Flexible Connection Agreements (FCAs) are spreading fast across Germany, and a common design is emerging: limits that move with local grid conditions, pegged to the live output of nearby wind and solar. Schleswig-Holstein Netz has published one of the first concrete templates, a preview of the terms developers will face across the country.

The base case headline is reassuring: A limited renewables-pegged import-export cap cuts revenues by less than 2%. It lines up with what a merchant battery would choose to do most of the time anyway: charge when renewables are high and prices are low, and discharge when they are low and prices rise. The cap only bites when local generation and national price signals diverge, costing a manageable 1.5% of revenue. That is an acceptable trade for faster connection.

Key takeaways

• Schleswig-Holstein Netz ties battery limits to local renewable load factors, with three cap variants. An overnight window that guarantees 25% charging headroom, ramp rates and ancillary service restrictions may also apply.
• The import-export cap alone is an acceptable compromise, up to a certain extent. Under Variant 1 it costs just 0.3 points of IRR. The strictest Variant 3 costs up to 2.0 points.
• The overnight window protects IRR only minimally. It lifts the import cap to at least 25% from 23:00 to 05:00, but the cap rarely falls that low overnight.
• The ramp limit and ancillary cap do the real damage, adding 1.0 to 1.4 points of IRR loss on top of the renewables cap.
• In negotiation, the terms worth fighting are the ancillary cap and the ramp limit's reach into ancillary delivery.

Weighing up an FCA offer? We have modelled terms like these across Germany and can help you quantify the impact and negotiate the clauses worth fighting. Reach out to cosima@modoenergy.com.

The cap tracks the weather, then three FCA terms stack on top

Schleswig-Holstein Netz sets the battery's allowed power band from the live output of local wind and solar. When renewables run high, discharging is restricted. When they fall away, charging is restricted.

Three variants set how hard the cap bites. Variant 1 starts cutting discharge once local renewables pass 50% of nameplate, reaching zero at 100%. Variant 2 starts at 40%. Variant 3 starts at 30% and hits zero at 60%.

Three further terms can sit on top. An overnight window from 23:00 to 05:00 guarantees at least 25% of rated power for charging, however low local renewable output falls. A ramp limit holds power change at the connection point to 10% per minute, a full ramp in 10 minutes. And ancillary participation is capped at 25% of installed capacity.

How much does each restriction cost?

We modelled every combination on a 100 MW, 4-hour battery with a 2027 COD.

The import-export cap alone has the lowest impact. Under Variant 1, 25-year average revenue falls 1.5% and IRR holds at 11.4%, against an 11.7% unconstrained base. Without the overnight window, the cap costs 0.3 to 2.0 points of IRR, depending on the variant. With it, IRR recovers only minimally in every variant.