Everyone is probably familiar with the old saying: “My electricity comes from the socket.” But of course, the matter is a bit more complicated. Behind energy supply lies a highly complex technical and economic structure involving two worlds: the physical world and the accounting world. In the physical world, electricity from a wide variety of sources is flowing through power grids locally and across Europe – thankfully, increasingly less from oil, gas, and coal, and more and more from hydropower, biomass, geothermal energy, as well as solar and wind energy.
"But especially users of green electricity want to be certain that the energy they consume comes exclusively from renewable sources. This is where the accounting system comes into play: In principle, electricity providers in Germany are allowed to market their electricity tariffs as green electricity if they meet the statutory minimum requirements. Additionally, providers must cancel guarantees of origin (GO) for the electricity from renewable sources they supply, in accordance with §42 of the German Energy Industry Act. This is done using the Register of Guarantees of Origin maintained by the Federal Environment Agency. The register documents how much electricity is generated from renewable energy sources. For each megawatt-hour of green electricity produced, the energy producer receives a digital certificate. This certificate, which serves as proof that a megawatt-hour of green electricity was generated, can then be sold by the producer to an electricity provider in Europe. The provider, in turn, sells the green electricity to its end customers in exactly the same quantity as it holds guarantees of origin in the register. This ensures that for every megawatt-hour of green electricity, one certificate is uniquely cancelled in the register. Once cancelled, the provider can no longer use or pass on the certificate. So far, so good."
