Impacts of Measures to Achieve Dispatchability on the Cost of PV-BESS Power Plants

The lack of flexibility of variable renewable energy resources, such as solar and wind, is a major concern of power system planners due to the increased risks to stability that low inertia and limited dispatchability could bring to a reliable operation. To mitigate these issues, some strategies may be used, such as: oversizing the generator, using battery energy storage systems (BESS), and increasing the dispersion of generators (greater spatial distribution). This paper presents a sensitivity analysis of the impacts that oversizing the PV generator and adding BESS would cause on the cost of PV-BESS power plant for a given criterion of dispatchability. Results show that accepting some low levels of loss of generation probability considerably reduces the cost of the system. Additionally, the introduction of night charge operation guaranteeing 25% of the BESS state of charge at the beginning of the day increases the reliability of the PV plant without major increases in overall costs.