Nanoscience and Energy Lecture 3Energy 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
Gb/yr3025 Rest of World20 Middle East15 E-Europe/Asia10 W-Europe USA 5 0 Year 30 40 50 60 70 80 90 0 10 20
Societal Drivers - Fossil Fuel Depletion D.E.Carlson, BP Solar World oil discovery rates declined since early 1960s; oil is consumed ~ 4 X greater rate than discovery rate. John A. Woollam, PV talk UNL 2007
Societal Drivers - Fossil Fuel DepletionD.E.Carlson, BP Solar Laherrere (2001): world oil production peaks ~ 2010. Natural gas by ~ 2030. John A. Woollam, PV talk UNL 2007
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 nations 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 nations existing hydropower capacity.
Solar irradiation in the USAShown is the averageradiation received on ahorizontal surfaceacross the continentalUnited States in themonth of June. Unitsare in kWh/m2 Clemson Summer School 6.6.06 - 8.6.06 Dr. Karl Molter / FH Trier / molter@fh- 23 trier.de
Solar Irradiation worlwide (kWh/m² a) on horizontal surface Clemson Summer School6.6.06 - 8.6.06 Dr. Karl Molter / FH Trier / molter@fh- 24 trier.de
ENERGIA EOLICALA CONVERSION DE LA FUERZADEL VIENTO A ENERGIAELECTRICA EMPLEANDOAEROGENERADORESENERIA EOLICA ES UNA DE LASMAS BARATAS DE DIFERENTESFORMAS DE ENERGIARENOVABLE
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. Thats enough electricity to power 2.3 million average American households. In 2006, an additional 2,454 MW were installed, bringing the Nations total installed capacity to 11,603 MW.
energy-states in solids: Band-Pattern Atom Molecule/Solid • • • • • • • • energy-states Clemson Summer School6.6.06 - 8.6.06 Dr. Karl Molter / FH Trier / molter@fh- 46 trier.de
energy-states in solids: Insulatorelectron-energy conduction-band Fermi- bandgap EG level EF (> 5 eV) valence-band Clemson Summer School 6.6.06 - 8.6.06 Dr. Karl Molter / FH Trier / molter@fh- 47 trier.de
Figure 9.12. A valence electron jumping across the energy gap in puresilicon 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.
energy-states in solids : metal / conductorelectron-energy Fermi- level EF conduction-band Clemson Summer School 6.6.06 - 8.6.06 Dr. Karl Molter / FH Trier / molter@fh- 53 trier.de
energy-states in solids: semiconductorelectron-energy conduction-band Fermi- bandgap EG level EF ( 0,5 – 2 eV) valence-band Clemson Summer School 6.6.06 - 8.6.06 Dr. Karl Molter / FH Trier / molter@fh- 54 trier.de
Figure 9.11. (a) Energy levels in an isolated silicon atom and (b) in asilicon crystal of N atoms, illustrating the formation of energy bands. The valence band contains 4N states and can accommodate all 4N valence electrons.