With more than a million homes in Germany having solar panels on their roofs, Germany can produce more renewable energy than it can use at times. Now Germany is turning to home battery-storage systems that are connected to the grid as a solution to the problem of excess electricity. These systems can soak up energy from the sun during the day, and use that energy after the sun sets when energy consumption tends to rise. Thus far, 100,000 German homes have installed battery-storage systems.