Introduction.

Most energy system models in the literature neglect the explicit representation of charging infrastructure deployment, thereby overlooking critical bottlenecks and investment trade-offs. As a result, previous assessments of smart charging strategies—namely V1G (unidirectional smart charging) and V2G (bidirectional vehicle-to-grid)—lack a grounded cost perspective and rely heavily on scenario assumptions rather than system-optimal configurations. In this study, we address this limitation by integrating charging infrastructure options directly into a sector-coupled energy system model, treating them as competing technologies alongside vehicle powertrains. This novel approach enables a more realistic analysis of the trade-offs between battery electric vehicles (BEVs), fuel cell electric vehicles (FCEVs), and internal combustion engine vehicles (ICEVs). We focus on understanding the system-level benefits of V1G and V2G in a context where electricity, transport, heat, and industry sectors are jointly optimized.

Model Settings and Scenarios.

We employ a high-resolution energy system model representing 35 European countries, operating at hourly temporal resolution to capture dispatch dynamics across sectors. Mobility demand is endogenously met through a mix of competing powertrains, and the associated charging infrastructure is deployed cost-optimally. We explore a scenario matrix based on three key dimensions: (1) charging infrastructure cost (low, base, high), (2) smartness of charging infrastructure (uncontrolled, V1G, V2G), and (3) transmission grid expansion (limited vs. unconstrained). This setup allows us to assess the interplay between infrastructure investment, technology adoption, and system operation.

Results and Discussion.

When charging is uncontrolled, the model shifts toward hydrogen vehicles to meet marginal mobility demand, as they offer operational advantages without peak charging constraints. In contrast, under smart charging regimes, the entire European vehicle fleet is electrified. Smart charging (V1G and V2G) can reduce peak charging infrastructure needs by a factor of 3 to 4, depending on the scenario. In many cases, V2G and transmission expansion prove to be substitutable, raising policy questions about the preference for domestic (V2G-based) versus cross-border (transmission-based) flexibility. While the social acceptance of new infrastructure remains a challenge, our analysis shows that up to 50% of EV charging load can be shifted to achieve system benefits. Smart charging and transmission jointly displace costly battery storage and enable broader use of heat pumps by reducing the reliance on combined heat and power (CHP) plants, thereby freeing biomass for industrial use. Overall, smart charging technologies reduce total system costs by 2–5%. Importantly, the average V2G-related battery usage remains within ±6% of total battery capacity, suggesting minimal impact on battery health and user behavior.

Conclusion.

Integrating charging infrastructure into energy system models reveals important trade-offs between transport electrification strategies, flexibility sources, and infrastructure investment. Smart charging, especially V2G, proves to be a key enabler of efficient sector coupling and cost-effective decarbonization, without imposing unrealistic burdens on end users or battery systems.