Avacon begins battery storage test in the city grid

15.04.2025

Source: E & M powernews

Avacon and Rolls-Royce are testing the use of large-scale battery storage systems in Twistringen. These are intended to cushion PV peaks and stabilize the power grid.

Avacon is working with Rolls-Royce to investigate how battery storage systems can help stabilize the grid in urban power grids as part of a field test in Twistringen, a town with a population of 13,000 located 100 kilometers northwest of Hanover (Lower Saxony). To mark the start of the second project phase, the partners presented the large-scale battery storage system installed at a school to the public on April 15 - with Lower Saxony's Economics Minister Olaf Lies (SPD) among the guests.

The Twistring storage facility has an output of 1.25 MW and a storage capacity of 2,500 kWh. The aim of the second project phase of the "Twistringen Energy Platform" is to show how generation peaks from photovoltaic systems can be absorbed in densely populated urban areas. The project follows on from the first project phase in Abbenhausen, a district with a population of 450. According to the partners, it has been shown on a smaller scale that the targeted use of large-scale storage systems can help to dampen PV peaks. "Balancing too much and too little can lead to an overall reduction in the price," said SPD politician Lies on the importance of storage systems.

Background: In the "Twistringen Energy Platform" research project, households initially store self-generated energy in home storage units. Surplus green electricity is stored centrally in a large battery storage unit. A smart software platform controls the interaction of the systems without affecting the households' own consumption. The aim is to increase the local self-consumption rate and relieve upstream voltage levels.

Systemic perspective on the energy transition

Lies sees battery storage systems as playing a key role in the success of the energy transition: "The storage issue is crucial. Projects such as the Twistringen energy platform show how smart storage solutions can work locally and stabilize grids." However, he also warned: "Battery storage is not a panacea where it doesn't matter where it is located." According to the designated successor to Minister President Stephan Weil (SPD), it is important to have a systemic view of the energy transition and to choose the location of the storage systems carefully.

Rainer Schmittdiel also addressed the importance of the location issue. Avacon's Chief Technology Officer sees great potential in the targeted use of battery storage systems - but only under the right regulatory framework conditions. "For storage solutions to have a positive impact on grid expansion measures, the location and control system must be right. This is exactly what we are demonstrating in Twistringen".

He explained: "Battery storage systems are not useful for the grid per se. We need to install them in places in the grid where they are at least grid-neutral." If installed in the wrong places, this could result in additional grid expansion and "that cannot be the goal." Their operating mode must be controllable in a grid-friendly manner in order to relieve the grid and store as much renewable electricity as possible and release it again where needed. A nationwide expansion of battery storage is only possible if legal requirements reward grid-friendly behavior.

Enormous number of applications for grid connection

The demand for large-scale storage systems is high: according to Avacon, there are currently over 1,500 connection applications for its own grid area alone, which want to connect a total output of 95,000 MW to the grid - "and that's just in relation to Avacon," says Schmittdiel. "The grid load in the whole of Germany is 80,000 MW". These figures show the "disparity between what investors want to connect to the grid and what we can connect".

It is now up to the grid operators to select the locations where battery storage makes sense based on ecological and economic aspects - together with politicians and investors. "At the end of the day, this saves on grid expansion and is easy on all of our wallets," said Schmittdiel, referring to the level of grid fees.

Lukas Köhler from Rolls-Royce Power Systems, provider of the MTU storage system installed in Twistringen including software control, also emphasized the contribution of intelligent software to grid stabilization. "Linking our battery storage system with PV systems and home storage systems shows how energy availability and security can be controlled digitally," said Köhler. His company sees "enormous growth" in the battery storage sector. According to Köhler, it is the "fastest growing business area for us".

Author: Davina Spohn