Against "dark doldrums"

An electricity storage system made of sand

The Finnish start-up Polar Night Energy uses sand to store surplus electricity. The idea has a certain charm, says "Krone" science expert Christian Mähr.

(Bild: Polar Night Energy)

The spectre of all alternative energy enthusiasts is the "dark doldrums", i.e. the windless night. A new method of bridging the gap is now literally based on sand. "Krone" science expert Christian Mähr took a closer look at the project.

A Finnish start-up had the impressively simple idea of using surplus green electricity from the sun and wind to heat a huge pile of sand. Is this a good idea? Decades ago, when solar panels were dauntingly expensive, such a proposal would have been considered crazy: turning precious solar power into heat, the "lowest" form of energy? Impossible! But times have changed.