Precious Nwonu, Enugu
Nigeria has secured a major legal victory in the long-running dispute over the Mambilla Hydroelectric Power Project, with an International Chamber of Commerce arbitration tribunal dismissing claims by Sunrise Power and Transmission Company Limited that could have exposed the country to more than $3.38bn.
President Bola Tinubu announced the development in a statement issued by the State House on Thursday, saying the ICC tribunal in Paris ruled in favour of Nigeria in the latest phase of the nearly nine-year legal battle.
The dispute began in October 2017 when Sunrise initiated arbitration proceedings against Nigeria over an alleged breach of a 2003 agreement relating to the development of the Mambilla power project in Taraba State.
According to the Presidency, Sunrise had sought $680m, including settlement payments and interest, in the latest proceedings, while a separate related claim involved more than $2.7bn in compensation and interest.
The combined claims therefore placed Nigeria’s potential financial exposure at more than $3.38bn.
The final award was issued on September 17, 2026.
Tinubu described the ruling as a significant development for the stalled hydropower project, saying it had removed a major legal obstacle that had hindered its progress for years.
“Today’s ICC ruling clears the single biggest legal hurdle that has paralysed the Mambilla hydro power project for years,” the President said.
### Tribunal dismisses Sunrise claims
Details of the arbitration award reported by TheCable showed that the three-member tribunal rejected Sunrise’s request for a declaration that Nigeria had violated its contractual obligations under a settlement agreement and an addendum entered into by both parties.
The tribunal also dismissed Sunrise’s demand for $400m, comprising a $200m settlement payment and another $200m described as a default payment.
It further ruled that Leno Adesanya, promoter of Sunrise Power, was bound by the arbitration agreement with Nigeria under the settlement agreement and addendum.
The tribunal consequently affirmed its jurisdiction over Nigeria’s counterclaims against Sunrise and Adesanya.
As part of the award, Sunrise and Adesanya were ordered to reimburse Nigeria for 75 per cent of the legal costs and expenses incurred in defending the case.
Nigeria’s legal expenses were estimated at $11.82m. Of that amount, $2.5m is expected to be paid from funds held in escrow by the ICC and released after notification of the final award.
The defendants were ordered to pay the remaining $9.32m, with interest at 10 per cent annually, compounded yearly, from the date they are notified of the award until the outstanding sum is settled.
The arbitration costs were fixed at $1.66m, with Sunrise and Adesanya responsible for 75 per cent and Nigeria responsible for the remaining 25 per cent.
The tribunal comprised Melaine van Leeuwen as president, with Stavros Brekoulakis and Simon Nesbitt serving as co-arbitrators.
Nigeria’s legal team was led by Elizabeth Oger-Gross and Tolu Obamuroh of Paul Hastings LLP.
Tinubu commended Attorney-General of the Federation and Minister of Justice, Lateef Fagbemi, officials of the Federal Ministry of Justice and members of the legal team for their handling of the case.
He also acknowledged former President Olusegun Obasanjo and the late former President Muhammadu Buhari for appearing as witnesses in Nigeria’s defence.
“I commend the patriotism and support of former President Olusegun Obasanjo, GCFR, and late President Muhammadu Buhari, GCFR, who testified in the case,” Tinubu said.
The President also recognised former ministers Babatunde Fashola and Suleiman Adamu, as well as other experts who participated in the proceedings.
He credited the National Security Adviser with supporting the government’s case and the Economic and Financial Crimes Commission with investigating aspects of the dispute.
### Project scaled down
The Mambilla project dates back to a 2003 agreement for the construction of a 3,050MW hydroelectric power plant in Taraba State under a build-operate-transfer arrangement.
The project was subsequently subjected to several revisions as the government sought to make it financially viable.
In 2016, Fashola, who was then Minister of Power, Works and Housing, described the proposed facility as a project capable of generating about 3,000MW.
However, in February 2021, former Minister of Power Saleh Mamman announced that the government had reduced the planned capacity by about half, from 3,050MW to approximately 1,525MW.
The reduction was intended to cut the estimated project cost by about $1bn and improve its financial viability.
Several months later, Mamman told the Senate Committee on Power that the project had been further rescoped to approximately 1,500MW to make it “bankable” and acceptable to prospective lenders.
The original project was estimated to cost between $5bn and $5.8bn, while the revised 1,500MW to 1,525MW project was estimated at about $4bn.
### Settlement dispute
The disagreement between the Federal Government and Sunrise continued despite attempts to settle the matter.
The parties entered into a settlement agreement in 2020, but subsequent disagreements over its implementation resulted in another round of arbitration.
Sunrise alleged that the Federal Government failed to fulfil its obligations under the settlement and sought financial compensation.
The latest ruling brings another chapter to the prolonged legal dispute surrounding the project.
Despite being identified by successive administrations as a major project for expanding Nigeria’s electricity generation capacity, the Mambilla plant has yet to become operational.
Its progress has been affected by legal disputes, financing difficulties and changes to its implementation structure.
A Federal Ministry of Power implementation document previously listed the arbitration, completion of financing arrangements with the Export-Import Bank of China and the need to rescope the project among the issues delaying its execution.
Tinubu said the Federal Government remained willing to work with legitimate investors and fulfil valid contractual commitments, while challenging 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,” he said.
The Mambilla ruling is the latest in a series of major international legal disputes involving Nigeria and multibillion-dollar claims.
In 2023, a UK court overturned an $11bn arbitration award obtained by Process & Industrial Developments Limited in connection with a failed gas processing agreement.
The Mambilla dispute has also featured in domestic investigations into alleged financial misconduct. The PUNCH previously reported that Justice James Omotosho of the Federal High Court sentenced former Power Minister Saleh Mamman to 75 years in prison in absentia following his conviction in a N33.8bn money laundering and fraud case brought by the EFCC.
The court also ordered Mamman to refund the outstanding portion of funds allegedly diverted from money earmarked for the Mambilla and Zungeru hydroelectric projects.
Meanwhile, former Power Minister, Prof. Barth Nnaji, recently attributed Nigeria’s prolonged difficulty in attracting investment into new power plants to policy inconsistency, inadequate infrastructure and changes to financing arrangements.
Speaking at the 2026 conference of the Nigerian Association for Energy Economics in Lagos, Nnaji discussed the country’s energy transition, the role of natural gas, financing challenges and delays affecting major projects, including Mambilla.
He said Nigeria had gone 11 years without financing a new major power plant and linked the situation to the discontinuation of a government-backed financing mechanism introduced during his tenure.