Wind farms and solar arrays steal the limelight, but the silent workhorse of the energy transition is clean power storage. This sand battery stores renewable energy as heat inside sand, releasing it when needed to warm homes and power factories. It was built by Polar Night Energy, and will be used to heat a whole town centre in #Finland. The World Economic Forum has published its annual ranking of national #energytransition efforts - from policy to investment, innovation and social equity. Where