Chapter 19 Alternative Energy and the Environment

Introduction to Alternative Energy Sources Alternative Energy –Renewable and nonrenewable energy resources that are alternatives to the fossil fuels Renewable Energy –Alternative energy sources, such as solar, water, wind and biomass, that are more or less continuously made available in a time framework useful to people Nonrenewable Energy –Alternative energy sources, including nuclear and geothermal, that are dependent on fuels or a resource that may be used up much faster than it is replenished by natural processes

Solar Energy Passive Solar Energy Systems –Direct use of solar energy through architectural design to enhance or take advantage of natural changes in solar energy that occur throughout the year without requiring mechanical power Active Solar Energy Systems –Direct use of solar energy that requires mechanical power; usually consists of pumps and other machinery to circulate air, water or other fluids from solar collectors to heat sink where the heat may be stored

Solar Collectors: provide space heating or hot water Photovoltaic cell: converts sunlight directly into electricity Power Towers: concentrate & collect heat from solar energy, generates steam to turn turbine  electricity

Solar Energy—Problems Large land area often required Toxic materials used to manufacture solar equipment (metals, glass, plastics, fluids…) Inconstant supply; hard to store electricity Expensive to purchase/install (but will eventually pay for self)

Hydrogen Fuel generated by the sun Stored in fuel cells, can be used in vehicles When combusted, produces water as emissions (2H 2 + O 2 → 2H 2 O) Problems: Not yet economical to produce pure H 2 gas; will be expensive to update infrastructure

Water Power A form of stored solar energy; is renewable Can be used to generate mechanical energy (pumps, sawmills, windmills) or electrical energy (hydroelectricity—dams)

Water Power—Problems Destroys ecosystems by flooding/depriving areas of water Blocks movement of fish; kills them Dams trap sediments; reservoirs fill up and sand doesn’t get to beaches  Danger of dam failure

Tidal Power Form of water utilizing ocean tides in places where favorable topography allows for construction of a power plant

Wind Power Alternative energy source that has been used for centuries More recently thousands of windmills have been installed to produce electric energy

Wind Power—Problems Kill birds Some people think they’re ugly, ruin scenery Alleged health problems nowindfarms.com

Biomass Energy Energy that is recovered from biomass, which is organic material such as plant and animal waste

Geothermal Energy Natural heat from the interior of the Earth that is converted to heat buildings and generate electricity Considered non-renewable