Modelling, design, and experimental validation of a grid-connected farmhouse comprising a photovoltaic and a pumped hydro storage system

Abstract

This paper investigates the value of using existing irrigation infrastructure to store surplus photovoltaic energy in a farmhouse. The irrigation system includes a reservoir and a water well. The depth of the water well is used to store energy in the form of gravitational potential energy. Throughout the day, photovoltaic energy is used to pump water from the bottom of a well to the reservoir at ground level, where this stored water is then used to meet demand by releasing the water back to the well through a hydro turbine. A controller is designed to manage the pump and the turbine efficiently to reduce daily electricity costs of the farmhouse. The proposed method is validated experimentally with a real pump and a turbine. The controller manages the pump power and turbine flow rate considering the losses of storage, the feed-in income, and the cost-saving for each decision. The proposed system is also simulated in MATLAB for a whole year using real data to investigate the economic aspects of this storage in different seasons with different irradiance, weather, energy demand, and water demand profiles.