Parbati-II is an 800MW run-of-the-river hydroelectric project under construction on the Parbati River, in Himachal Pradesh, India.
India’s state-run National Hydroelectric Power Corporation (NHPC) is the owner and developer of the project.
Construction works on the £670m ($815m) project were started in 2003, with commissioning originally scheduled for 2010. The construction works, however, suffered delays in between, due to poor geological strata of the area.
Now slated for commissioning in December 2021, the Parbati-II hydropower is expected to generate up to 3,125 million units (MU) of electricity a year.
Parbati-II project background
The 800MW Parbati-II project was envisaged as part of the 2GW Parbati hydropower scheme, which was planned to be developed in three stages to harness the hydroelectric potential of the lower reaches of the Parbati River.
The Parbati-I project was, however, abandoned due to environmental considerations, while construction works on the Parbati-II and the 510MW Parbati-III were started simultaneously.
The Parbati-III located downstream of Parbati-II was inaugurated in 2016, while it’s all four 130MW generating units were commissioned between March and June 2014.
The Parbati-III facility is expected to achieve its full utilisation, only after the commissioning of the Parbati-II plant.
Parbati-II location and plant make-up
The Parbati-II hydroelectric project is being developed in Pulga and Suind villages, in the Kullu district of Himachal Pradesh, approximately 260km away from Chandigarh.
The project includes a 83.7m-high concrete gravity dam in the Pulga village downstream of the confluence of Parbati River and Tosh Nallah, a 130-high and 17m-diameter Orifice type surge shaft, a 31.52km-long and 6m-diameter headrace tunnel, two 2.1km-long and 3.5m-diamter pressure shafts, and a surface power house in the Suind village.
The surface powerhouse will be equipped with four Pelton turbine generator units of 200MW capacity each.
Water from the power house will be discharged through four 60m-long, 5m-wide, and 4.5m-high tailrace channels.
An onsite 400kV gas-insulated switchyard (GIS) with dual outgoing 400kV feeders will be installed for exporting the power generated by the turbines.
Power supply and transmission
The electricity generated by the plant will be evacuated through the Parbati-Koldam 400kV (Quad) transmission system. From Koldam, the electricity will be further transmitted through Koldam-Nalagarh and Koldam-Ludhiana transmission lines.
Parbati Koldam Transmission Company (PKTCL), a joint venture between Adani Transmission (74%) and Power Grid Corporation of India (PGCIL), is responsible for the development of transmission infrastructure.
Power generated by the Parbati-II project will be sold to Himachal Pradesh, Delhi, Jammu & Kashmir, Punjab, Haryana, Rajasthan, Uttar Pradesh, and Chandigarh.
A joint venture between Patel Engineering and SEW Infrastructure was contracted for the civil as well as hydro-mechanical works for the dam, while the Himachal Joint Venture (HJV) was contracted for the construction of headrace tunnel (HRT) in September 2002.
Gammon India was contracted in the same year, for the construction of the power house, surge shaft, and pressure shafts.
The HRT construction contract with HJV was, however, terminated in March 2012. The remaining civil works for the HRT by tunnel boring machine (TBM) were contracted to a joint venture between Gammon and CMS in August 2013, while those involving drill and blast method (DBM) were awarded to Valecha Engineering in November 2013.
Bharat Heavy Electricials (BHEL) was contracted for the turbine generator units, transformers, switchyard, as well as other electrical and mechanical auxiliaries for the project in December 2002.
A joint venture between OP Metals and SPML Infra was contracted for the hydro-mechanical packages for the project in July 2007.
Other contractors and subcontractors involved in the project are Soma Enterprise, Robbins, CALTROP, SELI Technologies, Encardio Rite, and MK Rock Tech.