Energy storage systems are one of the key technologies for the energy turnaround. With their help, the fluctuating supply of electricity based on photovoltaics and wind power can be stored until the time of consumption. At Karlsruhe Institute of Technology (KIT), several pilot plants of solar cells, small wind power plants, lithium-ion batteries, and power electronics are under construction to demonstrate how load peaks in the grid can be balanced and what regenerative power supply by an isolated network may look like in the future.