Simultaneous sizing of a photovoltaic system and compressed air energy storage in a microgrid

Abstract

The integration of Compressed Air Energy Storage (CAES) with photovoltaic (PV) systems, complemented by grid interconnection capabilities and diesel generator backup, represents an advanced approach to sustainable microgrid design for future energy systems. In this study, a multi-objective optimization model for sizing PV-CAES systems is formulated as a Mixed-Integer Nonlinear Programming (MINLP) problem with two primary objective functions: (1) minimization of total system investment costs (CAPEX) and operational costs (OPEX), and (2) enhancement of system reliability and maximization of RE penetration. The Augmented -constraint method is applied to solve this multi-objective optimization problem by incorporating the reliability and RE penetration objectives as inequality constraints, while maintaining cost minimization as the overall optimization goal. In application to a case study of a South African commercial building, the optimized design saves annual operational costs by 35.2% and achieves 41.5% penetration of RE and 2.4% increase in reliability compared with conventional designs. The results demonstrate the success of the framework in providing economically viable PV-CAES configurations that simultaneously enhance sustainability and system reliability via comprehensive mathematical optimization.

HIGHLIGHTS • An optimization model is proposed for PV and CAES sizing in a microgrid. • Previous probabilistic methods are improved with mathematical optimization. • The model includes energy balance and storage dynamics constraints. • The approach reduces system cost and improves energy reliability. • Results support better microgrid planning with high renewable penetration.