Two ICSID Arbitral Tribunals, on the basis of similar reasons, reached the same conclusion: Achmea decision (available here) does not affect their jurisdiction.
In 9Ren v. Spain, the Arbitral Tribunal issued a final award, therefore also addressing the merits (ordering Spain to pay the investor approximately 40 million euros); nevertheless, I will focus on the most interesting issue: that relating to the arbitral jurisdiction.
In a nutshell, the Arbitral Tribunal states that it has jurisdiction on the basis of the following grounds.
First of all, the European Court of Justice judgment in Achmea does not extend to the treaty relevant in 9Ren v. Spain. Indeed, Achmea case concerned an intra-EU BIT (between the Netherlands and Slovak Republic), while in 9Ren the claim was brought on the basis of the Energy Charter Treaty (ECT), which is not an intra-EU BIT and has as its contracting parties EU States, non-EU States, and the EU itself. The Arbitral Tribunal, therefore, rejects Spain’s argument that within the remedial provisions of the ECT there are different categories of members with different access to different remedies, and that EU members ought to be considered to constitute a subset of countries with investor rights and remedies different to the rights and remedies available generally to ECT arbitral parties. And rejects this argument clearly stating that it "has no basis in the text of the ECT itself or in the Achmea decision."
The Arbitral Tribunal further states, rejecting additional arguments brought by Spain, that there was (and is) no material conflict between the ECT and EU law; that the latter does not modify Spain’s obligations under the ECT; that the Tribunal’s jurisdiction and its exercise rests upon the ECT; and that ICSID arbitration proceedings, under the ICSID Convention, do not have a seat or legal place in any national jurisdiction, still less in any EU Member State.
The Arbitral Tribunal in Rockhopper v. Italy, in its partial award (on the issue of jurisdiction) also takes a clear stand and points out that, so far, no Arbitral Tribunal has granted an objection to its jurisdiction on the basis of Achmea.
The Arbitral Tribunal in Rockhopper carries out a detailed analysis of Achmea decision and reaches the conclusion that the principles laid down therein are of very limited application, exclusively concerning the BIT relevant to that dispute (as said, between the Netherlands and the Slovak Republic), and that they do not apply to the ECT.
Also in this case, the Arbitral Tribunal states that it has jurisdiction on the case and the proceedings continue on the merits.
Meanwhile, it seems that the investor in 9Ren is enforcing the award in the US (as reported here): this choice is probably aimed at avoiding possible oppositions to the recognition and/or enforcement of the award before EU Courts on the basis of the Achmea arguments that have already been rejected by the Arbitral Tribunal.