Optimization of the usage of Samanalawewa water resource for power generation

Samanalawewa hydropower project includes a reservoir, a water way system and a 120MW power plant as the stage I development. Some provisions have been kept for stage II development to add another 120MW power plant to operate as a peak serving power plant. Since the impounding of the reservoir, there is a water leak which causes more than one fifth of energy loss of the current energy generation by Samanalawewa power plant. The construction of stage II is suspended with lower energy generation due to the leak. This research discusses about a Leak Pump Back System which will curtail the net water outflow from the leak. The leaked water pumping head is much lower than the design head of Samanalawewa power plant, resulting in high net energy gain. Since the pumped back water is regulated by the reservoir, the extra energy generation is dispatchable. This will further improve the feasibility of Samanalawewa stage II development. Currently Samanalawewa mini-hydropower plant is operating using the leaked water. The mini hydro plant can recover less than one third of energy which could be recovered by leak pump back system. Therefore the combined operation of mini hydro and leak pump back system will give more benefits, though the leak pump back system is going to limit the water supply to the mini hydro plant.