Summary

Source: icsid.worldbank.org

TABLE OF CONTENTS

I. INTRODUCTION
A. The Parties
B. The Tribunal and Secretary
C. The Dispute
D. Requests for Relief
II. PROCEDURAL HISTORY
A. Commencement of the Proceedings and Constitution of the Tribunal
B. The Written Phase and Pre-Hearing Steps
C. Substantive Oral Hearing
D. Post-Hearing Steps
E. Post-Hearing Additional Documents
(1) The Strabag v. Germany Award of 18 December 2024
(2) The International Court of Justice Advisory Opinion of 23 July 2025
(3) The German Federal Constitutional Court Decision of 18 September 2025
III. FACTUAL BACKGROUND
A. Regulatory Framework and Events Leading up to the 2008 Applications
B. The Claimants' June/July 2008 Applications
C. Changes to the Regulatory Framework Following the 2008 Applications
IV. JURISDICTIONAL OBJECTIONS
A. Jurisdiction Ratione Voluntatis (the Intra-EU Objection)
(1) Event Timeline for the Intra-EU Objection
(2) Key Treaty Provisions
(3) Submissions of the Parties
a. The Respondent's Position
i.Intra-EU Objection: Factual Basis
ii. Application of the German Federal Court of Justice Decision
iii. EU Law Interpretation
1) EU Measures
2) CJEU Judgments
(i) Achmea Judgment
(ii) Komstroy Judgment
(iii) PL Holdings Judgment
(iv) European Food Judgment
3) EU Member State Court and Tribunal Decisions
4) No Loss of Rights
iv. International Law Interpretation
1) Successive Treaties (VCLT Article 30)
2) General Interpretation (VCLT Article 31(1))
3) Context, Object and Purpose (VCLT Article 31(1), (2))
4) Supplementary Means (VCLT Articles 31(3) and 32)
5) EU Law Primacy (VCLT Article 5)
6) Other International Agreements
v. The Private Law Argument
b. The Claimants' Position
i.Intra-EU Objection: Factual Basis
ii. German Federal Court of Justice Decision
iii. EU Law Interpretation
vi. International Law Interpretation
1) Applicable Law (ECT Article 26(6))
2) Successive Treaties (VCLT Article 30)
3) General Interpretation (VCLT Article 31(1))
4) Context, Object and Purpose (VCLT Article 31(1), (2))
5) Supplementary Means (VCLT Articles 31(3) and 32)
6) EU Law Primacy (VCLT Article 5)
iv. The Private Law Argument
c. European Commission Submission
(4) Tribunal's Reasoning and Analysis
a. Determination of Applicable Law
i.International and EU Law Relationship
ii. Corpus of Applicable International Law
1) ICSID Convention Article 25(1)
2) ECT Articles 26(1), 26(3) and 16
3) Request for Arbitration
4) EU Law
5) Termination Treaty
6) VCLT Articles 30, 31 and 32
7) VCLT Article 5
8) Prior Awards and National Court Judgments
b. Determination of the Issue of Consent, Pursuant to Applicable Law
i.German Federal Court of Justice Decision
ii. EU law
1) EU Measures
2) CJEU Judgments
a. Achmea Judgment
b. Komstroy Judgment
c. PL Holdings Judgment
d. European Food Judgment
iii. VCLT
1) Successive Treaties (VCLT Article 30)
2) General Interpretation (VCLT Article 31(1))
3) Context, Object and Purpose (VCLT Articles 31(1), (2))
4) Supplementary Means (VCLT Articles 31(3) and 32)
5) EU Law Primacy (VCLT Article 5)
iv. Private Law Argument
B. Jurisdiction Ratione Materiae
(1) The Respondent's Position
a. Legal Definition of "Investment"
b. Application to the Facts
(2) The Claimants' Position
a. Legal Definition of "Investment"
b. Application to the Facts
(3) Tribunal's Reasoning and Analysis
a. Legal Definition of "Investment"
i.ICSID Convention Article 25(1) and ECT Article 1(6)
ii. The Travaux Préparatoires
iii. Teachings of the Most Highly Qualified Publicists
iv. Prior Decisions and Awards
b. Application of the "Investment" Definition to the Facts
C. Jurisdiction Ratione Personae
(1) The Respondent's Position
(2) The Claimants' Position
(3) Tribunal's Reasoning and Analysis
V. SUBSTANTIVE MERITS CLAIMS (ECT ARTICLES 10(1) AND 10(13))
A. Fair and Equitable Treatment (ECT Article 10(1))
(1) The Claimants' Position
a. Applicable Legal Standard
i.ECT Article 10(1) "Stable Conditions"
ii. Fair and Equitable Treatment and Legitimate Expectations
iii. Fair and Equitable Treatment and Proportionality
iv. Fair and Equitable Treatment and Transparency
v. Fair and Equitable Treatment and Good Faith
b. Facts Relating to the Claimants' Expectations
c. The Claimants' Reliance on Expectations
d. Alleged Breach of the Claimants' Expectations
(2) The Respondent's Position
a. Applicable Legal Standard
i.ECT Article 10(1) "Stable Conditions"
ii. Fair and Equitable Treatment and Legitimate Expectations
iii. Fair and Equitable Treatment and Proportionality
iv. Fair and Equitable Treatment and Transparency
v. Fair and Equitable Treatment and Good Faith
b. Facts Relating to the Claimants' Expectations
c. The Claimants' Reliance on Expectations
i. Approval Expectation
ii. Grid Connection Expectation
iii. Economic Incentive Expectation
d. Alleged Breach of the Claimants' Expectations
e. Non-Impairment Obligation of ECT Article 10
(3) Tribunal's Reasoning and Analysis
a. Applicable Legal Standard
i.ECT Article 10(1) "Stable Conditions"
ii. Article 10(1) and Legitimate Expectations
iii. Fair and Equitable Treatment and Proportionality
iv. Fair and Equitable Treatment and Transparency
v. Fair and Equitable Treatment and Good Faith
b. The Claimants' Expectations
i.Specific Commitments Based on the Omnibus Framework
ii. Specific Consent Commitment
iii. Specific Grid Connection Commitment
iv. Specific Economic Incentives Commitment
c. The Claimants' Reliance on Expectations
d. Alleged Breach of the Claimants' Expectations
B. Expropriation (ECT Article 13)
(1) The Claimants' Position
(2) The Respondent's Position
(3) Tribunal's Reasoning and Analysis
VI. COSTS
A. The Claimants' Position
B. The Respondent's Position
C. Tribunal's Reasoning and Analysis
VII. DECISION

A. THE PARTIES

1. This arbitration was commenced by six entities in the Mainstream group of companies including:

a. Mainstream Renewable Power Limited ("Mainstream" or the "First Claimant"), a private company limited by shares and incorporated in Ireland in February 2008;

b. International Mainstream Renewable Power Limited ("Mainstream International" or the "Second Claimant"), a private company limited by shares and incorporated in Ireland in August 2008;

c. Mainstream Renewable Power Group Finance Ltd ("Mainstream Finance" or the "Third Claimant"), a private company limited by shares and incorporated in Ireland in January 2009;

d. Horizont I Development GmbH ("Horizont I" or the "Fourth Claimant"), a limited liability company (Gesellschaft mit beschränkter Haftung) incorporated in Germany in October 2012;

e. Horizont II Renewable GmbH ("Horizont II" or the "Fifth Claimant"), a limited liability company (Gesellschaft mit beschränkter Haftung) incorporated in Germany in June 2009; and

f. Horizont III Power GmbH ("Horizont III" or the "Sixth Claimant"), a limited liability company (Gesellschaft mit beschränkter Haftung) incorporated in Germany in October 2012, (jointly, the "Claimants").

2. The First Claimant is a developer of wind and solar energy projects. It is the direct parent company of the Second and Third Claimants (owning 94% of the Second Claimant (the remaining 6% is owned by the Third Claimant) and 100% of the Third Claimant). The Second Claimant is the direct and sole parent company of the Fourth, Fifth and Sixth Claimants.

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C. THE DISPUTE

7. The dispute has arisen out of the German government's climate change-related measures.

These measures concerned its offshore wind regulatory and administrative framework, which existed within its broader renewable energy strategy and policy to scale up renewable electricity generation in accordance with climate change mitigation.1 The dispute arises out of the German government's initial establishment of a framework, against which the Claimants took their investment decision, which was subsequently adjusted in a manner that, ultimately, deprived the Claimants of almost any value in their initial investment. Another ECT award arose out of the same changes to the German offshore wind regulatory and administrative framework, Strabag SE, Erste Nordsee- Offshore Holding GmbH and Zweite Nordsee-Offshore Holding GmbH v. Federal Republic of Germany (ICSID Case No. ARB/19/29), which found the host State to have been in breach of ECT investment protections.

8. The alleged investment comprises the Claimants' three offshore wind farms on the offshore sites, Horizont, Horizont Ost and Horizont West (subsequently renamed Horizont I, Horizont II and Horizont III), in the German North Sea (collectively the "Horizont Projects" or "Projects"). The planned total maximum capacity for the Horizont Projects was around 1.13 GW in 2008 (approximately 226 wind turbines) with potential to increase to over 1.6 GW by installing larger turbines. The First Claimant applied for consent to develop these in June and July 2008 (the "Consent Applications").

9. The alleged host State measures arise out of the Respondent's changes to its offshore wind regulatory framework following the Claimants' investment. In particular, at the date of the Consent Applications, Germany's Federal Government's 2002 Strategy for Using Offshore Wind Energy (Strategie der Bundesregierung zur Windenergienutzung auf See) (the "2002 Offshore Wind Strategy") enacted various statutory or regulatory instruments applicable to offshore wind in Germany, including:

a. the 2004 Renewable Energy Sources Act (Erneuerbare Energien-Gesetz) (the "2004 EEG");

b. the 2004 Federal Spatial Planning Act (Raumordnungsgesetz) (the "ROG");

c. the 2006 Offshore Installations Ordinance (Seeanlagenverordnung) (the "2006 SeeAnlV"); and

d. the 2006 Energy Industry Act (Energiewirtschaftsgesetz) (the "2006 EnWG");

and published additional guidance and draft statutory or regulatory instruments, variously addressing offshore wind strategy and renewable permitting, grid connection and feed-in tariff regimes.

10. Subsequent to the Consent Applications: (i) the Respondent's 2012 amendments to the SeeAnlV indefinitely delayed the grant of consent/approval; and (ii) the Respondent's 2017 Offshore Wind Energy Act (Gesetz zur Entwicklung und Förderung der Windenergie auf See) ("WindSeeG") cancelled any rights arising out of the Consent Applications, replacing the existing consent system with a new tender for offshore wind areas in the German North Sea with limited grandfathering benefits. The Claimants argue that the 2012 and 2017 legislation breached the Respondent's Energy Charter Treaty 1998 ("ECT") obligation to provide fair and equitable treatment to qualifying investors (Article 10(1)), and the 2017 legislation breached its obligation not to expropriate qualifying investments without fair market value compensation (Article 13).

11. The Respondent disputes the Tribunal's jurisdiction to hear the dispute on three bases:

a. it denies consent to arbitration in intra-European Union ("EU") investment disputes, including pursuant to the ECT (ratione voluntatis);

b. it denies that the Claimants are qualifying investors within the meaning of the ECT (ratione personae); and

c. it denies that the Consent Applications for the Horizont Projects are qualifying investments within the meaning of the ECT (ratione materiae).

12. The Respondent further denies that it breached any substantive obligations pursuant to Article 10(1) and Article 13 of the ECT.

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VII. DECISION

1095. On the basis of the above considerations, the Tribunal:

a. declares, by majority, that the dispute is within the jurisdiction and competence of ICSID and the Tribunal;

b. declares, by majority, that all of the Claimants have standing to bring these claims;

c. declares that the Respondent has not violated its international legal obligations pursuant to ECT Article 10(1);

d. declares that the Respondent has not violated its international legal obligations pursuant to ECT Article 13;

e. directs that each Party bear its own costs and fees, and that each Party bear half of all procedural costs, including the costs of the Tribunal and ICSID, evenly; and

f. all other claims, requests, and submissions are dismissed.

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Mainstream Renewable Power Ltd and others v. Federal Republic of Germany (ICSID Case No. ARB/21/26)

CONCURRING AND DISSENTING OPINION
Antolín Fernández Antuña, FCIArb
Arbitrator

TABLE OF CONTENTS

I. INTRODUCTION AND SUMMARY
II. JURISDICTION RATIONE VOLUNTATIS: INTRA-EU LACK OF CONSENT
(i) The Issue: Interpretation of Article 26 ECT
(ii) Article 31 VCLT: The Vienna Convention Rule for Treaty Interpretation
(iii) Article 1(3) ECT: By ECT Definition, EU Member States Are Bound Inter Se by the EU Legal Order
(iv) Systemic Integration of EU Law: Article 31(3)(c) VCLT, Reinforced by the Applicable-Law Clause in Article 26(6) ECT
a. Article 31(3)(c) VCLT
b. Article 26(6) ECT
c. EU Law and CJEU Jurisprudence
(v) Article 2 ECT: Object and Purpose of the Treaty, a European Project
(vi) Further Instruments Confirming the Systemic Interpretation
a. The 1997 Statement at the Time of the ECT Ratification
b. The 2019 Declaration Signed by EU Member States
(vii) Article 16 ECT
(viii) Conclusion: Lack of Consent to Intra-EU Investor-State Arbitration
III. MERITS: THE FET AND EXPROPRIATION STANDARDS
(i) Background
(ii) No Liability Without Fault
(iii) The State's Right to Regulate and the Police Powers Doctrine
(iv) The Lack of FET Breach Precludes Expropriation

I. INTRODUCTION AND SUMMARY

1. I hereby express my concurring and dissenting Opinion with respect to the Award rendered in the present investor-State arbitration, a matter of considerable complexity in which a number of fundamental issues in international investment law have been addressed. I further express my appreciation to my fellow members of the Tribunal for the rigorous and insightful deliberations that have accompanied the resolution of this case.

2. I agree with my esteemed colleagues as to the final outcome of the merits part of the Award. The purpose of the German Offshore Wind Energy Act of 2017 ("WindSeeG")1 was to expand the use of wind energy in the interest of climate and environmental protection through more effective provisions, the State lawfully exercised its legitimate regulatory powers in the public interest, and the disputed measures did not breach any investment protection standard established under the Energy Charter Treaty ("ECT").2 Accordingly, no liability on the part of the Respondent arises.

3. However, I do not join the majority in declaring jurisdiction and competence. For the reasons stated below, I respectfully dissent as to one important ratione voluntatis objection: I find that there is no consent to intra-European Union ("EU") investor-State arbitration under the ECT (Part II of this Opinion) and that, consequently, there is no jurisdiction or competence in the present case.3

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Footnotes omitted