Group Capacity Management Service (GCMS): a guide for businesses
Direct answer
A group capacity restriction contract (group CBC) is an agreement in which several companies behind the same grid substation jointly commit to reducing their electricity consumption or feed-in during peak moments, in return for compensation. The group spreads the requested reduction across its combined capacity, so no single company carries the full burden. A congestion service provider (CSP) represents the group towards the Dutch grid operator.
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Group Capacity Management Service (GCMS): scattered information versus Energy Intelligence
In more and more parts of the Netherlands the electricity grid is full. Companies therefore wait for a new connection or for an expansion of their contracted transport capacity. Picture a business park where the bakery, the cold store and the machine factory all want to use more power. Grid operators offer congestion products to make better use of the existing grid. The group variant of the capacity restriction contract is one of them: neighbours on the same grid absorb peak moments together.
- The group spreads the requested capacity reduction across a larger combined capacity and decides itself who contributes at which moment.
- A congestion service provider (CSP) receives the grid operator's activation request one day in advance and arranges the adjustment for the whole group.
- Since May 2026 the capacity steering contract (CSC) has largely replaced the CBC for new applications; existing group CBCs remain valid.
Insight
Traditional approach
Information is scattered across portals, documents, invoices or separate spreadsheets.
Modern approach
Data, context and interpretation are brought together into a clear decision picture.
Decision-making
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Choices are made based on averages, assumptions or occasional analyses.
Modern approach
Scenarios, KPIs and current measurement data make the trade-off more concrete and repeatable.
Follow-up
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Actions often stay non-committal or disappear into separate reports.
Modern approach
Follow-up actions, monitoring and reporting are linked to the same energy data.
How does a group CBC work?
The group CBC is the group variant of the on-call capacity restriction contract (CBC-A). The grid operator forecasts when the local grid risks overload. One day in advance it sends a message to the group's congestion service provider. That CSP ensures the participating companies reduce their consumption or feed-in at the agreed moments. This can be done manually or automatically via an energy management system. The grid operator pays compensation for the activated capacity. The participants and the CSP divide that compensation according to their own agreements. The key difference with an individual contract: the group itself decides who contributes how much at which moment to the requested reduction.
- The grid operator announces an activation one day in advance to the group's CSP.
- Participants reduce their consumption or feed-in manually or automatically via an energy management system.
- The compensation for the activated capacity is divided between the participants and the CSP.
- The group spreads the requested reduction across its combined capacity.
When are you eligible?
A group CBC is only possible in areas where the grid operator has established congestion. Whether the contract is feasible depends on the local grid situation and on whether the companies can adjust their consumption profiles. At Liander, concrete entry conditions apply. The participants must be grid neighbours: they share the same substation installation. A certain scale is also required, both in the number of participants and in the size of the connections. Other Dutch regional grid operators offer comparable congestion products with their own conditions. Always check first with your own grid operator what is available in your area.
- Your company is located in a congestion area of the grid operator.
- The group consists of at least two connected parties behind the same substation installation.
- Each participant has a connection larger than 3x80 amperes or a medium-voltage connection.
- Each participant has a smart meter or an energy management system.
- At least one participant already has an individual CBC-A or wants to conclude one.
How does the group CBC relate to other flexibility contracts?
The capacity restriction contract comes in two basic forms. With a fixed time window contract, the moments at which you adjust your offtake or feed-in are agreed in advance. With an on-call contract, you hear one day in advance whether action is needed. The group CBC builds on that on-call variant. Several compensation forms exist, such as a fixed monthly fee for availability or a payment per activated megawatt hour. Since May 2026 the capacity steering contract (CSC) has largely replaced the CBC for new applications. The CSC can both reduce and increase consumption and also has a group variant. Existing group CBCs simply remain valid.
- CBC with fixed time windows: adjustment at moments agreed in advance.
- On-call CBC (CBC-A): adjustment only when the grid operator forecasts an overload.
- Compensation can consist of a fixed monthly fee, an amount per megawatt hour or compensation for missed subsidy income.
- Since May 2026 the CSC has largely replaced the CBC and can both reduce and increase consumption.
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