Nigeria Wins Major Legal Battle Over $3.38bn Mambilla Hydropower Claims

The Federal Government of Nigeria has won a nearly nine-year international arbitration dispute with Sunrise Power and Transmission Company Limited over the long-delayed Mambilla Hydroelectric Power Project in Taraba State.

The ruling, delivered by an International Arbitration Tribunal under the International Chamber of Commerce (ICC) in Paris on September 17, 2026, rejected claims that could have exposed Nigeria to more than $3.38 billion in compensation and interest.

President Bola Tinubu announced the victory in a statement issued by the State House on Thursday, describing the ruling as a major breakthrough for the stalled 1,500-megawatt project.

According to the Presidency, Sunrise had sought $680 million in the latest arbitration, while a related case involved claims exceeding $2.7 billion. The combined claims therefore put Nigeria's potential financial exposure at more than $3.38 billion.

The dispute began in October 2017 when Sunrise initiated arbitration proceedings against Nigeria over an alleged breach of a 2003 agreement concerning the development of the Mambilla power project.

The tribunal dismissed Sunrise's claim that Nigeria had violated its contractual obligations under a settlement agreement and an addendum. It also rejected the company's request for Nigeria to pay $400 million, consisting of a $200 million settlement sum and another $200 million in alleged default payments.

The tribunal further ruled that Sunrise promoter, Leno Adesanya, was bound by the arbitration agreement and confirmed its jurisdiction over Nigeria's counterclaims against Sunrise and Adesanya.

Sunrise and Adesanya were ordered to reimburse Nigeria for 75 per cent of the country's legal fees and expenses incurred during the arbitration. Nigeria's legal costs were put at $11.82 million, with $2.5 million expected to come from funds held in escrow by the ICC.

The pair were also ordered to pay the outstanding $9.32 million, with interest accruing at 10 per cent annually until the amount is fully settled.

The arbitration costs were fixed at $1.66 million, with Sunrise and Adesanya responsible for 75 per cent and Nigeria covering the remaining 25 per cent.

Mambilla Project Rescoped

The Mambilla Hydroelectric Power Project was originally planned as a 3,050MW facility. However, the Federal Government later reduced the proposed capacity to about 1,525MW and subsequently rescoped it to approximately 1,500MW.

Officials said the reduction was intended to lower costs and make the project financially viable and acceptable to potential lenders.

The original project was estimated to cost between $5 billion and $5.8 billion, while the rescoped version was estimated at about $4 billion.

Despite being identified by successive administrations as a major component of Nigeria's efforts to increase electricity generation, the project has remained largely uncompleted because of legal disputes, financing difficulties and changes to its implementation arrangements.

President Tinubu said the arbitration victory had removed a major legal obstacle that had hindered the project's progress.

He also commended Attorney-General of the Federation and Minister of Justice, Lateef Fagbemi, officials of the Federal Ministry of Justice and Nigeria's legal team for their handling of the case.

Former President Olusegun Obasanjo and the late former President Muhammadu Buhari also testified in Nigeria's defence during the proceedings. Former Power Ministers Babatunde Fashola and Suleiman Adamu were among other witnesses involved in the case.

The Federal Government has said it remains committed to working with legitimate investors and honouring valid contractual obligations while defending the country's interests in international disputes.

The Mambilla project is expected to remain dependent on the completion of financing arrangements and other implementation requirements before construction can fully progress.

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