The Federal Network Agency (BNetzA) has commented on key questions regarding the process and the costs connected to grid connections for BESS. The reason for this is the strong increase in large BESS and the associated uncertainty about their regulatory classification.
The statement clarifies the BNetzA‘s understanding of grid connection procedures, construction cost contributions (BKZ), and realization- or reservation-deposits. In view of connection requests of around 260 GW regarding the transmission grid alone and the growing importance of BESS for grid stability, supply security, and system flexibility, this clarification is highly welcome.
At the same time, the explanations – particularly regarding BKZ and deposits – raise new follow-up questions that are of significant relevance for project development.
Regulatory dual role of BESS
BESS assume a dual role – they withdraw electricity from the grid and feed it back later. Therefore, according to the BNetzA’s view, both the regulations for consumption and generation facilities should apply to BESS.
For BESS with a nominal capacity of 100 MW or more, connected to a supply network of 110 kV or more, the BNetzA refers to the power plant connection regulation (KraftNAV). However, the KraftNAV shall only apply for the power feed-in/generation side of the BESS. The consumption side, on the other hand, should be subject to the general provisions of the Energy Industry Act (EnWG).
The BNetzA’s view has far-reaching practical implications: Since the KraftNAV, according to its interpretation, only applies to the generation side of a BESS, the consumption side can be considered separately. Therefore, the BNetzA deems it permissible to levy construction cost contributions (BKZ) for the consumption side of large BESS. Otherwise, § 8 para. 3 KraftNAV would oppose this. § 8 para 3 KraftNAV states clearly that under the rules of the KraftNAV a BKZ cannot be charged.
The BNetzA also rejects a reduction of the BKZ solely due to the storage function of the BESS – i.e., the time-delayed feeding back of electricity. Only in exceptional cases, such as with flexible connection agreements (FCA), a reduction of the BKZ can be considered.
From a legal standpoint the partial application of KraftNAV to BESS appears hardly convincing. According to § 1 para. 1 KraftNAV, the requirements apply to certain facilities as a whole, not to individual functions such as generation or consumption. In fact, there are no “pure” generation facilities. Every generation unit, whether a coal-fired power plant or a BESS, also has its own consumption.
Furthermore, the following consideration clearly shows the weaknesses of BNetzA’s position: According to BNetzA’s logic, network operators could, on the one hand, charge a reservation fee for the generation capacity according to § 4 para. 1 KraftNAV and at the same time demand a construction cost contribution (BKZ) for the withdrawal capacity. Such a double burden would clearly contradict the principle of non-discriminatory grid connection.
Realization deposit
Regardless of the question of the applicability of the KraftNAV, the BNetzA expressly approves the practice of some network operators to demand a realization deposit to ensure the seriousness of grid connection requests.
If the project is implemented, the deposit is to be reimbursed or reduced from the BKZ and/or the connection cost contributions. If the project cannot be realised, however, a refund is not due if the causes lie within the responsibility of the applicant.
The BNetzA expressly aligns the refund modalities with the mechanism of § 4 KraftNAV. Regarding the amount, it considers deposits up to 1,500 EUR/MW connection capacity permissible; in the application area of KraftNAV, however, the legally stipulated maximum amount of 1,000 EUR/MW applies.
Open follow-up questions
The explanations of the BNetzA leave essential follow-up questions open. The relationship between reservation fees according to the KraftNAV and BKZ payments requires further clarification.
Moreover, the interplay between BKZ and the realization deposit remains unresolved. Since some network operators already demand advance payments on the BKZ in the reservation process, a precise delineation would be necessary here. Such advance payments effectively fulfil the same function as a realization deposit. A parallel application of both instruments would lead to an inappropriate double burden on connection applicants.
Likewise, the BNetzA should have taken a clear position on BKZ repayment obligations in the event of project termination or failure. In view of the case law of the Federal Court of Justice, according to which the BKZ fulfills both steering and control functions as well as financing functions, the question arises whether and to what extent a project developer has a claim to a refund of prepaid BKZ if the project fails. The better arguments speak for a refundability of the BKZ in the event of contract termination – minus the actual financing needs incurred by the network operator.
(22 October 2025)