Control Strategies for Photovoltaic Energy Storage Systems

In recent years, with the impact of global climate change and specific commitments, such as the European Climate Law, to reduce greenhouse gas emissions by 55% from 1990 levels by 2030, renewable energy has become an indispensable application in achieving carbon emission reduction goals. Taiwan has also been actively promoting the development of renewable energy, with a target to reach 20 GW of solar power generation by 2025. With a large amount of renewable energy integrated into the grid, its intermittent and unpredictable nature poses significant challenges to grid stability and power dispatch, particularly evident in the formation of the duck curve during the second-peak load period. Balancing power supply and demand is a critical issue, especially after the sun sets. To address this problem, the Taiwan Power Company has proposed the construction of solar energy storage systems (ESSs), and this study is focused on the development of a solar ESS controller using a programmable logic controller platform along with power sensors. The controller is designed to measure the real-time power generation of solar photovoltaic systems and to develop a control strategy for the ESS. It enables the solar photovoltaic system to charge the ESS during the day and discharge it during the second-peak load period. This approach not only helps mitigate the challenges of second-peak load power dispatch but also enhances the utilization of power lines effectively.