Wamalwa, FhazhilSichilalu, Sam M.Xia, Xiaohua2017-02-142017-01Wamalwa, F, Sichilalu, S & Xia, X 2017, 'Optimal control of conventional hydropower plant retrofitted with a cascaded pumpback system powered by an on-site hydrokinetic system', Energy Conversion and Management, vol. 132, pp. 438-451.0196-8904 (print)1879-2227 (online)10.1016/j.enconman.2016.11.049http://hdl.handle.net/2263/59026This paper presents an optimal control strategy for a hydropower plant retrofitted with a hydrokineticpowered cascaded pumpback system in dry season. Pumpback operation aims at recycling a part of the down-stream discharge back to the main dam to maintain a high water level to optimise the energy value of the available water. The problem is formulated as a multi-objective optimisation problem to simultaneously minimise the grid pumping energy demand, minimise the wear and tear associated with the switching frequency of the pumps, maximise the restoration of the volume of the dam through pumpback operation and maximise the use of on-site generated hydrokinetic power for pumping operation. The performance of the proposed cascaded model is compared with the classical single pump pumped storage model. Simulation results based on a practical case study shows that the cascaded pumpback model can reduce the pumping energy demand by up to 48.18% and increase the energy yield of the resultant system by up to 47.10% in dry season.en© 2016 Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Energy Conversion and Management. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Energy Conversion and Management, vol. 132, pp. 438-451, 2017. doi : 10.1016/j.enconman.2016.11.049.Hydrokinetic generatorCascaded-pumpingPumpback operationHydropowerHydraulic headOptimal pumping strategyPostprint Article