The European Union's court has annulled the European Commission's approval of state aid for the construction of Hungary's Paks II nuclear power plant, reversing a decision that had cleared the way for one of the EU's most contested energy subsidy schemes.

The ruling, handed down by the EU court, strips the Paks II project of the state aid clearance it had previously received from the Commission. The decision marks a significant legal defeat for Budapest and for the Commission's original competition assessment, and it leaves the financing structure of the planned nuclear plant without approved subsidy cover.

What did the court decide?

The court annulled the Commission decision approving Hungarian state aid for the construction of the Paks II nuclear power plant. The effect of annulment is direct: the approval no longer stands, and the aid measure returns to the position it occupied before the Commission cleared it.

The case concerns Hungary's plan to finance the construction of two new reactors at the Paks site on the Danube. The Commission had previously found that the support scheme could pass muster under EU state aid rules. The EU court has now overturned that approval.

Why does the ruling matter?

Annulment decisions by the EU courts are rare in state aid cases, and rarer still in the energy sector, where the Commission enjoys wide discretion in assessing whether member state support for large infrastructure projects complies with the internal market rules.

For Hungary, the immediate consequence is procedural and financial. The state aid approval formed part of the legal foundation for the Paks II financing. Without it, the project's funding arrangements face renewed uncertainty and the Hungarian government must consider whether to restructure the aid, notify a modified scheme, or challenge the judgment on appeal.

For the Commission, the judgment constrains the framework it applied when evaluating the nuclear support package. The court's finding that the approval was flawed signals that the Commission's assessment of the aid did not withstand judicial scrutiny on the points the court examined.

What does the ruling change for practitioners?

State aid lawyers will read the judgment as a reminder that Commission clearance decisions in the energy field remain fully exposed to annulment actions. Applicants challenging such decisions — here, parties opposed to the Hungarian nuclear subsidy — can succeed where the Commission's substantive analysis is found deficient.

The practical consequences include:

• The Paks II state aid approval is void; Hungary cannot rely on it going forward.
• The Commission must reassess the measure if Hungary re-notifies or modifies the aid.
• Third parties and competitors gain a precedent for contesting nuclear and energy subsidies at the EU courts.
• Investors and contractors tied to the project face renewed legal and financial risk pending any appeal.

Any party considering an appeal — Hungary, the Commission, or the original challengers — faces the standard two-month window to bring the matter before the Court of Justice. Until the appeal question is resolved, or a fresh Commission decision issues, the aid stands unapproved.

What happens next?

The judgment does not itself prohibit the Paks II project. It removes the state aid approval. The path forward depends on Hungary's response: a re-notification of the aid, a renegotiated financing structure, or an appeal to a higher EU court.

The ruling also lands at a sensitive moment for EU energy policy, where member states are split over nuclear power's role in the transition. A court-sanctioned rollback of nuclear state aid in a member state will sharpen that debate and give opponents of similar subsidy schemes a fresh legal reference point.

For now, the Paks II project's subsidy architecture has no valid authorization, and the burden returns to Budapest and Brussels to rebuild it on terms the EU courts will accept.