Berlin-based energy startup Lumenion has presented the pilot of its 2.4-megawatt-hour (MWh) steel storage system in a housing project in Germany’s capital. The technology would allow the company to store excess renewable electricity – produced in especially windy and sunny periods – as heat (up to 650°C) in steel plates. When required, the stored energy can be converted back into electricity by means of a turbine unit or used for heating.

“Our steel storage technology enables clean energy to be used with a time lag – both as heat and as electricity,” said the company’s founder, Alexander Voigt. “We are already planning systems with 40 and even 500 MWh.” The small pilot project in Berlin, however, does not include a power generator.

“Turning the stored energy back into electricity is not profitable under the current regulatory framework and we would normally only plan to do this with 50 MWh facilities or larger,” spokesperson Philip Hiersemenzel told the Clean Energy Wire. The installation will now be connected to a gas-fired cogeneration unit and integrated into the district power and local heating supply system operated by Vattenfall Energy Solutions. Test operation will begin in early 2020, said Hiersemenzel.