Renewable Flashcards
What is renewable energy?
A renewable energy resource is one that can be replaced faster than it is used up.
Wind energy
Wind is produced as a result of giant convection currents in the Earth’s atmosphere, which are driven by heat energy from the Sun. This means that the kinetic energy in wind is a renewable energy resource - as long as the Sun exists, the wind will too.
Advantages and disadvantages of wind
Advantages
Wind is a renewable energy resource and there are no fuel costs.
No harmful polluting gases are produced.
Disadvantages
Wind farms are noisy and may spoil the view for people living near them.
The amount of electricity generated depends on the strength of the wind.
If there is no wind, there is no electricity.
Water energy
Water can be used to drive turbines directly. There are several ways that water can be used, including waves, tides and falling water in hydroelectric power schemes.
Wave
The water in the sea rises and falls because of waves on the surface. Wave machines use the kinetic energy in this movement to drive electricity generators.
Tides
Huge amounts of water move in and out of river mouths each day because of the tides. A tidal barrage is a barrier built over a river estuary to make use of the kinetic energy in the moving water. The barrage contains electricity generators, which are driven by the water rushing through tubes in the barrage.
Hydroelectric
hydroelectric power (HEP) stations use the kinetic energy in moving water. But the water comes from behind a dam built across a river valley. The water high up behind the dam contains gravitational potential energy. This is transferred to kinetic energy as the water rushes down through tubes inside the dam. The moving water drives electrical generators, which may be built inside the dam.
Geothermal
Hot water and steam from deep underground can be used to drive turbines: this is called geothermal energy. Geothermal and nuclear energy are the only energy resources that do not come from the Sun.
