Anyone who wants to implement greenfield battery storage projects faces a problem: Is the battery storage system permitted under building regulations? Project developers answered this question with a yes, while the authorities answered with a no in some cases. The authorities’ practice was inconsistent and unsettling. Some authorities even demanded proof of grid suitability. Nice try, but that’s not in the law.
In November 2025, the solution came as a surprise: shortly before the vote in the Bundestag on the amendment to the Energy Industry Act (EnWG), a change to the Building Code (BauGB) slipped in: All battery storage systems with a storage capacity of 1 megawatt hour (MWh) or more should be considered privileged projects in rural areas. The law did not contain any further requirements.
Developers, investors and we as legal advisors were delighted with this unexpected planning and investment security. Finally, no more discussions with the authorities; finally, uniform application of the law!
The newly created privilege had barely been decided when objections began to arise. Just one week after the Bundestag’s decision, the Bundesrat accepted a resolution proposed by the state of North Rhine-Westphalia. According to this resolution, the federal government should promptly follow up with criteria for the privilege in order to ‘control’ the expansion of battery storage facilities.
Even before the first new regulation had come into force, a correction was decided in the Bundestag. The privilege was divided into two separate categories: co-location and stand-alone. This regulation came into force shortly before Christmas.
According to the new Section 35 (1) No. 11 of the Building Code, a battery storage facility is permissible if it has a ‘spatial-functional connection’ with an ‘existing’ renewable energy plant. And this is where the ambiguities start: What is a spatial-functional connection and when is a renewable system ‘existing’? Does the renewable system already have to be built? Or approved? The Bundesrat also finds this unclear, but argues that permit for the renewable system and the battery storage facility can be applied for at the same time. This view makes sense, but the law reads differently.
According to the explanatory memorandum to the law, the spatial connection should not be limited to the immediate vicinity; areas at some distance should also be considered if adjacent areas are not available or suitable. But this has to be decided on a case-by-case basis. We will have to wait and see how the authorities and the courts assess this.
Moreover, the functional connection should be understood to mean that operation is not restricted by planning law. Can we therefore conclude that the storage facility may be operated as a grey electricity storage facility? Probably yes, but it is not entirely clear.
The privileges for stand-alone storage systems offer even more uncertainty. According to the new Section 35(1) No. 12 of the Building Code, other battery storage systems (which are not co-located) can only be granted privileged approval if the following criteria are met:
(1) The battery storage facility may be located no more than 200 metres from the property boundary of a substation converting from maximum to high voltage or from high to medium voltage, or of a (existing or decommissioned) power plant with a rated output of 50 megawatts or more.
(2) The battery storage facility has a rated output of at least 4 megawatts.
(3) All battery storage facilities approved under this regulation in the same municipality may together occupy a maximum of 0.5% of the municipal area and may not exceed a total area of 5 hectares.
In practical terms, this means that stand-alone storage facilities are permitted, but only under strict conditions. And here, too, relevant questions remain unanswered. How is the distance measured? 200 metres from property boundary to property boundary? And is the property equivalent to the parcel of land or the plant site? Or does the battery storage facility perhaps have to be located within 200 metres of the substation site after all?
These questions are also being asked by the Bundesrat. It also rightly criticises that the areas directly adjacent to the substation are needed for substation expansions and are therefore often not available at all. However, the explanatory memorandum to the law refers to a ‘perimeter’.
If this interpretation prevails, a considerable proportion of potential areas would be lost. Even a regulation of 200 metres from property boundary to property boundary is almost impracticable.
Most project developers can live with the 4 MW hurdle, but now things are getting tricky. If several projects are planned in one municipality, it becomes a race against time. This is because it is unclear when the area limit will take effect. Presumably, all projects that have already been approved (regardless of whether they have been implemented) will be taken into account. To do this, the regulatory authority must carry out a comparison. This could pose enforcement problems.
To say something positive: the regulation for co-located battery storage is sensible and helpful. For project developers, this means for the time being: use co-location wherever possible.
For stand-alone storage systems, however, one uncertainty has been replaced by another. The majority of projects will probably still require a development plan. This means long processing times and uncertainties. But hey, we still have the thorny issue of grid connection to deal with…!