SGRE officially launched its Electric Thermal Energy Storage (ETES) project in Hamburg, northern Germany.
Volcanic rocks are heated to 750C using a resistance heater and blower, which can be powered by wind turbines.
The heat can then be used to generate steam to drive a power generator during periods of high demand.
SGRE’s pilot can store 130MWh of energy for up to one week, the turbine manufacturer said, but added it plans to grow the technology to provide GWh of storage.
"The technology reduces costs for larger storage capacities to a fraction of the usual level for battery storage," according to SGRE.
SGRE is partnering with local utility Hamburg Energie — which will market the stored electricty — and the Hamburg University of Technology on the pilot, which has received funding from the German government.
SGRE also claimed the technology offers a second-life option to existing power plants as it uses standard components.
"Decoupling generation and consumption of fluctuating renewable energy via storage is an essential contribution to implementing the energy system transformation. We therefore need cost-effective, efficient and scalable energy storage systems," said Andreas Feicht, state secretary at the federal ministry of economics and energy, who attended the official inauguration.