Evaluation of the design and performance of a micro hydropower plant in a pressurised irrigation network: Real world application at farm-level in Southern Spain

Agriculture is one of the most energy intensive activities within the European Union. The common absence of electric infrastructure in these rural settings has led to the need for in situ generation in many cases. The existing excess pressures in large pressurised irrigation networks makes the generation of micro hydropower here a possible alternative renewable energy source. Pump-as-turbines have been proposed as a cost-effective technology for such purposes, taking advantage of the excess pressure in pipe networks to produce energy. This paper presents a methodology for the design of a plant for micro hydropower generation in an agricultural farm and outlines the predicted benefits of the installation. These predicted benefits were also compared with the measured performance of the plant for the 2019 irrigation season. The main aim of the plant was to replace a diesel generator that supplied energy to the farm. The excess pressure found in the pipe network varied between 0m and almost 60m. The nominal power of the pump-as-turbine was selected to supply the maximum energy requirements of the farm. The predicted operation time of the plant was estimated at up to 3199 h concentrated between April and September. An annual savings of approximately (sic)2950 and 11 t eCO(2) were also estimated. The measured results showed an actual operation time of 2443 h between May and September, as in April the monitoring system was not operational. For this operation time, the savings were (sic)2258 and 8.4 t eCO(2). Considering the April theoretical irrigation time obtained, the savings raised up to approximately (sic)2434 and 9.1 teCO(2). The return on investment of the installation was computed to be recovered in less than ten years. (C) 2021 Elsevier Ltd. All rights reserved.