The inertia of electric vehicles, considered a peculiarity of the automobile in general, can become a quality thanks to V2G. In fact, according to estimates, the vast majority of vehicles spend more than 90% of their time immobile. But in the mid-1990s, an idea emerged: Once electric vehicles stopped, their batteries could serve as a backup electrical resource for the grid. To supply a house with electricity, for example, or supply surplus resources to the grid if necessary.
What was initially an intuition of two American academics gave rise in 2002 to the concept of “V2G” or “vehicle to grid”, which translates in French as “vehicle connected to the grid”. It is difficult, given the few electric vehicles then in circulation, to test V2G technology on a full scale. Large-scale experiments began in early 2010: in Japan, the United States, Denmark and the United Kingdom. In France, the deployment of this technology took off with the creation of Dreev in 2019. A joint venture created by EDF in partnership with Nuvve, a Californian start-up specializing in the exploration of V2G.
Projects have been multiplying for a few years now: Dreev announces around 200 V2G terminals in France today, as well as deployments organized under Flexitanie from 2020 onwards in Occitania. A project in which the Purpan School of Engineers participated, or companies such as Hotravail, which works mainly in landscaping and environmental maintenance, with vehicles used by professionals of various trades: painters, carpenters, plumbers. Or even the company D&S, specialized especially in the prevention of nuclear risks.
200 V2G terminals in France
For the vehicles of the companies involved, the implementation of this technology, through two-way terminals specially designed to recharge the cars and unload them according to the needs of the network, is almost without consequences. The only specificity is that drivers must indicate, in an app, at what times they want to use their vehicle and with what level of charge they want this vehicle to be “fueled” when turning it off to drive it. An operating mode suitable for vehicles in the fleet of companies or local authorities that can anticipate the times when these vehicles are immobilized, most often at night. With one benefit: the use of energy through the network is remunerated.
V2G: a giant battery, an electric vehicle cluster
The distribution of these terminals remains limited at the moment by the availability of technology in vehicles. Only those with a Chademo plug allow bi-directional current. But this situation is about to change. The extension of the technology to other vehicles occurs as V2G expands its potential. because since 1er In February, RTE, the entity responsible for organizing the French electricity grid, certified the participation of electric vehicles in the real-time balance of the electricity system. “As soon as consumption and production are not perfectly balanced, an imbalance is created in the network, which can reach a blackout”, explains Éric Mevellec, general manager of Dreev. Until now, structures such as gas or coal plants could participate in the rebalancing if necessary. “From now on, we are certified to participate in the “primary reserve” of the network and participate in the adjustment of energy balances, indicates this manager. And the Dreev technology has shown that the formation of an aggregate of electric cars can behave as efficiently as a giant battery”, concludes Éric Mevellec.
V2G in balance
A resource that could prove valuable as more and more uncertainty looms over the future of energy resources. A year ago, Éric Mevellec estimated that the penetration of V2G for efficient use of the network should reach 10 to 20% of the French fleet of electric vehicles.
“Whatever the future nuclear and renewable mix in Europe, there will be significant needs for flexibility and that flexibility will be largely enabled by energy storage,” continues Éric Mevellec. From this perspective, how far will the spread of V2G reach tomorrow? “The cards are shuffled and it is difficult to know by what proportion this share can increase. But it can become very significant”, projects this official.
Microgrid V2G: Closed-circuit electric vehicles
These uncertainties about long-term energy availability also support the continuation of other experiments around exploiting the energy of stationary electric vehicle batteries. The ones carried out with the Smile project, for Smart Ideas to Link Energies, translated as “Smart Ideas to Connect Energies”, launched in 2016 in the Brittany and Pays de la Loire regions, are yet another “micro-grid”. In other words, the use of closed-circuit battery power to power residential buildings or offices. Instead of V2G, for vehicle connected to the network, we speak of “vehicle to home”, V2H, or “vehicle to building”, V2B.
These experiments also promote the storage of renewable energy, produced among other things from photovoltaic panels. In Belle-Île-en-Mer, in Morbihan, the Flexmob’île project is testing, on the scale of a VVF holiday center, the possibility of storing the energy produced by solar panels with a power of 76 kW in a cabinet containing batteries of state-of-the-art electric vehicles, for a total power of 200 kW.
This cabinet can provide power not only for the vacation resort, but also for V2G electric vehicles. “In partnership with Renault, we will have V2G vehicles. These Zoé, which are not sold, are adapted by the manufacturer to operate in landfills”, explains Jo Brohan, president of Morbihan Energias, a public establishment for inter-municipal cooperation. Like the electrical cabinet, these Zoé will supply the VVF building with electricity if needed. “We will see how these vehicles will be used and how electricity will be produced and stored depending on on-site consumption and mobility needs. It’s an ongoing learning process,” explains Jo Brohan.
Lightening the power grid thanks to V2G vehicles
Such experience leads us to consider, on an island scale, the possibility of producing renewable energy, storing it and returning it, if necessary, by electric vehicles. More generally, these micro-grid devices can also help relieve the power grid in the event of demand voltages. “Tomorrow, it is not the amount of energy consumed that will be a problem, but the timing of its consumption”, anticipates Jo Brohan. And to answer, there will probably never be many electric vehicles stopped…