A novel photovoltaic-pumped hydro storage microgrid applicable to rural areas
School of Engineering
This paper proposes a novel photovoltaic-pumped hydro storage microgrid design, which is more cost-effective than photovoltaic-battery systems. Existing irrigation infrastructure is modified in order to store energy at a low cost. This energy storage system pumps water from the bottom of a water well to a reservoir at ground level to store surplus energy in the form of gravitational potential energy. This stored water can be released back to the well through a turbine to generate clean electricity when it is needed, or it can be used for irrigation. This microgrid needs a complex management system that takes into account energy generation, energy demand, water demand, energy tariff, and system losses to determine pump power, turbine flow rate, as well as irrigation times. The proposed energy management system considers the current and future state of the system and compares cost-saving and feed-in income for each decision by using two forecasting methods and a multi-level optimisation algorithm. The performance of the management system is experimentally verified on a real pump and turbine. The objective of this study is not only to manage pump power and turbine flow rate, but also to manage irrigation times and water volume. The results show that adding irrigation and water management assist the energy management system in using stored water more efficiently. As a result, electricity costs are reduced by more than 31% compared to existing management methods. The proposed system is simulated in MATLAB to calculate annual electricity costs. The payback period and lifetime benefit of the proposed storage are calculated to investigate the economic aspects of the system.