South Gloucestershire FoE has pledged to try and get 50 people to sign up for 'green' electricity. 'Green' electricity comes from renewable sources, such as wind, wave, hydro, tidal, solar, geothermal or biomass. All of us, as consumers, can now buy our electricity from whichever company we choose, and some companies are now offering green electricity.

Lots of electricity companies make green claims, but not all are quite what they seem. So Friends of the Earth recommend four electricity company tariffs:-

• Good Energy,
• Ecotricity 'Old Energy' tariff
• Green Energy 100
• RSPB Energy (from Scottish and Southern Energy plc)

The electricity you get is exactly the same regardless of who you buy it from. The electricity supply companies are effectively retailers; they contract to buy electricity from the producers, the electricity generators, so what matters is who they buy it from. Some suppliers also generate, but the theory is the same if you draw a line between the retail and generation parts of the company.

All the electricity goes into a vast pool - the National Grid - that you draw your electricity from. When you buy green electricity, the supply company is promising to buy that much electricity from a green generator. What matters is where your money goes, rather than where the electrons came from. At any one moment there may be no windmills turning if there is no wind, but over a period the windmill owner will be paid using your money for the amount of electricity you have used.

However, the government requires all supply companies to buy a proportion of their electricity from renewable generators, currently 3%. So a supply company could sell 3% of its electricity as green electricity at premium prices without doing anything more than its legal minimum.

It has now become more complicated because the renewable obligation can be traded. A supply company buying more than the 3% renewable can sell its surplus at a premium to another supply company with less than 3% renewable. This means there is a premium for renewable electricity even if there were no consumer demand. The supply company can sell its green electricity twice by selling once to another supplier and once to consumers.

The companies and tariffs recommended by FoE all buy as much green electricity as they sell, and do not sell it on to other supply companies. FoE also does not count as green any electricity generated from refuse incinerators.

The company Ecotricity has a slightly different approach. It is a renewable generator as well as a supplier, and it undertakes to spend most of its profits on building more renewable generation, i.e. more windmills. It only has enough windmills to generate about 10% of its supply, so it buys the rest from the general brown (i.e. non-green) electricity market. Ecotricity offers two tariffs to consumers, 'Old Energy' that is 100% green to satisfy FoE, and 'New Energy' that is 90% brown, but funds the building of new windmills.

Alan