Closed distribution system tariffs are subject to strict statutory rules under Dutch law. The operator of a closed distribution system (CDS, in Dutch: gesloten distributiesysteem or GDS) is not subject to the same ex-ante tariff regime as a regular transmission or distribution system operator: the Netherlands Authority for Consumers and Markets (ACM) does not set its tariffs in advance. That does not mean, however, that the operator is free to charge its connected parties whatever it wishes. Since the entry into force of the Dutch Energy Act (Energiewet) on 1 January 2026, Article 3.114 of that Act contains the tariff standard for closed systems: the operator must draw up and publish a calculation method in advance, and that method must result in tariffs that reflect the costs of its statutory tasks and obligations and that are transparent and non-discriminatory. In addition, any connected party may file a complaint with the ACM under Article 5.4 of the Energy Act; if the ACM finds that the calculation method or the tariff does not meet the statutory requirements, it orders an adjustment and its decision is binding. In this article we discuss how the tariff standard works, which costs belong in the calculation method, why the contractual basis is at least as important as the statutory standard, and how the complaint procedure before the ACM unfolds. We outlined the broader framework of the regime for closed systems in our overview article on private networks and closed distribution systems.
From the Electricity Act 1998 to the Energy Act: recognition instead of exemption
Until 1 January 2026, the regime for closed distribution systems was laid down in Article 15 of the Dutch Electricity Act 1998 (Elektriciteitswet 1998), which operated through an exemption (ontheffing) from the obligation to appoint a system operator. The Energy Act, which replaces both the Electricity Act 1998 and the Gas Act, takes a different starting point: the closed system must be recognised (erkend) as such. The conditions for recognition are set out in Article 3.7 of the Energy Act. The European background remains unchanged: Article 38 of Directive (EU) 2019/944 treats closed distribution systems as distribution systems, but allows them, under conditions, to be exempted from prior approval of tariffs or calculation methods. That exemption expressly does not remove the requirements of transparency and non-discrimination. Operators holding an exemption under the old regime are well advised to have their position reviewed against the transitional law and the recognition conditions of the Energy Act.
Closed distribution system tariffs: the standard of Article 3.114 of the Energy Act
The core of the tariff regime is found in Article 3.114(1) of the Energy Act, which provides, in essence, that:
An operator of a closed system charges […] a tariff established in accordance with a calculation method drawn up and published by it in advance, which results in tariffs that reflect the costs […] and are transparent and non-discriminatory.
This standard contains three elements, each of which imposes its own requirements in practice. First, the calculation method drawn up and published in advance: the operator cannot set tariffs retroactively or on an ad hoc basis, but must make the methodology known to the connected parties beforehand. Second, cost-reflectivity: the tariffs must reflect the costs associated with the operator’s statutory tasks and obligations. Third, transparency and non-discrimination: the method must be verifiable and comparable connected parties must be treated equally, unless an objective difference justifies different treatment. An operator that has these three elements in order enjoys, within those limits, the freedom to design a methodology that fits the nature of the system and the site; an operator that neglects them risks a binding correction by the ACM.
Which costs belong in the calculation method?
The Act does not prescribe a catalogue of costs, but the requirement of cost-reflectivity yields a workable classification. The calculation method may, in principle, include: the costs of connections and modifications of connections, the costs of operation, maintenance, control and metering of the system, the charges the operator itself pays to the public system operator for the transfer point to the public grid, and an attributable share of general overhead. By contrast, costs that cannot be attributed to the distribution function do not belong in the tariffs, such as costs of the operator’s other business activities or costs that are already compensated through other channels, for example through rent or service charges for the site.
The operator must be able to substantiate the chosen calculation method and the cost components included in it in a verifiable and traceable manner. For certain categories of system operators, Article 3.42 of the Energy Decree (Energiebesluit) prescribes separate accounts; irrespective of that, an operator that cannot justify its cost calculation is immediately at a disadvantage in the event of a complaint: what cannot be substantiated cannot be charged. The Energy Act also facilitates this substantiation: Article 4.10 of the Energy Act expressly provides that the operator of a closed system may use data from the register for, among other things, determining tariffs and performing connection and transport agreements.
The contractual basis: no payment obligation without a clear clause
The statutory tariff standard is one thing; the contractual basis of the payment obligation is another, and case law shows that this is precisely where things often go wrong. The ‘s-Hertogenbosch Court of Appeal held that a supply agreement provided no basis for a periodic connection charge, because the payment obligation was not clearly apparent from the contract documents (ECLI:NL:GHSHE:2024:2263). The Dutch Supreme Court upheld that judgment (ECLI:NL:HR:2026:94). That case concerned heat supply, but the lesson applies with equal force to tariffs within a closed system: a professional operator must record separately and comprehensibly what an amount is charged for, how it is calculated, and whether it relates to connection, maintenance, transport, metering or another service. An unclear tariff clause is at the operator’s risk.
If the tariff clause is included in general terms and conditions, the risk of annulment is added to this. A clause that is unreasonably onerous is voidable under Article 6:233 of the Dutch Civil Code, and in case of doubt as to its meaning, the interpretation most favourable to the counterparty prevails (Article 6:238 of the Dutch Civil Code). A clause in which the operator merely reserves, in general terms, the right to change its tariffs, without clarity on the why, when, how often and by what standard, runs that risk concretely. We therefore advise operators to record the tariff methodology explicitly in the connection and transport agreements: which cost categories are passed on, according to which allocation key, how investments in reinforcement or replacement are processed, when and by what standard tariffs are indexed or revised, and which accountability information the connected party receives periodically. For connected parties, the mirror image applies: whoever signs a vague tariff clause is buying a future dispute. At the very least, negotiate access to the underlying cost substantiation.
That the contractual and technical set-up of a private network remains a separate point of attention is also illustrated by the Arnhem-Leeuwarden Court of Appeal: a private network operator must take into account the connected parties’ free choice of supplier, but it does not automatically follow that the operator must itself arrange an EAN code or a separate connection (ECLI:NL:GHARL:2026:316).
The complaint before the ACM: a binding decision within two months
A connected party that considers that the calculation method or the tariff does not meet the statutory requirements may file a complaint with the ACM under Article 5.4 of the Energy Act concerning the way in which the system operator performs its statutory tasks. The ACM decides, in principle, within two months; where additional information is requested, that period may be extended once by two months. The decision is binding. The procedure contains safeguards for both parties, including the system operator’s right to submit its views and a hearing. If the ACM finds that the calculation method or the tariff is not in accordance with the requirements of Article 3.114(1), it orders, under Article 3.114(2), an adjustment of the method or the tariff.
In assessing cost-reflectivity, the ACM may use points of reference, but it does not simply apply the tariff methodology for public system operators: the assessment is tailored to the statutory tasks, the characteristics of the system, the cost substantiation and the chosen calculation method. For the operator, a complaint in any event means that the entire cost structure of the system will be placed on the table; for the connected party, it is an accessible and fast instrument for critically reviewing its own energy costs. For connected parties with a small connection, the operator must in addition offer a transparent, simple and accessible complaints procedure (Article 3.34 of the Energy Decree).
Three points of dispute in practice
The sharpest discussions arise in three situations for which the Act offers no ready-made solution and which must therefore be addressed primarily by contract. The first is the major investment: if the system has to be reinforced to accommodate the growth or electrification of a single connected party, the question arises who bears that investment and how it is processed in the calculation method. The second is vacancy or departure: if a large connected party leaves the site, the fixed costs of the system must be spread over fewer shoulders, and the question is whether that risk lies with the operator or with the remaining connected parties. The third is the newcomer: on what terms does a new party on the site obtain access to the system, and does it contribute to historical investments? Whoever addresses these scenarios in advance in the calculation method and the agreements avoids having to resolve them later through an ACM complaint or civil proceedings.
Conclusion
Under the Dutch Energy Act, the operator of a closed system does not enjoy tariff freedom, but it does have room, within the standard of Article 3.114, to apply its own calculation method, provided that the method is published in advance and results in cost-reflective, transparent and non-discriminatory tariffs. The ACM enforces that standard, upon complaint by any connected party, with a binding decision, and the civil courts enforce the contractual basis: a tariff without a clear clause is vulnerable, however reasonable its level may be. A traceable cost substantiation, a properly published calculation method and clear contractual arrangements are, together, the best insurance against tariff disputes. Are you the operator of a closed system and would you like to have your calculation method, recognition or agreements reviewed against the Energy Act, or are you a connected party with doubts about the tariffs you pay? The energy law attorneys of Law & More advise and litigate on both sides of this relationship, both before the ACM and before the civil courts.
Frequently asked questions
Is the operator of a closed system free to set its own tariffs?
No. The tariffs do not have to be set in advance by the ACM, but under Article 3.114 of the Energy Act the operator must draw up and publish a calculation method in advance that results in tariffs that reflect the costs of its statutory tasks and obligations and that are transparent and non-discriminatory.
Does the old regime of Article 15 of the Electricity Act 1998 still apply?
No. The Energy Act has applied since 1 January 2026. The closed system must be recognised under Article 3.7 of the Energy Act and the tariff standard is contained in Article 3.114. Operators holding an exemption under the old regime are well advised to have their position reviewed against the transitional law.
May the operator pass on the charges of the public system operator?
Yes. The charges the operator pays to the public system operator for the transfer point are connected with its tasks and may be included in the calculation method, provided that the allocation to the connected parties is transparent and non-discriminatory.
Can a connected party have an excessive tariff adjusted?
Yes. A connected party may file a complaint with the ACM under Article 5.4 of the Energy Act. If the ACM finds that the calculation method or the tariff does not comply with Article 3.114, it orders an adjustment. The ACM’s decision is binding and follows, in principle, within two months.
Can a connected party recover amounts already paid?
That depends first and foremost on the contractual basis. It follows from case law (ECLI:NL:HR:2026:94) that a payment obligation that is not clearly apparent from the contract documents provides no basis for the amount charged. In addition, an unreasonably onerous tariff clause in general terms and conditions may be voidable. Seek advice in good time, also with a view to limitation periods.
Must the operator keep separate accounts?
Article 3.42 of the Energy Decree requires certain categories of system operators to keep separate accounts. Irrespective of whether that obligation applies to a specific operator, the operator must be able to substantiate its calculation method and cost components in a verifiable and traceable manner; without that substantiation, a tariff will not survive a complaint before the ACM.
What can Law & More do for you?
We advise operators on the recognition of the closed system, the design and publication of the calculation method and the connection and transport agreements, and we represent parties in complaint procedures before the ACM and in civil tariff disputes. For connected parties, we assess the calculation method, the tariffs and their contractual basis. We regularly advise on closed distribution system tariffs disputes, from the recognition procedure through to complaints before the ACM.
Tom Meevis, energy law attorney and managing partner at Law & More. For questions about closed distribution systems, tariffs or disputes with the ACM, please contact us at [email protected] or +31 40 369 06 80.
