The report, “PV-Powered Charging Stations: Sizing, Optimization and Control,” analyzes workplace charging sites, microgrid configurations, vehicle-to-grid (V2G) operation, battery swapping concepts, and electric bus charging infrastructures . As its authors explain, matching charging demand with solar production is central to maximizing self-consumption and reducing costs.
Six years of workplace charging data
One of the report’s core case studies evaluates a workplace charging facility in southern France using six years of empirical data. The dataset includes more than 32,000 charging transactions from over 350 EV users across roughly 80 charging points.
Using this real-world data, researchers developed a modular sizing methodology to assess different charging strategies. The analysis compared uncontrolled charging and solar-aligned smart charging.
The results show that optimized charging significantly improves alignment between PV generation and EV demand. Solar smart charging reduces required PV peak capacity compared to uncontrolled charging, while increasing PV self-consumption and lowering grid exchange. The modular structure of the methodology allows operators managing multiple sites to replicate sizing procedures efficiently once the core relationships between PV production and charging demand are established.
Grid-connected systems outperform off-grid
The report also examines PV-powered charging stations based on microgrids, combining PV arrays, battery storage systems and utility grid connections. Using mixed-integer linear programming, systems were optimized over a 25-year lifetime based on levelized cost of energy (LCOE) and life-cycle emissions (LCE).
The results indicate that cities with high solar irradiation exhibit lower LCOE and LCE compared to cities with low solar irradiation. It is also observed that the ranking of cities based on average solar irradiation does not necessarily correlate with the ranking of LCOE and LCE.
The analysis also highlights the importance of seasonal variability. Higher annual solar irradiation does not automatically translate into lower system costs. Monthly and seasonal mismatches between production and charging demand can drive up required system capacity.
A comparison between Dijon and Poitiers illustrates this effect. Although Dijon has higher annual irradiation, weaker winter and autumn solar availability reduces PV self-consumption and increases required system sizing compared to Poitiers, where demand and production are better aligned.
Vehicle-to-grid potential
The report evaluates V2G operation through simulation of charging schedules. In optimized scenarios, EVs charge during periods of high PV generation and discharge during peak demand, while still meeting required state-of-charge at departure.
Results show that intelligent scheduling can reduce energy costs compared to unmanaged charging. However, the authors note several implementation challenges, including battery degradation from additional cycling, the need for robust communication systems, and the importance of long-term simulations to evaluate operational impacts over time.
Annual simulation frameworks are recommended to better understand degradation effects and long-term system performance.
Battery swapping increases flexibility
Battery swapping concepts are also modeled in the report. In this configuration, batteries are charged independently from vehicle use, remaining connected to the grid for extended periods. This allows charging to be scheduled during periods of high PV production.
A modeled region of approximately 200,000 inhabitants was used to compare swapping with conventional charging approaches. Results indicate that battery swapping can increase PV integration and reduce grid electricity demand, as stationary batteries provide greater flexibility in aligning charging with solar availability.
Electric bus charging trade-offs
The electrification of public transport is examined through a case study of the bus network in Compiègne, France. Three charging strategies were modeled: depot-only charging, terminal charging and opportunity charging.
Depot-only charging requires large onboard batteries of 422 kWh. Opportunity charging significantly reduces required battery capacity but introduces high peak power demands. Simultaneous charging events can require grid connections of up to, as a maximum, 1,200 kW.
A 100 kWp PV installation can exceed total bus consumption during summer months but falls short in winter, underscoring the need for seasonal balancing and potentially stationary storage.
The study concludes that charging strategy selection directly affects battery sizing, grid stress and renewable integration potential.
Data-driven design and multi-objective optimization
Across all use cases, the report emphasizes that empirical data improves system sizing accuracy and that charging control strategies materially influence self-consumption and economic performance.
Rather than relying on annual averages, the authors stress the importance of hourly and seasonal analysis. Multi-objective optimization—balancing cost, emissions and operational constraints—is identified as essential for large-scale deployment.
The report also points to ongoing challenges, including computational scalability for large EV fleets, improved battery degradation modeling, and standardization of communication protocols.
Overall, Task 17 concludes that PV-powered charging stations are technically feasible and economically viable when supported by intelligent control, detailed data analysis and site-specific system design.
Author: Bettina Sauer
This article is part of a monthly column by the IEA PVPS programme. It was contributed by IEA PVPS Task 17. The main goal of this working group is to accelerate and structure the deployment of PV in the transport sector.
The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.
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