A house today, together with its appliances such as a heating pump, refrigerator or consumer electronics, is usually an electricity consumer. However, a Smart Grid will make it possible to reverse the flow of current. Photovoltaic systems are today already feeding electricity into the supply network. In the future, the car may also become an power supplier. The idea: when a large amount of electricity is available, the car battery charges up. If power consumption increases, for example in the early evening, the flow is reversed. The car feeds electricity into the network. In the future, when millions of electric cars are connected to the supply network, they will even be able to buffer the fluctuating supply of solar and wind power. In place of building storage systems to cushion current fluctuations, cars and their batteries will automatically provide storage capacity.