The Renewables Obligation (RO) Certificate scheme was initially introduced in 2002, designed to incentivise renewable generation into the electricity generation market. It is overseen by Ofgem, who manage the whole process and all payments.
The following is a description from the Ofgem Guidance Document, detailing how the ROCs scheme works;
Accredited generators are issued ROCs based on the net renewable electricity that is generated each month by an accredited renewable generating station. ROCs can then be sold directly or indirectly to suppliers who will redeem them against their renewables obligation.
The number of ROCs issued per megawatt hour (MWh) is determined by the technology/fuel used by the station, its size, its location and how long it has been accredited under the RO. In order to be accredited under the Orders, generating stations must meet certain statutory criteria. Once accredited, further criteria must be met if ROCs are to be issued.
If accreditation has been granted and ROCs have been issued, the onus is then on the generator to transfer the certificates to a suitable party. We have no responsibility for ROCs once they have been issued, unless we are of the view that they should not have been issued in the first instance and should be revoked.
Once a ROC has been issued and transferred to a supplier, that supplier can redeem that ROC against their renewables obligation. The ROC can only be redeemed by a supplier against the obligation period in which it was issued or against the following obligation period. For example, a ROC issued in respect of generation in June 2011 can be redeemed by a supplier in respect of the 2011/12 or 2012/13 obligation periods only.
In terms of seeking accreditation and being issued with ROCs, operators of renewable generating stations will need to comply with the following steps. The onus is on the generator to ensure that they are familiar with our Register and generator guidance documents in advance of setting up a generator account and using the functionality of that account.