Sizing of solar PV systems with battery energy storage for different consumption profiles

Abstract

As global populations rise, projected to reach 10 billion by 2050, growing energy demand presents challenges in accessibility, affordability, and sustainability. Reliance on non-renewable energy sources has intensified CO₂ emissions, exacerbating climate change and driving the world closer to environmental tipping points. To address these issues, the European Union (EU) has introduced frameworks like the Energy Union Strategy and the European Green Deal, targeting climate neutrality by 2050. These initiatives prioritise decarbonisation, energy efficiency, and the integration of renewable energy sources, particularly photovoltaic (PV) systems. However, as the percentage share of renewable generated electricity, mainly from PVs, increases, energy storage becomes necessary to ensure grid stability and provide users a minimum level of self-sufficiency. This research explores optimal battery sizing and deployment strategies to enhance self-sufficiency and grid resilience in residential and commercial settings. By analysing energy consumption profiles and simulating PV-battery systems, it aims to determine configurations that maximise efficiency and sustainability. Focusing on Malta's context, the study evaluates the potential of energy storage to offset renewable energy variability and reduce dependence on fossil fuels, contributing to the broader goal of achieving carbon neutrality. Results have shown a clear trend: as battery capacities increase, self-sufficiency also rises. For instance, for dwellings, a small battery size of 5kWh would be sufficient to cover just over 60% of the dwelling's needs in terms of self-sufficiency for an average consumption of 15kWh/day. Furthermore, a 10kWh battery increases self-sufficiency to almost 70%, with diminishing returns for larger battery capacities. In contrast while battery storage improves self-sufficiency for offices, the gains are modest for smaller PV systems. Larger installations with moderate batteries, such as 15kWh, offer better results, though cost-effectiveness remains a key factor. In a 107kWp PV system, introducing a 15kWh battery resulted in a self-sufficiency of around 62% with an average consumption of 194kWh/day. Overall, the findings underline the importance of optimising the PV system's size and the battery's capacity to align with the energy consumption patterns specific to office buildings.