Optimal Design and Management of a Hybrid Photovoltaic-Pump Hydro Energy Storage System

The exploitation of renewable sources is an opportunity to increase the number of people who have access to electricity. To assure better living conditions, the free and simple access to water is another fundamental key point in many developing countries. Stand-alone photovoltaic pumping systems are often installed in remote areas where the grid is not available: they are used for irrigation and/or other local water needs and can supply also electricity to small consumers. In this paper a system aimed at supplying electricity and water to an isolated small village has been studied. Ground water is pumped into a storage reservoir and can be used both for irrigation and domestic use. The system is composed by a photovoltaic plant, a pump as turbine (PAT), a diesel internal combustion engine for integration purposes and a battery storage. By means of an optimization model based on the Particle Swarm Theory, the size of the system and its managing strategy have been optimized in order to fulfill the requirement of the users, to improve the system efficiency and minimize the overall costs. The most suitable hourly-based profile of the flow rates of a pump-as-turbine as well was found.