VIJAYAWADA: The Donkarayi Canal Power House, a modest yet strategically vital 25 MW hydroelectric station near the Andhra Pradesh-Odisha border, is currently undergoing its first major refurbishment in over a decade. Commissioned in 1983, the plant has long served as a critical link in the Sileru hydroelectric cascade, ensuring efficient water utilisation across multiple downstream projects.
The station, equipped with machinery supplied by Bharat Heavy Electricals Limited (BHEL), generates about 100 million units annually. It draws water from the Upper Sileru Power House at Guntawada and local catchments, channelling discharge through a 15.6-km canal into the Lower Sileru Power House. This cascading system maximises energy extraction from the same water volume, making Donkarayi indispensable despite its relatively small capacity.
The current overhaul, entrusted to Chennai-based Shree Abirami Engineering Works Limited, was initiated after an oil leak in December 2025 raised concerns over turbine efficiency.
Engineers are working round-the-clock to refurbish turbine components, replace worn-out parts, and restore mechanical performance to near-original standards.
The works are expected to conclude by the end of May, extending the unit’s operational life and improving reliability.
Parallel to turbine refurbishment, modernisation of the power canal is underway to reduce hydraulic losses and improve efficiency. Reinforcement of canal lining is expected to benefit not only Donkarayi but also downstream stations like Lower Sileru.
The Donkarayi unit forms part of a larger hydro ecosystem that includes Upper and Lower Sileru projects. In related developments,
Andhra Pradesh and Odisha recently completed a residual life assessment of the Machkund Hydro Electric Project, finding it structurally sound with only targeted repairs required.
Proposals for similar overhauls at other major hydro stations, including Srisailam Right Bank, remain under consideration.
While small in scale, Donkarayi’s strategic role in water transfer and energy optimisation makes it a cornerstone of Andhra Pradesh’s hydroelectric network.
Once refurbishment works are complete, the revitalised unit is expected to continue quietly powering the grid while reinforcing the state’s renewable energy backbone.
Lower Sileru
The Lower Sileru Power House continues to play a pivotal role in Andhra Pradesh’s energy strategy. Designed to harness the hydraulic head between Donkarayi and Polluru, the project exemplifies efficient use of natural gradients for sustainable power generation.
Water from the Donkarayi reservoir is conveyed through a 15.6-km canal to a forebay with 0.143 TMC live storage, before being routed via tunnels and penstocks to drive turbines. Commissioned in two stages between 1976 and 1978, the station’s original four units of 115 MW each have consistently delivered reliable performance.
Now, in a major expansion, two additional 115 MW units are under construction, scheduled for commissioning in June and October 2026.