Three foundations have brought collective actions under the Dutch Act on Collective Damages Claims (WAMCA) against ten energy suppliers, including Vattenfall, Eneco, and Essent. They allege that the standard clause used to raise variable tariffs since 2017 is unfair and seek refunds. On October 28, 2026, the District Court of Amsterdam kept the claims together and adjourned further decisions pending a related Supreme Court ruling, which it expects on December 4, 2026.
Latest development Oct 28, 2026
On October 28, 2026, the District Court of Amsterdam held that it may hear the claims against all ten suppliers as one case, because each used the same tariff clause. It refused the suppliers’ wider document requests. The court adjourned further decisions until the Supreme Court rules in the Vattenfall case, which it expects on December 4, 2026.
Why it matters
The Supreme Court’s ruling in the Vattenfall case and this collective action will decide whether Dutch suppliers could raise variable energy tariffs under their standard clause. SEH says millions of households paid too much since 2017.
Background
Dutch energy suppliers use general terms drafted by their trade association, Energie-Nederland. Article 19.3 of the 2017 terms lets a supplier change the tariffs of a variable-rate contract for reasons such as government decisions, wholesale prices, margins, and cost changes. On February 24, 2023, a subdistrict judge of the District Court of Amsterdam ruled in one consumer’s case against Vattenfall. The judge held that the clause was unfair because consumers could not foresee its financial consequences. The judge annulled the clause and barred Vattenfall from raising that customer’s tariffs from April 1, 2022. The Court of Appeal of Amsterdam upheld the ruling on March 25, 2025, and Vattenfall appealed to the Supreme Court of the Netherlands.
On June 30, 2025, Stichting Eerlijke Handelspraktijken (SEH) brought a collective action under the Dutch Act on Collective Damages Claims (WAMCA) against Vattenfall, Eneco, Essent, Energiedirect, Greenchoice, and Budget Thuis. Stichting Consumer Justice (SCJ) and Stichting Consumenten Competition Claims (SCCC) followed on September 29 and 30, 2025. SCJ also sued Greenchoice Zakelijk, ENGIE, Oxxio, and Vandebron and acts for small businesses as well as consumers. The foundations seek declarations that the clause is unfair and void, a ban on its use, and refunds or damages. SEH says millions of households paid too much under variable contracts since April 1, 2017. The suppliers have said they will contest the claims, and Vattenfall says a variable tariff can change during the contract.
On May 29, 2026, Advocate General W.L. Valk advised the Supreme Court to quash the Vattenfall ruling and refer the case back. His opinion noted that 56% of Dutch households had a variable-rate energy contract in 2022. On October 28, 2026, the District Court of Amsterdam rejected the suppliers’ venue objections and requests to split the case, finding that all ten used the same clause. It refused their requests for documents on how the foundations were set up. It adjourned further decisions until the Supreme Court rules and gave the parties until December 23, 2026, to comment on that ruling.
Timeline 7 events
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Scheduled judgmentSupreme Court expected to rule in the Vattenfall case
The District Court of Amsterdam said it expects the ruling on this date and gave the parties until December 23, 2026, to comment on it.
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JudgmentAmsterdam court keeps the claims together and awaits the Supreme Court
The court rejected the suppliers’ venue objections and requests to split the case and refused their wider document requests.
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OtherAdvocate General advises quashing the Vattenfall appeal ruling
Advocate General W.L. Valk advised the Supreme Court to quash the Court of Appeal’s judgment and refer the case back.
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FilingTwo more foundations file parallel collective actions
Stichting Consumer Justice sued on September 29, 2025, adding four suppliers, and Stichting Consumenten Competition Claims sued the original six a day later.
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FilingStichting Eerlijke Handelspraktijken sues six energy suppliers
The foundation brought a collective action over tariff increases on variable contracts since April 1, 2017, against Vattenfall, Eneco, Essent, Energiedirect, Greenchoice, and Budget Thuis.
District Court of Amsterdam: ECLI:NL:RBAMS:2026:10575NL Times
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AppealCourt of Appeal of Amsterdam upholds the ruling against Vattenfall
The appeal court held that consumers could not estimate how their costs would change under the clause. Vattenfall then appealed to the Supreme Court.
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JudgmentSubdistrict judge finds Vattenfall’s tariff change clause unfair
In one consumer’s case, the judge annulled the clause and barred Vattenfall from raising that customer’s tariffs from April 1, 2022.