Definition of Alternative energy

Alternative energy is energy derived from sources that do not harm the environment or deplete the Earth's natural resources. Typical sources include wind and solar. Nuclear energy is usually excluded from this definition.

Future energy development, providing for the world's future energy needs, currently faces great challenges. These include an increasing world population, demands for higher standards of living, a need for less pollution, a need to avert global warming, and a possible end to fossil fuels (see Hubbert peak theory). Without energy, the world's entire industrialized infrastructure would collapse; agriculture, transportation, waste collection, information technology, communications and much of the prerequisites that a developed nation takes for granted. A shortage of the energy needed to sustain this infrastructure could lead to a Malthusian catastrophe.