There is a certain elegance surrounding an idea out of Germany this week, which suggests that existing coal power plants can be re-purposed for energy storage, by converting the steam fired boiler into a massive battery store for energy. The idea comes from the German Aerospace Center (DLR) and it is planning a pilot using a molten salt thermal storage tanks, heated using excess renewable energy. Recently we have been seeing energy storage usually using Lithium Ion or Vanadian Flow grid scale batteries, placed alongside renewable assets in order to save their outputs for periods when the sun is not shining for solar, or the wind not blowing hard enough for wind. Batteries delay the delivery of electricity to the…