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Energy Storage

Why V2G is the future of energy storage

March 31, 2023
  • Vehicle-to-grid will join li-ion batteries and pumped storage as major capacity provider

  • Study shows V2G can actually improve car battery performance

  • Tesla CEO Elon Musk has expressed scepticism, but rise of V2G is inevitable

One of the next major trends in energy storage will be vehicle-to-grid, or V2G, storage. This form of ‘storage on wheels’ is set to be almost as big a contributor to global capacity as dedicated lithium-ion batteries and pumped hydro – the dominant forms of storage currently – within the next 20 years.

Simply put, V2G charging enables energy to flow bi-directionally - from the grid into an electric car and back again. It’s a system that allows electric vehicle (EV) owners to make money by selling energy from their vehicle back to the grid.

And V2G will soon take-off. In one of the most recent developments, Nottingham City Council announced last week that it had launched a V2G demonstrator project. The council’s fleet depot is home to 40 vehicle-to-grid (V2G) bi-directional chargers with three solar arrays and two 300kW E-STOR energy storage systems from Connected Energy. The council has said the V2G project will enable it to avoid high electricity tariffs and give it the opportunity to sell electricity back to the grid.

How V2G earns money for EV owners

V2G technology can also be lucrative for private EV owners. A V2G trial programme run in the UK – by OVO Energy, Kaluza, Nissan Motor Company, research consultancy Cenex, and Indra Renewable Technology – involved V2G connected car-owners selling energy from their vehicle back to the grid at a rate of 30p per kWh. The programme concluded that “customers in the trial have been able to earn as much as £725 a year without needing to do anything except keep their cars plugged in when they are not in use”.

It's not hard to see why V2G is set to become one of the major sources of global energy storage capacity. Unlike stationary energy storage systems, which can require significant investment, plots of land, and planning permission, electric vehicle sales are continuously increasing with the result V2G can become a much bigger contributor of storage capacity with “no extra cost”, according to Finland-headquartered electric vehicle charging services company Virta.

It’s a compelling argument. It is estimated that globally there will be 140-240 million electric vehicles by 2030. “This means that we'll have at least 140 million tiny energy storages on wheels with an aggregated storage capacity of 7 TWh,” claims Virta. “We believe that electric cars are simply the smartest way to help with renewable energy management and production, as EVs will be part of our lives in the future — regardless of the ways we choose to use them.”

As one participant in the OVO Energy V2G trial commented: “Ninety per cent of the time my car is sat doing nothing. You have a huge energy storage device sitting on your drive. You’ve invested all that money in a car, so why not use it more of the time, rather than have it sitting doing nothing.”

Where major carmakers stand on V2G

While V2G implementation will take off, it will only do so once a number of barriers have been surmounted. To begin with, not all electric cars are V2G compatible, with a number of manufacturers at different stages in the development of the technology. Here’s a run-down of the current position of a number of major carmakers in relation to V2G:


Though the Nissan Leaf has been V2G compatible since 2013, it was only in September last year that the carmaker approved its first V2G charger for the car.


In September last year, it emerged that Volkswagen had signed a memorandum of understanding with Ellia Group to explore how V2G technology can potentially stabilise the energy grid, while at the same time rewarding EV drivers.


US-based Duke Energy announced in August last year that it was beginning a research and development pilot programme to evaluate the possibility of using the Ford F-150 Lightning vehicle – which has V2G capabilities – to feed the power grid.


In April last year, Hyundai – in partnership with mobility provider We Drive Solar – launched a project in the Dutch city of Utrecht, which will involve the deployment of 25 of its IONIQ 5 cars equipped with V2G technology. Hyundai said in a statement that Utrecht was the “first city in the world to deploy V2G technology on such a large scale”.


In April last year, Porsche issued a statement saying that, as part of a wider pool of vehicles, electric cars could “effectively act as a power plant and help supply what is known as balancing power – electrical power that balances out fluctuations in the power grid”. The statement added that a pilot test conducted by Porsche, the grid operator TransnetBW and consulting firm Intelligent Energy System Services (IE2S), had demonstrated that “electrical balancing power can be stored in the high-voltage batteries of an intelligent swarm of electric cars”. As part of the test, a total of five series-production Taycan vehicles were connected to the power grid via the Porsche Home Energy Manager (HEM) both in a domestic environment and under laboratory conditions.


Earlier this month, it was reported that Tesla vehicles will be V2G compatible “within the next two years”.


V2G technology is currently being “researched and tested” by BMW, but, as yet, there appears to be no indication as to when the carmaker will be able to offer a V2G-compatible car.


The car manufacturer’s EQS model will allow bidirectional charging in Japan. It says that the CHAdeMO (Charge de Move) charging standard in the country “supports bidirectional charging, which is the prerequisite for applications such as V2G and V2H (Vehicle-to-Home)”.


In 2020, Fiat Chrysler Automobiles began a V2G project - in partnership with ENGIE and electricity grid operator Terna Group - at the Mirafiori plant in Italy.

Does V2G enhance or damage EV batteries?

Another potential barrier that may need to be overcome is the perception that V2G capability could ultimately shorten the life of electric vehicle batteries. Virta has highlighted the fact that “some V2G opponents” claim that using V2G technology makes car batteries less long-lasting. However, Virta disputes this, saying that V2G discharging doesn’t affect the battery life, as it “only happens for a few minutes each day”. It adds that car batteries are “being drained daily anyway – as the car is used, the battery is discharged so we can drive around”.

Indeed, there have even been claims that V2G technology could even improve a car battery’s performance. A study by the University of Warwick – which involved the development of a “comprehensive battery degradation model based on long-term ageing data collected from more than fifty long-term degradation experiments on commercial C6/LiNiCoAlO2 batteries” – concluded that the smart grid is able to extend the life of the EV battery “beyond the case in which there is no V2G”. The study showed that simulation results indicate that “if a daily drive cycle consumes between 21% and 38% state of charge, then discharging 40%–8% of the batteries state of charge to the grid can reduce capacity fade by approximately 6% and power fade by 3% over a three-month period”.

Tesla’s Musk: ‘Few will use bi-directional charging’

Despite the fact that earlier this month, as previously mentioned, it was claimed that Tesla vehicles will be V2G compatible within two years, the company’s CEO Elon Musk has said that he doesn’t think many people will use bi-directional charging, unless they have a Powerwall [a Tesla battery that stores energy, detects outages and automatically becomes a homes power source when the grid goes down] because “if you unplug your car, your house goes dark and this is extremely inconvenient.”

Musk’s scepticism about the potential for widespread utilisation of V2G technology caused surprise in the industry, though there was speculation that the comments merely reflected the fact that Tesla is, at this precise moment in time, more interested in the greater deployment of its stationary storage products, such as MegaPack and Powerwall. On the other hand, could it be that Musk’s comments are part of a cunning ploy to increase the uptake of the ‘Powerwall’ product in preparation for the wider adoption of V2G technology?

Rise of V2G will be inexorable

All the signs are that V2G will rise to prominence as one of the key contributors of energy storage capacity around the world in the coming years. DNV has said that smart meters, smart grids and “regulatory changes” in the coming years will incentivise car owners to use V2G technology. The risk management body has concluded that, from 2040 onwards, the impact of V2G systems worldwide will be “almost as large as that of dedicated li-ion batteries (or more advanced chemistries) and pumped hydro”, reaching 220 TWh/yr globally by 2050.

The rise of V2G will be inexorable. The ever-increasing number of electric cars on the road means that the failure to widely deploy such technology would represent a glaring oversight in the drive to develop a carbon-free society.

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Energy Storage Report scrutinises the energy storage industry. Offering in-depth analysis of the technologies, trends and issues that are part of this exciting sector.

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