June 26, 2025 /eszoneo/ —
Germany’s energy transition is driving a fundamental reassessment of how electricity network charges are structured, particularly for battery storage systems. With the current exemption from grid usage fees for storage set to expire in August 2029, regulators and stakeholders are actively seeking cost-reflective mechanisms that align with system needs. Recent modeling shows that dynamic, locationally and temporally variable grid fees could drastically improve grid support while maintaining economic viability for large-scale batteries. As a response to this regulatory pivot, battery developer Eco Stor has commissioned a policy impact study to advocate for dynamic tariffs in Germany’s consultation process.
In May, the Federal Network Agency initiated a discussion on a redesign of the grid charges with a 57-page discussion paper. The aim of the new framework regulation “General Grid Fee Systematics” – abbreviated “AgNes” – is to adapt the grid charges to the requirements of the energy transition. The discussion paper raises many open questions, including those concerning grid charges for battery storage. It is considered relatively certain that the current exemption from grid usage charges for electricity storage systems, which is valid until early August 2029, will then be abolished.
As part of the consultation, battery storage developer and operator Eco Stor commissioned the consulting firm Neon Neue Energieökonomie, led by Lion Hirth, to evaluate and compare various options. Eco Stor plans to submit the results of this analysis as part of the AgNes consultation process. Based on a battery operation planning model, Neon analyzed the behavior of a typical large-scale battery storage system under various grid fee variants (static and dynamic). The analysis quantified not only redispatch costs but also grid supportiveness and overall economic welfare.
Neon’s study shows that even purely market-driven large battery systems already provide grid-supporting services. “The often-claimed grid-harming effect of market-based large-scale batteries could be disproven,” said Eco Stor. Specifically, Neon matched the battery’s activity on the day-ahead market with historical redispatch patterns throughout the year. It found that batteries already slightly reduce redispatch costs over the course of the year. “This positive effect on the grid is, however, purely coincidental, as the German electricity market design does not price grid congestion. With systematic incentives, batteries could provide much more grid support,” the analysis states.
So what would be the best incentive? The study shows that static grid charges tend to have a counterproductive effect. “Conventional energy- and capacity-based tariffs may generate revenues for grid operators but do not promote grid-friendly behavior of storage systems. From an economic perspective, they are inefficient and reduce welfare,” the analysis says. In contrast, dynamic energy-based pricing could be a solution: such grid charges—e.g., as time- and location-based special fees for battery storage—could reduce redispatch costs up to 500% more effectively than static charges, according to Neon Neue Energieökonomie. Batteries could also relieve the grid more deliberately with dynamic grid fees.
For operators of market-driven storage systems, the introduction of dynamic energy-based grid fees would only “slightly” affect economic operations, according to the study. “The combination of grid and market benefits leads to an overall economic welfare gain of around 40% compared to the status quo,” the result states.
A dynamic energy-based tariff has the greatest effect in terms of grid service and economic benefit, the analysis shows.
Eco Stor, like other market players, has long been advocating for recognition of grid-supportive behavior of large-scale storage systems. It is undisputed that there is an urgent need to expand large battery storage systems that can provide flexibility in the electricity market amid growing PV and wind feed-in. “This study by Neon clearly shows: Dynamic grid charges create a true win-win situation for both the power grid and the market,” says Georg Gallmetzer, CEO of Eco Stor. “We urgently need a reform that rewards grid-friendly behavior instead of hindering it.”
However, Neon Neue Energieökonomie also identified a scenario that could be even more beneficial for all parties. “From our point of view, it’s pretty clear: for grid-supportiveness of large-scale batteries, a split into price zones would be best,” writes Lion Hirth. “Since politicians and the Federal Network Agency don’t want that, the second-best solution is a dynamic energy-based tariff.”
SOURCE: pv magazine
