Increasingly, our customers are looking to us to offer them a choice of products with environmental benefits, so we've developed a number of propositions for both the domestic and business sectors.

In the domestic market we launched Go Green, a combined electricity and gas tariff which matches customers' electricity usage with renewable-source electricity, and balances C02 emissions from gas consumption through investment in sustainable projects around the globe. In 2007 we supplied 58.1GWh of renewable electricity and 23.3GWh of gas with carbon offset to residential customers. Offsetting for gas emissions was undertaken by Climate Care, a world-leader in originating and managing emission reduction projects.

In the business market, our Climate Change Levy (CCL) Exempt products provided customers with the opportunity to avoid paying the Climate Change Levy of £4.41/MWh, as we submitted CCL exempt certificates on their behalf. There are currently two types of CCL products available, from either renewable sources or good quality combined heat and power (CHP), and in each case we generate or buy the equivalent amount of CCL exemption certificates.

Another innovative product was Business EasyGreen, available to business customers consuming less than 10 GWh per year. Here, we match every unit of electricity EasyGreen customers use with a unit generated from renewable sources to put back into the National Grid. In parallel to this, we'll offset a business's carbon emissions by working with Climate Care to help fund sustainable energy projects.

The prices of our Go Green and EasyGreen products are slightly above our standard rates, partly covering the additional cost of offsetting, but also because of the wholesale market value of renewable electricity and the opportunity cost of renewable electricity sold into the residential market.