Nigeria Wins Major ICC Arbitration Battle Over Mambilla Power Project as $3.38bn Claims Are Rejected
By Iroyin Yoruba Television News Desk
Nigeria has secured a major legal development in the long-running dispute surrounding the Mambilla Hydroelectric Power Project after an International Chamber of Commerce (ICC) arbitration tribunal in Paris rejected claims brought by Sunrise Power and Transmission Company Limited and its promoter, Leno Adesanya, against the Federal Government.
The tribunal issued its final award on September 17, 2026, bringing a significant stage of the international arbitration dispute to a close after years of litigation and negotiations surrounding the proposed hydropower project in Taraba State.
The Federal Government said the claims rejected by the tribunal had a combined value of about $3.38 billion, comprising a claim for $680 million plus interest connected to a settlement agreement and a separate claim involving more than $2.7 billion in compensation and interest over disputes associated with the Mambilla project.
President Bola Ahmed Tinubu described the decision as clearing what he called the “single biggest legal hurdle” that had delayed the Mambilla hydropower project for years.
Sunrise Power, however, has not accepted that the broader legal dispute is necessarily finished. Its promoter, Leno Adesanya, said on September 18 that the company's lawyers were reviewing the tribunal's decision and would advise on possible next steps after examining the findings, reasoning and implications of the award.
The latest development therefore concerns a major arbitration decision, but it does not by itself mean that the Mambilla power station is immediately ready for construction.
The project still has a long history involving different governments, contracts, proposed settlements, competing accounts of official approvals and years of legal proceedings.
What the ICC tribunal decided
The arbitration was conducted under the auspices of the International Chamber of Commerce in Paris.
According to the Federal Government's account, the tribunal rejected Sunrise Power's claims against Nigeria.
One of the claims involved $680 million plus interest in connection with a settlement dispute. A separate arbitration connected to the original Mambilla dispute involved more than $2.7 billion in compensation and interest.
Other reporting based on the tribunal's award said Sunrise had also sought an order requiring Nigeria to pay $400 million, comprising a $200 million settlement sum and a further $200 million default amount.
The tribunal rejected that claim as well.
The tribunal also ordered Sunrise Power and Adesanya to reimburse a substantial portion of Nigeria's legal costs incurred during the arbitration.
Reports on the award said the amount ordered was about $11.819 million, representing 75 percent of Nigeria's legal fees and expenses, with part of the amount to be released from funds held in escrow and the remainder payable by the claimants.
The financial consequences are therefore different from a situation in which a government loses an arbitration and is ordered to pay compensation.
In this case, the published accounts indicate that the tribunal rejected the principal claims and imposed a cost contribution against the claimants.
Why the decision matters to the Mambilla project
The Mambilla Hydroelectric Power Project has been discussed for decades as one of Nigeria's major potential sources of additional electricity generation.
The project is located in Taraba State and has been described in government and industry documents at different stages using different generating-capacity figures.
The 2003 dispute involving Sunrise centred on a proposed project variously described in contemporary and later documents as a 3,050-megawatt or 3,960-megawatt development.
The Federal Government's latest statement refers to the Mambilla project as a 3,960MW hydroelectric development, while the original Sunrise dispute has also been reported as involving a proposed 3,050MW plant.
That difference reflects changes in the project's configuration over time rather than a simple contradiction in the latest arbitration decision.
The project itself has been repeatedly redesigned and reconsidered under different administrations.
The central issue for Nigeria now is that a major international arbitration concerning rights claimed by Sunrise Power has been decided in the Federal Government's favour.
President Tinubu said the ruling removes the biggest legal obstacle that had paralysed the project.
That does not automatically provide financing, construction contracts, engineering arrangements or a completed generation facility.
It does, however, alter the legal environment in which the government can consider the project's next stage.
The dispute goes back to 2003
The roots of the current dispute go back more than two decades.
Sunrise Power was incorporated in Nigeria in 2001 and began pursuing opportunities in the power sector, including the Mambilla project.
According to evidence examined by the arbitration tribunal, Sunrise and its Chinese partners expressed interest in participating in the project from 2001.
A technical committee later assessed proposals from companies interested in the project.
The committee eventually recommended Sunrise for the proposed hydropower development.
The process culminated in a letter dated May 22, 2003, issued by the then Minister of Power and Steel, Olu Agunloye, purporting to award Sunrise a build-operate-transfer contract.
The legality and authority behind that award became one of the central issues in the subsequent dispute.
The Federal Government's position has been that the contract was not properly authorised.
The State House said the Federal Executive Council did not authorise the 2003 contract
Former President Olusegun Obasanjo has also previously disputed the assertion that he authorised the award.
The issue was subsequently examined through Nigerian investigations, court proceedings and international arbitration.
The proposed build-operate-transfer model
The 2003 arrangement was not structured as a straightforward government-funded construction contract.
It was intended as a build-operate-transfer project.
Under such a model, the private developer would finance and construct the facility, operate it for an agreed period and recover its investment through the project's revenues before transferring the asset under the agreed terms.
Contemporary accounts of the proposed Mambilla arrangement put the investment requirement at approximately $6 billion.
The exact configuration and generating capacity changed in different phases of the project's history.
The original dispute nevertheless centred on whether Sunrise had acquired enforceable contractual rights through the 2003 award.
Sunrise's position was that it had.
The Federal Government's position was that the contract did not receive the necessary approvals.
That disagreement eventually became the foundation for the international arbitration.
How the Federal Executive Council became central to the dispute
One of the most important questions in the dispute was what happened at the Federal Executive Council meeting of May 21, 2003.
According to evidence reported from the arbitration and previous Nigerian proceedings, then-President Obasanjo had directed the power minister to present the matter to the Federal Executive Council.
The government's position was that the council did not approve the contract.
Sunrise relied on the award letter issued by Minister Agunloye the following day as evidence of a contractual commitment.
This created a fundamental legal question: could the minister's action legally bind the Federal Government if the required approval had not been granted?
The answer to that question became important not only to the original contract but also to later agreements and settlements intended to resolve the dispute.
The tribunal's final award has now rejected Sunrise's claims in the arbitration.
However, the detailed legal reasoning behind every aspect of the award is contained in the tribunal's final decision, which the parties and their lawyers are examining.
The role of the former presidents
The Mambilla dispute has crossed several administrations.
The original contract controversy occurred during the administration of President Olusegun Obasanjo.
The project remained unresolved under subsequent administrations.
Former President Muhammadu Buhari also became involved in the later stages of the dispute, particularly around attempts to resolve the legal problems preventing the project from moving forward.
President Tinubu's September 17 statement specifically commended former Presidents Obasanjo and Buhari, saying both had testified in the arbitration.
The reference to their testimony is significant because the arbitration required the tribunal to examine decisions and events stretching back more than 20 years.
Former ministers Babatunde Fashola and Suleiman Adamu were also identified by the President among witnesses who participated in defending Nigeria's position.
The case therefore involved evidence from officials who served under different administrations and who had knowledge of different stages of the project's history.
The 2017 arbitration
The legal dispute entered international arbitration in a major way in 2017.
Sunrise Power commenced proceedings before the ICC International Court of Arbitration in October 2017.
The company sought compensation in connection with the alleged breach of the 2003 Mambilla contract.
The claim was widely reported at about $2.354 billion.
Former President Muhammadu Buhari later said he had not authorised a settlement agreement involving Sunrise, while former President Obasanjo had also disputed the authority behind the original 2003 contract.
The arbitration was subsequently suspended while the parties pursued settlement discussions.
That produced another chapter in the dispute.
The 2020 settlement agreement
In 2020, the Federal Government and Sunrise reached a settlement arrangement intended to resolve the original dispute.
The agreement involved a proposed $200 million payment to Sunrise in exchange for the company dropping its claims relating to the project.
However, the settlement itself later became the subject of another dispute.
Sunrise subsequently argued that Nigeria had failed to comply with the settlement agreement.
That led to a second arbitration.
The latest ICC proceedings therefore involved not simply the original 2003 contract but also questions concerning the subsequent settlement arrangement.
This is why the government's September 17 announcement referred separately to the $680 million claim and the larger compensation claim connected with the original Mambilla dispute.
The latest tribunal decision has rejected Sunrise's claims arising from those disputes.
The $400 million settlement claim
One specific claim examined by the tribunal concerned Sunrise's demand for $400 million.
The claim was connected to the 2020 settlement agreement.
According to reporting on the tribunal award, Sunrise sought $200 million as the settlement amount and another $200 million as a default sum.
The tribunal rejected the request.
This part of the award is particularly important because it shows that the latest case was not limited to the question of what happened in 2003.
The tribunal also had to examine the later legal relationship between Sunrise and Nigeria.
That relationship included agreements reached after years of litigation.
The rejection of the settlement-related claim means the Federal Government has avoided the immediate financial exposure Sunrise was seeking in that part of the case.
The $2.35 billion claim
The other major figure associated with the arbitration is approximately $2.35 billion.
That amount was connected to Sunrise's original claim over the alleged breach of the 2003 Mambilla agreement.
Nigeria's defence was that the agreement could not create the rights claimed by Sunrise because of the circumstances surrounding its award and approval.
The tribunal ultimately rejected Sunrise's claims.
The decision therefore removes the immediate prospect of Nigeria paying the large compensation amount sought by Sunrise in the arbitration.
It is important, however, to distinguish the rejection of a claim from the completion of the Mambilla project itself.
The arbitration determines the legal dispute presented to the tribunal.
It does not construct a dam, arrange financing or automatically appoint a contractor.
Those are separate steps that the Nigerian government would have to address.
The legal-cost award
The tribunal's decision also has a direct financial consequence for Sunrise and Adesanya.
Reports based on the award said they were ordered to reimburse Nigeria for 75 percent of its legal fees and expenses.
The amount was reported at approximately $11.819 million.
Part of that amount was to be recovered from money held in escrow by the ICC.
The remaining balance was reportedly subject to payment by the claimants, with interest applying to the unpaid amount under the terms of the award.
For Nigeria, the cost award is separate from the much larger claims that were rejected.
It means the government not only avoided the compensation claims but was also awarded a contribution toward its arbitration expenses.
The $500,000 payment examined by the tribunal
The arbitration also examined a payment of $500,000 made in January 2003 to Jennifer Douglas, who was then married to Atiku Abubakar, who was serving as Vice-President.
The transaction occurred on January 30, 2003, through China Castle Investments Limited, a company associated with Leno Adesanya.
The payment took place approximately two weeks after Sunrise presented its tender for the Mambilla project and several months before the disputed May 2003 award.
The tribunal examined Adesanya's explanation of the payment.
According to reporting on the final award, Adesanya said the transaction was connected to a foreign-exchange transaction carried out for Atiku.
The tribunal did not accept that explanation based on the evidence before it.
Reports on the award said the tribunal found that there was insufficient corroborating evidence and identified inconsistencies in Adesanya's explanation. It also examined the licensing status of the entities involved in the transaction.
This aspect of the award has generated substantial public attention.
However, it is important to distinguish the tribunal's findings concerning the payment from a finding that a particular individual received a bribe.
Reporting on the award states that the tribunal did not make a finding that Atiku Abubakar received a bribe.
The evidence concerning the payment formed part of the tribunal's broader assessment of the circumstances surrounding the Mambilla dispute.
The tribunal's examination of the project history
The final award examined events beginning before the 2003 contract.
The arbitration record included evidence about Sunrise's formation, its discussions with government officials, its Chinese partners, the technical evaluation of proposals and the subsequent government decision-making process.
According to the published details, Sunrise and North China Power Engineering Company began discussions with Nigerian officials about Mambilla from 2001.
The project was then estimated at different stages to cost billions of dollars.
A technical committee eventually assessed competing proposals and recommended Sunrise.
The committee's recommendation became part of the chain of events leading to the disputed May 2003 award.
The arbitration therefore required the tribunal to look beyond the wording of a single contract document.
It examined the sequence of events that led to the document and the actions of the people involved.
The dispute over Atiku's role
The tribunal also examined the role of then-Vice-President Atiku Abubakar in the early stages of the Mambilla process.
The published details of the award show that Atiku participated in meetings concerning the project and led a Nigerian delegation to China in 2002.
Sunrise and Adesanya reportedly argued that Atiku lacked the political authority to influence the eventual award.
The tribunal examined that argument against the documented history of his involvement in the project.
Again, the existence of involvement in government discussions does not by itself establish criminal wrongdoing.
The arbitration was concerned with the contractual and evidentiary issues presented in the case.
The tribunal's findings must therefore be read in the context of the legal questions before it.
Former Minister Olu Agunloye
Another central figure in the history is Olu Agunloye, who served as Minister of Power and Steel when the disputed May 2003 award was issued.
The Economic and Financial Crimes Commission has separately prosecuted Agunloye over allegations connected with the Mambilla contract.
A 2025 EFCC-related court report said prosecutors alleged that Agunloye awarded the contract to Sunrise without the required presidential or Federal Executive Council approval.
Agunloye has pleaded not guilty to the charges.
That criminal case is separate from the ICC arbitration.
The arbitration's findings should not automatically be treated as a final determination of guilt in a Nigerian criminal court.
The two proceedings have different legal frameworks, parties and purposes.
Agunloye's own position
Agunloye has previously disputed the government's account of the 2003 award.
In a detailed public defence, he maintained that he followed due process and obtained the necessary approvals.
He argued that the Mambilla arrangement was a build-operate-transfer contract that did not require the Federal Government to provide the construction financing.
He also disputed claims that the contract was unauthorised.
Those arguments illustrate the longstanding disagreement surrounding the project.
The latest ICC decision, however, is the formal determination now affecting the international arbitration claims brought by Sunrise.
The separate Nigerian criminal proceedings involving former officials remain distinct.
Why Mambilla has remained unfinished
The legal dispute is only one of the reasons the Mambilla project has remained uncompleted.
The project has also faced questions involving financing, procurement, contractual structures, project design and changes in government policy.
Over the years, different administrations have pursued different approaches to the development of the project.
The Federal Government has at various points discussed construction arrangements involving Chinese companies.
A 2017 government announcement said an engineering, procurement and construction contract for the Mambilla project had been signed after decades of delay.
But legal disputes subsequently remained a major obstacle.
The continuing arbitration meant that the government faced uncertainty over the rights claimed by Sunrise.
The September 2026 award changes that legal landscape.
The significance for Nigeria's electricity sector
Nigeria continues to face substantial challenges in electricity generation, transmission and distribution.
Large-scale hydroelectric projects can provide generation capacity while also diversifying the country's electricity mix.
The Mambilla project has long been discussed as a major potential addition to Nigeria's power-generation capacity.
The project is located in Taraba State, where the Mambilla Plateau provides the geographical setting for the proposed development.
Its potential scale means that any serious attempt to revive it would involve significant engineering, financing and transmission requirements.
A successful legal resolution therefore matters because investors and contractors generally require clarity over the legal rights attached to a major infrastructure project before committing substantial capital.
The government now has the benefit of the September 2026 arbitration award as it considers the project's future.
The ruling does not mean electricity will flow immediately
One of the most important distinctions in understanding the latest development is that an arbitration victory is not the same thing as project completion.
Nigeria has not announced that the Mambilla plant will begin construction immediately as a direct consequence of the ICC decision.
The government still needs to determine the project's technical configuration, financing structure, procurement process, contractual framework and implementation timetable.
It also needs to address the transmission infrastructure required to evacuate electricity from the project.
The ICC ruling deals with the legal claims brought by Sunrise.
The next stage of the Mambilla project will involve government policy, engineering and investment decisions.
President Tinubu's description of the ruling as clearing a major legal hurdle therefore points to the legal significance of the award rather than an announcement that construction has already restarted.
Sunrise says the matter is not necessarily over
On September 18, one day after the tribunal's award, Leno Adesanya said Sunrise's lawyers were reviewing the decision.
He said the company respected the arbitration process and the tribunal's decision but wanted to study the findings, reasoning and implications before determining what to do next.
Adesanya said the company would consider all lawful options available to it.
He also said Sunrise remained committed to protecting its rights and interests concerning the Mambilla project.
That statement means the Federal Government's declaration of victory should not be interpreted as a statement by all parties that every possible legal issue has ended.
The immediate arbitration award is clear in its outcome, but the legal options available to the parties following an international arbitration award depend on the governing rules and applicable law.
Sunrise's lawyers are now examining those issues.
The government's response
President Tinubu welcomed the tribunal's decision and commended the Attorney-General of the Federation and Minister of Justice, Lateef Fagbemi, together with officials who worked on the defence.
He also praised Nigeria's external legal defence team, led by Elizabeth Oger-Gross and Tolu Obamuroh of Paul Hastings LLP.
The President said Nigeria would continue to work with genuine investors while defending what his administration considers opportunistic claims against the country's public assets and interests.
The statement also thanked witnesses and experts who participated in the case.
Among those named were former presidents Obasanjo and Buhari and former ministers Fashola and Suleiman Adamu.
What the ruling means for government finances
The most immediate financial implication is the rejection of the large compensation claims.
The Federal Government had faced potential exposure to billions of dollars if Sunrise's claims had succeeded.
The tribunal's rejection therefore removes that immediate liability arising from the claims presented in the arbitration.
In addition, the reported order requiring Sunrise and Adesanya to reimburse 75 percent of Nigeria's arbitration costs creates a financial obligation in the opposite direction.
However, the government should not treat the rejected claims as money received.
Avoiding a liability is different from generating new revenue.
The fiscal significance is that Nigeria has avoided the payment sought by the claimant and has received an award for a portion of its legal costs.
The wider investment message
International arbitration cases can influence perceptions of a country's investment environment because they demonstrate how contractual disputes between governments and private companies are handled.
The Nigerian government has emphasised that it remains willing to work with genuine investors and honour its legal obligations.
At the same time, it has signalled that it will defend contracts and claims that it considers legally unsupported.
The Mambilla case therefore provides an example of how Nigeria is using international arbitration to contest a major infrastructure claim.
For foreign investors, the important issue will be the precise reasoning contained in the tribunal's final award and how Nigeria implements the legal consequences of that award.
For the government, the decision provides greater room to consider the project's future without the immediate compensation claims that had been attached to Sunrise's position.
The next challenge: turning legal clarity into infrastructure
The Mambilla project has now reached a point where the legal outcome may allow attention to shift more strongly toward implementation.
That does not guarantee that the project will proceed quickly.
Large hydropower projects require extensive feasibility work, environmental and social assessments, financing, land and community arrangements, engineering design, construction contracts