Hybrid power plants (HyPPs) are becoming an increasingly attractive option for enhancing the services and revenue streams of
renewable power plants. However, achieving their full potential requires an effective energy management strategy.

This paper presents a sensitivity study on the impact of allowing battery energy storage systems (BESSs) to charge from the grid in a
photovoltaic (PV) and BESS HyPP. To evaluate this, various HyPP configurations are compared by simulating their optimal
operation using a novel energy management system, which optimises the participation in the energy and aFRR markets and
includes detailed energy balance equations for electricity buying and selling. The Iberian Electricity Market is taken as the
study case, using data from 2024 in which new market conditions have been implemented. Based on the results, allowing BESS
charging from the grid affects the final revenues, though the impact is only significant at high BESS/PV power ratios. In addition,
in both grid charge and only-PV charge scenarios, increasing the BESS rated power provides greater revenue than increasing its
capacity.