As well as reducing our energy consumption we need to change the way energy is produced. Not everyone is in a position to be able to purchase technologies such as photovoltaic cells or wind turbines, but it’s worth looking at where your electricity comes from. You could, for example, consider going on a green electricity tariff, which, in theory, means that some or all of the energy you consume has come from a renewable source, but the way the tariffs work is quite complex. The amount of energy that comes from renewable sources varies from company to company, and some tariffs are better than others.

Good Energy: This company can supply electricity in Mendip, and is currently the UK's only electricity company selling 100% renewable electricity. It also supplies electricity to Friends of the Earth and makes a £30 donation to them if you switch. Call 0845 4561640.

There are other companies offering 'green' tariffs, and the following offer advice on switching. is an independent, CO2 footprint and price comparison service which provides customers with free advice on green energy deals. You can also call their hotline on 0800 634 1606.

Green Electricity Marketplace lists and analyzes green tariffs.