Renewable energy certificates (also known as RECs, renewable energy credits, green tags, green energy certificates, or tradable renewable certificates) represent the technology and environmental attributes of one megawatt hour of electricity generated from clean renewable sources. These attributes may be sold separately from the associated electricity.

Because RECs are sold separately from electricity, they can be purchased from locations anywhere, enabling organizations to support clean energy. Here in Connecticut, ratepayers can support clean energy by buying RECs through the CTCleanEnergyOptions Program.