The Renewables Obligation (RO) 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 (the Renewables Obligation (Scotland)) in Scotland in April 2002 and in Northern Ireland in April 2005, replacing the Non-Fossil Fuel Obligation which operated from 1990. The RO places an obligation on licensed electricity suppliers in the United Kingdom to source an increasing proportion of electricity from renewable sources, similar to a renewable portfolio standard. In 2010/11 it is 11.1% (4.0% in Northern Ireland). This figure was initially set at 3% for the period 2002/03 and under current political commitments will rise to 15.4% (6.3% in Northern Ireland) by the period 2015/16 and then it runs until 2037 (2033 in Northern Ireland). The extension of the scheme from 2027 to 2037 was declared on 1 April 2010 and is detailed in the National Renewable Energy Action Plan. Since its introduction the RO has more than tripled the level of eligible renewable electricity generation (from 1.8% of total UK supply to 7.0% in 2010). The Renewable Obligation scheme Suppliers meet their obligations by presenting Renewable Obligation Certificates (ROCs) to Ofgem. Where suppliers do not have sufficient ROCs to cover their obligation, a payment is made into the buy-out fund. The buy-out price suppliers pay is a fixed price per MWh shortfall and is adjusted in line with the Retail Prices Index each year. The proceeds of the buy-out fund are paid back to suppliers in proportion to how many ROCs they have presented. For example, if they were to submit 5% of the total number of ROCs submitted they would receive 5% of the total funds that defaulting supply companies pay into the buy-out fund. ROCs are intended to create a market, and be traded at market prices that differ from the official buy-out price. If there is an excess of renewable production, beyond the supplier obligation, the price of ROCs would fall below the buy-out price. The price of ROCs could approach zero if renewable and non-renewable generation costs became similar, when there would be little or no subsidy of renewable generation. If there is less renewable production than the obligation, the price of ROCs would increase above the buy-out price, as purchasers anticipate later payments from the buy-out fund on each ROC. Obligation periods run for one year, beginning