In a recent decision(1) the Supreme Court found that an arbitral tribunal had not violated the plaintiff's right to be heard or procedural public policy. The arbitral tribunal had refused to reconsider its preliminary award on jurisdiction following the European Court of Justice's judgment in Slowakische Republik v Achmea BV. Facts The dispute arose out of Spain's decision to end previously granted incentives for photovoltaic installations through the enactment of a new regulation in 2013. After this decision, 26 EU-based investors, which had made significant investments and taken the necessary steps to be able to benefit from such incentives, started arbitration proceedings against Spain based on Article 26(4)(b) of the Energy Charter Treaty (ECT), seeking damages for the violation of Article 10(1) thereof. A three-member arbitral tribunal was constituted in accordance with the United Nations Commission on International Trade Law Arbitration Rules, under the auspices of the Permanent Court of Arbitration and with the seat set in Geneva.