Comparing energy resources

There are different energy resources in the world and the amount of energy stored by them varies greatly. For example, the nuclear energy within 1 kg of uranium contains a very large amount of energy, but the gravitational potential energy stored by many thousands of tonnes of water held back by a dam contains less.

Fossil fuels

Fossil fuels are a chemical store of energy and include coil, oil and natural gas. Most of the UK's electricity is produced by burning fossil fuels, mainly natural gas (30% in 2015) and coal (23%). A very small amount is produced from oil (under 1%).

Using fossil fuels to produce electricity

  1. Fossil fuel is burnt to boil water and turn it into steam.
  2. The steam rises past turbines and causes them to spin.
  3. The turbines are connected to generators which are spun to generate electricity.
  4. Transformers are used to step up the voltage before feeding the electricity into the National Grid.
  5. Transformers are used to step down the voltage before feeding electricity into homes.
The National Grid and the system energy is used to power homes

Advantages and disadvantages of fossil fuel power

AdvantagesDisadvantages
Readily available (at the moment)Non-renewable source – will eventually run out
Relatively easy to produce energy from themIncreasing fuel costs
Release carbon dioxide (CO2 ) when burnt – greenhouse gas
Release sulphur dioxide (SO2 ) when burnt – acid rain

Nuclear power

Electricity is generated in nuclear power stations using a fission reactor powered by uranium fuel. 22% of the UK's electricity is generated using nuclear fission.

Uranium fuel rods heat gas, pump through heat exchanger, heats water, produces steam, turn turbines. Core encased in thick concrete, has boron control rods and graphite moderator to regulate gas flow.The process of a nuclear fission power reactor

Advantages and disadvantages of nuclear power

AdvantagesDisadvantages
No release of carbon dioxide (CO2 ) – greenhouse gasNon-renewable source – will eventually run out
No release of sulphur dioxide (SO2 ) – acid rainExpensive to commission and decommission power stations
1 kg of uranium produces millions times more energy than 1 kg of coalHazardous radioactive waste produced
Danger of release of radioactive materials into the environment