Required Components? Flat-plate collector Water pump Blowers Heat exchanger Improved insulation Solar hot water Solar space heater Both
Solar Production of Electricity Photovoltaic Cell
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.
How Photovoltaic Cells Work: Part 2 Kinetic energy from sunlight dislodges electrons from lower layer – creates an electric potential between the two layers.
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.
Disadvantages of Solar Energy Technologies Expense Only works during the day Requires backup energy sources, e.g., batteries Some climates not sunny enough
Promise of Solar Energy (More or Less?) The use of solar electrical power will: create ____ reliance on coal or nuclear power. lead to significantly _____ acid rain. produce ____ electrical power for villages in developing countries.
Hidden Costs of Traditional Energy Sources Air pollution Strip-mining Nuclear wastes
Indirect Solar Energy Hydropower Wind power Biomass energy
Hydropower: Benefits or Drawbacks? Level of pollution generated Level of environmental degradation Amount of energy produced
Hydropower: Benefits or Drawbacks? Geographical distribution of energy produced Ecological impacts above and below dam Societal disruptions
Wind Power: Benefits or Drawbacks? Size limitations of wind turbines Megawatts of electricity produced Level of pollution generated
Wind Power: Benefits or Drawbacks? Level of environmental degradation Geographical distribution of energy produced Aesthetics
Biomass Energy Burning firewood Burning wastes Burning biogas (methane)
Biomass Energy: Benefits or Drawbacks? Availability of the biomass resource Access to the biomass resource Public acceptance and utilization of biomass energy Past history of human harvests within a maximum sustained yield
Renewable Energy and Transportation Biofuels: ethanol and biodiesel Hydrogen: the fuel for the future
Tidal Power: Benefits or Drawbacks? Consistent source Level of pollution Cost-effectiveness Technology required for extraction Geographical distribution of energy produced
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 oil Cost effectiveness to capture and distribute heat energy Industrial interest in the OTEC alternative
Policy for a Sustainable Energy Future National energy policy A clean energy blueprint
National Energy Policy (True or False) Mandates to increase fuel efficiency in cars Exploitation of public lands for fossil fuel reserves Subsidies to producers of solar energy technology Research and development on renewable energy technologies
A Clean Energy Blueprint Supply side Establish a Renewable Portfolio Standard Maintain production tax credits Extend net metering Substantially increase research-and- development on renewable energy and efficiency
A Clean Energy Blueprint Demand side Improve efficiency standards Enhance building codes Provide incentives for combined heat and power facilities Raise fuel economy (CAFÉ) standards Increase research and development on high-efficiency vehicles (hybrid electric and fuel cell vehicles).