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Renewable Energy Basics
Allen J. BardThe University of Texas at Austin
March 27, 2009
American Chemical Society Energy Briefing
ROLE OF RENEWABLE ENERGY
•Transportation – Fuels from biomass and coals
•Transportation – Electrification of light vehicles (hybrids and plug-ins)
•Renewable energy in electricity generation
Types of renewables
Well-established: Hydroelectric, geothermal, biomass
Near Term: Wind, solar –thermal, solar-photovoltaic
Advanced: Third generation photovoltaic, enhanced geothermal (EGS), hydrokinetic (waves, tides), solar hydrogen, mass storage
Energy Sources for Electricity 2007
U.S. Electric Net EnergyGeneration (2007)4,200 TWh (terawatt-hours)or 4.2×1015 Whor 4,200 billion kWh
U.S. Electric Net PowerAvailable (Nameplate Capacity) (2007)1.1 TW (terawatts)or 1.1×1012 Wor 1.1 billion kW
Renewable Energy Sources for Electricity 2007
Transmission & Distribution (T&D)(the Grid)
Considerations for renewables:
•Capacity factor - what percentage of the 8760 hours of the typical year the equipment will be generating electricity and at what power level relative to its full capacity.
•Dispatchability - ability to deploy electricity generators (usually in order of cost of generation) to meet demand.
•T&D
•Cost
GenerationDemand
Transmission & Distribution (T&D)(the Grid)
•Capacity factor - (without storage) wind (30-40%) ; solar ( 26-28%)•Dispatchability - Poor
Above about 20% renewables, need to have some form of electricity storage or else distributed generation.
•T&D - May require new transmission lines only used a fraction of the time. Combine with other (e.g. natural gas) generators.
GenerationDemand
Distributed
Approximate current costs of renewablesResidential electricity costs ≈ 10 cents/kWh (with no charge for waste)(~1 cent/kWh for each $10/ton CO2 - proposed $50/ton would increase to 15 cents/kWh)
Wind 6 - 8 cents/kWh
Solar thermal - 19 - 28 cents/kWh
Solar photovoltaic (Si crystal) - 46 - 70 cents/kWh
Conventional geothermal - 6.2 - 7.6 cents/kWh
Growth of Renewable Electricity (2002-2007)TotalCapacity(GW)
0
1000
500
Quick approximate calculation
1% addl. Wind=42 TWh/year
Assuming 40% cap. Factor
New nameplate power=12 GW
Assuming 2.5 MW turbines
Need 4,800 turbines/year or
13 turbines/day installed
Efficiency of photovoltaic devices
Disruptive technologies and paradigm shifts
•Third generation photovoltaics•Solar hydrogen systems•Inexpensive electricity storage systems•Hydrokinetics•Geothermal
•NEW DISCOVERIES!
Energy Information Administration www.eia.doe.gov
Energy Efficiency and Renewable Energy http://www.eere.energy.gov/
Sources of information on energy