Electric vehicles in solar energy communities—Impact on asset dimensioning and the low-voltage grid

The uptake of distributed, renewable generation and the shift to electric mobility are building blocks for the energy system decarbonisation, promoted in the broad public particularly through energy community organisations. The goal of this research is to evaluate the investment drivers in solar energy communities with and without private vehicle electrification and its physical impact on the low-voltage distribution grid. The community investment decision is formulated as a mixed-integer linear problem, and a three-phase unbalanced power flow simulation analyses the impact of various community scenarios on a real Spanish distribution grid. The PV panel placement and sizing is driven by the minimal possible load-generation mismatch and the feed-in remuneration. Hence, accounting for electric vehicle distribution and charging strategies in the community planning phase affects the cost-optimal layout of PV systems. Going from uncontrolled electric vehicle charging with maximum power to a uniform charging strategy increases the viability in PV investments while significantly reducing the occurrence of excessive voltage drops. The occurrence of overvoltage from distributed solar generation more than doubles from 4.9% to 10.6% when increasing the PV penetration in the energy community by only 9% with an unfavourable panel distribution. Increasing the PV penetration by 59% with a more optimal panel allocation yields a comparatively lower occurrence of overvoltage of 10.0% highlighting the need for informed community planning. • Low load-generation mismatch and feed-in remuneration drive EC investment decision. • Uniform low-power charging yields lower cost function than uncontrolled charging. • PV generation causes significant overvoltage issues in scattered residential areas. • Sub-optimal PV distribution has larger grid impact at lower penetration levels. • Balancing EV and PV phase connections is critical for grid operation.