It was no April Fool’s joke, and it fundamentally changed Germany and the world of energy supply: 25 years ago, on April 1, 2000, the Renewable Energy Sources Act (EEG) was passed. It has accelerated the expansion of electricity and heat generation from wind, solar, hydropower, biomass and geothermal energy. The combination of feed-in tariffs and access to the electricity market and grid proved to be a recipe for success and an export hit: Worldwide, the EEG was an important starting signal for the rapid development of renewables, whose costs have fallen so dramatically that they are the cheapest source of electricity in large parts of the world. Many countries have copied the design of the EEG.