The Erathna Mini Hydropower Project is located in the Kuruwita Divisional Secretariat in the District of Ratnapura. The plant is ‘Run-of-the-River’ and utilizes the water flow of the upper reaches of the Kuru Ganga, which originates at the Adam’s Peak at an elevation of 2,100 meters above the mean sea level. The river leaves the boundary of the sanctuary at an elevation of 1,030 meters and continues onward as a tributary of the Kalu Ganga. The hydro plant infrastructure is sited on a total land extent of approximately 4.0 Ha, spanning two villages - Pelendakanda and Adavikanda. The land extent covers the land trace from the Weir through the Headrace channel up to the Forebay tank, the Penstock path, the Powerhouse and the Tailrace. The Powerhouse is located on the right bank of the river at Adavikanda and easily accessible by road. The water catchments area for the plant is estimated to be 14.5 square kilometres in extent. The water diversion point and the Weir are at an elevation of 840 meters above the mean sea level. The diverted water flows through the intake and along a covered Headrace channel to the Forebay tank.  

It is then channelled down through a penstock of 2.4 kilo meters long to the Powerhouse, which is at an elevation of 377 meters. This provides a total energy head of 463 meters. Before reaching the Powerhouse, the Penstock bifurcates into two pipelines that feed twin Pelton turbines. The turbines drive the synchronous electric generators. The expended water is then released along the Tailrace channel to the Kuru Ganga.

The generated power is fed through two primary transformers and transmitted via an 18 km long interconnection line connecting to the Kosgama – Ratnapura 33 kV power line. The plant consists of turbine machinery manufactured by Voith Siemens, a reputed German producer of turbine machinery. The entire plant is operated, regulated and monitored from water intake to power generation by means of a computerized control system.

Project Highlights