A total of 140 Tesla mass storage devices have recently been installed in Terhills in eastern Belgium and connected to the national power grid. The Powerpacks have a storage capacity of 210 kilowatt hours (kWh) each and can deliver an output of 18.2 megawatts (MW) at short notice. This corresponds to just under a quarter of the 81 MW which, according to the European Network of Transmission System Operators for Electricity ( ENTSO-E ), is required for emergency supply in Belgium.

Tesla built the system together with the Belgian energy technology company Restore which, as a demand response aggregator, manages the power supply between network operators and customers. The storage devices are intended to offset fluctuations in the European power grid and to maintain the necessary mains frequency of 50 Hertz. The electricity, which is stored at high frequency in the batteries, is fed into the grid when required as a service to the grid operators – for which purpose gas turbines, for example, which are significantly more expensive to operate, would otherwise have to be used.

Another similar project is in the pipeline in the UK. In December 2017 Tesla built its biggest storage device to date in Australia: it has a capacity of 129 MWh and can feed in 100 MW of