VEHICLE to GRID (V2G)

BIDIRECTIONAL CHARGING
https://electricvehiclegeek.com/vehicle-to-grid-v2g-technology/
https://solartechonline.com/blog/bidirectional-ev-charger-guide/
https://grist.org/how-evs-can-fix-the-grid-and-lower-your-electric-bill/
How EVs can fix the grid and lower your electric bill
by Matt Simon / Oct 17, 2025

“Depending on whom you’re asking, renewable energy and electric vehicles will either destroy the grid or save it. The sun doesn’t always shine and the wind doesn’t always blow, true enough, while a gas-fired power plant can generate electricity any time. That supposed precarity of renewables will get even shakier, critics argue, as Americans ditch conventional vehicles for electric ones, which will draw ever more power from an already strained grid. Luckily, that’s not a realistic scenario because of what renewables and EVs have in common: giant batteries. Solar and wind farms are plugging into huge banks of them to store energy to use as needed, fixing their intermittency challenge. (Engineers are turning Earth itself into an even bigger battery.) And a growing number of cars with cords feature vehicle-to-grid technology, or V2G, also known as bidirectional charging. They can draw clean power when renewables are humming on the grid, and their owners get paid to send some back to a utility to meet growing demand — creating a vast distributed network that could make the electrical system more reliable, not less. Research has found that globally, less than a third of EV owners would have to opt into such a system to meet the rising need for energy storage.

Until now, we’ve been customers of utilities — with power flowing one way to homes — but more and more we’ll be active participants in the grid, sending extra battery power the other way. That shift is getting a head start in Maryland, where last month the Baltimore Gas and Electric Company partnered with Sunrun, which provides home solar and batteries, and Ford, which makes the electric F-150 Lightning, to activate the nation’s first residential V2G pilot project. “This is the first time there are actual customers who are off-boarding power from their electric vehicles to the grid, and we’re doing it at peak times in the evening,” said Chris Rauscher, vice president of grid services at Sunrun, referring to the periods of greatest need for electricity. “So we’re actually reducing the stress and the demand on the grid — crushing the curve, crushing the peak — which helps lower costs for everyone.”

To understand how this works, think of EVs less like vehicles and more like immense batteries on wheels. In fact, the Lightning’s battery is 10 times bigger than a residential pack, Rauscher said. “There’s more energy capacity deployed today in electric vehicle batteries on the road in the U.S. than in all stationary batteries combined,” Rauscher added. “This is a massive resource.” And it’s only getting more massive: The Natural Resources Defense Council has estimated that if California V2G’ed all of the 14 million EVs it’s expected to have by 2035, it could power every home in the state for three days. In these early days of the tech, though, only a handful of models sport V2G capabilities, but the number is growing. The hardware and software aren’t wildly complicated. A special charger juices up the vehicle’s battery, then draws from the car to power a house, in the case of vehicle-to-home systems, or sends it back to the utility, in the case of vehicle-to-grid.

Utilities will have to communicate with anyone participating in such a program, for instance with an app that allows a customer to, say, ask that their vehicle never be discharged below a certain percentage. Each utility will also need to figure out how much to compensate people for their power in order to incentivize them to join in. That might mean paying for the amount of energy provided, the same principle behind net metering, in which residential solar customers are reimbursed for the energy they give to the grid. “We’re still in a bit of an early stage here,” said Divesh Gupta, director of clean energy solutions at Baltimore Gas and Electric Company. “There are a lot of things that need to be worked out, particularly on the customer-experience side.”

That battery power need not go all the way back to the grid, though, to help utilities. For years now, owners have been using their Ford Lightning trucks to power their homes. These batteries are mammoth — the extended-range version can go 300-plus miles — and powering a home with one uses just 5 or 6 miles of that range per hour. So say an owner returns home at 6 p.m., when demand on the grid is skyrocketing as everyone else is knocking off work and switching on air conditioners and other energy-hungry appliances. Because consumption is rising, so too is the price of electricity. But a Lightning owner doesn’t have to pay that if they’re using their battery to power their home for five hours until they go to bed, using 25 to 30 miles of range on their battery. “It basically makes the house disappear, effectively, from the grid,” said Ryan O’Gorman, Ford’s business lead for vehicle-to-grid and vehicle-to-home. Then the owner can charge again when demand, and electricity prices, are lower. If they work from home, for example, they can charge during the day, when lots of solar power is coursing through the grid.

More homes tapping EV batteries also eases demand on the grid, which is especially welcome during a heat wave when everyone’s running their AC units. Those heat waves will only get worse from here — a growing challenge for utilities to provide the power that keeps people cool and safe. At the same time, ever more data centers are devouring ever more power and stressing the grid to its limits. That infrastructure also must accommodate other forms of decarbonization, like heat pumps and induction stoves, that are essential for weaning us off fossil fuels. Instead of sitting idly in a garage depreciating, V2G turns an EV into an asset for bolstering the grid and powering the home cheaply. “Cars are parked more than 22 hours a day,” O’Gorman said. “When we look at the advantages of an EV, now that vehicle can provide savings and potentially revenue flows for the customer.” (Interestingly, even electric trains can now send juice back to the grid and generate revenue, thanks to what they gain from regenerative braking: In the Bay Area, the Caltrain system is now being compensated for that energy, slashing its estimated annual power cost from $19.5 million to $16.5 million.)

The residential V2G program in Baltimore follows other experiments across the nation with larger vehicles. In Oakland, California, for instance, the utility Pacific Gas & Electric worked with the electric bus provider Zum to deploy vehicles that take kids home in the afternoon, return to the lot, and plug back into the grid. Because their batteries are so large, they have ample power left over, sending that extra energy to the grid just as demand is spiking. They charge overnight, take kids to school, and plug in again to charge. This kind of predictability could make commercial fleets even more powerful for V2G than residential vehicles, experts say. A school bus is on a schedule a utility can rely on — it’s parked and available at certain times of day and making the rounds at others. Plus, in the summer, they would be available almost constantly. Other fleets, like delivery and government vehicles, follow regular timetables as well. Fleet managers can also procure large numbers of the appropriate chargers, buying into the system en masse, compared to a homeowner shelling out for just one. “In the short term, we see commercial-level V2G applications as more viable due to infrastructure costs, but we expect affordable domestic units to emerge as the market matures and demand grows,” said a spokesperson for Nissan, which has long included bidirectional charging in its electric Leaf.

Utilities are still figuring out how to coordinate this ballet between vehicle, charger, and grid on a citywide scale. But the payoff could be big, because all those EVs are existing infrastructure that could help reduce the need to build dedicated battery plants to store renewable energy. The less a utility has to build, the fewer costs it has to pass on to ratepayers. And with more V2G, a utility that has to import lots of electricity from a neighboring state can now store power locally. Thus this technology could reduce energy bills. And for participants, their vehicles now provide transportation and energy storage. “It would seem pretty easy to imagine that that’s going to be cheaper than building just stationary battery storage facilities that do nothing but support the grid in times of need,” said Rudi Halbright, product manager of VGI pilot implementation at Pacific Gas & Electric. “Because you’re not getting that secondary use with those batteries. They’re kind of sitting around a lot of the time.”

People are more complicated than battery banks, though. Folks with busy lives want the convenience of charging their cars whenever they like and might not even realize how much prices fluctuate throughout the day, said David Victor, a professor at the University of California, San Diego, who studies the behavior of EV drivers. Many like the peace of mind of having a fully charged vehicle ready at all times. “I take from that that V2G is going to be really, really hard for fleets outside of professionally managed fleets,” Victor said, “that we know reliably are going to be available at the time that the V2G asset is going to be needed.”

Still, given the number of EVs out there, only a fraction of owners need to participate to make a sizable impact. And residential and commercial V2G can complement each other — and in turn, complement a utility’s larger battery facilities — a widescale diversification of energy storage that could accelerate the adoption of renewables. “I fundamentally believe that bidirectional electric vehicles are going to be something that no one’s ever heard of, until suddenly everyone has it,” Rauscher said. “Once we have enough customers enrolled and deployed out there, some percent of customers not plugging in and performing doesn’t really matter.”

“Nissan is the first automotive brand to achieve grid certification for AC-based solution in UK”

MOBILE POWER PLANTS
https://drive.com.au/v2g-critically-important-for-electric-car-adoption
https://designnews.com/mathworks-q-a-on-bidirectional-charging
Electric vehicle batteries can function as mini power plants, providing energy back to the grid when coordinated at scale
by Dan Carney / October 28, 2025

“The growing fleet of electric vehicles has both the potential to strain the electric grid while charging and the ability to stabilize the grid by discharging as needed using vehicle-to-grid (V2G) technology. Modeling the behavior of the EV fleet in these situations is crucial to maximizing the benefit of V2G, so Design News spoke to MathWorks‘s product manager for electrical technology, Graham Dudgeon, to hear how the company’s customers are planning for bidirectional charging to become more widespread.

“Electric school buses with Zum bidirectional charging stations”

Q: What is the primary opportunity you see with regard to charging the EV fleet?

Dudgeon: The number of electric vehicles on the roads is increasing and is expected to continue increasing. Now, the electric vehicle has a battery on board, and that battery must be charged. And so that, that fundamentally, is what must happen for the experience of the driver, [to have a] fully charged battery so they can drive. The battery’s primary value is to propel the car. Now, there is an emerging concern, and that is, if we have an increasing number of electric vehicles that need to be charged, and they act only as a load on the electric grid, then the potential for stressing the grid and destabilizing the grid is there.

So, what we need to do is put our attention back on the battery and think about what its true value actually is, and its true value is as a mini power plant, either propelling the vehicle or providing energy back to the grid. When it provides energy back to the grid, that’s where this notion of vehicle-to-grid comes from, also vehicle-to-home. [That is] a lower scale, but using the energy from the battery back into another system that is not the propulsion of the vehicle. So that’s the concept. Now, where does the value come from? If you think about a single vehicle at a grid level, it doesn’t have much of an impact at the grid level. But when you think about thousands or millions of vehicles, that’s when value starts appearing. But you must coordinate those vehicles. The energy that they are either consuming or supplying must be coordinated. When you think about it that way, all those vehicles become an aggregate energy storage system, a virtual power plant, and the benefit for the grid is that you have a large energy storage device.

I’ll give you one or two examples of where that value comes from. During a typical day, there is a demand on the grid, and at some point of the day, that demand will be quite high, the so-called peak demand can be very problematic. And so, any way that you can bring that peak down, particularly in, you know, those days when it’s expected to be a problem, in terms of stress in the grid. Anything you can do is beneficial. So, when we think about aggregate electric vehicles through a V2G smart system, I think of it as being able to sculpt the grid response, adding and extracting energy so that you can bring peaks down, store batteries up, then have them provide power to bring the peak down. That’s one example. It also enhances what’s called security. Security being if we have a failure of a generation asset on the grid, can we still provide the loads? And if we have a large aggregate storage system, the answer to that is we’re in a far better position to have a secure grid.

Q: We learned about that fragility with the Texas ice storm a few years ago

Dudgeon: I did hear about that on the periphery, but I didn’t study it in great detail. But yes, it seems like a system like this, if it had been in place, might have stabilized things for them. When it comes to the grid, having options, generation capacity, so basically, energy available, and then energy that you could quickly deliver in a very specific way, that’s when you get the benefits.

Q: What are the challenges & obstacles to getting the infrastructure in place that would provide this benefit?

Dudgeon: There are obstacles outside of the engineering. I can talk about the engineering specifically; I think the main challenge is scale. And when we think about scale, potentially millions of vehicles, then the question becomes, “How do you architect the system to be able to coordinate all those devices?” Because there are two things at play here, there’s satisfying the owner of the vehicle. That means charging their battery so that when they need to use their car, they have a charged battery. That’s number one. Secondly, using that battery in that interim period when you’re parked to provide benefit for the grid. That then becomes an optimization problem, a constrained optimization problem, and if you’re working across potentially millions of vehicles, then you’ve got a very large optimization space.

“Nissan Leaf and Fermata Energy FE-15 bidirectional charger”

So that’s one aspect. Another aspect is predicting the behavior of the vehicles when they plug in and when they disconnect. And so predictive algorithms of how those vehicles are behaving at scale are an important part of that as well. So, there are some sort of fundamental challenges, and the first question you need to answer, though, when you’re looking at scale is, “Can this be done in an ideal setting? Do we have the capabilities and the tools?” The fundamental question is, “Can we coordinate these vehicles to provide value?” Once you have that answer, you work towards implementation.

Q: Do we have the answer, and is it “Yes?”

Dudgeon: Stuff I’m seeing, just from my own observations, is that this is incremental. The adoption of the technology, we’re seeing sort of incremental moves towards smart charging, localized vehicle-to-grid systems. I mean, when I say I’m seeing it, it is because I’m reading about this stuff. So, we’re seeing those examples of sort of smaller test cases. This is risk mitigation as well. We can get benefits at local levels. It might be a fleet of buses, for example, that you’re charging in a smart way, that you’re providing energy to buildings locally. But as time progresses, then that scale would inevitably start happening because of technology progression. But how fast it will happen and what form it will take? That’s a difficult one to answer.

Q: Are you anticipating that this would be primarily fleet-owned vehicles or individual vehicles as well?

Dudgeon: I think this would be a combination, from our perspective in MathWorks. When we’re looking at supporting our customers who are looking at developing innovative technology, we’ll support them regardless of the application, of course, whether they’re looking at the bidirectional charger itself and developing that, or whether they’re thinking about the optimization of larger systems at more of a system level. Our objective is to provide tools that can help answer those questions.

“The top assignees to file patents are from China, the US, Korea, and Japan”

Q: It seems to me as if it would be a little easier to get fleet customers to participate with bidirectional charging than individuals, because then you have to win each individual driver over one at a time

Dudgeon: That’s a question I’m not in a position to answer. I look more at the technology, not at the social aspects. That’s not my area. I focus more on technology.

Q: Are there technological challenges for those individual owners with regard to the infrastructure in their own home, getting the necessary wiring, getting the circuit breaker box, any of those kinds of things that you can talk about?

Dudgeon: Yes, certainly charging at home, you don’t have access to high power capability that you would have at a charging station. There would be aspects of that that would need to be looked at. Certainly, when you’re going to the higher-power charging, you’re going to higher voltage

Q: How will that look to the individual owner?

Dudgeon: It’s difficult to see how it will all pan out, but certainly we’ll see the high-power charging happening at the, you know, the EV charging station level. That’s where most of the innovations are occurring in terms of the ability to fast-charge vehicles.

Q: From your discussions with your customers, are you getting any feel for a timetable during which bidirectional charging might begin to gain some momentum and become more widely adopted?

Dudgeon: We are not getting insights into that, but one of the insights that we do have is, for example, one of our customers is Lumen, who we have a customer reference with. They have developed their charging systems in anticipation of the demand for V2G increasing in the future. They’re using model-based design in the development of their technology to be ready for when it happens.

Q: Have you done a model that would show with a connected fleet of a certain number of vehicles, where there’s a surge in demand for electricity, the grid would be some percentage more resilient as a result of having this V2G there?

Dudgeon: I put together some examples of looking at the impact at the grid level. When you are considering a number of vehicles, you know, a few hundred, maybe what that might look like, but very basic stuff in terms of what has to be done. Now let me explain so when we’re looking at our software and how it scales and whether it can provide that value, or we’re looking at stylized examples, so let’s consider we’ve got a few hundred assets that we want to connect to a grid, that we have a certain demand, and that we want to see if that can then benefit the grid in some way.

We can do that, but there is a part of this that’s important, and it’s the design space. There is no single answer to this when you consider all the potential, the permutations and combinations of what can happen. You need to have tools in place that help you explore that design space with confidence, because your design space for V2G systems can be immense, and so the tools in place to help you. The fundamental question is, “Can this be done, and what might our solution look like?” That’s very dependent on the individual customer looking at this. We don’t say, “Hey, this is what this should look like.” We provide the tools which allow our customers to explore that design space and mitigate the risk of what they’re doing so that they have an increased level of confidence with their engineering design tasks.

“Sion Bidirectional Charging”

Q: What other considerations are you looking at?

Dudgeon: We’re looking at the different engineering tasks that must be done with these systems, and it’s quite a broad range, of course, when we’re thinking about charging infrastructure overall, but down with the charging system itself. When we’re looking at the power electronic control designers who are developing those bidirectional chargers, now what they’re fundamentally looking at is, “Can we shape that voltage and current so that we can supply energy and so we can extract energy?”

But there are additional engineering considerations at the vehicle level as well. One of those considerations with the power electronics is “How much loss is occurring?” Because loss is heat. An example of a circuit topology which is quite popular, is a dual-active bridge. The dual active bridge is quite simple in its form, but it can switch at very high frequencies. And with power electronics, the faster you switch, the more the device heats up, because there’s an increased level of switching loss. The design of those power converters necessarily includes cooling as well. And this is going to be the case for a battery that’s acting as a small power plant. It’s going to have to be cool because it’s going to be heating up, whether you’re charging it or discharging it. This is another part of the design space, locally on the vehicle itself, and being able to use simulation as your means to look at the architectures, size your components, look at the electrical and thermal aspects, and develop that electrical and thermal cooling system is all part of the challenge down at the local level. As you go through the whole sequence of events up to large-scale V2G adoption and optimize response, there are a number of engineering tasks involved and a number of engineering questions that need to be answered.

Q: Do you see the increasing use of silicon carbide as an enabling technology for V2G?

Dudgeon: We do see it, silicon carbide and switching at very high frequencies, because it improves the overall response. The higher the frequency you switch at, the higher you move your so-called harmonics up the spectrum, you get much cleaner responses. The price you pay is increased loss, so the cooling comes into play. But then the better you’re cooling, the smaller you could make your power converter. These are all questions that must be answered. And so having a simulation environment enables you to explore all of that, from both the physical components themselves all the way through to the way you’re controlling them.”

PREVIOUSLY