15 Solar Production of Electricity Photovoltaic Cell
16 How Photovoltaic Cells Work: Part 1 Each cell consists of two thin mylar layers.Lower layer has atoms with single electron in outer orbit – easily lost.Upper layer has atoms lacking one electron in outer orbit – easily accepts electrons.
17 How Photovoltaic Cells Work: Part 2 Kinetic energy from sunlight dislodges electrons from lower layer – creates an electric potential between the two layers.
18 How Photovoltaic Cells Work: Part 3 The potential provides the energy for an electrical current through the rest of the circuit.Electrons from lower layer flow through a device back to upper side.
24 Disadvantages of Solar Energy Technologies ExpenseOnly works during the dayRequires backup energy sources, e.g., batteriesSome climates not sunny enough
25 Hidden Costs of Traditional Energy Sources Air pollutionStrip-miningNuclear wastes
26 Indirect Solar EnergyHydropowerWind powerBiomass energy
27 Wind Power: Benefits or Drawbacks? Size limitations of wind turbinesMegawatts of electricity producedLevel of pollution generated
28 Wind Power: Benefits or Drawbacks? Level of environmental degradationGeographical distribution of energy producedAesthetics
29 Biomass Energy Burning firewood Burning wastes Burning biogas (methane)
30 Biomass Energy: Benefits or Drawbacks? Availability of the biomass resourceAccess to the biomass resourcePublic acceptance and utilization of biomass energyPast history of human harvests within a maximum sustained yield
31 Renewable Energy and Transportation Biofuels: ethanol and biodieselHydrogen: the fuel for the future
37 Tidal Power: Benefits or Drawbacks? Consistent sourceLevel of pollutionCost-effectivenessTechnology required for extractionGeographical distribution of energy produced
38 OTEC: Benefits or Drawbacks? In an average day the heat absorbed by the surface water in only one square mile is equivalent to the burning of 7,000 barrels of oilCost effectiveness to capture and distribute heat energyIndustrial interest in the OTEC alternative
39 Policy for a Sustainable Energy Future National energy policyA clean energy blueprint
40 A Clean Energy Blueprint Supply sideEstablish a Renewable Portfolio StandardMaintain production tax creditsExtend net meteringSubstantially increase research-and-development on renewable energy and efficiency
41 A Clean Energy Blueprint Demand sideImprove efficiency standardsEnhance building codesProvide incentives for combined heat and power facilitiesRaise fuel economy (CAFÉ) standardsIncrease research and development on high-efficiency vehicles (hybrid electric and fuel cell vehicles).