Feasibility study of development and exploitation projects of hydroelectric power stations in urban main water supply systems using hierarchical analysis method (case study: part of Tehran main metropolitan water main pipeline system)

Preserving theenvironment and making fossil fuels viable for energy production,as well as power grid losses and low efficiency of thermal power plants,have drawn human attention to the use of alternative and renewable resources of energy such as hydro energy.One of the most effective approaches to operational management of the urban water supply networks is to control the surplus hydraulic pressure in some parts of the system.Therefore,utilizing the potential head along main gravity pipelines route to recover energy can be considered as a favourable strategy for optimum flow control and managementof the water pressure in the network.In this study,by applying hydraulic simulation of a given water supply network,the important hydraulic parameters such as available net pressure head in various locations of water pipeline and water reservoirs inflow have been derived Hence,by considering these essentialparameters and taking into account the topographicstatus of water transmission route and hydraulic grade line elevation at each point,the power output was calculated at nine selected hydropower sites.In addition,to Prioritizing the construction and operation of the proposed hydropower potentials and providing useful guidanceto authorities,investors and executive managers,a multi-criteria decision-making analysis based on the analytic hierarchy process was conducted according to five key criteria including technical,economic,social,passive defence and environmental aspects.Hence,a comprehensive multi-criteria model based on AHP and questionnaires has been developed to rank hydro energy production in proposed sites in a water supply network.By analysing the expert questionnaires and weighting to each of the criteria and sub-criteria (pairwise comparison) inthe Expert Choice software,it was found that thetechnical,economic,environmental,passive defence and social criteria were ranked in firstto fifth place, respectively.The results showed that micro hydropower potential sites in R.1183, R.1453 and R.57reservoirs with installed capacity of 3100, 4107 and 1072 KW respectively,were ranked in the first to third priority of construction in the studied water supply network.