biol270chap_14

biol270chap_14 - Chapter 14 Renewable Energy Renewable...

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Unformatted text preview: Chapter 14 Renewable Energy Renewable Energy Renewable Energy Putting solar energy to work Indirect solar energy Renewable energy for transportation Additional renewable­energy options Policy for a sustainable­energy future Renewable­energy Use in the Renewable­energy Use in the United States Examples of Renewable Energy Examples of Renewable Energy Sources Putting Solar Energy to Work Putting Solar Energy to Work Principles of solar energy Solar heating of water Solar space heating Solar production of electricity The promise of solar energy Principles of Solar Energy Principles of Solar Energy Constant Abundant Free Everlasting Hurdles in Using Solar Energy Hurdles in Using Solar Energy Collection Conversion Storage Cost­ effectiveness Terms and Definitions: Solar Terms and Definitions: Solar Heating Systems Active: moves water or air with pumps and blowers Passive: moves water or air with natural convection currents or gravity Active solar (Solar Heating of Active solar (Solar Heating of Water: Flat­plate Solar Collector) Easy construction Early use Heat can be used to supplement hot water heater or as part of the home heating System. Solar Water Heaters Solar Water Heaters Rooftop Water Heaters Rooftop Water Heaters Passive solar Passive solar Simple approach (no moving parts) Uses air convection Often part of home design Solar Space Heating Solar Space Heating Passive solar Passive solar as part of home design The house is a heat exchange machine Passive solar Passive solar as part of home design The house is a heat exchange machine Passive solar Passive solar Incorporating the yard Passive solar Passive solar Passive solar Passive solar Retrofits are possible but the home limits possibilities Overall effect: 15% and up (up 80%) reduction in heating costs compared to conventional homes Home energy use Energy use by activity Solar Production of Electricity Solar Production of Electricity Photovoltaic Cell Solar: photovoltaic Solar: photovoltaic How Photovoltaic Cells Work: 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 Works: How Photovoltaic Cells Works: Part 2 Kinetic energy from sunlight dislodges electrons from lower layer – creates an electric potential between the two layers. How Photovoltaic Cells Works: How Photovoltaic Cells Works: 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. PV System Inverter PV System Inverter Connects PV panels to the electric grid. Converts direct current coming from PV panels to alternating current. Estimated 5-15 energy return on investment over 30 yrs (5-15 times your money back) Concentrating Solar Power Concentrating Solar Power (industrialize it) PV power plants Solar­trough collectors Power towers Dish­engine system PV Power Plant PV Power Plant 34 foot panels 6.5 Mw at peak 220 panels Power Tower Power Tower Solar Dish Engine System Solar Dish Engine System Disadvantages of Solar Energy Disadvantages of Solar Energy Technologies Expense Only works during the day Requires back­up energy sources, e.g., batteries Some climates not sunny enough Weekly Electrical Demand Weekly Electrical Demand Cycle Indirect Solar Energy Indirect Solar Energy Hydropower Wind power Biomass energy Hydropower (indirect solar) Hydropower (indirect solar) The hydrologic cycle Hoover Dam Hoover Dam Wind Power (indirect solar) Wind Power (indirect solar) Differential heating and cooling Air moving from high pressure to low pressure areas Wind Power Wind Power Wind Power is scalable Wind Power is scalable Biomass Energy (indirect solar) Biomass Energy (indirect solar) Biomass Energy Biomass Energy Burning firewood Burning wastes Burning biogas (methane) Renewable Energy and Renewable Energy and Transportation Biofuels: ethanol and biodiesel Hydrogen: the fuel for the future Biofuels Biofuels Ethanol (alcohol) Ethanol Great additivewill replace MTBE as a gas additive Biofuels Biofuels Biodiesel Hydrogen Hydrogen Hydrogen powered carInternal combustion engine (20% energy transferred to work) Hydrogen­ oxygen Fuel Cell Hydrogen­ oxygen Fuel Cell 45-60% energy transferred to work Additional Renewable Energy Additional Renewable Energy Options Geothermal energy Tidal power Ocean thermal­energy conversion (OTEC) Geothermal Energy (scalable to an Geothermal Energy (scalable to an extent) Benefits to individual homes for heating and cooling Industrial use geography limited by geology Tidal Power Tidal Power Very geographically limited Ocean thermal­energy conversion Ocean thermal­energy conversion OTEC In an average day the heat absorbed by the surface water in only one square mile is equivalent to the burning of 7000 barrels of oil. Cost effectiveness to capture and distribute heat energy. Industrial interest in the OTEC alternative A Sustainable Energy Future A Sustainable Energy Future An issue of scale National energy policy Used to guide future directions through mandates and incentives (laws and taxes) Industrial and individual (grassroots) 2005 Energy Policy Act (True or 2005 Energy Policy Act (True or False) Mandates to increase fuel efficiency (CAFÉ) 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 A Clean Energy Blueprint Supply side Establish a Renewable Portfolio Standard Maintain production tax credits Extend net metering (plug­in and save) Substantially increase research­and­ development on renewable energy and efficiency A Clean Energy Blueprint 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). ...
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This note was uploaded on 02/17/2011 for the course BIOL 270 taught by Professor Jones during the Spring '06 term at South Carolina.

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