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Everything a Solar EPC Should Know About Smart EV Charging

August 9, 2025

Implementing advanced control strategies for EV charging is the key to achieving specific operational goals, such as maximizing solar self-consumption, enhancing revenue streams, supporting grid stability, or reducing the overall carbon footprint.

Although there are very ambitious plans to roll out EV charging infrastructure, it is not without causing major disruption at various levels of the energy value chain. The modern equivalent of the gas station, a distributed EV charging network, faces complex issues that are best addressed through solar-powered EV charging microgrids, which provide an efficient and resilient foundation for sustainable energy delivery.

According to the IEA Global EV Outlook 2025, more than 58 million electric vehicles were in operation worldwide as of end-2024, with the global EV fleet continuing to grow at a sustained pace. The rapid expansion of electric mobility, driven by major advancements in battery technology, has made EVs increasingly attractive to a broadening consumer base. This momentum continues to accelerate and is widely recognized as a key factor in global decarbonization efforts.

1. Solar EV Charging Infrastructure Configurations and Strategies

Charging Stations

For a Solar EPC, selecting the optimal configuration requires first defining the primary purpose of the charging system. Common objectives include:

Aligning fast-charging operations with local solar generation
Utilizing excess local PV production & avoiding curtailment
Minimizing grid power purchase from the building
Reducing the building’s peak load demand
Lowering the carbon footprint of the building
Providing grid services to the local utility

In addition, a qolar EPC should have understanding of the final client / end-user load profile in order to define the most suitable system configuration and control approach.

Commercial or Workplace Buildings

Based on pre-2025 pricing assumptions, the EV charging market is projected to reach 33 billion euros by 2030. At present, most vehicle charging takes place at privately owned stations. However, within the next decade, it is expected that 40 to 50 percent of total charging energy will come from public infrastructure, including semi-public locations such as supermarket parking lots.
In commercial and industrial buildings, EV charging demand is mostly correlated with PV excess production. Yet, many existing infrastructures, such as gas stations or small offices, were not originally designed to accommodate EV chargers. As a result, implementing advanced control strategies in solar-powered EV charging stations is essential to synchronize charging with local production and maximize on-site energy use.

2. PV Integration: What Changes When You Add EV Charging to a Solar Site

Adding EV charging solar integration to an existing or new PV installation changes the design problem significantly. A site without EV charging can be sized around a relatively predictable load profile. The moment EV chargers are added, the load becomes variable, potentially large, and potentially coincident with periods of peak solar production or, more problematically, periods of low solar production.

This variability is why EV charging is not simply a load to add to a solar energy model. It is a dynamic, controllable load that can be actively managed to align with solar availability. The degree to which it can be aligned, and the value captured from doing so, depends directly on the intelligence of the control system coordinating between the PV inverter, the charger, any battery storage on site, and the grid connection

The Role of PV in Charging Speed

In a solar powered EV charging setup, the PV array can supply part or all of the charging power depending on the time of day and available irradiance. A vehicle arriving at a workplace car park at 9 AM on a clear day may receive most of its charge from solar generation. The same vehicle arriving at 6 PM may draw predominantly from the grid, unless a battery storage buffer has captured midday solar production for later use.

This is the fundamental design challenge for solar EPCs: the EV user’s charging window and the solar generation window do not always overlap. A smart EV charging controller addresses this by adapting charging speed dynamically, accelerating when solar production is high and moderating when it falls, rather than drawing a fixed power from the grid regardless of conditions.

PV Charge and Grid Export Considerations

One specific scenario that solar EPCs must plan for is PV charge excess, where solar production exceeds the combined demand of the building and the EV chargers. Without a zero-export controller or a battery buffer, this excess would be injected into the grid, which may be penalized, limited, or simply undervalued depending on the local tariff structure. In many commercial installations, the preferred outcome is to use that excess production to charge vehicles faster, charge an on-site battery, or reduce drawing from the grid during subsequent hours.

A practical rule for EPCs: if a commercial site has significant solar capacity and regular EV charging demand, these two loads should be designed together, not as separate systems added sequentially. The control layer that coordinates them is what determines whether the two assets amplify each other's value or simply coexist without interaction.

3. Dimensioning a Solar EV Charging Station

Sizing a solar EV charging station correctly requires the EPC to address three questions simultaneously: how much solar capacity is needed to meaningfully contribute to EV charging loads, what charger power level is appropriate for the expected use pattern, and whether a battery buffer is necessary to bridge the gap between solar generation and charging demand.

Charger Power Level and User Profile

EV chargers are commonly categorized as Level 2 (typically 7 to 22 kW AC) or DC fast chargers (50 kW and above). For commercial and workplace applications, Level 2 chargers are typically the right choice, since vehicles are parked for several hours and do not require the rapid top-up that DC fast charging provides. A Level 2 charger can realistically be powered from a modest solar contribution, whereas a DC fast charger requires power levels that solar alone, without significant battery storage, is unlikely to meet except during peak irradiance.

When Battery Storage Makes Sense

Adding a battery to a solar EV charging station makes sense when the charging demand pattern does not align well with the solar generation curve. A supermarket with most EV charging happening in the evening, after solar generation has declined, is a clear candidate for battery integration. The battery charges during midday solar production and discharges to supply EV chargers during the evening peak, capturing the value of solar production without requiring the EV user to be present during peak solar hours.

Without a battery, the system is limited to opportunistic solar charging, providing solar power only when the vehicle is connected and the sun is shining simultaneously. With a battery, the system becomes a true solar EV charging platform, capable of delivering a meaningful share of solar energy to every vehicle, regardless of arrival time.

4. Control Strategies for Smart EV Charging

In order to reap the most benefit from specific smart charging strategies, effective cooperation between EV drivers and charging stations is essential. The objectives of EV owners and charging station operators do not always align, making coordination critical to achieving optimal outcomes.

There are two main control strategies that can be implemented for smart EV charging:

Strategy 1: Maximizing EV Charging

The user will benefit from the maximum power output of the EV charger whether it is fed from the grid or from solar. The main features are:

Limitation of injection: If solar production surpasses load consumption, PV production will be curtailed so it is not injected into the grid.
Load balancing: If load consumption surpasses the maximum power purchase from the grid, EV charging speed will be reduced to remain under a determined power purchase threshold.

This strategy maximizes user comfort but does not maximize PV penetration.

Strategy 2: Maximizing PV Penetration

The solar producer will maximize PV penetration by adapting EV charging speed to solar production. The main features are:

Smart charging: If solar production surpasses load consumption, EV charging speed will be increased to use the excess solar production.
Limitation of injection: If solar production surpasses load consumption, PV production will be curtailed so it is not injected into the grid.

This strategy is well suited to maximize PV penetration but user comfort is diminished. In practice, charging stations will need to mix these two main strategies depending on the profile of their users.

5. How to Manage All These Energy Supplies

Solar EV charging stations integrated with the grid enable control strategies for both behind-the-meter and front-of-the-meter applications. Implementing an EV charging energy management system can optimize the charging process, ensuring efficient integration with various energy sources and enhancing the overall performance of the charging station.

Effective synergy between PV generation, grid connection, battery storage, and EV chargers can only be achieved through smart control. Without a controller coordinating these assets, each one operates in isolation, and the combined system often performs worse than any single component would suggest. The controller is what turns a collection of hardware into an intelligent, coordinated energy platform.

6. Advanced Control and Optimization with ePowerControl EV

The ePowerControl EV connects to PV inverters, EV chargers, battery storage systems, and meters, enabling independent monitoring and control of each device to deliver the following functions:

Anomaly detection: Identifies irregularities across a portfolio of self-consumption charging stations, enabling rapid intervention before issues escalate.
Smart charging: Adjusts charging speed based on battery state, solar production, and building load, automatically navigating between the two main strategies described above.
Vehicle-to-Grid (V2G): Manages EV battery charging and discharging based on utility signals, allowing EVs to participate in grid services and generate additional revenue.
Solar optimization: Optimizes solar input for efficient real-time charging and demand management, ensuring that PV production is captured and directed where it has the highest value at any given moment.

The ePowerControl EV is part of Elum Energy’s broader ePowerControl product family, which covers C&I solar installations, hybrid systems, and utility-scale power plants through the same control philosophy: vendor-agnostic compatibility, configurable strategies, and continuous optimization across all connected assets. For a broader overview of how solar controllers work within an energy management architecture, see our guide on energy management software for solar plants.

7. A Real Example: Solar EV Charging in Guadeloupe

One of the concrete deployments of solar powered EV charging in Elum Energy’s project portfolio is a zero-export installation combined with EV charging at a supermarket in Guadeloupe. This project illustrates several of the design principles discussed above: the site has significant solar capacity, a commercial building load, and EV chargers serving customers during shopping hours.

The zero-export configuration ensures that solar generation is never injected into the grid, a common requirement in non-connected island zones (ZNI) in France where grid conditions are more constrained than on the mainland. Instead, all PV production is consumed on-site, distributed between the building load and the EV chargers according to availability. The ePowerControl EV manages this dispatch in real time, prioritizing solar self-consumption while maintaining the grid power purchase within the contracted limit.

This type of deployment is a strong illustration of why solar EV charging works best when the control layer is designed into the system from the outset. The supermarket’s EV chargers and its PV array are not independent assets; they are coordinated components of a single energy management platform, and the economic case for both is strengthened by their interaction.

For EPCs working in island zones, territories with constrained grids, or any site where zero export is a requirement, solar EV charging is a particularly valuable configuration: excess solar production that cannot be exported can instead be captured by EV chargers, turning a compliance constraint into a commercial asset.

Frequently Asked Questions

Is a dedicated controller required for solar EV charging, or can the inverter manage it alone?

A standard PV inverter is designed to manage the conversion of solar DC power to AC and, in some configurations, to limit injection to the grid. It is not designed to coordinate the behaviour of an EV charger, a battery, and a building load simultaneously. Without a dedicated controller, each device follows its own internal logic, and the result is typically that EV chargers draw from the grid regardless of solar availability. A controller is what closes the loop between solar generation and charging demand, making the decision in real time about how much power to direct to the charger versus store in a battery versus feed back to the grid.

What communication protocols does an EV charging controller use to interface with PV inverters?

Most EV charging controllers, including ePowerControl EV, communicate with PV inverters over Modbus TCP or Modbus RTU, which are the dominant industrial protocols for solar equipment. Some newer inverters also support SunSpec Alliance registers over Modbus, which provides a standardised data model across brands. The controller also connects to energy meters via Modbus to read real-time grid import and export, and to the EV charger itself via OCPP (Open Charge Point Protocol), the standard communication protocol for EV charging infrastructure. Verifying that all devices on a site support compatible protocols is one of the first steps in an EV charging integration project.

How does Vehicle-to-Grid (V2G) interact with a solar PV installation?

Vehicle-to-Grid (V2G) allows a bidirectional EV charger to discharge energy from the vehicle’s battery back into the building or the grid. In a solar context, this creates an additional storage asset: the EV battery can absorb excess midday solar production and return it during the evening peak, in a similar way to a fixed battery storage system. The key difference is that V2G availability depends on the vehicle being connected and its state of charge, which makes the dispatch logic more complex than for a fixed BESS. A controller that supports V2G must therefore track vehicle connection status, battery state, and user departure preferences alongside the solar and grid signals it already manages.

What grid connection requirements apply to a solar EV charging station in a commercial building?

Grid connection requirements for commercial solar EV charging installations vary by country and utility, but several constraints are common across markets. Many utilities apply a maximum subscribed power limit to the connection, above which a penalty tariff or disconnection risk applies. A smart EV charging controller can enforce a power ceiling that prevents the combined draw of the building load and EV chargers from exceeding this limit, a function known as load balancing or dynamic load management. In some markets, particularly island grids and non-interconnected zones, zero-export constraints also apply, meaning that the solar generation must not inject power into the grid even when it exceeds local consumption. In these configurations, the controller curtails solar output or diverts it to the EV chargers to remain within the constraint.

How does solar EV charging reduce a building's peak demand charges?

Commercial electricity tariffs in many markets include a demand charge component, billed on the highest power draw recorded during the billing period, typically over a 15-minute interval. EV chargers, particularly Level 2 units charging multiple vehicles simultaneously, can trigger significant demand spikes. A solar EV charging controller addresses this by capping the total power drawn from the grid below the demand charge threshold, reducing EV charging speed when the building load is high and accelerating it when solar production reduces the grid draw. This strategy, combined with solar self-consumption, can meaningfully reduce both energy charges and demand charges on the same installation. For a detailed breakdown of how demand charge reduction works in C&I solar and storage projects, see our article on demand charges explained.