P1aL15 Renewable Energy

Key Words

Biomass - biological material that can be used as a fuel.

Generator - machine that turns kinetic energy into electrical energy.

Geothermal - heat from hot rocks.

Hydroelectric - falling water drives turbines which drive generators

Renewable - resources that will not run out and are constantly replaced.

Tidal Power - energy generated by water flows due to tides.

Wave Power - energy generated by wave action.

Wind farm - a number of wind turbines in a small area.

Wind Turbine - a machine that drives a generator, and is driven by the wind.

Test Yourself

Homework
Physics GCSE
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Grade E

Electricity can be generated by other methods other than burning fossil fuels:

  • Some burn waste, like rubbish that will otherwise go to landfill;
  • Other use biomass, like willow wood.  The willow is harvested, and the trees re-grow from the stumps.
  • Biogas is methane from rotting biological waste.  The material produced when we sit on the lavatory decomposes to release a lot of methane.

Wind turbines have huge blades that drive a generator.  The kinetic energy from wind is transferred to kinetic energy in the generator, which is transferred to electrical energy.  A number of turbines form a wind farm.

In Hydroelectric power stations, water is stored by blocking a deep valley with a dam.  The water then is piped from the reservoir through a water turbine which drives a generator.  In some power stations the generators can act as motors that drive the turbines as pumped.

 

Grade C

Tides rise and fall all the time.  The energy to do this comes from the Moon.  In tidal power stations a dam is built across a river estuary where is is quite a large tidal fall.  The water flows through turbines to generate electricity.  These power stations are immensely expensive to build and some people worry about the effects they will have on the environment.

Wave energy has been tried.  The most effective type of power station is one where air in a large container is displaced by a wave.  Small air turbines (like fans in reverse) drive generators.  Currently these machine are small-scale.

Geothermal energy comes from hot rocks deep below the surface.  Water is pumped down to the rocks.  It is turned to steam and drives a turbine.  These are common in areas with volcanic activity.

 

Grade A

Solar power stations are powered by the Sun, which heats the ground at a rate of about 500 W/m2 .  The suns rays are focused onto a heat exchanger by computer controlled mirrors called heliostats.  The air heated in the exchanger reaches a temperature of 700 oC and is used to boil water.