Siemens Gamesa has started building a facility in Hamburg which will use hot rocks to store energy.
The project aims to use surplus power from wind farms to run heaters, taking approximately 1,000 tonnes of rocks up to 600°C.
This heat will drive a 1.5MW steam turbine, feeding electricity back to the grid when demand outstrips supply.
The wind turbine manufacturer’s current build is a 30MWh precursor to a GW-scale thermal facility, planned for early 2019.
It is expected to store enough thermal energy to deliver electricity for up to 24 hours at a system efficiency of around 25%, potentially rising to 50% if the technology is scaled up to more than 100MW.
At that scale, Siemens Gamesa expects the technology to deliver stored energy at a cost of less than £0.09 per kWh.