Fossil fuels are . When they run out, they cannot be replaced.

Renewable energy can be . Most renewable energy comes from the [?]:

- power comes from the kinetic energy of falling that has been stored in a reservoir, behind a dam.
- Wind turbines use the energy from the wind. The United Kingdom is a very island.
- (photovoltaic cells) convert the energy from into electricity. Your calculator might have one.
- Wave energy uses the energy in from the sea.

energy uses the heat from hot underground rocks to heat the water. This heat comes not from the Sun, but deep .

Tidal power harnesses the rise and fall of the . The tidal water passes through in a dam.