Mambilla Project: ICC Ruling Clears Major Legal Obstacle as Nigeria Defeats $3.38bn Claims

Nigeria has secured a major victory in its long-running arbitration dispute with Sunrise Power and Transmission Company Limited over the Mambilla Hydroelectric Power Project in Taraba State, with an International Chamber of Commerce tribunal in Paris ruling in favour of the Federal Government.

The ruling effectively removes potential exposure of more than $3.38bn arising from two related claims brought by Sunrise over the troubled power project.

The latest arbitration involved a $680m claim for a settlement sum and interest, while a separate proceeding involves a claim of more than $2.7bn in compensation and interest connected to the development of the Mambilla project. 

The final award was issued on September 17, 2026, almost nine years after Sunrise commenced arbitration proceedings against Nigeria.

President Bola Tinubu announced the outcome in a statement on Thursday, describing the decision as a significant development for the long-delayed project.

“Today’s ICC ruling clears the single biggest legal hurdle that has paralysed the Mambilla hydro power project for years,” the President said.

Details of the arbitration award show that the three-member tribunal rejected Sunrise’s claim that Nigeria had breached its contractual obligations under a settlement agreement and an addendum.

The tribunal also dismissed the company’s request for $400m, consisting of a $200m settlement payment and another $200m described as a default payment.

The panel further ruled that Sunrise promoter, Leno Adesanya, was bound by the arbitration agreement with Nigeria and affirmed its jurisdiction over Nigeria’s counterclaim against Adesanya and Sunrise.

Sunrise and Adesanya were also directed to reimburse Nigeria for 75 per cent of its legal fees and expenses incurred in defending the arbitration.

Nigeria’s legal costs were put at approximately $11.82m, with $2.5m to be recovered from funds held in escrow by the ICC.

The respondents are expected to pay the remaining $9.32m, with interest accruing at 10 per cent annually until the amount is settled. The arbitration costs were fixed at about $1.66m, with Sunrise and Adesanya responsible for 75 per cent and Nigeria for the balance.

The tribunal was chaired by Melaine van Leeuwen, with Stavros Brekoulakis and Simon Nesbitt serving as co-arbitrators.

Nigeria’s defence was led by Elizabeth Oger-Gross and Tolu Obamuroh of Paul Hastings LLP.

Tinubu praised the Attorney-General of the Federation and Minister of Justice, Lateef Fagbemi, and officials of the Federal Ministry of Justice for their handling of the case.

He also commended Nigeria’s external legal team for its defence of the country.

“This latest decision affirms the Nigerian State’s determination not to succumb to predatory and exploitative claims by corrupt local and international entities and their enablers and funders,” Tinubu said.

The President also recognised the roles played by former President Olusegun Obasanjo and the late former President Muhammadu Buhari, who testified during the proceedings.

“I commend the patriotism and support of former President Olusegun Obasanjo, GCFR, and late President Muhammadu Buhari, GCFR, who testified in the case, which dated back to an illegal 2003 contract to build a 3,050-megawatt hydroelectric plant in Taraba State under a build-operate-transfer model. The Federal Executive Council never authorised the contract,” he said.

Tinubu further acknowledged former ministers Babatunde Fashola and Suleiman Adamu, as well as other witnesses and experts who participated in Nigeria’s defence.

He also commended the National Security Adviser and the Economic and Financial Crimes Commission for their roles in the matter. 

The Mambilla project has undergone several changes since it was first conceived.

The original proposal envisaged a 3,050MW hydroelectric facility in Taraba State under a build-operate-transfer arrangement.

The planned capacity was later reduced to about 1,525MW, before being rescoped to approximately 1,500MW as the Federal Government sought to make the project financially viable and “bankable” for lenders.

The project has remained stalled for years, with contractual disagreements, financing challenges and changes in implementation arrangements contributing to the delays.

The arbitration dispute itself dates back to October 10, 2017, when Sunrise commenced proceedings at the ICC International Court of Arbitration over an alleged breach of the 2003 agreement.

A settlement agreement was subsequently reached in 2020, but disagreements over its implementation resulted in further arbitration.

The latest ICC ruling has now rejected the related claims and removed a significant legal dispute surrounding the project.

The President said the Federal Government would continue to work with legitimate investors while defending the country against claims it considers unjustified.

“I want to assure you that 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.

The Mambilla ruling comes amid the Federal Government’s broader efforts to resolve longstanding legal disputes involving major infrastructure and power projects.

For the Mambilla project, the arbitration decision removes one of the major legal issues that has hindered progress, although financing and implementation requirements remain relevant to its eventual construction.

The Federal Government had previously identified financing arrangements, project rescoping and legal disputes among the issues affecting the project’s execution.

The project is intended to form part of Nigeria’s efforts to expand electricity generation and improve the country’s power supply capacity.