Sonnen said this week it planned to take part in a pilot project on grid congestion management – something akin to, but slightly removed from, grid balancing. It explained that what can sometimes happen is like a traffic jam on a motorway, as the electricity grid experiences blockages at points where it is over-burdened.
These bottlenecks can be compensated by means of targeted charging or discharging of the system and Sonnen plans to try using its virtual battery, made up of thousands of home batteries, to help grids address this issue.
This German project is only coming to light now, but began in April 2019 with TransnetBW, a local transmission operator in Baden-Württemberg, a region of Germany, and energy distributor Netze BW. They approached Sonnen and the pilot was set up, with support from Baden-Württemberg’s Ministry of the Environment.
Those sonnenBatterie units installed in this region can be charged or discharged, depending on demand, in order to selectively remove power from congested network nodes, or to put it back. The closer a storage system is when it intervenes into a bottleneck, the greater the benefit in terms of assisting the electricity grid.
Presumably some sonnenBatterie will be closer than others and will be intelligently selected for the task. It is controlled by Sonnen’s DA/RE software, which stands for Data Exchange in Redispatch and Sonnen calls it a pioneering development in the field of grid security. The aim is to use the potential for flexibility inherent in decentralized systems to stabilize the entire electricity system.
We’re not sure anything like this has ever been tried before, but we can find no mention of it and it does provide the potential to present home batteries with another revenue, essentially making them cheaper to install in the first place – and more available to finance funding. This is precisely what happens in front of the meter in grid scale batteries for grid stability.
“The great strength of Sonnen’s virtual battery lies in the available flexibility that is distributed over the whole state. The networked sonnenBatteries are able to use their storage capacity to provide the grid with an effective buffer within a matter of seconds; right where the bottleneck actually exists,” says Jean-Baptiste Cornefert, Managing Director of Sonnen eServices. And of course no investment in infrastructure is required, in markets where sonnenBatteries are already widely installed.
Redispatch is one way of providing flexibility, which Sonnen is in a position to offer with its virtual battery. The sonnenBatteries are selectively charged or discharged as required to provide the necessary compensation. By means of this congestion management, Sonnen can ensure that no “jams” arise in the transmission and distribution networks.