Alternative energy Because fossil fuels are irreplaceable and dirty, many people want to develop cleaner, renewable sources of energy. Water power has been used in water mills for thousands of years. But today it is used mostly to generate electricity. Very few of the world's rivers have yet been developed, so the potential is huge. But the need to build big dams to control the flow is a real drawback.
Curved mirrors track the sun and focus the rays to heat oil in pipes.
The heat is transferred to water, which boils. The steam drives turbines linked to electricity generators. A forest of wind turbines, which turn electricity generators. Oil Oil is found all over the world, from the Middle East to Alaska. Some oil fields are in the sea - but onshore fields are in places covered by the sea millions of years ago.