AgNes: what the BNetzA grid-fee reform means for storage

Anyone planning a battery storage system today that will still be running past 2029 runs into AgNes sooner or later. That is the name of the Bundesnetzagentur’s ongoing determination proceeding on the general electricity grid-fee system. The reform affects generation plants and, for the first time, storage systems directly. What follows for a specific project depends on which statements are already settled and which are still proposals.

What AgNes is

AgNes stands for the reform of the general electricity grid-fee system (Allgemeine Netzentgeltsystematik Strom), a Bundesnetzagentur determination proceeding meant to reorganise the basis of grid-fee calculation. One central goal is to spread costs more in line with actual causation across all user groups, including generation plants and storage systems, which have mostly stayed outside the system until now. The proceeding runs publicly at the Bundesnetzagentur’s decision chambers and goes through several rounds of consultation before it becomes a binding determination.

The interim position of 27 May 2026

On 27 May 2026 the Bundesnetzagentur published a press release with its current thinking on the reform. It states that grid fees will remain cost-based in principle and that, going forward, storage systems and generators too are to share in grid costs, with an adjusted cost split. Under this position, home storage systems on the low-voltage grid remain excluded, with no separate grid fee planned for them. For newly built storage systems, other than these home systems, a moderate capacity-based fee is meant to apply, similar to the treatment of generation plants but without an energy charge on the energy put into storage.

The press release defines the exception by grid level and by the home-storage customer group, independent of any particular capacity limit. For a commercial storage system connected at a commercial or industrial connection point, this exception generally does not apply, even if the system also sits on the low-voltage grid. An operator should clarify their own classification as home or commercial storage in the specific case once the Bundesnetzagentur sets out the criteria more precisely in the formal consultation, rather than assume a fixed capacity threshold.

What is settled for existing storage systems

For existing storage systems, the interim position contains one statement that matters in practice. The fee obligation for these systems is meant to start only once the special rules under §118(6) EnWG expire, where they apply. That is a confirmation of the existing statutory framework by the agency, not a new rule and not a replacement of the existing exemption. For a project that has already reached, or is aiming for, the 20-year exemption under §118(6) EnWG, the AgNes position so far changes nothing.

What is still open

The interim position is explicitly not a closed proceeding. The Bundesnetzagentur announced the formal consultation on the full draft for summer 2026, aiming for a determination by the end of 2026. Open questions include the exact level of the capacity-based fee for new storage systems, expected to be moderate on current indications, and whether and from when time-variable grid fees for storage will be introduced, with a window between 2030 and 2033 under discussion. Details can still change before the final determination.

Why the reform is happening at all

The reform’s trigger lies in the growing scale of the German grid and the changed makeup of its users. As solar, wind and increasingly storage expand, who draws or feeds in how much power and when has shifted, and the existing grid-fee system was built largely for classic consumers without their own generation or storage. The Bundesnetzagentur justifies the reform as realigning cost distribution with actual grid use, rather than leaving certain user groups structurally outside it.

What a buyer should do now

For today’s investment decision, what is already law matters most, above all §118(6) EnWG with its fixed 4 August 2029 deadline. The AgNes process should feed into planning as something to watch, not as a basis for assumptions beyond the current interim position. It makes sense to schedule a project so commissioning falls safely before the deadline, and to work the final AgNes determination, expected at the end of 2026, into ongoing planning once it is published, rather than wait for it.

For a project that only goes live after 2029, the AgNes determination becomes a direct part of the calculation, because the system would fall under the new capacity-based fee from the start, if it is adopted in that form. For such projects it makes sense to wait for the final determination at the end of 2026 before locking in the technical design, rather than build solely on the current interim position.

A regular check of the Bundesnetzagentur’s AgNes publications belongs in every ongoing storage project, whether the system is already built or still in planning, because the final shape only becomes clear as the proceeding continues. How the AgNes development affects a specific project, and how solid the timeline to 2029 really is, is what a feasibility study works through in detail. As of September 2026.

Sources

1. Bundesnetzagentur, "Bundesnetzagentur stellt aktuelle Überlegungen zur Reform der Netzentgeltsystematik Strom vor" (press release, in German), 27 May 2026
2. Bundesnetzagentur, AgNes determination proceeding (in German)
3. §118(6) EnWG, gesetze-im-internet.de