The Renewables Obligation (RO) is a support scheme that requires electricity suppliers to source a growing share of their power from renewable generators. It began in 2002 in Great Britain, followed by Northern Ireland in 2005, and paid for much of the first wave of UK wind farms, biomass plants and large solar farms. It closed to all new generating capacity on 1 April 2017 and has been replaced for new projects by Contracts for Difference.
How ROCs work
Accredited generators receive Renewables Obligation Certificates (ROCs) for each megawatt-hour they produce. Different technologies earn different numbers of ROCs per MWh, a system known as banding. Generators sell the certificates to suppliers alongside, or separately from, their power.
Each year suppliers must present a set number of ROCs per MWh they supply, or pay a buy-out price for any shortfall. The buy-out money is shared out among suppliers who presented ROCs, which gives the certificates their value. Ofgem runs the scheme.
| Measure, 2026–27 | Figure |
|---|---|
| Obligation, Great Britain | 0.472 ROCs per MWh |
| Obligation, Northern Ireland | 0.184 ROCs per MWh |
| Total obligation, UK | 120.1 million ROCs |
| Buy-out price | £69.34 per ROC |
From 2026–27 the buy-out price is uprated with the Consumer Prices Index rather than the Retail Prices Index.
Cost and end date
Suppliers pass the cost of buying ROCs on to customers’ bills. By our own calculation (120.1 million certificates at the £69.34 buy-out price), the 2026–27 obligation is worth roughly £8 billion, which makes the RO one of the largest policy costs on electricity bills. Support for each station lasts 20 years, and the scheme ends on 31 March 2037, after which its cost will fall away.
Read more: Wind energy: how wind turbines power Britain.