The European research project EV4EU has concluded after four years of operation. Their goal was to develop and test solutions that would allow electric vehicles to not only consume electricity but also serve as flexible resources within the energy system, namely bidirectional charging. Key results include a fully functional prototype of a bi-directional charging station based on the Combined Charging System (CCS) and freely available open source software for charging point operators. The project, funded by the EU with approximately nine million euros, was coordinated by the Portuguese research institute INESC-ID. In total, 16 project partners and six associate partners participated.
At the heart of the project was the Vehicle-to-Everything (V2X) concept. This general term encompasses various ways of feeding energy back into the vehicle’s battery or exchanging it with other systems, such as Vehicle-to-Grid (V2G). In this case, the electric vehicle supplies power to the public grid, which can help mitigate peak loads or use excess renewable energy at a later time.
Vehicle-to-Home (V2H) refers to the supply of power to a house from the vehicle battery, for example when a rooftop photovoltaic system generates little power. Vehicle-to-Building (V2B) targets commercial or public buildings. Vehicle-to-Load (V2L), on the other hand, allows electrical devices to be powered directly from the vehicle, such as tools or camping equipment. While V2L also involves energy sharing, it does not automatically contribute to network stability.
CCS prototypes and open source software
A key technical achievement of EV4EU is the successful development and testing of a fully functional prototype for bi-directional DC charging based on the Combined Charging System (CCS). This addresses a critical component to broader adoption of the technology: returning power through an established DC charging interface. Additionally, the partners developed open source tools for charging point operators to manage standards-based communication for smart and bidirectional charging.
Control of the batteries available in the vehicles also played a central role. EV4EU examined how a virtual power plant could aggregate and optimize various flexible resources for deployment in energy markets. “This approach can increase revenue and at the same time offer direct benefits to users,” said project coordinator Hugo Morais. However, this requires that vehicles be connected at the necessary times and that their owners allow sufficient flexibility in the loading and unloading processes.
Four pilot projects throughout Europe
Project partners tested their approaches in Portugal, Slovenia, Greece and Denmark. In Portugal, unidirectional and bidirectional charging points were integrated into residential buildings and public facilities, among others. The demonstration showed an average reduction in charging costs for private households of 8.6 percent, as well as up to 21.9 percent higher integration of renewable energy.
In Slovenia, the focus was on virtual power plants and local market platforms in office buildings and schools. The tests confirmed the added value of V2X compared to purely smart charging, which only controls the timing of energy consumption. In Athens, Greece, partners tested flexible capacity contracts and dynamic pricing signals to limit overcharging and high power demands at public charging locations. Meanwhile, the Danish demonstration managed loading groups in the parking lots. Control algorithms aimed at reducing phase imbalances and improving local use of renewable energy.
User acceptance remains critical
In addition to technical feasibility, EV4EU also examined business models, regulatory frameworks and the needs of vehicle users. He now maintains that bidirectional charging can only work as a flexibility option if the mobility needs of users are guaranteed and battery aging is taken into account. Appropriate control algorithms can optimize charging and discharging processes to limit additional stress on the battery.
The results show that V2X goes beyond individual vehicles and charging technologies: coordinated communication, appropriate market models and incentives for participants are required. The project provides proven technical approaches and practical knowledge for this purpose. The next step is to implement these solutions on a larger scale and under the respective national networks and market conditions.
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