Non-renewable energy sources
Fossil fuels are formed in a process that takes millions of years. Fossils fuels are being used faster than they are being formed. They are called non-renewable energy sources because once they are finished they are none to replace it. Fossil fuels include coal, oil and natural gas.
Renewable energy sources
These include:
Biofuels are any fuels obtained from living or recently living organisms such as animal waste or woodchip. They include ethanol, straw, nutshells, plants, methane and biodiesel. A biofuel is carbon-neutral because the carbon it takes in from the atmosphere as carbon dioxide can balance the amount released when it is burned.
Nuclear power is generated in nuclear power stations by using plutonium and uranium as fuel. This is not a chemical reaction, but the splitting of atoms during which thermal energy is released to produce steam.
Wind power is generated by a wind turbine which is an electricity generator at the top of a tower. The wind’s force drives the turbine’s blades around which turns the generator.
Wave power is generated by a wave generator which uses the waves to make a floating generator move up and down. This motion makes the generator produce energy.
Hydroelectric power is generated when rainwater is collected in a reservoir, flows downhill and drives the turbines that turn electricity generators at the foot of the hill.
Tidal power is produced at a tidal power station which traps water from the high tides behind a barrage. The high tide can then be released into the sea through turbines which drive generators in the barrage.
Solar power is generated in solar cells which convert the sun’s energy into electricity. Solar cells are connected together to make solar cell panels. A solar heating panel
heats water that flows beneath it. A solar power tower uses thousands of mirrors to reflect sunlight on to a large water tank.
Geothermal energy comes from energy released by radioactive substances deep in the earth. This energy heats the rocks and as a result energy is transferred by heating towards the earth’s surface. Geothermal power stations are built in areas with hot rocks where water is pumped into to produce steam. The steam drives electricity turbines.
A power station
Energy stored in fuel is used to heat water and turn it into steam. The steam turns a turbine which in turn makes the generator run.
Environmental issues
Fossil fuels produce increased levels of greenhouse gases which could cause global warming. It also produces sulphur dioxide which causes acid rain. Fuel rods of nuclear reactors contain radioactive waste which has to be stored for centuries. If an explosion were to occur at a nuclear power station, nuclear material can be spread over a wide area which would be affected for many years. Renewable energy resources can affect plant and animal life