Grid congestion (netcongestie) does not give a Dutch grid operator a free hand to refuse transport. Under the Energy Act (Energiewet), in force since 1 January 2026, a grid operator (netbeheerder) may only refuse if it can show with data that the physical capacity is insufficient and that congestion management cannot solve the problem; the main exception is the priority framework, which lawfully lets certain categories of projects move ahead in the queue.
A refusal must be reasoned, capacity must be allocated without discrimination, and if you are refused you can take the dispute to the Netherlands Authority for Consumers and Markets (Autoriteit Consument & Markt, ACM) or to the civil court. Below we set out what the Energy Act and the codes under it require of grid operators, the difference between physical and contractual congestion, how the queue and the priority framework work, what you can be paid for flexibility, and which remedies are worth pursuing.
Which rules apply to grid congestion since 1 January 2026?
Since 1 January 2026 the Energy Act applies, and it replaced both the Electricity Act 1998 (Elektriciteitswet 1998) and the Gas Act (Gaswet). The core duties of grid operators are the same in substance; what changed is the wording, the numbering and the technical codes underneath.
The Energy Act brings the rules on connection, transport, metering, supply and data together in a single statute and implements the European electricity market package. The core duties remain: the grid operator must connect and must transport, it must treat grid users without discrimination, and it may only refuse if it can substantiate that it lacks capacity.
The second layer, the technical codes, matters more than it sounds. For years the congestion management rules sat in chapter 9 of the old electricity grid code (Netcode elektriciteit), which practitioners cited by heart. In February 2026 the ACM adopted a new set of codes under the Energy Act, published in the Government Gazette (Staatscourant) on 20 February 2026. They include the Systeemcode elektriciteit 2026, which took over the rules of the old grid codes. Article references to the old codes, and to chapter 9 in particular, no longer point anywhere. If you rely on a template objection or an advice memo written before 2026, check the citations before you send it.
Above both sits the case law. Decisions of the ACM in dispute procedures, judgments of the civil courts and rulings of the Trade and Industry Appeals Tribunal (College van Beroep voor het bedrijfsleven, CBb) built the practical standard for what a grid operator must prove. That body of case law was decided largely under the old Electricity Act. It remains relevant, because its principles, the duty to transport, the duty to give reasons and the prohibition of discrimination, were carried over into the Energy Act.
What is the difference between physical and contractual congestion?
Contractual congestion means the capacity is fully booked on paper; physical congestion means the network components actually reach their limits. The distinction is the basis of most successful challenges to a refusal.
Contractual congestion means that the sum of the transport rights already granted exceeds the technical capacity of a cable or transformer. It says nothing about what actually flows through that cable. Solar parks produce nothing at night, wind farms produce nothing in still weather, and industrial connections rarely draw their contracted maximum for more than a few hours a year. A grid operator that refuses transport only because its books are full, while the component is demonstrably not loaded to its limit in the relevant hours, has not yet shown a sufficient ground for refusal.
Physical congestion means that the thermal or voltage limits of the components are actually reached, or would be reached if the new request were granted. That can be a valid ground for refusal. But it is a factual claim and it must be evidenced: measured loads, the capacity of the specific substation and cable, and the periods in which the limit is reached. The burden of substantiating this rests on the grid operator. A general reference to a congestion map does not discharge it.
Between the two lies the question that decides most cases. Even where physical congestion exists, the grid operator must first examine whether congestion management can create room. Only if that examination shows that it cannot, may transport be refused.
What must a grid operator do before it refuses transport?
A refusal is the end of a sequence of steps, not the starting point. The grid operator must establish the physical constraint, investigate whether congestion management can create room, and apply it where it can.
In practice this means the grid operator must determine whether the constraint is physical, carry out a congestion investigation (congestieonderzoek) for the area concerned, publish the outcome, and determine whether enough flexibility can be contracted from connected parties to accommodate the request. Where flexibility is available, congestion management must be applied. The grid operator has no discretion to prefer refusal simply because managing the constraint is more work.
The refusal itself must be reasoned. In practice that means naming the substation and the component that is constrained, giving the load data on which the conclusion rests, stating what the congestion investigation found and why flexibility is insufficient, and explaining where you stand in the queue. A generic letter stating that “the region is congested” gives you nothing to test and is open to challenge. When you receive such a letter, ask for the underlying data in writing. Your request itself creates the record on which a later dispute will be decided.
There is a second, quieter obligation: transparency about the queue. A grid operator must be able to show where you stand, on which date your request was registered as complete, and what happened to requests registered later. Without that, the non-discrimination requirement cannot be tested. If the grid operator cannot produce this information, that is itself a weakness in its position.
How does the queue work, and who gets priority?
Capacity is in principle allocated in order of application: first come, first served. Since 1 January 2026, a priority framework of the ACM allows grid operators to give precedence to three defined categories of projects.
First come, first served is not an administrative convenience. It is the default expression of the duty not to discriminate. A grid operator that lets a later applicant through while an earlier one waits must be able to justify that on objective grounds.
The priority framework has a legal basis. The CBb annulled an earlier version of the ACM’s framework, while confirming that the ACM is competent to adopt one. The ACM then adopted a new framework in December 2025, which has applied since 1 January 2026, with a transition period until 1 July 2026. It allows grid operators to give precedence to:
- congestion relievers: projects that themselves create room on the grid;
- safety: connections for, for example, hospitals, emergency services, police and defence;
- basic needs: connections for societal needs such as housing, education and public transport.
Everything outside those categories stays in the ordinary queue. For a producer this cuts both ways. If your project falls within a priority category, you have to claim and substantiate this rather than assume it. If it does not, the framework is a lawful reason for others to move ahead of you, but only within its boundaries. Priority granted outside the framework, or without a recorded justification, is exactly the kind of deviation that makes a refusal open to challenge.
How does congestion management work, and what are you paid?
Congestion management means the grid operator contracts flexibility from connected parties, so that it can allocate more capacity than the physical peak would allow. You are paid for that flexibility, either at a price you bid yourself or, where participation is compulsory, at a regulated price.
Two families of products do the work. In redispatch, the grid operator asks a party to increase or reduce its feed-in or offtake at a given moment, against payment. In a capacity limitation contract (capaciteitsbeperkingscontract), the party accepts in advance, against a fee, that its feed-in or offtake will be capped during defined congestion periods. On top of that, grid operators offer alternative transport rights, such as time-bound transport rights and fully variable transport rights, which give access during part of the hours or whenever capacity is available.
Participation is not purely voluntary. According to the ACM’s overview of congestion measures, parties with a connection of 1 MW or more in a congestion area are obliged to make their available flexibility known and to offer it, and installations of 60 MW or more are obliged to participate in capacity limitation. That obligation gives the mechanism enough liquidity to function.
The price depends on the route. In market-based congestion management you set your own bid. Where the grid operator applies congestion management on the basis of the participation obligation, you receive a price that may not exceed what is customary in normal economic transactions. That formula protects the grid operator against opportunistic pricing. It also protects you, because a payment that ignores the actual loss you suffer is equally out of line with normal economic transactions.
Your loss is not only the value of the electricity you did not deliver. Where output is curtailed, the missed subsidy revenue under a scheme such as the SDE++ and the consequences under an existing power purchase agreement, including any obligation to deliver a contracted volume, form part of your real opportunity cost. Those elements belong in the negotiation and, if it comes to that, in the evidence. There is no published tariff for flexibility. Whether a price is in line with the market is assessed afterwards, against comparable transactions and the underlying costs. That makes contemporaneous records of your own costs unusually valuable.
The room to negotiate the rest of the contract is limited. The definition of the product, the technical requirements, the response times and the settlement rules come from the codes. Terms that deviate from them, or that treat one grid user differently from another, are not enforceable. What you can genuinely negotiate is the volume, the duration, the availability windows and, where the regulated price rule applies, the price within that ceiling.
Which remedies do you have: the ACM or the civil court?
You can submit a dispute with a grid operator to the ACM, which gives a binding decision, or go to the civil court. The two routes can be used in parallel.
The first route is the dispute procedure at the ACM. Under Article 5.4 of the Energy Act, you can submit a dispute with a grid operator about the way it applies the statutory rules and the codes to the ACM. According to the ACM, it takes a decision within two months of receiving the complaint, and it can extend that period by two months if it needs more information. The advantage is that a regulator with technical expertise tests the load data and the congestion investigation, and the costs are modest compared with litigation. You can appeal an ACM decision to the CBb, where you can also ask for interim relief if the matter cannot wait.
The second route is the civil court, which is the route where speed or money is the issue. Summary proceedings (kort geding) are appropriate where a decision cannot wait, for example because a subsidy deadline or a contractual delivery date will be missed while the case is investigated. The claim is then for an order that the grid operator make an offer for transport. Proceedings on the merits are the place for damages and declaratory relief. Note that a grid operator acts as a company when it deals with connection and transport requests. Its refusal is in principle not an administrative decision, so damages are claimed from it under civil law, not under the General Administrative Law Act (Algemene wet bestuursrecht).
Which route fits depends on what you actually need. If your objective is access, the ACM route is usually stronger, because the regulator can order the grid operator to make an offer and is equipped to test the technical justification. If your objective is compensation for a project that has already been delayed, the civil court is the forum. A claim in tort under Article 6:162 of the Dutch Civil Code (Burgerlijk Wetboek, BW) requires you to prove the unlawful act, the loss, and the causal link between them.
How do you prove your loss?
The recoverable loss is usually not the hardest question; proof is. Almost all of the relevant evidence sits with the grid operator, so ask for the data at the moment of the refusal and build your own loss file at the same time.
A refusal that turns out to be unlawful can cause lost margin on electricity not delivered, forfeited subsidy revenue, penalties or lost value under an offtake agreement, financing costs on an asset that stands idle, and the cost of a delayed project as a whole. All of that is in principle recoverable if you can establish the unlawfulness and the causal link.
The difficulty is that the load measurements, the congestion investigation, the queue administration and the decisions on other applications in the same area are all in the hands of the grid operator. That imbalance is why the transparency and reasoning duties matter so much in practice. Ask for the data in writing when you receive the refusal, and keep the answer. If the grid operator refuses or answers vaguely, that refusal becomes part of your case. In civil proceedings, the court can also order a party to provide copies of specific documents relevant to the dispute. Since 1 January 2025 this right of access to evidence is laid down in Article 194 of the Dutch Code of Civil Procedure (Wetboek van Burgerlijke Rechtsvordering, Rv).
Build your loss file at the same time, not afterwards. Contemporaneous records of production forecasts, subsidy entitlements, contractual commitments and financing costs are far more persuasive than a reconstruction made two years later by an expert.
Consider this hypothetical example. A developer of a 5 MW solar park receives a refusal letter that only refers to the congestion map. It immediately asks for the load data of the substation, the results of the congestion investigation and its queue position, and records its SDE++ deadline and financing costs. When the grid operator turns out not to have examined congestion management, the developer has the file it needs for an ACM dispute or summary proceedings.
What should producers and developers do now?
Your legal position is largely determined before any dispute arises. Submit complete requests, record all communication and do not accept a refusal letter at face value.
Submit transport requests complete, because the date on which a request is registered as complete fixes your queue position. Record every communication with the grid operator. When a refusal arrives, ask on which component the constraint sits, what the congestion investigation showed, why flexibility is insufficient, and where you stand in the queue. Check whether your project falls within one of the priority categories and, if so, claim that explicitly.
Consider whether flexibility is a way in rather than a concession. A project that can be curtailed at peak moments, that combines generation with storage, or that shifts consumption can often be connected where a firm request would be refused. The contractual form of that arrangement is negotiable even though the product itself is not. Our articles on energy storage and solar energy projects set out the surrounding requirements.
In summary
- Since 1 January 2026 the Energy Act and the new codes, including the Systeemcode elektriciteit 2026, apply; old Netcode references are outdated.
- A grid operator may only refuse transport if it shows physical congestion with data and shows that congestion management cannot create room.
- Capacity is allocated first come, first served, except for the three categories in the ACM’s priority framework.
- Parties of 1 MW or more in a congestion area must offer flexibility; under that obligation the price may not exceed what is customary in normal economic transactions.
- You can submit a dispute to the ACM (decision within two months, extendable by two) or go to the civil court for access or damages.
Frequently asked questions about grid congestion
Which remedies does a producer have if the grid operator refuses transport despite the flexibility offered?
You have two routes, which can run in parallel. You can submit the dispute to the ACM under Article 5.4 of the Energiewet and ask for a binding decision that the grid operator must comply with its transport obligation. You can also bring the grid operator before the civil court, if necessary in summary proceedings (kort geding), and claim an order that it make an offer for transport, arguing that the refusal breaches the Energy Act and the codes.
Can a producer claim compensation for the unlawful application of congestion management?
Yes, if you can prove that the grid operator acted unlawfully, for example by deviating from the queue without justification or by refusing to apply congestion management where it was possible. The claim is based on tort (Article 6:162 BW) or, where there is a contract, on breach of contract. You must prove the unlawful act or breach, the loss and the causal link. Loss can include lost income, missed subsidy revenue and consequential loss.
How does the court assess whether the grid operator distributed capacity without discrimination?
The grid operator must show that it applied its objective allocation rules consistently: in principle first come, first served, and otherwise only the priority categories of the ACM framework. Any deviation from the queue must be objectively justified and recorded. A lack of transparency about the queue makes it difficult for the grid operator to show that it did not discriminate.
What freedom do parties have when negotiating a congestion management contract?
Limited freedom. The definition of the product, the technical requirements and the response times follow from the codes, and terms that deviate from them are not enforceable. What you can negotiate is mainly the volume, the duration, the availability windows and the price. Under the participation obligation, the price may not exceed what is customary in normal economic transactions.
How is the price for congestion management capped, and how is market conformity tested?
Where the grid operator applies congestion management on the basis of the participation obligation, the codes provide that you receive a price that is not higher than what is customary in normal economic transactions. In market-based congestion management you set your own bid. Whether a price is in line with the market is assessed afterwards, in an ACM dispute or before the civil court, against comparable transactions and the underlying costs, including opportunity costs such as lost subsidy revenue. There is no published price list.
Can a producer force the grid operator to give more reasons for a refusal based on physical congestion?
Yes. A refusal must be reasoned, and a general reference to congestion in the region is not enough. Through the ACM or the civil court you can demand that the grid operator substantiate its position with specific data on the substation capacity, the congestion investigation and your queue position. In civil proceedings you can also ask the court to order the provision of specific documents under Article 194 Rv.
What role does the ACM play in disputes about congestion management?
The ACM settles disputes between grid users and grid operators. Under Article 5.4 of the Energy Act you submit a complaint, after which the ACM investigates whether the grid operator acted in accordance with the law and the codes. The procedure involves written submissions and often a hearing. The ACM decides within two months, which it can extend by two months. The decision is binding and can be appealed to the CBb.
Can a producer ask the ACM in advance to assess whether an offered price is in line with the market?
Not as an individual advance ruling outside a dispute. The ACM sets the rules in the codes and decides disputes. If your negotiations with the grid operator break down over the price, you can start a dispute procedure, and the ACM will then assess whether the price complies with the rules.
Which arguments work best against a price that is not in line with the market?
Arguments based on transparency and evidence. Show that the grid operator gave no objective basis for its price, or that it ignored your actual opportunity costs, such as lost subsidy revenue or obligations under a power purchase agreement. Support this with records of your own costs and, where available, with data on prices paid for comparable flexibility.
What is the difference between physical and contractual congestion, and why does it matter?
Contractual congestion means all transport rights are booked on paper, even if they are not fully used. Physical congestion means the cables or transformers actually reach their limits. The difference matters because a full order book alone does not justify a refusal: the grid operator must show the physical constraint and show that congestion management cannot create room. If it cannot, you have a strong basis to challenge the refusal.
Law & More advises producers, developers and industrial grid users on transport requests and refusals, congestion management and flexibility contracts, disputes before the ACM, appeals to the CBb, and civil claims for access or damages. Our energy law practice page gives an overview of the field. Unsure where you stand? Tell us about your situation. We will let you know your options within one working day.
