Cost Analysis of Pump as Turbine for Pico Hydropower Plants – A Case Study

Abstract

The energy scenario in rural, remote and hilly areas of India is characterized by inadequate, poor and unreliable supply of energy services. In such regions, the load density is low and extension of grid system is totally uneconomical, hence the small hydropower schemes can provide a solution for the energy problems besides solar photovoltaic, which is not available throughout the day. The main hindrance in implementing such hydropower schemes is high initial cost of conventional hydro turbines. The cost of these plants can be brought down by using centrifugal pump in turbine mode in context of various advantages associated with the pumps viz. low initial and maintenance cost, ready availability, simple construction etc. However, the efficiency of pump as turbine (PAT) is lower than that of conventional hydro turbines. For commercial justification of PAT technology, a cost analysis of 3 kW capacity pico hydropower plant was carried out by considering PAT and Francis turbine as a prime mover. The hydro turbine test rig was developed by installing PAT and its performance characteristics were plotted. The annual life cycle cost (ALCC) analysis was carried out based on initial cost of the project, capital recovery factor and annual expenses. Based on the analysis, the ALCC and the cost of electricity generated per unit were found to be very less for PAT than that of Francis turbine, which has justified the use of PAT for the case under consideration.