Vehicle to grid: energy with a return ticket

Pilot projects: GridPilot and beyond

V2G is not limited to theoretical discussions —it is already being tested in real projects across Europe. One notable initiative is GridPilot, developed by the Spanish company Ayesa as part of the European Scale-Up project.

In Madrid, for example, bidirectional systems have been installed in park-and-ride facilities to manage electric vehicle charging and discharging, monetising the energy supplied when the grid requires support.

Key features of the GridPilot pilot:

• It considers variables such as vehicle availability, parking duration, dynamic electricity prices, and conditions on the local grid.
• It applies artificial intelligence to optimise charging and discharging decisions in real time —integrating EVs with other distributed resources such as solar panels and stationary storage.
• The project is co-funded by the European Union (Horizon 2020) and extends to other cities, including Turku (Finland) and Antwerp (Belgium).

These pilots show that V2G technology is already in the testing phase and that technical barriers are manageable when vehicles, chargers, and algorithms are designed to work together.

Expected benefits of V2G

Some of the most relevant benefits of connecting electric vehicles with V2G capabilities include:

1. Load balancing: redistributing energy at critical moments to mitigate demand peaks and valleys.
2. Maximising renewable energy: absorbing surplus generation during high renewable electricity generation and supplying that energy back when demand requires it.
3. Reduced grid investment: vehicles function as distributed storage, reducing the need to expand power lines or build additional backup plants.
4. Income for EV owners: through compensation schemes for injected energy, drivers could benefit financially from participating in energy services.
5. System resilience: in extreme events (outages, local overloads), a distributed V2G-enabled fleet can serve as an internal support.

These benefits only materialise if technical, regulatory, and economic frameworks align to ensure efficiency, viability, and security.

Technical, regulatory, and market challenges

Widespread adoption of Vehicle to Grid also faces several challenges:

Standardisation and interoperability

To ensure compatibility among different car brands, chargers, and operators, unified standards are necessary (such as ISO 15118 for vehicle-to-charger communication). If each manufacturer uses their own protocol, scalability becomes difficult.

Battery lifespan

Using EV batteries for additional charge/discharge cycles may accelerate degradation. Optimising these cycles and financially compensating for the degradation impact are necessary steps.

Market design and regulation

Electric vehicles must be recognised as active agents in the electricity system, capable of participating in electricity markets (ancillary services, day-ahead market, and balancing). Regulation should evolve to enable contracts, rates, and compensation mechanisms tailored to V2G.

Costs and usability

Bidirectional chargers, smart control systems, and communication infrastructure can be costly. Adoption will depend on economic returns and ease of use for consumers.

Cybersecurity and data management

Bidirectional connectivity involves continuous flows of sensitive data (battery status, consumption profiles, forecasts). A secure, auditable, and robust architecture is essential.

A study on grid-connected systems in the Spanish market highlights that one of the main barriers is cycle cost and its relationship with the profitable operating time in the day-ahead market.

Toward a decentralised, participatory grid

The emerging energy paradigm is one of a distributed, digital, and participatory grid. In this scenario:

The consumer evolves into a prosumer, capable not only of consuming energy but also of storing it and injecting it back into the system when most efficient.
Electric vehicles stop being just transport and become energy assets that participate in grid balancing.
Electric infrastructures shift toward more flexible, adaptive, and efficient models, able to optimise existing resources and respond better to the needs of an increasingly distributed and collaborative system.

Vehicle to Grid embodies this vision: enabling seamless interaction between mobility and the electricity system, fostering a sustainable, intelligent, and collaborative model.