Irradiation worlwide (kWh/m² a) on horizontal surface

ENERGIA EOLICA

LA CONVERSION DE LA FUERZA DEL VIENTO A ENERGIA ELECTRICA EMPLEANDO AEROGENERADORES

ENERIA EOLICA ES UNA DE LAS MAS BARATAS DE DIFERENTES FORMAS DE ENERGIA RENOVABLE

Wind Energy

• In 2005, the United States installed more new wind energy capacity than any other country in the world. The new capacity, totaling 2,431 megawatts (MW), was worth more than $3 billion in generating equipment, and it brought the total national wind energy capacity to 9,149 MW. That's enough electricity to power 2.3 million average American households. In 2006, an additional 2,454 MW were installed, bringing the Nation's total installed capacity to 11,603 MW.

Centralized Solar Power

Review of Electronic Properties of Solids

Free Electron Fermi Gas

Energy Bands, Semiconductors, Doping

Hydrogen Molecule

6.6.06 - 8.6.06 Clemson Summer School

Dr. Karl Molter / FH Trier / molter@fh-trier.de

46

energy-states in solids: Band-Pattern

Atom Molecule/Solid

ene

rgy-

stat

es

• • • • • • • •

6.6.06 - 8.6.06 Clemson Summer School

Dr. Karl Molter / FH Trier / molter@fh-trier.de

47

energy-states in solids: Insulator

electron-energy

conduction-band

valence-band

Fermi- level EF

bandgap EG

(> 5 eV)

Figure 9.12. A valence electron jumping across the energy gap in pure

silicon resulting in the generation of a free electron and hole in the crystal:

(a) energy band model, (b) bond model.

Figure 9.13. Extrinsic n-type silicon doped with P donor atoms. (a) Energy

band diagram and (b) Bond model.

Figure 9.14. Extrinsic p-type silicon doped with B acceptor atoms. (a)

Energy band diagram and (b) Bond model.

6.6.06 - 8.6.06 Clemson Summer School

Dr. Karl Molter / FH Trier / molter@fh-trier.de

53

energy-states in solids : metal / conductor

electron-energy

conduction-band

Fermi- level EF

6.6.06 - 8.6.06 Clemson Summer School

Dr. Karl Molter / FH Trier / molter@fh-trier.de

54

energy-states in solids: semiconductor

electron-energy

conduction-band

valence-band

Fermi- level EF

bandgap EG

( 0,5 – 2 eV)

Figure 9.11. (a) Energy levels in an isolated silicon atom and (b) in a

silicon crystal of N atoms, illustrating the formation of energy bands. The

valence band contains 4N states and can accommodate all 4N valence

electrons.

pn Junctions

Amorphous Semiconductors