Nigeria has won a major international arbitration dispute over the Mambilla Hydroelectric Power Project after an International Chamber of Commerce (ICC) tribunal in Paris rejected claims by Sunrise Power and Transmission Company Limited that could have exposed the country to more than $3.38 billion in potential liabilities.
President Bola Ahmed Tinubu disclosed the outcome on Thursday, September 17, 2026, describing the ruling as a major development in the long-running legal dispute surrounding the Mambilla power project in Taraba State.
Key Highlights
- ICC tribunal in Paris rules in favour of Nigeria in the Mambilla arbitration.
- Sunrise Power claims with combined potential exposure of more than $3.38 billion were rejected.
- The dispute involves a $680 million settlement-related claim and a separate claim exceeding $2.7 billion.
- The tribunal also ordered Sunrise Power and its promoter to reimburse 75% of Nigeria’s legal costs.
- The Mambilla project was originally conceived as a 3,050MW hydropower plant.
- The ruling removes a major legal obstacle surrounding the long-delayed project.
ICC Tribunal Rejects Sunrise Power Claims
The arbitration dispute involved two related claims brought by Sunrise Power.
The company had sought about $680 million in settlement-related payments and interest in one proceeding. It was also pursuing a separate claim of more than $2.7 billion in compensation and interest over disputes connected to the development of the Mambilla project.
Together, the claims represented potential financial exposure of more than $3.38 billion for Nigeria. The ICC tribunal rejected the claims, delivering an award in Nigeria’s favour.
Reports on the final award also indicate that the tribunal dismissed Sunrise Power’s claim relating to a 2020 settlement agreement and rejected its demand for $400 million comprising a $200 million settlement sum and a $200 million default payment.
Nigeria To Recover Part Of Legal Costs
Beyond rejecting the claims, the tribunal ordered Sunrise Power and its promoter, Leno Adesanya, to reimburse 75% of Nigeria’s legal fees and expenses incurred during the arbitration.
The legal costs were assessed at about $11.82 million, with approximately $9.32 million to be paid directly and $2.5 million to be released from funds held in escrow by the ICC, according to details of the award reported by The Nigeria Lawyer.
The arbitration costs were also allocated largely against Sunrise Power and Adesanya.
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Tinubu Hails Nigeria’s Legal Team
Reacting to the ruling, President Tinubu commended Attorney-General of the Federation and Minister of Justice, Lateef Fagbemi, the Federal Ministry of Justice and Nigeria’s external legal team for their roles in defending the country.
Tinubu also acknowledged former President Olusegun Obasanjo and the late former President Muhammadu Buhari, who testified in the proceedings.
Former Power Ministers Babatunde Fashola and Suleiman Adamu, as well as other witnesses and experts, were also recognised for their contributions to Nigeria’s defence.
Tinubu said Nigeria would continue to work with genuine investors while defending the country’s interests in international disputes. The President further described the ICC ruling as clearing a major legal obstacle that had delayed the Mambilla project for years.
Mambilla Project And The Original Dispute
The Mambilla Hydroelectric Power Project has been the subject of contractual, financial and legal disputes for more than two decades.
In 2003, then Minister of Power and Steel Olu Agunloye awarded Sunrise Power a build-operate-transfer contract for the proposed development of a 3,050MW hydropower plant in Taraba State.
The project was initially estimated to cost about $6 billion, with Sunrise expected to finance and develop the facility and recover its investment through electricity sales. The validity and approval of the contract later became central issues in the dispute.
Sunrise commenced arbitration proceedings against Nigeria at the ICC in October 2017, seeking about $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 a 10% penalty clause in the event of default. The settlement later became the subject of another dispute, resulting in the additional claim that eventually rose to about $680 million with interest.
Mambilla Project Capacity Later Reduced
The Mambilla project originally envisaged a 3,050MW hydropower plant. The Federal Government later reduced the planned capacity to about 1,525MW and subsequently rescoped it to approximately 1,500MW to improve its financial viability and make it more attractive to lenders.
Despite being identified by successive administrations as an important project for Nigeria’s electricity generation capacity, implementation has faced legal, financing and contractual challenges.
The latest ICC ruling is therefore significant to the project’s legal history, although separate domestic proceedings connected to the Mambilla project remain ongoing.
EFCC Investigation Into Mambilla Contract
The Mambilla project has also featured in separate criminal proceedings in Nigeria.
In December 2023, the Economic and Financial Crimes Commission declared former Minister Olu Agunloye wanted over allegations relating to the award of the Mambilla contract.
During court proceedings in 2025, an EFCC investigator testified that the contract had not received approval from former President Olusegun Obasanjo and the Federal Executive Council before it was awarded. Agunloye has pleaded not guilty to the charges.
Sunrise promoter Leno Adesanya has also been involved in related legal proceedings. In September 2024, the Federal High Court in Abuja ordered the EFCC to remove Adesanya from its wanted list. The Court of Appeal subsequently stayed execution of that judgment pending the determination of the Federal Government’s appeal.
Nigeria’s Other Major Arbitration Cases
The Mambilla ruling adds to several major arbitration and international legal disputes involving substantial claims against Nigeria.
In October 2023, a London court set aside arbitration awards against Nigeria in the Process & Industrial Developments (P&ID) case. The awards, initially valued at $6.6 billion plus interest, had risen above $11 billion by the time of the UK proceedings.
Nigeria also secured a favourable arbitral outcome in November 2025 in a dispute involving civil works at the Ajaokuta Steel Complex.
In February 2026, Nigeria won another arbitration involving European Dynamics UK Limited over a national electronic government procurement project, with the tribunal dismissing claims reportedly valued at about $6.2 million.
The latest ICC award represents another major development in Nigeria’s long-running legal disputes over large infrastructure projects and removes the Sunrise Power claims from the international arbitration proceedings.
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