Guarantee of Origin (GoO) is the official standard to certify the renewable origin of electricity in Europe. Unbundled from the physical electricity, one guarantee of origin always represents the injection of on MWh of green electricity into the grid.

I-REC (International Renewable Energy Certificate) is the internationally used standard to certify the renewable origin of electricity. One I-REC guarantees the origin of one MWh of green electricity injected into the grid.

A Renewable Energy Certificate (REC) is the official standard to certify the renewable origin of electricity in North America, comprising USA and Canada. Unbundled from the physical electricity, one Renewable Attribute Certificate equals one MWh of renewable electricity.