Optimal Sizing and Operation of a Co-located BESS and PV Power Plant for Revenue Stacking

As renewable energy penetration increases, co-located battery energy storage and photovoltaic systems (BESS+PV) play a growing role in grid flexibility and market integration. This paper presents a multi-market optimization framework for a co-located BESS+PV system operating under grid capacity constraints. A mixed-integer linear programming model is developed to co-optimize participation in day-Ahead (DA), intraday (ID), and automatic Frequency Restoration Reserve (aFRR) markets. Results show that multi-market strategies increase profitability, with the DA+ID+aFRR case achieving the highest revenue and requiring 34MWh/20MW of storage, compared to only 5MWh/1.74MW in the DA-only scenario. Monte Carlo simulations highlight the influence of aFRR activation patterns and confirms model convergence with a mean C-rate of 0.54. Findings emphasize the value of co-optimization and the need to account for market uncertainty in system design.