Integration of Water Supply, Conduit Hydropower Generation and Electricity Demand

South Africa is acknowledged to be not particularly endowed with the best hydropower conditions as it might be elsewhere in Africa and the rest of the world, however, large quantities of raw and potable water are conveyed daily under either pressurized or gravity conditions over large distances and elevations. There exists conduit hydropower generation potential in the water supply and distribution systems belonging to municipalities, water supply utilities and mines. Bloemwater, a water utility, constructed a stand-alone turbine, based on the available pressure and flow which generates a constant output ranging between 55 and 96 kW and when sufficient, supplies the head-office. Initially a manual changeover was utilized to switch between the hydropower and the local electricity supplier when the hydropower was insufficient to meet the demand i.e. switching of the full load from the one source to the other. To maximize the utilization of the hydropower, an automatic change over panel was developed to deal with the variable electricity demand from the office. The office building’s electrical distribution was divided into different distribution boards to allow each sector to be supplied and switched individually with 6, PLC controlled, motorized change-over switches. The PLC constantly evaluates and subsequently executes switching actions so that Bloemwater can utilize the maximum renewable hydropower, but also limits power interruptions to a minimum because of these switching actions. This technical paper describes the development of this conduit hydropower plant by evaluating the interrelationship of water supply, electricity demand and operating cycles, providing Bloemwater with the optimum solution with increased resiliency and sustainability.