Rapid change happens when new technologies “marry”. When the telephone and the computer wedded, the Internet was born. Now, an interesting marriage emerges between microgrids, providing sustainable, renewable energy and the blockchain, the bitcoin technology to record transactions. Transactivgrid is a sustainable energy grid based in Brooklyn, New York. The grid connects users to solar energy in the neighborhood and makes use of a blockchain system to ensure all payments are secure. The blockchain allows the energy transactions within the microgrid to be recorded and effectively verified for buyers and sellers even on a very small scale—this ensures that no energy is lost.