Recently scientists and engineers have developed methods to capture energy from sources that have unlimited supply. These sources are called renewable energy sources because they can be replenished in a short period of time, during a person's lifeltime. In today's society, we mainly convert renewable energy sources into electricity.

SUNLIGHT: Solar panels to capture the sun's energy. We can use the sun's energy today, because the sun will shine again tomorrow.

WIND: Wind turbines capture the wind's energy. We can use the wind's energy now, because the wind will blow again later.

TIDES: Tidal stream generators capture the tide's energy. We can use the tide's energy now, because ocean waves keep moving.

RIVERS: Dams enable us to capture the energy of a moving river. We can use the river's energy now, because more rain will fall to replenish the water.