Renewable energy technologies enable us to create electricity, heat and fuel from renewable sources. Solar, wind, hydro, wave, heat-exchange, tidal, wave and bioenergy technologies are all powered by the sun, directly or indirectly. Tidal and wave energy technologies are also powered by the moon. Geothermal technologies are powered by deep heat from the Earth's core. Bioenergy technologies allow us to convert the solar energy stored in plants, food wastes, farm wastes, forest wastes, sewage, and algae into heat, electricity and fuel, using a variety of approaches. These technologies allow us to heat and cool our buildings, generate electricity, and to travel by land, sea, and potentially also by air without generating dangerous greenhouse gases and other forms of pollution.
Renewable energy uses natural resources such as sunlight, wind, tides and geothermal heat which are naturally replenished. Most forms of renewable energy are cheap to operate, but relatively expensive to install, as they have to take quite dispersed energy and concentrate it into a useful form.