Generating electricity
Electricity can be generated using a number of different energy sources and is a very convenient form of energy. Some sources are renewable while others are non-renewable.
——————————————————
Fossil fuels
Fossil fuels are a form of non-renewable energy. They include:
- – coal
- – oil
- – natural gas
All of these were created from living organisms that died millions of years ago. The energy was stored but when these fuels are burnt it’s released as heat energy.
In the UK around three-quarters of the country’s electricity is created by fossil fuels. It’s generated in power stations as shown in the flow chart below.
Fossil fuel: energy stored as chemical energy
?
Transferred as heat energy
?
Water and steam: energy stored as heat energy
?
Transferred as kinetic energy
?
Turbine
?
Transferred as kinetic energy
?
Generator
?
Transferred as electrical energy
The start up times for power stations varies with gas-fired stations taking the shortest time followed by oil-fired and lastly coal-fired. As oil-fired and gas-fired power station are the fastest to start up the electricity the produced is usually used as an extra supply at peak periods.
The trouble with fossil fuels is that there’s only a limited supply of them. It takes millions of years for them to form so once they’ve been used up they can’t be renewed.
Another major disadvantage is the fact that when they’re burned that release carbon dioxide. Carbon dioxide is a greenhouse gas and it’s build up as led to an increase in the greenhouse effect and global warming. Coal is the worst producer while natural gas creates the least amount.
Oil and coal also produce sulphur dioxide. Not only is this harmful when breathed it, it also contributes to acid rain which is bad for the environment.
To combat the build up of carbon dioxide carbon capture is being used. This involves extracting carbon dioxide from other waste products and storing it underground, for example under the sea in old gas or oil fields.