The Renewable Energy Certificate System (RECS) is a voluntary system for international trade in renewable energy certificates that was created by RECS International to stimulate international development of renewable energy. It advocates the use of a standard energy certificate to provide evidence of the production of a quantity of renewable energy, and provides a methodology which enables renewable energy trade, enabling the creation of a market for renewable energy and so promoting the development of new renewable energy capacity in Europe.
A RECS energy certificate is issued for every 1 megawatt-hour (MWh) of renewable energy produced by an electricity generation facility that has been registered with the relevant national RECS issuing body. These certificates can be transferred between market parties in different countries, and are used to provide evidence of the consumption of renewable energy – at which point they are made non-transferable, in order to ensure that the "renewable benefit" is not double-sold.
The market for RECS certificates is administered by the Association of Issuing Bodies (AIB) according to its European Energy Certificate System (EECS), in the same way as the obligatory guarantees of origin required by the various European Union Directives that are gradually replacing voluntary RECS certificates in Europe.