Grid congestion (netcongestie) does not give a Dutch grid operator a free hand to refuse transport. Under the Energiewet, in force since 1 January 2026 and replacing the Elektriciteitswet 1998 and the Gaswet, a netbeheerder must offer transport unless it can demonstrate, with data, that the physical capacity is genuinely insufficient and that congestion management cannot resolve the problem. A refusal must be reasoned, the allocation of capacity must be non-discriminatory, and a producer who is refused can take the dispute to the Autoriteit Consument en Markt (ACM) or to the civil court.
That is the legal position; the practical position is that waiting lists for transport capacity run for years across large parts of the country. This article sets out what the Energiewet and the codes adopted under it actually require of grid operators, where the line runs between physical and contractual congestion, how the queue and the priority framework work, what a producer is entitled to be paid for flexibility, and which remedies are worth pursuing when transport is refused.
The legal framework since 1 January 2026
The Energiewet entered into force on 1 January 2026 and repealed both the Elektriciteitswet 1998 and the Gaswet. It consolidates the rules on connection, transport, metering, supply and data into a single statute and implements the European electricity market package. The core duties are unchanged in substance: the grid operator must connect and must transport, it must treat grid users in a non-discriminatory way, and it may only refuse where it can substantiate that it lacks capacity. What has changed is the wording, the numbering and, importantly, the layer of technical rules underneath.
That second layer matters more than it sounds. For years the congestion management rules sat in chapter 9 of the code that practitioners cite by heart, and that code has now been replaced. On 20 February 2026 the ACM adopted a set of new codes under the Energiewet, including the Systeemcode elektriciteit 2026, which took over from the old electricity code with effect from 21 February 2026. Article references to that old code, and to its chapter 9 in particular, no longer point anywhere. Anyone relying on a template objection or an advice memorandum written before that date should check the citations before sending it.
Above both sits the case law. Decisions of the ACM in dispute procedures, judgments of the civil courts and rulings of the College van Beroep voor het bedrijfsleven (Trade and Industry Appeals Tribunal) built the practical standard for what a grid operator has to prove, and that body of case law was decided largely under the old Act. It remains relevant, because the principles it applies, the duty to transport, the duty to give reasons and the prohibition of discrimination, were carried over into the Energiewet.
Physical congestion and contractual congestion
The single most useful distinction in this field is between congestion on paper and congestion in the copper, and it is the distinction on which most successful challenges rest.
Contractual congestion means that the sum of the transport rights already granted exceeds the technical capacity of a cable or a transformer. It says nothing about what is flowing 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 because its books are full, while the asset is demonstrably not loaded to its limit in the relevant hours, is not refusing on a legally sufficient ground.
Physical congestion means that the thermal or voltage limits of the components are actually reached, or would be reached if the new connection were granted. That is a real ground for refusal, but it is a factual assertion and it has to 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 it rests on the grid operator, and a general reference to a congestion map does not discharge it.
Between the two sits the question that decides most files: 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 a grid operator must do before refusing transport
A refusal is the end of a sequence, not a starting point. The grid operator must establish whether the constraint is physical, carry out a congestion investigation for the area concerned, publish the outcome, and determine whether flexibility can be contracted from connected parties in sufficient volume to accommodate the request. Where flexibility is available, congestion management must be applied; the grid operator does not have a discretion to prefer refusal 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 the applicant position in the queue. The ACM has repeatedly held that a generic letter stating that the region is congested falls short of that standard, and has ordered grid operators to give a concrete, verifiable justification. A producer receiving such a letter should ask for the underlying data in writing, because the request itself creates the record on which a later dispute is decided.
There is a second, quieter obligation: transparency about the queue. A grid operator must be able to show where an applicant stands, on what date the request was registered as complete, and what happened to requests registered later. Without that, the non-discrimination requirement cannot be tested, and the inability to produce it is itself a weakness in the operator position.
The queue and the priority framework
Capacity is allocated in order of application. First come, first served is not an administrative convenience but the default expression of the non-discrimination duty, and a grid operator that lets a later applicant through while an earlier one waits must be able to justify that on objective grounds.
Since 1 January 2026 there is an exception with a legal basis. Following a ruling of the College van Beroep voor het bedrijfsleven, the ACM adopted a priority framework that allows grid operators to give precedence to defined categories: projects that themselves relieve congestion, connections that serve safety and security such as hospitals, emergency services, police and defence, and connections that serve basic societal needs such as housing and education. Everything outside those categories stays in the ordinary queue.
For a producer this cuts two ways. If your project falls within a priority category, that has to be claimed and substantiated rather than assumed. 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 precisely the kind of deviation that makes a refusal contestable.
Congestion management and what a producer is paid
Congestion management works by contracting flexibility from connected parties so that more capacity can be allocated than the physical peak would allow. Two families of product do the work. In redispatch the grid operator asks a party to increase or reduce output or offtake at a given moment, against payment. In capacity limitation the party accepts, in advance and against a discount or a fee, that its feed-in or offtake will be capped during defined congestion hours; time-bound and flexible transport agreements are the contractual form this usually takes.
Participation is not purely voluntary. Parties above a defined connection size in a congestion area are required to make their available flexibility known and to offer it, which is what gives the mechanism enough liquidity to function. In return, the price is regulated: compensation for congestion management may not exceed what is customary in normal economic transactions. That formula protects the grid operator against opportunistic pricing, and it protects the producer, because a payment that ignores the actual loss suffered is equally out of line with normal economic transactions.
The producer loss is not only the value of the electricity not delivered. 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 the 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: conformity with the market is assessed after the fact, against comparable transactions and the underlying costs, which makes contemporaneous documentation 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, and terms that deviate from them or that treat one grid user differently from another are not enforceable. What is genuinely negotiable is the volume, the duration, the availability windows and the price within the regulated ceiling.
Remedies: the ACM procedure and the civil route
A producer confronted with a refusal, an unexplained queue position or an unreasonable congestion management offer has two routes, and they can be used in parallel.
The first is the dispute procedure at the ACM. Article 5.4 of the Energiewet allows a party in dispute with a grid operator about the way the statutory rules and the codes are applied to submit the dispute to the ACM, which gives a binding decision. Under the ACM working method for energy disputes the decision is taken within two months of receipt of the complaint, extended to four months where further investigation or a hearing is needed. The advantage is that the case is decided by a regulator with the technical expertise to test load data and congestion investigations, and the costs are modest compared with litigation. An ACM decision can be appealed to the College van Beroep voor het bedrijfsleven, where interim relief can be requested if the decision cannot wait.
The second 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 where a subsidy deadline or a contractual delivery date will be missed while the file is being investigated, and 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 for declaratory relief. Under the General Administrative Law Act, a claim for compensation can also follow an unlawful decision of a public authority.
Which route fits depends on what you actually need. If the objective is access, the ACM route is usually the stronger one because the regulator can order the operator to make an offer and is equipped to test the technical justification. If the objective is compensation for a project that has already been delayed, the civil court is the forum, and a claim in tort under article 6:162 of the Burgerlijk Wetboek requires you to prove the unlawful act, the loss, and the causal connection between them.
Damages and the evidence problem
The recoverable loss in a congestion case is usually not the hardest question; the hardest question is proof. 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 the unlawfulness and the causal link can be established.
The difficulty is that almost all of the relevant evidence sits with the grid operator: the load measurements, the congestion investigation, the queue administration and the decisions taken on other applications in the same area. That asymmetry is why the transparency and reasoning duties matter so much in practice. Ask for the data at the moment of the refusal, in writing, and keep the answer. If the operator refuses or answers vaguely, that refusal becomes part of the case; and in civil proceedings a party can be ordered to produce specific documents that are relevant to the dispute.
Build the 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.
What producers and developers should do now
Congestion is a legal position as much as a technical one, and the position is largely determined before any dispute arises. Submit transport requests complete, because the date on which the request is registered as complete fixes the queue position. Record every communication with the grid operator. When a refusal arrives, do not accept the letter at face value: ask on which component the constraint sits, what the congestion investigation showed, why flexibility is insufficient, and where you stand in the queue.
Consider whether flexibility is a route 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, and the contractual form of that arrangement is negotiable even though the product is not. Our articles on energy storage and solar energy projects set out the surrounding requirements, and our energy law practice page gives an overview of the field.
Law & More advises producers, developers and industrial grid users on transport requests and refusals, congestion management and flexibility contracts, dispute procedures at the ACM and appeals to the College van Beroep voor het bedrijfsleven, and civil claims for access or damages. If a refusal is blocking your project, please contact us so that the file can be assessed while the evidence is still current.
Frequently asked questions (FAQ)
What legal remedies are available to a producer if the grid operator unjustly refuses transport despite offered flexibility?
If a grid operator refuses transport despite the producer offering flexibility, the producer has two primary legal routes. First, they can file a complaint with the ACM under Article 5.4 of the Energiewet (formerly Elektriciteitswet 1998), requesting a binding decision to enforce the transport obligation. Alternatively, or in parallel, the producer can summon the grid operator in civil court (potentially via summary proceedings or kort geding) to demand performance of the contract or specific performance of the statutory duty to transport, arguing that the refusal violates the Energiewet.
To what extent can a producer claim compensation for the unlawful application of congestion management by the grid operator?
A producer can claim compensation if they can prove the grid operator acted unlawfully (tort/onrechtmatige daad), for example, by discriminating in the queue or failing to apply mandatory congestion management measures. Damages can include lost income (including missed subsidies) and consequential losses. Under the separate rules for the offshore grid, specific compensation regimes apply for offshore connections. For onshore cases, the producer must prove the unlawful act, the damage, and the causal link (Article 6:162 BW or Article 8:88 Awb).
What criteria does the judge use to assess the non-discriminatory distribution of transport capacity by the grid operator?
Judges assess non-discrimination based on the principles of objectivity and transparency derived from the transport obligation in the Energiewet (formerly Elektriciteitswet 1998). The grid operator must demonstrate that they applied a consistent “first-come, first-served” principle or another objective prioritization mechanism published in the electricity codes. Any deviation from the queue must be objectively justified by technical limitations or regulatory exemptions; arbitrary deviations or lack of transparency regarding the queue position will be deemed discriminatory (as confirmed in the case law on transport refusals).
What freedom do parties have when negotiating a congestion management contract?
Contractual freedom is significantly limited by the regulatory framework. While parties must sign a contract, the core terms—such as the definition of the redispatch product and the operational response times—are mandated by the electricity codes. Parties cannot negotiate terms that deviate from these technical standards. Furthermore, the price is capped by regulations to ensure it is not higher than customary in normal economic transactions, preventing purely commercial price setting.
How is the price for congestion management services legally capped, and how is market conformity tested?
The price is capped by the price rule in the electricity codes, which states it must not exceed what is customary in normal economic transactions. Market conformity is tested ex-post by the ACM in dispute resolutions or by the civil court. They compare the agreed price against market data, historical prices, and the underlying costs of the producer (including opportunity costs). There is no pre-approved price list; the “market” determines the cap.
Can a producer force the grid operator to provide additional motivation for a refusal based on physical congestion?
Yes. Under the transport obligation in the Energiewet (formerly Elektriciteitswet) and the electricity codes, a refusal must be “reasoned.” Case law confirms that generic statements about congestion are insufficient. A producer can legally enforce—via the ACM or civil court—that the grid operator provides specific data regarding the substation capacity, the relevant congestion management investigations, and the queue status to substantiate the claim of physical congestion.
What role does the ACM play in disputes over congestion management, and how does the dispute resolution procedure work?
The ACM acts as the independent dispute settler for the energy sector. Under Article 5.4 of the Energiewet, a party can submit a formal complaint. The ACM investigates whether the grid operator has acted in accordance with the law and the electricity codes. The procedure involves an exchange of written views and often a hearing. The resulting decision is binding on both parties, though it is subject to appeal at the CBb.
Can a producer have the ACM assess beforehand whether an offered congestion management price is market-conform?
No, a producer cannot force the ACM to perform an ex-ante (preliminary) individual assessment of a specific price offer in the absence of a dispute. The ACM reviews methods collectively. However, if negotiations break down and a dispute arises regarding the price, the producer can then initiate a formal dispute resolution procedure, at which point the ACM will retrospectively assess if the price was market-conform.
Which arguments are most successful when challenging non-market-conform congestion management prices?
The most successful arguments rely on transparency and comparative data. A producer should argue that the grid operator failed to provide an objective basis for their price or ignored the producer’s actual opportunity costs (e.g., lost subsidy revenue). Citing the congestion management rules of the electricity codes, the producer can argue that the offered price does not reflect “normal economic transactions” by providing evidence of higher prices paid for similar flexibility services in the market or neighboring regions.
What is the difference between physical and contractual congestion, and why is this distinction crucial for producers?
Contractual congestion means all transport rights are booked on paper, even if they aren’t fully used. Physical congestion means the cables are actually reaching their thermal limits. This distinction is crucial because contractual congestion is not a valid legal ground to refuse transport. A producer can successfully challenge a refusal if they can prove (or force the grid operator to admit) that the congestion is merely contractual, compelling the grid operator to apply congestion management and offer access.
