Energy world



Acid rain
Rain that has become acidic (with a pH of less than 5.6) from the reaction between oxygen in the atmosphere and NOx and SO2, released into the atmosphere when fossil fuels are burned, resulting in mild sulphuric, nitric and other acids being formed. When it falls as a mild acidic solution, it can slowly corrode buildings and be harmful to the environment.

A group of objects that operate together, such as solar panels connected together in a power system.


A thousand million or 1,000,000,000. ‘Giga’ is the prefix for a billion – a gigawatt is one billion Watts.

Energy produced from the use of biofuels.

Fuels made from any recent living organic materials or their by-products such as wood and straw, or gas generated by the breakdown of manure by bacteria.

Any recently living or organic material for example trees, crops and vegetable peelings.


Carbon dioxide
A colourless, odourless gas. It is denser than air. Each carbon dioxide molecule is made of one carbon atom and two oxygen atoms. The symbol for carbon dioxide is CO2.

Carboniferous Period
The name given to the period of time between 345 and 280 million years ago.

When a material deteriorates due to a chemical reaction with its environment it has been corroded. something. An example being the oxidation of iron to form iron oxide (rust). 


No longer in service.


The process of producing chemical changes in a substance by passing an electric current through it.

A form of alcohol. It is found in alcoholic beverages but can also be used as a fuel.

A source of power that makes people move or objects work.

To breathe out.


Fossil fuel
Any fuel made from ancient animal or plant remains, such as coal, oil, gas and peat.


This is one of the new ‘cleaner coal’ technologies. In this process coal is washed, ground into a fine powder and then reacted with oxygen and steam to form a gas. The gas can then be burnt in a gas turbine to produce electricity.

A device that either uses a rotating magnet and fixed coils of wire, or a fixed magnet and rotating coils of wire to produce electricity.

Heat energy from the Earth.

A gigawatt (GW) is one billion Watts.

Gravitational potential energy
This is the energy that an object has if it is above the ground and could possibly fall under the effect of gravity.

Greenhouse effect
The process by which heat energy from the Sun is trapped in the Earth’s atmosphere. Certain gases in the atmosphere, such as carbon dioxide, cause the greenhouse effect.

Greenhouse gases
Gases that absorb the heat of the sun in the Earth's atmosphere, producing the greenhouse effect. Carbon dioxide is a major greenhouse gas. Other greenhouse gases include methane, ozone, chlorofluorocarbons, and nitrous oxide.


A very quick loss of a valuable substance.

Heat exchanger
A device that transfers heat from one liquid or gas to another. It can do this through a solid wall or even if the liquids or gases are in contact with each other. They are used in fridges and in air conditioning.


An energy link between different countries or systems. Examples are the electrical interconnector between the UK and France and the gas pipeline linking the UK with the European gas network at Zeebrugge in Belgium.


A Joule (J) is a unit of energy.


A kilowatt (kW) is one thousand Watts.

Kilowatt hour
A kilowatt hour (kWh) is a unit of energy. One kilowatt hour is the amount of energy that would be used by a device with a power of 1 kilowatt which was left to operate for 1 hour. It is equivalent to 3,600,000 joules.

Electricity companies measure the amount of electricity we use in our homes in kilowatt hours and they often call each one a ‘unit’.

Kinetic energy
This is the energy that a body has because of its motion.


A megajoule (MJ) is one million Joules.

A megawatt (MW) is one million Watts.


National Grid
A giant network of overhead lines and underground cables used to transport all of the electricity supplies around the country.

Net exporter
If a country exports more of a particular item than they import, they are said to be a net exporter of that item.

Net importer
If a country imports more of a particular item than they export, they are said to be a net importer of that item.

A particle with no electrical charge which, together with the proton, makes up the nucleus of an atom.

Energy resources which, once used, cannot be replaced. Examples are coal, oil and gas.

Nuclear fission
The process of releasing energy from the nucleus of a large atom by splitting it into two or more pieces.

Nuclear fusion
The process of releasing energy from the nucleus of a small atom by fusing it together with the nucleus of another small atom.


The use of semi-conductors, such as silicon, to produce electricity directly from sunlight. Often shortened to ‘PV’.

A particle with a positive charge which, together with the neutron, makes up the nucleus of an atom.

To grind or crush into a fine dust.


Any energy resource that cannot be ‘used up’. Examples are solar power, wind power and wave power.


A material that can conduct electrical current better than an insulator, but not as well as a conductor. Silicon and germanium are examples of semi-conductors. They are widely used in electronic components because their electrical conductivity can be changed by the application of an electric field.

Strip mining
Mining thin seams of coal near the surface by stripping away the surface material above them to enable large excavators to be used to recover the coal.

Sulphur dioxide
A colourless, rather smelly gas. It reacts with water and oxygen in the air to produce sulphuric and sulphurous acids, which can fall as acid rain.

Something that will be able to be maintained in the future.

This is gas used in ‘cleaner coal’ technology power stations. It is created by reacting coal dust with oxygen and steam at high-pressure. The resulting synthesis gas or ‘syngas’ contains a large proportion of hydrogen.


A terawatt (TW) is a unit of power equivalent to 1 trillion Watts. A trillion is a 1 followed by 12 zeroes or 1,000,000,000,000 A trillion is generally written as 1012.

A terawatt hour (TWh) is a unit of energy equivalent to 3,600,000,000,000,000 Joules. That is the amount of energy used by a machine rated at 1 terawatt power (i.e. using a trillion joules per second), operating for one hour.

A device where blades are rotated by the force of a stream of liquid or gas.


Something that will not be able to be maintained in the future.

A type of uranium where the nucleus is made up from 92 protons and 143 neutrons.

A type of uranium where the nucleus is made up from 92 protons and 144 neutrons.


A Watt (W) is unit of power. 1 Watt is equivalent to 1 Joule per second.