Sustainable energy is the provision of energy that meets the needs of the present without compromising the ability of future generations to meet their needs.

Sustainable energy sources are most often regarded as including all renewable sources, such as plant matter, solar power, wind power, wave power, geothermal power and tidal power. It usually also includes technologies that improve energy efficiency.

Conventional fission power is sometimes referred to as sustainable, but this is controversial politically due to concerns about peak uranium, radioactive waste disposal and the risks of disaster due to accident, terrorism, or natural disaster.

This sets sustainable energy apart from other renewable energy terminology such as alternative energy and green energy, by focusing on the ability of an energy source to continue providing energy.

Sustainable energy can produce some pollution of the environment, as long as it is not sufficient to prohibit heavy use of the source for an indefinite amount of time.

Sustainable energy is also distinct from Low-carbon energy, which is sustainable only in the sense that it does not add to the CO2 in the atmosphere.

Energy efficiency and renewable energy are said to be the twin pillars of sustainable energy.