Vehicle-to-grid trials worldwide show clear value for fleets. Dunstan Power, MD of smart charging design consultancy Versinetic, explores what UK operators can learn.

For fleet operators, electrification is now firmly on the agenda. Most discussions focus on charging infrastructure, running costs and range. But another technology is emerging that could change the economics of electric cars and vans altogether: vehicle-to-grid (V2G).

V2G allows electric vehicles not only to charge but also to discharge energy back into the grid or a building. For fleets with dozens to thousands of vehicles parked for long periods, this creates the possibility of reducing energy costs, strengthening resilience and even generating revenue. Far from being theoretical, a growing number of real-world projects are already proving the concept.

Managing the basics: VIGIL in the UK

Any fleet considering V2G must first think about control. The UK’s VIGIL (VehIcle-to-Grid Intelligent control) project, led by Aston University and ByteSnap Design, demonstrated how to balance EV charging and discharging with building demand and local network constraints. Although small in scale, VIGIL showed that smart platforms are essential to coordinate multiple vehicles. For fleets, the takeaway is simple: without intelligent management systems, V2G at depots or offices will not be practical.

Cutting costs in logistics: xSite in Germany

One of the clearest fleet-based demonstrations comes from logistics company FIEGE in Germany. Its xSite project, developed with E.ON and GridX, installed a mix of smart AC chargers and DC bidirectional chargers at its Greven site.

The system enables company cars to provide energy back to the building when demand peaks, while charging at cheaper times. Annual savings are estimated between €6,000 and €13,000 (c£5,239 to £11,351) across just 12 chargers. The project highlights how fleet downtime, often seen as wasted time, can instead be turned into measurable energy value.

Delivering services in Canberra, Australia

Australia’s Realising Electric Vehicle-to-Grid Services project trialled 51 fleet EVs connected through bidirectional chargers across 11 buildings in Canberra. Supported by the Australian Renewable Energy Agency, it tested how vehicles could supply reserve power and frequency control to the grid.

Results showed that even a single EV could earn significant value in ancillary service markets. More importantly, when storms disrupted power supplies in 2024, vehicles from the trial fed electricity back into the grid to help maintain stability. This demonstrated that fleet V2G offers not only cost reduction but also resilience, an increasingly valuable trait for operators dependent on reliable power.

Scaling up with DROSSONE in Italy

Italy’s DROSSONE project is testing V2G at scale by using a manufacturer’s fleet of EVs parked at a central site. Starting with 280 vehicles, the project is on track to reach 700 by 2027, providing up to 25MW of capacity for grid services.

The model shows how aggregating a large number of cars can create a significant energy resource. While the vehicles are not in active use during the day, they still contribute value by supplying frequency response to the grid. For large fleets in the UK, DROSSONE underlines the principle that scale magnifies benefits: once infrastructure is in place, every additional vehicle strengthens the business case.

Linking vehicles to markets: PowerLoop in the UK

In the UK, Octopus Energy’s PowerLoop trial has been preparing cars to participate in the National Energy System Operator’s Balancing Mechanism. More than 130 EVs have been enrolled, with participants able to save up to £725 a year through V2G tariffs.

Although primarily aimed at households, the model is transferable to business fleets, especially company cars and vans with predictable usage patterns. For fleet managers, PowerLoop demonstrates how vehicles can be integrated into wider energy markets, not just as transport assets but as part of a flexibility network.

Shared cars as grid assets in Utrecht

Although not a corporate fleet, the Dutch city of Utrecht’s car-sharing V2G project is worthy of a mention as it is an important example of how managed vehicles can be aggregated to deliver energy services. The initiative involves 500 bidirectional Renault 5 E-Tech cars integrated with 20 charging plazas across the city. Together, these shared cars absorb surplus solar during the day and feed electricity back at peak demand.

For UK operators, the lesson is that the principles demonstrated in Utrecht can apply to pool cars, shared vans or rental fleets. By treating a group of vehicles as a collective energy resource, fleets can play a wider role in balancing local energy systems.

For UK fleet operators, V2G is not yet mainstream, but the direction is clear. As more manufacturers enable bidirectional charging and as energy markets open up, fleets will have the opportunity to treat their vehicles as more than just transport.

Cars and vans parked in depots, car parks or driveways represent untapped energy capacity. With the right systems in place, that capacity can reduce costs, improve resilience and support the wider grid. For fleets looking to make the most of their electrification investments, V2G is a technology that deserves attention today.