Optimization of Annual Energy Generation in run of the River of Hydro Power Plants

Annual variation in water infl ow down to 50 % of its maximum value is quite common in run of the river hydro plants (with storage of 1–3 hours of power generation capacity) with multiple stations located on the same river in intervals of 30–50 km. The low capacity factors (< 40 %) call for effi cient water management for modulation of unit and station loads to co-ordinate operations and maximize energy generation. The effi ciency characteristics (which represent the utilization effi ciency of water resources) of the hydro units are not fl at but decrease with decrease in load. The net operating effi ciencies of individual hydro power plant units decrease sharply at lower loading levels below 80 % of the rated capacity due to swirling and vorticity components on one hand and erosion-cavitation on the other hand. The parameter (Pmin/Pmax) amongindividual units infl uences the net overall effi ciency to the tune of 2–10 % points in multi-turbine, multi-station environments of a river. By optimal selection of the loads to maximize this parameter, the energy generation can be maximized. The ultimate solution to optimal water utilization is to achieve a flat efficiency curve over the load range through 3-d designs of turbine runner. Silt control also plays a role in the energy effi ciency but is controllable and secondary.