The multilateral protection that underpinned energy investment for nearly three decades has splintered, leaving investors and counsel to navigate a jurisdiction-dependent patchwork rather than a single, reliable regime. For most of its life, the Energy Charter Treaty (ECT) offered investors in oil, gas and power projects a direct route to sue host states before an international tribunal. That architecture has now fractured through a combination of a key ruling of the Court of Justice of the European Union (CJEU), a coordinated wave of state withdrawals, and an unsettled modernisation process.
How the treaty came apart
The decisive legal shift originated in Luxembourg. In Achmea v. Slovakia, the CJEU held that investor-State arbitration clauses in intra-EU bilateral investment treaties (BITs) were incompatible with EU law. It later extended that reasoning to the ECT: in Republic of Moldova v. Komstroy (2021), the Court held that the investor-State arbitration mechanism in Article 26(2)(c) of the ECT does not apply to disputes between an investor from one EU Member State and another Member State.
Komstroy gave the European Commission the basis to move against the treaty directly. Rather than contest claims individually, the EU pursued a "coordinated withdrawal." France, Germany and Poland exited in December 2023, followed by Luxembourg and Slovenia in 2024. The Council approved the withdrawal of the EU and Euratom on 30 May 2024, taking effect on 28 June 2025, with the Netherlands leaving the same day; Portugal, Spain and the United Kingdom followed between February and April 2025. The UK's departure stands apart: it left from outside the EU bloc, citing incompatibility with its net-zero commitments. In June 2024, 26 Member States and the EU also signed a declaration affirming that Article 26 does not apply to intra-EU proceedings.
No clean break
The withdrawals have not ended exposure. Article 47(3) of the ECT contains a sunset clause: investments made before a withdrawal takes effect remain protected for a further 20 years. Pre-withdrawal investors in states such as France, Germany or the UK can, in principle, still bring claims for two more decades against the very states that exited partly to escape that risk.
The position is complicated further by modernisation. In December 2024, the Energy Charter Conference adopted amendments that strip protection from new fossil fuel investments made after 3 September 2025 and shorten the sunset period for pre-existing fossil investments to 10 years, for parties that ratify the revised text. Because the EU and UK left before the modernised treaty entered into force for them, it remains unsettled which sunset period, if any, governs fossil fuel investments in those jurisdictions.
Tribunals diverge
Arbitral tribunals have not applied Komstroy uniformly. ICSID tribunals, operating outside the EU legal order, have largely continued to accept jurisdiction over intra-EU ECT claims. In Infracapital v. Spain (ICSID Case No. ARB/16/18), the tribunal rejected Spain's request to reconsider jurisdiction, calling Komstroy irrelevant to its findings; the tribunal in Sevilla Beheer v. Spain likewise held it was not bound by the ruling. At the enforcement stage, the English High Court in Infrastructure Services Luxembourg (formerly Antin) v. Spain held that the CJEU is not the ultimate arbiter under the ICSID Convention or the ECT.
That trend is not uniform. The Stockholm-seated Green Power v. Spain SCC tribunal accepted the intra-EU objection in 2022, and on 11 October 2024 two ICSID tribunals—in claims by Sapec S.A. and European Solar Farms A/S against Spain—upheld the objection for the first time, finding no valid standing offer to arbitrate between a Member State and an EU investor. Outcomes now turn heavily on the seat of arbitration and the specific tribunal, with the Stockholm Chamber of Commerce announcing in October 2024 that it would favour non-EU seats for intra-EU investment disputes to protect award enforceability.
The options that remain
- Sunset-clause claims. Pre-withdrawal investments may be protected for up to 20 years, though intra-EU claims face the Komstroy carve-out and the 2024 declaration, making forum and seat decisive.
- The modernised treaty. States that remain and ratify the 2024 amendments operate under a narrower instrument that excludes new fossil fuel protection but preserves the ISDS mechanism for renewables and other covered investments.
- Bilateral investment treaties. A home-state BIT may fill the gap; the UK alone retains 85 BITs in force, overlapping with roughly 20 of the 50 ECT Contracting Parties.
- Contractual and domestic protections. Stabilisation clauses, choice-of-law provisions and arbitration clauses in project contracts, alongside domestic investment laws, are increasingly the primary line of defence, though generally less robust than treaty coverage.
- Corporate structuring. Routing investments through jurisdictions that retain coverage risks scrutiny as treaty shopping rather than legitimate structuring.
Seventeen EU countries, together with non-EU Contracting Parties including Switzerland, Japan, Türkiye and states across the Western Balkans and the former USSR, remain ECT members. The treaty has not disappeared so much as regionalised. The practical question is no longer whether the ECT applies, but a layered inquiry into the investment's vintage, its host state, that state's ratification status, the availability of an alternative BIT, and—critically—where a claim would be seated and which institution would hear it.