Optimal Management and Control of Solar PV Attached Electricity Storage According to Energy Price Signals

Abstract

End – consumers have become more active in the effort to achieve secure operation of the electricity grid. Demand response offers a set of solutions allowing consumers to achieve normalised load profiles and increase the balance between energy generation and consumption. Storage technologies and renewable energy sources integrated in microgrid topologies allow them to participate in demand response programs while maintaining their consumption behaviour and achieving energy cost reduction. The aforementioned integration requires the development of control capabilities and communication with the energy market. Consequently, this project aims at investigating the possibility of energy cost reduction and reliability of power supply through the development of a microgrid which incorporates a control design and a management strategy.The project proposes a microgrid control strategy suitable for both power quality and energy management applications. This control strategy is implemented through a controller regulating the operation of the battery storage system. More specifically, regarding the power quality side of the controller, the system is able to identify and overcome any possible operational grid faults securing the provision of continuous power supply and voltage stability under any conditions. Concerning the energy management capabilities of the microgrid, the controller’s main goal is to achieve energy cost savings and to extend the lifetime of the battery storage system, through its communication with the spot energy market and by taking advantage of the hourly volatility of the electricity prices while considering the ageing factor of the battery storage system. The battery storage system operates only when the electricity prices can compensate for the energy cycling costs, thus prolonging its life span. Whether the batteries are charging or discharging is decided by the level of the hourly electricity prices. This way the potential economic benefits are maximised. This microgrid development was based on the case study of a technical building for the telecommunications company KPN. The company’s goal is to reduce its electricity bill while maintaining its load profile, integrating renewable technologies and active storage systems. For this reason, the development and modelling of a microgrid with the control attributes described in the previous paragraph and integrated PV and storage system is required. The developed microgrid and the implemented control strategy were modelled in Matlab/Simulink. From the simulation results, it was observed that the controller responds appropriately to electricity prices levels, it respects the battery’s capacity limitations and it acknowledges the PV and storage system’s priority over the grid. Furthermore, it was able to achieve high levels of power quality for the microgrid and energy cost reduction for KPN under certain technological and market conditions. Regarding the latter, it was observed that the main influencing factors for the proposed system’s economic performance are the investment costs for the PV and storage systems.Electrical Engineerin