of their electricity from eligible renewables sources; a proportion that will increase each year until 2015 from a 3% requirement in 2002–2003, via 10.4% in 2010-2012 up to 15.4% by 2015–2016. The UK Government announced in the 2006 Energy Review an additional target of 20% by 2020–21. For each eligible megawatt hour of renewable energy generated, a tradable certificate called a renewables obligation certificate(ROC) is issued by OFGEM. On or before 31 September following the RO year (1 Apr - 31 Mar) Suppliers can meet their Renewables Obligation by: acquiring and redeeming ROCs, paying a buy-out price equivalent to £33.24/megawatt hour in 2006/07 and rising each year with retail price index;or a combination of redeeming ROCs and paying the buy-out price. When a supplier meets all or part of its obligation by paying the buy-out price for each MWh of its obligation not discharged by the redemption of ROCs, the money is put into a holding account called the buy-out fund. The buy-out fund is recycled before 1 November to those electricity suppliers who presented ROCs against their Renewables Obligation. This 'recycling' is distributed equally for each ROC redeemed, those suppliers who did not redeem any ROCs will receive no 'recycling' from the buy-out fund. The renewables obligation also makes requirements about how the electricity can be generated. An example is that the co-firing of biomass with coal is to be phased out - and will not be eligible for Renewable Obligation Certificates after 2016 (although the government has announced its intention to revisit the co-firing rules as part of the 2006 Energy Review). The renewables transport fuel obligation is a separate law, which although is not in force yet, is set to become law. It would require bio-ethanol and bio-diesel to be added to road fuel, up to a limit of 2 or 5.75%. The land required for this would be considerable. It has been estimated (by the NFU) that the biomass could be grown by using all of the UK's net wheat exports, and growing wheat on 1,200 square kilometres of land. Housing and community grants Grants to assist with the installation of renewable energy sources in domestic properties and for community groups were made available through the Clear Skies organisation, and the Major Photovoltaics Demonstration programme. In 2006 these were replaced by the Low Carbon Buildings Programme (LCBP). CRC Energy Efficiency Scheme The CRC Energy Efficiency Scheme