Nigeria has secured a major victory in an international arbitration dispute after a tribunal constituted under the auspices of the International Chamber of Commerce (ICC) in Paris rejected claims by Sunrise Power and Transmission Company Ltd over the long-running Mambilla Hydroelectric Power Project in Taraba State.
President Bola Ahmed Tinubu disclosed the development in a statement on Thursday, September 17, 2026, following the issuance of the tribunal’s award.
The ruling effectively removes a potential financial exposure of more than $3.38 billion for the Federal Government.
The claims comprised a demand of approximately $680 million, including settlement sums and interest, and a separate claim exceeding $2.7 billion in compensation and interest arising from disputes connected to the development of the 3,960MW Mambilla Hydroelectric Power Project.
President Tinubu said the outcome demonstrated the government’s determination to defend Nigeria against claims it considers detrimental to the national interest while maintaining its commitment to legitimate investors and its legal obligations.
He commended the Nigerian legal and government teams involved in the defence, including Attorney-General of the Federation and Minister of Justice, Lateef Fagbemi; officials of the Federal Ministry of Justice; and Nigeria’s external counsel, Elizabeth Oger-Gross and Tolu Obamuroh of Paul Hastings LLP.
The President also acknowledged former President Olusegun Obasanjo and the late former President Muhammadu Buhari, who testified during the arbitration proceedings. Former Ministers of Power Babatunde Fashola and Suleiman Adamu, as well as other witnesses and experts, were also recognised for their contributions to Nigeria’s defence.
Long-running Mambilla dispute
The Mambilla project has been at the centre of contractual, financial and legal controversies for more than two decades.
In 2003, then Minister of Power and Steel, Olu Agunloye, awarded Sunrise Power a build-operate-transfer contract for a proposed 3,050MW Mambilla hydropower plant, estimated at about $6 billion.
Under the proposed arrangement, Sunrise was expected to finance and develop the project and recover its investment through electricity sales over an extended period.
The legality of the contract subsequently became a major issue in related legal proceedings.
During court proceedings in 2025, an Economic and Financial Crimes Commission investigator testified that former President Obasanjo and the Federal Executive Council had not approved the contract. According to the testimony, Agunloye awarded the contract on May 22, 2003, shortly after an FEC meeting at which the proposal was reportedly withdrawn.
Agunloye has pleaded not guilty to the criminal charges arising from the matter.
Arbitration claims
Sunrise commenced arbitration proceedings against Nigeria before the ICC on October 10, 2017, seeking approximately $2.354 billion over an alleged breach of the 2003 agreement.
A settlement was subsequently negotiated under which Nigeria agreed to pay Sunrise $200 million, with the agreement providing for a 10 per cent penalty in the event of default.
Sunrise later brought another claim of approximately $400 million relating to the settlement. With interest, that claim eventually rose to about $680 million.
The latest ICC award has rejected the related claims, significantly reducing the financial risk to Nigeria arising from the dispute.
Domestic proceedings continue
The Mambilla controversy has also produced separate proceedings in Nigerian courts.
In December 2023, the EFCC declared former Minister Olu Agunloye wanted over alleged fraud linked to the Mambilla contract.
In September 2024, the Federal High Court in Abuja ordered the EFCC to remove Sunrise promoter Leno Adesanya from its wanted list over allegations connected to the project. The Court of Appeal subsequently stayed execution of that judgment pending determination of the Federal Government’s appeal.
Another major arbitration victory
The Mambilla outcome adds to a series of significant arbitration and commercial litigation victories recorded by Nigeria in recent years.
In October 2023, the Commercial Court in London set aside arbitration awards against Nigeria in the long-running Process & Industrial Developments (P&ID) case. The awards, initially valued at $6.6 billion plus interest and later exceeding $11 billion, arose from a failed gas processing agreement. The court found that the awards had been obtained by fraud and that the manner in which they were procured was contrary to public policy.
In November 2025, Nigeria also secured a favourable arbitral award in a dispute involving civil works at the Ajaokuta Steel Complex. A tribunal constituted under the Alternative Dispute Resolution Centre of the Federal High Court dismissed claims by Fougerolle Nigeria Ltd and Fougerolle SA amounting to approximately N4 billion and €185.7 million.
More recently, in February 2026, Nigeria prevailed in an arbitration involving European Dynamics UK Ltd over a national electronic government procurement project. The tribunal dismissed the company’s claims, which the Attorney-General’s office put at approximately $6.2 million.
The latest Mambilla ruling therefore represents another important development in Nigeria’s efforts to defend itself against major financial claims arising from long-running contractual and investment disputes.
For a country facing substantial infrastructure financing needs, the outcome also underscores the financial significance of effective legal representation in complex international arbitration proceedings.
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