Oxford Dictionary - energy fuelled in ways that do not use up natural resources or harm the environment.
Princeton WordNet - energy derived from sources that do not use up natural resources or harm the environment.
Responding to Climate Change 2007 - energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, wind).
Natural Resources Defense Council - energy that is not popularly used and is usually environmentally sound, such as solar or wind energy (as opposed to fossil fuels).
Materials Management Services - Fuel sources that are other than those derived from fossil fuels. Typically used interchangeably for renewable energy. Examples A** include: wind, solar, biomass, wave and tidal energy.
Torridge District Council - Energy generated from alternatives to fossil fuel. Need not be renewable.
Concise OED Alternative Energy. Accessed May 2, 2008.
WordNet. Alternative Energy entry.
RICC 2007. Term Glossary.
Torridge District Council. TDLP PART 1 - GLOSSARY.