Electricity is a convenient secondary energy source. It can be generated from various primary energy resources - renewable ones such as wind, water or solar power, or non-renewable ones such as fossil fuels and nuclear fuels.
Renewable energy resources such as solar power and wind power can meet some of the UK's electricity needs. Each resource has advantages and disadvantages. But in all cases some energy is lost to the environment. Fossil fuels produce carbon dioxide when they are used. Nuclear fuels generate harmful radioactive waste - different levels of which are stored in different ways.
[ This page has been adapted from www.bbc.co.uk/schools/gcsebitesize/science