Almost every supplier now sells a “green” tariff. Many of them simply buy guarantees of origin: certificates from existing hydro plants, often in Norway, that cost a fraction of a cent per kilowatt-hour. The power in the grid and the plants being built do not change.
What to look for
A green supplier worth the name buys its electricity directly from renewable producers, invests in new plants, and has no links with coal or nuclear companies. Independent labels such as the German Grüner Strom Label or the ok-power label check this, and Greenpeace France ranks the French suppliers every year.
Why cooperatives
Energy cooperatives belong to their customers. Profits go back into new solar and wind projects rather than to shareholders, and members have a vote.