The urgently needed expansion of renewable energies can only succeed in the long term if investments in PV systems are worthwhile even without subsidies. FairGrid aims to achieve this by, among other things, increasing own consumption and facilitating the marketing of solar electricity fed into the grid. FairGrid focuses on the use of decentralised control systems in households and companies, and its software offers a variety of other useful functions such as more stable electricity grids, higher energy efficiency and simple and transparent billing.