Capacity control contract: breakthrough for storage in congested areas 

The ACM, with its draft decision of August 14, 2025 the capacity control contract (CSC). introduced in the Grid code electricity. This is an important step where Energy Storage NL (ESNL). and the electricity storage working group have strongly advocated in recent years. This decision finally makes it possible to structurally and contractually deploy flexibility from energy storage and other controllable assets for congestion relief. 

From constraint to control

Until now, through the capacity curtailment contract (CBC), grid operators could only make arrangements to reduce grid usage. limit. Think of a solar farm or customer voluntarily adjusting their transmission capacity downward (i.e. less feed-in). The new capacity control contract changes this fundamentally: network operators can now also request active use in the opposite direction of congestion.  

• At decreasecongestion a connected party with battery or local generation (such as CHP) may be asked to feed in extra; 
• At import congestion an affiliate may be asked to make a minimum purchase. 

Breakthrough for the storage industry

For the storage industry, this decision is special because it: 

• Unlocking new business models: storage can now be compensated contractually for providing grid services that are more than just reduction. 
• Creating structural value: unlike temporary flex tenders, the CSC offers a sustainable market-driven tool that will permanently give storage an even more positive role in the electricity system. 
• Making room for more connections: by steering the grid "against the peak," transmission capacity is freed up for companies and projects that are now in the queue. This can accelerate the rollout of both renewable generation and large-scale storage. 

ESNL sees the capacity control contract as an important step: it recognizes that storage is not just a passive buffer, but an active system component. Allowing storage systems to offer their flexibility on a contractual and market-based basis creates a new playing field for investment. This strengthens the business case for storage and enhances their role in the energy transition.  

At the same time, ESNL still sees important follow-up steps. At this stage, the CSC is not yet subject to the participation obligation for congestion management. As a result, in places where the demand for flexibility is greatest, grid operators will only have to rely on the existing contract forms (CBC and redispatch). To take full advantage of the potential of energy storage, it is important that CSCs are also integrated into that duty. ESNL therefore advocates that grid operators get to work as soon as possible to work out the necessary code change with the market. ESNL stands ready to contribute to this. 

Call to members and industry

The ACM has opened a consultation period until Nov. 6, 2025. ESNL will provide input on behalf of its members. Especially now, practical experience from the industry can help to further optimize the conditions so that the CSC becomes widely applicable in practice.