On July 15, 2025, the Federal Court of Justice (BGH) issued a landmark ruling that permanently changes the economic planning of battery storage projects in Germany. With decision EnVR 1/24, the court confirmed that construction cost subsidies (BKZ) for grid connections of battery storage are generally permissible. The BGH thus follows the line of the Bundesnetzagentur (BNetzA), which had introduced the so-called capacity price model as the assessment basis.
What Are Construction Cost Subsidies for Battery Storage?
A construction cost subsidy is a one-time payment by the connection applicant to the grid operator, due upon the creation or reinforcement of a grid connection. According to the Bundesnetzagentur, construction cost subsidies serve as a steering instrument to manage demand for connection capacity and to design grid expansion on a cost-causation basis.
Until the 2025 ruling, it was unclear whether battery storage systems — which not only draw power but also feed it in — could be exempt from this regulation. Especially for large battery storage systems above 10 MW, the subsidies could quickly reach six-figure amounts — a risk that held back many project developers.
The Legal Dispute: From OLG Düsseldorf to the BGH
In December 2023, the Higher Regional Court of Düsseldorf (Case 3 Kart 183/23) ruled that levying a construction cost subsidy on grid-connected storage was discriminatory. The court argued that storage systems are not traditional consumers.
The BGH overturned this ruling on July 15, 2025. The decision states that the feed-in function of a battery storage system does not change the dimensioning of the connection — the determining factor remains the requested withdrawal capacity. The grid operator may therefore bill according to the Bundesnetzagentur's capacity price model.
This confirms that battery storage systems are subject to the same connection rules as other large consumers.
Significance of the Ruling for Project Developers and Investors
The ruling finally provides legal certainty, but for project developers it means additional financial hurdles:
First: Early cost burden — Construction cost subsidies are often due at the time of the grid connection commitment, long before a battery storage system generates revenue.
Second: Realistic capacity dimensioning — since BKZ is based on ordered capacity, overly generous dimensioning directly leads to higher costs.
Third: Financing implications — Banks and investors will henceforth regard BKZ as a fixed component of project costs.
Fourth: Grid planning & communication — the Bundesnetzagentur has clarified that construction cost subsidies may also be levied above the low-voltage level.
Recommendations for Ongoing and Planned Projects
Project developers should now assess how construction cost subsidies affect existing plans and profitability models. It is important to incorporate grid connection costs and BKZ risk positions into project financing at an early stage.
Contractual arrangements such as payment caps, staged payments, or withdrawal clauses for delayed grid connections will also become standard in the future.
Additionally, it is worth examining alternatives — such as bundling several smaller storage systems or co-location with PV or wind installations to utilize existing grid capacities and proportionally reduce the construction cost subsidy.
Conclusion
The BGH ruling creates legal certainty but no financial relief. Battery storage projects remain capital-intensive, especially when construction cost subsidies are due early. Anyone wanting to be commercially successful must understand grid planning, BKZ management, and financing as an integrated package going forward.
If your project is stalling due to a high or early construction cost subsidy, we can help — we acquire battery storage projects (Ready-to-Build or in development) where grid connection costs are blocking implementation.
