NHPC Ltd. has postponed the commissioning of the Parbati-II hydropower project to FY25. Tunnelling challenges had caused nearly 13 years of delays in this project.
NHPC Ltd., India’s largest state-owned hydropower enterprise, initially planned to finish the 800 MW project in Himachal Pradesh’s Kullu area by March 2024. The facility has four units, each with a 200 MW capacity.
Recent heavy rains and flooding in Himachal Pradesh have caused severe disruptions to the hydropower plant’s infrastructure. This includes access roadways and approaches, resulting in additional delays.
“We had originally intended to commission two units in this financial year (FY24). However, the rains and floods in Himachal Pradesh have been a setback, particularly for this project. As a result, these two units will now be commissioned in early FY25,” according to Rajeev Kumar Vishnoi, Chairperson and Managing Director (CMD) of NHPC Ltd.
Vishnoi also mentioned that the project’s costs would rise slightly due to repairs from the natural disaster. He did not, however, give a precise estimate of the extra expenses the Central Public Sector Undertaking (CPSU) will face.
“There may be some additional costs incurred for repairing the damages caused by the floods. Additionally, there will be other expenditures related to expediting the lining work and employing some non-conventional construction technologies. However, the additional cost is not expected to be substantial, and it won’t have a significant impact on the tariff,” according to Vishnoi.
They initially planned to commission the Parbati-II project in 2010 when they started it in 2003. However, ongoing delays resulted from various challenges, including tunnelling difficulties, water and sand seepage, flash floods, cloudbursts, and unfavorable geological conditions.
In response to earlier delays, Vishnoi clarified that the main difficulty with the Parbati-II project was the increasingly challenging tunnel excavation over time. “We were using two different construction technologies for excavation: tunnel boring machines and drill-and-blasting methods. Just as we were nearing completion of this excavation, the disaster occurred,” he said.
The tunnel is currently all but finished, except for a 65-meter section towards one end. NHPC has decided to use an improved construction method to speed up the remaining lining work. They have approximately 65 meters of tunneling left to complete. However, the lining project extends over a distance of more than three kilometers.
During the Annual General Meeting (AGM) held on August 31, Vishnoi announced that the first unit of the Subansiri Lower hydropower project in Arunachal Pradesh is anticipated to be commissioned in January 2024, with the second unit following in March 2024.
NHPC Ltd. obtained forest clearance on October 12, 2004. Subsequently, construction work on the 2,000 MW Subansiri Lower hydropower project commenced in January 2005. Local stakeholders suspended the project’s construction progress from December 2011 until October 2019 due to protests and agitations. On October 15, 2019, after receiving approval from the National Green Tribunal (NGT), construction recommenced.