EV4EU project advances bidirectional charging
The EU bidirectional charging project EV4EU has concluded its work after four years. The partners developed a bidirectional CCS charging prototype and open-source software for charging point operators, among other things. Four demonstration projects show how electric cars can contribute to the adaptability of the power system.
Image: Gen-I
The European research project EV4EU has concluded after four years of operation. Its goal was to develop and test solutions enabling electric vehicles not only to consume electricity but also to serve as flexible resources within the energy system – namely, bidirectional charging. Key outcomes include a fully functional prototype of a bidirectional charging station based on the Combined Charging System (CCS) and freely available open-source software for charging point operators. Funded by the EU with approximately nine million euros, the project was coordinated by the Portuguese research institute INESC-ID. A total of 16 project partners and six associated partners were involved.
At the heart of the project was the Vehicle-to-Everything (V2X) concept. This umbrella term encompasses various ways to feed energy back from the vehicle battery or exchange it with other systems, such as Vehicle-to-Grid (V2G). In this case, the electric vehicle supplies power back to the public grid, which can help mitigate peak loads or utilise excess renewable energy at a later time.
Vehicle-to-Home (V2H) refers to supplying a house with energy from the vehicle battery, for example when a rooftop photovoltaic system is generating little power. Vehicle-to-Building (V2B) addresses commercial or public buildings. Vehicle-to-Load (V2L), on the other hand, enables electrical devices to be powered directly from the vehicle—such as tools or camping equipment. While V2L also involves energy exchange, it does not automatically contribute to grid stability.
CCS prototypes and open-source software
A key technical achievement of EV4EU is the development and successful testing of a fully functional prototype for bidirectional DC charging based on the Combined Charging System (CCS). This addresses a critical component for wider adoption of the technology: feeding power back through an established DC charging interface. Additionally, the partners developed open-source tools for charging point operators to manage communication based on standards for smart and bidirectional charging.
The control of available vehicle batteries also played a central role. EV4EU examined how a virtual power plant could aggregate and optimise various flexible resources for deployment in energy markets. “This approach can increase revenue while delivering direct benefits to users,” said project coordinator Hugo Morais. However, this requires vehicles to be connected at the necessary times and that their owners allow sufficient flexibility in charging and discharging processes.
Four pilot projects across Europe
The 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 per cent, as well as up to 21.9 per cent higher integration of renewable energy.
In Slovenia, the focus was on virtual power plants and local market platforms in office and school buildings. The trials confirmed the added value of V2X compared to purely smart charging, which only controls the timing of power consumption. In Athens, Greece, the partners tested flexible capacity contracts and dynamic price signals to limit overloading and high power demands at public charging locations. The Danish demonstration, meanwhile, managed charging groups in car parks. Control algorithms aimed to reduce phase imbalances and improve the 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. It now argues that bidirectional charging can only function as a flexibility option if users’ mobility requirements are ensured and battery ageing is taken into account. Appropriate control algorithms can optimise charging and discharging processes to limit additional stress on the battery.
The results show that V2X extends beyond individual vehicle and charging technologies: coordinated communication, suitable market models, and incentives for participants are required. The project provides tested technical approaches and practical insights for this purpose. The next step is to implement such solutions on a larger scale and under the respective national grid and market conditions.