Alternative energy refers to energy sources that do not come from fossil fuels. This term is often used interchangeably with renewable energy, which refers to an energy source that is naturally replenished, such as wind energy, solar energy, hydroelectric, rain, tides, and geothermal heat.
The generation of electricity by means of alternative energy sources is usually more expensive than traditional, coal-powered generators. However, because renewable energy has no fuel costs and often requires less maintenance than fossil fuel generators, renewable energy is usually less expensive than fossil fuel-derived energy once initial capital costs are covered. Renewable energy generators and power plants usually emits little-to-no pollution while operating, though they can cause other environmental effects, such as effects on neighboring ecosystems.
There is debate whether to classify hydroelectric dams as renewable.
- U.S. Department of the Interior Offshore Energy and Minerals Management - Renewable Energy Program Definitions
- Portsmouth Sustainable Energy Cost Analysis
- New York Times Online: Cost Works Against Alternative Energy, March 2009.
- Environmental Impacts of Renewable Energy Technologies