As the central register for the energy transition, the Market Master Data Register (MaStR) collects data on all relevant market players in the electricity and gas energy markets and, in a second step, on all generation plants: All new plants and all existing plants, plants for the generation of renewable and conventional energy, electricity and gas generation plants. If you operate an electricity or gas generation plant (e.g. photovoltaic plant, wind energy plant, combined heat and power plant, battery storage, biomethane plant), you must register it in the MaStR. You are also obliged to register if no subsidy is granted or claimed for the electricity from the plant. All running plants must be registered regardless of when they were commissioned - even if your plant has been running for many years. This means that even if you have already registered your plant in various other places, for example with your grid operator or in previous registers of the Federal Network Agency, you must register these plants again in the MaStR. As a citizen (natural person), you can also register via forms in exceptional cases upon request. Authorities can access the data in the MaStR. This enables them to either significantly simplify their own surveys or dispense with them altogether. Plant operators and other market players can refer to the data they have entered in the MaStR.