Natural sources of energy are replenished without consuming an irreplaceable fuel resource, and so are thought of as renewable. Such sources are found with sunlight, wind, sea waves and tides, and geothermal heat. Of these sources, the individual home and property owners can seek energy independence by relying on sunlight for photovoltaic (PV) energy collection, solar thermal collection, passive solar energy retention and geothermal heat recovery.
On an industrial scale, wind, sea wave, tidal and geothermal development projects are funded with the advantages of tax depreciation that household energy investors are denied.