Hydro-power energy recovery in pressurized irrigation networks: A case study of an Irrigation District in the South of Spain

Abstract

As a result of climate change, higher irrigation water demands are predicted in the future in pressurized irrigation networks. This will result in larger energy requirements and greater CO2 emissions levels for irrigation networks powered by pumping systems. Therefore, measures to counteract this growth in energy and CO2 emissions in the agri-food sector, such as energy recovery using hydropower, are becoming imperative.The Bembézar Margen Izquierda (BMI) Irrigation District, in Southern Spain, has been analysed and simulated for several water demand scenarios using a model based on the hydraulic simulator EPANET. Results show that a substantial amount of energy used for the distribution of irrigation water can be recovered. Flows and heads available at four different locations in the network showed suitability for the installation of one traditional Francis turbine and three Pumps-as-turbines (PAT).The methodology used was divided into four phases. In the first phase, the network was simulated with all hydrants simultaneously open and the best locations to install HPP (Hydro Power Plant) were assessed. In the second phase, the maximum, minimum and mean flows and available head values per month at each HPP location were obtained using on-demand simulations applying the Clément methodology. In the third phase, the flow and net head available in the turbines were transformed into energy. In the last phase a feasibility study was carried out through three indices. Applying this methodology, the maximum recoverable energy was estimated as 270.5 MW h and the maximum carbon savings potential was estimated as 108 t eCO2. These technologies represent a positive competitive advantage for agricultural production reducing the carbon footprint and therefore improving the sustainability of the agricultural production.