Integrated PV-battery design mapping strategies and control in decentralised energy communities for enhanced grid congestion relief

The growing adoption of residential and community-based photovoltaics (PV) have raised concerns about grid congestion and transformer overload. This paper evaluates three strategies for PV–battery integration in decentralised energy communities using real network and residential data to address these challenges: (SI) distributed PV-battery systems (one-to-one), (SII) distributed PV sharing a central community battery (many-to-one), and (SIII) a community-scale shared PV supported by distributed batteries (one-to-many). Based on time-series simulations of energy flows and detailed grid analysis in Pandapower, each configuration is evaluated on PV export reduction, peak load relief, transformer loading, battery utilisation, net load, and self-consumption. Results indicate that SII most effectively relieves grid congestion, although at the cost of higher system losses due to frequent charging and discharging across multiple homes. The yearly percentage of surplus PV stored in the battery is 17.75% for SI, 20.38% for SII, and 18.58% for SIII. While SI is simpler, it offers the lowest peak reduction potential. Community PV (SIII) reduces overall battery requirements by distributing solar power among participants. SII achieves up to 53.50% self-consumption, an 80.2% summer load peak reduction, and a drop in transformer loading from 4.4% to 0.4%. These findings offer actionable insights for designing a resilient grid and sustainable energy communities.