Alternative energy is typically defined as coming from sources that do not deplete natural resources or harm the environment. Wind power is a typical example. The term alternative is used to contrast with fossil fuels according to some sources. Renewable energy differs from Alternative energy in that it may have significant environmental impact, as is the case for most hydroelectric dams.
energy fuelled in ways that do not use up natural resources or harm the environment.[1]
Princeton WordNet
energy derived from sources that do not use up natural resources or harm the environment.[2]
Responding to Climate Change 2007
energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, wind).[3]
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).[4]
Materials Management Services
Fuel sources that are other than those derived from fossil fuels. Typically used interchangeably for renewable energy. Examples include: wind, solar, biomass, wave and tidal energy.[5]
Due to a steadily rising gas price in 2008 with the US national average price per gallon of regular unleaded gas above $4.00[6], there has been a steady movement towards developing higher fuel efficiency and more alternative energy vehicles for consumers. In response, many smaller companies have rapidly increased research and development into radically different ways of powering consumer vehicles. While Hybrid Vehicles (such as Toyota's Prius) and Electric Vehicles (such as the Tesla Roadster) are commercially available, other technologies such as fuel cells, flywheels, and ultracapacitors are starting to emerge as viable options.[7]
