Anyone who believes that batteries will make long-term storage of electricity in the grid possible is mistaken. A solution for bridging dark lulls when the sun is not shining, and the wind is not blowing is not in sight with this technology. But batteries can certainly contribute to stabilising an electricity grid with a high proportion of wind and solar power. And that is also necessary. Because volatile renewables have made electricity grids much more vulnerable. Explanations by Hans-Peter Sollinger: