Shimla, Feb 20 (IANS): The first unit of 111 MW Sawra Kuddu Hydroelectric Project in Himachal Pradesh's Shimla district will start generating power by April, state-run Himachal Pradesh Power Corporation Ltd (HPPCL) said on Thursday.

The process of filling headrace tunnel will start shortly, HPPCL Director (Civil) D.S. Thakur said.

He said the execution of the project started in June 2007. The main bottleneck in its construction was excavation of 11.365 km headrace tunnel owing to adverse geological rock conditions.

Besides tough rock strata, high ingress of water along with flowing rock conditions at various locations had to be tackled cautiously with high engineering proficiency.

The work of the barrage was awarded to Patel Construction Company and headrace tunnel was initially awarded to Aban Coastal joint venture in June 2007.

Later, the barrage construction was carried out by Hindustan Construction Company Ltd in November 2014.

The project comprises a diversion barrage on the Pabbar river near Hatkoti and underground powerhouse on the left bank of the river near Snail village.

The project will generate 386 million units per annum in a 90 per cent dependable year, earning a revenue of Rs 115 crore to the state.

It has 11.365 km long, 5 m finished diameter headrace tunnel and three 37 MW Francis turbines.

After commissioning the project, each project affected family will be provided 100 units of electricity per month free for 10 years. In addition, one per cent of the revenue from power generation will be contributed for the local area development during the operation stage.

HPPCL has already commissioned two hydroelectric projects -- Sainj Hydroelectric Project (100 MW) and Kashang Hydro Electricproject Stage-1 (65 MW) in September 2017.

It has also commissioned a 5 MW Solar Power Project constructed near the hilltop Naina Devi shrine in Bilaspur district in 2019.

The work of Shongtong Karchham Hydroelectric Project (450 MW) is on.