Blockchain has the potential to simplify entire industries, trade and supply chains. It saves paper, electricity and the use of recyclable materials, because all necessary documents are digitalised, to which everyone involved has access. With a private block chain, small businesses can trade electricity, gas and renewable energy certificates. Blockchain offers a reliable way to track greenhouse gas emissions, as emission data from industrial plants, cars or airplanes are recorded directly. If someone is obliged to present CO2 certificates, they can search for suitable suppliers via the decentralised block chain network and offset their emissions simply and directly online.