Trimet, Germany’s largest producer of aluminum, is testing technology to turn its smelters into a "virtual battery" capable of delivering 1.12 gigawatt-hours of flexible capacity.

The family-owned business is investing €36 million ($39 million) in a two-year industrial-scale pilot of systems that will allow power use across 120 electrolysis cells to be dialled up or down by 25 percent in either direction, for up to several hours.