Compare green tariffs on two things: the commercial terms and the evidence for the renewable electricity claim. Check the unit rate, standing charges, contract duration and volume terms, then ask what evidence covers your consumption and reporting period.

Certificate-backed tariffs and direct sourcing

A supplier can use REGOs to substantiate renewable generation for fuel mix disclosure. A power purchase agreement may give you a contractual relationship with a particular project. Ask who retains the certificates, how the contract deals with mismatched volumes and what the supplier will document. Both kinds of arrangement can serve different procurement and reporting goals.

Check the claim before relying on it

Match sites, dates and megawatt hours to the evidence you receive. Certificates do not trace the individual electricity delivered to a particular site. For a practical check, use our renewable electricity evidence checker. See Ofgem’s explanation of REGOs for the scheme.