FCA as a way out despite grid constraints – but at what price?

The German Energy Industry Act (EnWG) opens up a path to the grid for BESS even where grid capacity is not sufficient for an unrestricted commitment: the flexible grid connection agreement (FCA). Instead of rejecting the connection for lack of capacity, the grid operator may offer it subject to conditions. For BESS, this is often the only realistic way to obtain a grid connection. How these conditions are structured determines whether the project ultimately remains economically viable.

Many FCA drafts submitted to us for review are not designed with BESS in mind, but are derived from generic connection terms. The result: clauses that fail to properly reflect the bidirectional operation of BESS and hit them harder economically than the actual grid constraint would require.

The power limit is not the only restriction

In the public debate and in the statute itself, the FCA restriction for BESS is usually reduced to a single figure: a static or dynamic limit on maximum charging or discharging capacity. For BESS, this often falls short. At least two further parameters are legally and technically relevant, and their economic impact is regularly underestimated:

Power gradients. How quickly may a BESS switch between charging and discharging, or change its output/intake capacity? The German Technical Connection Rules generally set binding reference values for this – for example, 0.33 to 0.66% of installed capacity per second at the high-voltage level; other values apply at other voltage levels. FCA clauses that fall below these values at the relevant connection point restrict exactly the feature that makes BESS economically attractive: their speed. Whoever curtails responsiveness curtails the business model.

Access to the balancing power market. For BESS, providing balancing power is often not a side business but a core revenue component. If an FCA restricts or excludes participation in the balancing power market through the grid operator's dispatch instructions, this can hit a project harder economically than a moderate, straightforward capacity limit.
Both types of restriction are, in principle, permissible components of a flexible grid connection agreement within the meaning of Section 17 (2b) EnWG. What matters, however, is whether they are technically necessary for the specific grid constraint at the relevant connection point and proportionate in scope.

The grid connection charge must reflect the restriction

Whoever restricts how a BESS may be used also restricts the value of the grid connection to its operator – and this must be reflected in the calculation of the grid connection charge (Baukostenzuschuss, BKZ). If the BKZ is calculated on the basis of a connection capacity that, due to gradient or balancing-power restrictions, cannot economically be used in full, the operator ends up paying for a value it is not contractually entitled to. This link between the depth of the restriction and the BKZ calculation is simply not reflected in many draft agreements – creating considerable potential for negotiation and dispute.

What we review for BESS projects

• Permissibility of the proposed FCA clauses at the specific site: are the power limit, gradient requirement and balancing-power restriction necessary and proportionate in light of the actual grid constraint?
• Plausibility check of the BKZ calculation in relation to the agreed restrictions
• Negotiation of practical alternatives to blanket dispatch instructions that do justice to bidirectional BESS operation
• Representation vis-à-vis grid operators and, where necessary, the Federal Network Agency (Bundesnetzagentur)

An FCA is not a form to be signed without scrutiny, but a contract that can and should be negotiated. Where BESS projects run into grid constraints, we combine detailed regulatory expertise with a clear focus on the project's economic viability.