Siemens Gamesa Renewable Energy (SGRE) has commissioned a pilot electric thermal energy storage system (ETES) in Hamburg-Altenwerder, Germany.

Representing a significant step forward in energy transition, the newly opened plant will have the capacity to store 130MWh of power for up to seven days.

Siemens Gamesa renewable energy CEO Markus Tacke said: “With the commissioning of our ETES pilot plant, we have reached an important milestone on the way to introducing high-performance energy storage systems.

“Our technology makes it possible to store electricity for many thousands of households at low cost. We are thus presenting an elementary building block for the further expansion of renewable energy and the success of the energy transition.”

The company’s cost-effective system has the capacity to store large quantities of energy. SGRE’s facility comprises nearly 1,000t of volcanic rock as an energy storage medium.

The rocks are heated to 750°C using a blower and a resistance heater that converts electrical energy into hot air. The stored energy is re-electrified with the help of a steam turbine.

The Hamburg University of Technology’s Institute for Engineering Thermodynamics and local utility company Hamburg Energie are participating in the project, which is called Future Energy Solutions.

The German Federal Ministry of Economics and Energy has funded the project.

TU Hamburg conducts research into the thermodynamic fundamentals of the solid bulk technology used, while the Hamburg Energie oversees the marketing of the stored energy on the electricity market.

In the future, SGRE intends to develop a system that can store energy in the range of several GW hours.