Price signals to make large-scale batteries even more grid-friendly

04.09.2025

Source: E & M powernews

A team from the consulting firm Neon Neue Energieökonomik was commissioned by Eco Stor to investigate the question of how useful large-scale batteries are for the grid.

Large-scale storage systems have made the headlines in recent months and years, not least due to the large number of grid connection applications for large-scale storage systems and the grid operators' reactions to them. The fall in prices for battery cells and market opportunities, for example on the balancing power market, have paved the way for battery storage systems to enter the electricity system.

The authors write in their introduction that large-scale batteries are sometimes criticized for "optimizing themselves on the market at the expense of the grid". However, the fact that battery storage systems are actually based exclusively on market prices - regardless of the local grid situation - is due to the German electricity market design. Grid congestion would not be priced in a uniform price zone. As a result, "all players on the electricity market are blind to the grid".

Against this backdrop, the question often arises as to whether batteries are useful for the grid. The team led by Prof. Lion Hirth wants to answer this question and at the same time define "grid serviceability" in the first place. This can be summed up in a nutshell: Grid-compatible is what reduces grid costs.

Based on two large-scale batteries, one in Schleswig-Holstein and one in Bavaria, the authors of the study are able to prove - surprisingly for them, as they write - that large-scale batteries actually relieve the grid. According to the study, they can avoid redispatch costs of 3 to 6 euros per kW of battery capacity per year.

Dynamic redispatch price signal most promising

"In this sense, large-scale batteries are therefore by no means to be classified as a burden on the grid, even if this is sometimes suggested in the energy policy debate," emphasizes Lion Hirth. However, the grid relief is purely coincidental, as there are no regional prices that take grid bottlenecks into account.

The client of the study, storage system developer Eco Stor, sees batteries as an indispensable element of the energy system of the future. In order to "get the best out of batteries", however, grid-friendly incentives are necessary, says Managing Director Georg Gallmetzer.

For this reason, the authors of the study investigated which instruments can strengthen grid support, because even if large batteries are already reducing redispatch costs today, this contribution is much smaller than it could be.

According to the authors, of the three instruments analyzed, one price signal proved to be particularly promising, increasing the electricity price by 100 euros/MWh in the event of positive redispatch demand at the affected location and decreasing it by 80 euros/MWh in the event of negative redispatch demand. This creates a targeted financial incentive for storage facilities to act in a grid-friendly manner in congestion situations.

"A dynamic redispatch price signal creates both the greatest added value for the grid and the least loss of added value for the market," explains Clemens Lohr from Neon. The existing market signal would be specifically changed in the direction of grid-friendly operating modes without restricting participation in day-ahead, intraday or control power markets.

Against this backdrop, the economists propose a special grid fee as the instrument with the greatest economic value added, which is determined daily by the grid operators and reflects the expected local congestion situation.

The study "Netzdienlichkeit von Großbatterien" is available on the Internet. It is an extension of the study "Grid charges for large-scale batteries", which was submitted in June as a consultation contribution to the AgNes procedure (general grid charge system for electricity).

Author: Fritz Wilhelm