Nigeria has secured a major victory in the long-running legal dispute over the Mambilla Hydroelectric Power Project, with an International Chamber of Commerce (ICC) arbitration tribunal in Paris dismissing a $2.35 billion claim brought by Sunrise Power and Transmission Company Limited.
The award, issued on Thursday, September 17, 2026, represents a significant development in the dispute surrounding the proposed hydropower project in Taraba State.
The Federal Government, in a statement issued by the State House, said the tribunal rejected Sunrise’s claims against Nigeria arising from a disputed settlement agreement and its addendum.
The tribunal also rejected Sunrise’s demand for $400 million, comprising a $200 million settlement sum and a further $200 million default payment.
Beyond dismissing the company’s claims, the tribunal ordered Sunrise and its promoter, Leno Adesanya, to reimburse Nigeria 75 per cent of the legal fees and expenses incurred during the arbitration, amounting to $11.82 million.
Of that amount, $2.5 million is to be released from funds held in escrow by the ICC, while the remaining $9.32 million is payable directly, with interest accruing at 10 per cent annually, compounded annually, until full payment.
The tribunal also fixed the arbitration costs at $1.656 million, with Sunrise and Adesanya ordered to bear 75 per cent and Nigeria 25 per cent.
The three-member tribunal was chaired by Melaine van Leeuwen, with Stavros Brekoulakis and Simon Nesbitt serving as co-arbitrators. Nigeria’s defence team was led by Elizabeth Oger-Gross and Tolu Obamuroh of Paul Hastings LLP.
How the dispute began
The dispute dates back to a 2003 agreement concerning the proposed Mambilla hydropower project, originally conceived as a 3,050-megawatt facility to be developed under a build-operate-transfer arrangement.
Sunrise subsequently commenced arbitration proceedings against Nigeria in 2017, seeking more than $2.3 billion in compensation over what it described as a breach of its contractual rights. A separate dispute later emerged from a 2020 settlement agreement that was intended to resolve the earlier arbitration.
The project and the circumstances surrounding the original agreement have remained controversial across successive administrations.
Former President Olusegun Obasanjo, who testified in the proceedings, has previously said he did not authorise the 2003 contract. He said he had opposed the proposal when it was presented to the Federal Executive Council and questioned how a minister could commit the Federal Government to such a major project without presidential approval.
Former President Muhammadu Buhari also testified in relation to the dispute and previously said he did not approve the 2020 settlement agreement with Sunrise.
The controversy has also resulted in separate investigations and criminal proceedings involving Olu Agunloye, who was Minister of Power and Steel under Obasanjo when the original agreement was signed. The EFCC has accused Agunloye of corruption in connection with the Mambilla contract, allegations he has contested.
In 2024, the Federal High Court in Abuja ordered the EFCC to remove Adesanya’s name and photograph from its wanted list in connection with the Mambilla dispute, while holding that the contractual issues before the ICC should be allowed to proceed through arbitration.
Presidency welcomes ruling
Reacting to Thursday’s award, President Bola Tinubu commended Attorney-General of the Federation and Minister of Justice Lateef Fagbemi and officials of the Federal Ministry of Justice for their role in defending Nigeria’s position.
Tinubu also praised the country’s defence team, led by Oger-Gross and Obamuroh, describing their work as professional and effective.
The President acknowledged the contributions of former President Obasanjo and the late President Buhari, as well as former ministers Babatunde Fashola and Suleiman Adamu and other witnesses and experts who participated in the proceedings.
He also commended the National Security Adviser and the Economic and Financial Crimes Commission for their support and investigations relating to the matter.
Tinubu said the ruling demonstrated the Federal Government’s resolve to defend Nigeria’s interests while remaining committed to legitimate investors and its international legal obligations.
“While our country remains committed to partnering with genuine investors and honouring its legal obligations, it will continue to defend all opportunistic claims instituted against our commonwealth strongly,” the President said.
He described the ICC decision as clearing what he called the “single biggest legal hurdle” that had stalled the Mambilla hydropower project for years.
The Mambilla project, if eventually completed, is expected to significantly expand Nigeria’s electricity generation capacity. The latest arbitration ruling, however, resolves the particular dispute between Nigeria and Sunrise; it does not by itself amount to a completion of the long-delayed power project.