There are a number of suppliers offering 'green' electricity in the United Kingdom, either supplying electricity

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

 from existing environmentally friendly

Environmentally friendly

Environmentally friendly are terms used to refer to goods and services, laws, guidelines and policies claimed to inflict minimal or no harm on the environment....

 energy sources, promising to invest a proportion of profits into new renewable energy

Renewable energy

Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...

 generating capacity, carrying out carbon offset

Carbon offset

A carbon offset is a reduction in emissions of carbon dioxide or greenhouse gases made in order to compensate for or to offset an emission made elsewhere....

ting, or some combination of these approaches.

Care needs to be taken in selecting a green energy supplier. A National Consumer Council report in December 2006 concluded that many green tariffs are not delivering the environmental benefits they claim to, and that consumers may not be making the positive contribution they think they are.
In the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, suppliers are legally obliged to purchase a proportion of their electricity from renewable sources under the Renewables Obligation

Renewables Obligation

The Renewables Obligation is designed to encourage generation of electricity from eligible renewable sources in the United Kingdom. It was introduced in England and Wales and in a different form in Scotland in April 2002 and in Northern Ireland in April 2005, replacing the Non-Fossil Fuel...

 and there is a danger that energy suppliers may sell such green electricity under a premium 'green energy' tariff, rather than sourcing additional green electricity supplies.