An independent inquiry into the August 2025 cofferdam collapse at the 1,530MW Tarbela-5 Extension Hydropower Project has pinned responsibility on all three key parties — the contractor, consultant, and employer Wapda — citing a series of unauthorized design changes and contractual violations that went unchecked. The failure has set the project back by at least two years, with costs ballooning from Rs82 billion to Rs317 billion, making it potentially the country's most expensive renewable energy source. Main Developments The three-member inquiry committee, led by Federal Flood Commission chairman Ather Hameed, found that the contractor — Power Construction Corporation of China Ltd (PCCCL) along with HEI and HEM — proposed altering the cofferdam design to a rock-filled structure, a weaker option contractually not permitted. The consultant, UK's MM Pakistan-BIDR China, conditionally accepted this deficient design without ensuring technical compliance. Wapda, as the employer, approved the design change when construction was nearly finished, without questioning either its contractual validity or technical shortcomings, the committee stated. The 15-page report, seen by Dawn, noted that all parties attempted to attribute the collapse to flooding, but investigations found river flows were within normal annual levels and well below the cofferdam's original design capacity. Read also: Mining Chief Blasts Taxes Hurting Balochistan Investment Irregular payments for temporary work instead of permanent works further compounded the financial damage, compromising the government's compensation rights against the contractor. The project's levelised generation cost over 30 years may now reach Rs27-28 per unit — the highest among Pakistan's renewable energy projects — making it economically unviable, according to the Planning Commission. Background The Tarbela-5 Extension project, initially approved in 2017 at Rs82.36 billion, involves $700 million in loans from the World Bank and the Asian Infrastructure Investment Bank. Cofferdams are temporary structures built to divert water during construction; their failure can halt all work and trigger cascading cost vulnerabilities under multiple contractual and financial heads. Wapda had earlier terminated the consultancy contract of MM Pakistan-UK, citing the firm's failure to provide a suitable and adequately qualified project manager, with staffing issues persisting throughout its tenure. Additionally, MM Pakistan issued a notice of termination in May 2025 and unilaterally withdrew its staff from the site, violating the required 30-day notice period in the contract. Why It Matters The inquiry report makes startling revelations about how multibillion-rupee infrastructure projects of national importance, involving billions of dollars in foreign loans, are prepared, contracted, executed and monitored. The collapse exposes systemic weaknesses in oversight — where no party took independent responsibility for design changes, and where the employer approved modifications without questioning contractual validity. With costs escalating by 285 percent and completion now targeted for June 2028 instead of 2026, the project's economic viability is in serious doubt. The resulting electricity cost of Rs27-28 per unit would burden consumers and make the project unsustainable, potentially affecting Pakistan's energy planning and foreign investment confidence. What's Next The project is now scheduled for completion by end-June 2028, but cost escalations are still rising. Wapda's termination of the consultancy contract and the contractor's unilateral withdrawal raise questions about how remaining work will be managed. The inquiry committee's findings may lead to further contractual actions or legal proceedings against the responsible parties, though no such steps have been announced yet.