Households replacing power stations in Germany - sonnen is putting the largest virtual battery of its kind into operation creating the power grid of the future

For the first time, sonnen is providing balancing power for the energy market by means of residential energy storage systems networked across the whole of Germany. The sonnen virtual battery, which is now online, is currently the largest of its kind that is able to compensate for fluctuations in the power grid. As a result, German households are now in a position to take over all the tasks of conventional power stations.

Wildpoldsried, Bayreuth, Olten (CH) 05.12.2018 – sonnen together with its technology partner, tiko Energy Solutions, has obtained pre-qualification from the transmission system operator TenneT to provide primary balancing power using its Germany-wide network of residential battery storage systems.

In this way, sonnen is providing the energy market with the largest virtual battery currently available consisting exclusively of individual residential energy storage systems. Now along with supplying its customers with clean and locally-generated electricity, sonnen is now able to provide flexibility for the energy markets and expanding its offering to act as the utility of the future. The virtual battery will be used to compensate for fluctuations in the power grid among other services.

“As a young company, we are very proud to be writing energy history. In doing so, we are showing that our customers in Germany can assume all of the functions that were previously reserved for large power stations. They can create and store energy and also ensure the security of supply within the power grid. The shift from the old energy system with central power stations to a new distributed system with the people at its core, is finally coming about as a result", says Jean-Baptiste Cornefert, Managing Director of sonnen eServices.

The sonnen virtual battery takes a unique approach. It consists of thousands of individual energy storage systems installed across the entire country, each of which can be used to manage energy consumption for individual households. In addition, when fluctuations arise in the power grid, these batteries independently arrange themselves into a large-scale virtual battery. Since each sonnenBatterie has a different state of charge the large number of individual batteries will be aggregated into blocks starting at 1 MW, which are then made available to the energy market. During TenneT's certification of the virtual battery, it had to first discharge one megawatt of power to the grid and then re-charge the same amount back from it within 30 seconds. With the passed test, the virtual battery has qualified for participation in the so-called primary operating reserve market.

The power from the virtual battery can be used to rapidly compensate for short-term fluctuations in the power grid within the shortest possible time. If deviations arise in the grid frequency of 50 Hz, the energy storage systems are able to automatically, and in a matter of seconds, either supply energy to the power grid or take energy from it - depending on what is currently required. Until now, it has mainly been CO2-intensive power stations that have been used for this primary balancing power; sonnen’s networked residential energy storage systems are helping accelerate the removal of these power stations from the grid in Germany.

 “We are proud of the fact that with sonnen we are now able to implement our virtual power plant technology. This is pioneering work for the German market; it means that energy storage systems are able to deliver the two-fold benefits of managing personal consumption while providing various services to the energy market. With sonnen, we have now been able to show, among other things, that it is also possible to provide primary balancing power in Germany by means of home energy storage systems," says Fréderic Gastaldo, CEO of tiko Energy Solutions.

"The ability of networked battery storages operating as a virtual power plant to stabilize the grid in the event of frequency fluctuations is another step on the way to a greater system integration of renewable energy," said Lex Hartman, CEO of TenneT. System services that serve to stabilize the power supply would previously be provided mainly by conventional power plants. With the increasing share of renewable energies in electricity generation, renewables will need to take on a greater responsibility, Hartman said.

Pre-qualification for the primary balancing power market is subject to the most stringent of requirements in terms of technology and safety in the energy market. By achieving the highest level of certification, sonnen’s network of residential energy storage systems is destined to provide further services within the power grid. In contrast to large stationary storage systems or fixed power stations, sonnen’s flexibly distributed virtual power plant can be deployed in nearly every location in Germany.

sonnen has around 30,000 sonnenBatterie systems in Europe, each with a capacity between 5 to 15 kWh. The total network has a capacity of up to 300 MWh and the potential to supply around 120,000 households with electricity for one hour.