P1.4 Generating Electricity

Power Stations

The majority of the electricity we use is generated in power stations.

Process

1. Burning fuel which give off heat energy. The heat energy is used to heat water in the boiler. This produces steam
2.The steam turns a turbine
3. The turbine drives a generator
4. The generator generates electricity

Biofuels

Most fuels used in power stations are non-renewable, these include: Coal, Oil, Gas and Nuclear

One renewable fuel which can be used in power stations is biofuel. Examples include: methane (manure), ethanol (fermented sugar cane), straw and woodchip.

Biofuels are carbon-neutral. This is because the CO2 released when burnt is equal to the amount taken in while growing.
When coal, oil and gas are burnt they produce CO2. This is a greenhouse gas, contributes to global warming and climate change. One possible solution to this problem is Carbon Capture and Storage.

When Coal is burnt it produces sulphur dioxide (SO2) which causes acid rain.
Gas fired power stations have an advantage over oil and coal in that they have a very quick start up time.

Carbon Capture and Storage is a way to prevent carbon dioxide building up in the atmosphere. It is a rapidly evolving technology that involves separating carbon dioxide from waste gases. The carbon dioxide is the stored underground, for example, in old oil fields or gas fields such as those found in the North Sea.
This technology traps some carbon dioxide emitted by power stations and stops it from entering the atmosphere. It is carbon negative.

Nuclear Power Stations

How do we get energy from the nucleus?

The fuel used is either Uranium or Plutonium. The nucleus is unstable because it is extremely large. When a slow moving neutron is absorbed by the nucleus it causes the nucleus to split into two smaller nuclei. This is called nuclear fission.

These neutrons will repeat the process.

Inside a Nuclear Reactor

Nuclear reactors use Uranium or Plutonium to generate heat and turn water into steam. The Uranium is stored in sealed cans in the reactor core. Uranium has an unstable nucleus which can split into two smaller nuclei releasing energy, this is nuclear fission.

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