Germany's heatwave fuels electricity price spikes, sparks storage tech

A prolonged heatwave in Germany has created a mismatch between renewable generation and demand. Strong, wind‑still high‑pressure conditions have curtailed wind output while abundant solar power in daylight has led to negative spot prices as supply exceeds consumption. After sunset, the lack of dispatchable coal and nuclear plants, combined with high CO₂ levies on the remaining fossil units, has caused night‑time electricity prices to soar above 70 ¢ per kWh.

In response to the recurring over‑production of green electricity, a start‑up in Gießen — Powerlith GmbH — has deployed a novel high‑temperature storage system. The pilot, operating since 2022, uses ceramic stones heated up to 1,200 °C by excess solar power, achieving up to 95 % efficiency and the ability to store heat for weeks. The stored heat can later be converted back to electricity or supplied as process heat to industry, offering a potential solution to Germany’s intermittent‑renewable challenges.