Sustainable energy sources are energy sources which are not expected to be depleted in a timeframe relevant to the human race, and which therefore contribute to the sustainability of all species.
Sustainable energy sources are most often regarded as including all renewable sources, such as solar power, wind power, wave power, geothermal power, tidal power and others.
Discounting the small risk of large-scale nuclear accidents, terrorism and other major disasters, nuclear power and nuclear fusion meet this definition of sustainability, but there is controversy over whether or not they should be regarded as sustainable for social and political reasons.
