I was on a panel at Electrify Adelaide last week, sat next to Saul Griffith, who was promoting his brilliant new book Plug In. During audience questions, someone asked how important Vehicle-to-Grid (V2G) would be in the years ahead.
Saul handed me the mic. I took a deep breath and said:
“This might be unpopular, but I think home batteries will become cheaper and more convenient than a V2G charging system. That means V2G will likely be niche. Why bother plugging your EV to power your house or arbitrage the grid when you can just have an EV and a big home battery?”
This is not a popular point of view in the electrification community. I braced for a polite roasting. Instead, Saul nodded. He said he liked the opinion. His take: V2G should already be standard on every EV, and bi-directional chargers should be cheap. But they’re not. With home battery prices dropping fast, affordable V2G risks arriving too late to matter.
Saul Griffith, Finn Peacock and a panel of speakers at Electrify Adelaide.
The Focus Should Be Daytime EV Charging
Then Saul made a bloody good point. Australia’s immediate focus shouldn’t be running cars backwards into the grid. It should be ensuring as many EVs as possible can charge when the sun is shining. Too many electric cars sit idle all day without access to a charger, only to be plugged in during the evening peak or overnight. That’s the most pressing problem right now, and it’s so easy to fix.
I agree with Saul. The danger of obsessing over the “perfect” solution: V2G, bi-directional chargers, regulatory approvals, new standards, is we risk overlooking the good solution that’s already here. Mass provision of one-way charging is cheap, simple, and proven. Put chargers where cars sit during daylight hours, and you soak up solar that would otherwise be wasted. With cars sitting idle for hours at a time, they don’t even have to be particularly fast chargers. It doesn’t solve everything, but it solves a lot. And it can be rolled out now.
I turned to Saul and quipped: “So you are promoting G2V!”
Saul laughed: “Yeah, G2V! I knew there was a reason I like this guy.”
That made this engineer’s day. Saul’s a rock star in electrification.
Put Chargers Where They Are Needed
So let’s not let perfect get in the way of good. Instead of holding out for affordable, widespread V2G, let’s simply roll out a ton of basic chargers where cars are actually parked during the day. Let’s get serious about G2V right here, right now.
Phase Shift is a weekly opinion column by SolarQuotes founder Finn Peacock. Subscribe to SolarQuotes’ free newsletter to get it emailed to your inbox each week along with our other home electrification coverage.
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Thanks for clearly stating the obvious. V2G zealots are often too fixated on their own narrow circumstances rather than what needs to be enabled for mainstream relevance. If EV are not charging during the day then V2G can only be a niche, so get on with the virtuous circle of building chargers so that users will charge where their car is parked, not just at home. I’d also say that it needs to be attractive enough from a cost perspective to make it worth the effort. No one will pay 50-70c/kwh when they can charge at home for a fraction of that. Perhaps the ‘slow’ chargers sitting on the transmission network and billing against your home bill at your home rate is the right solution.
Basically, you’d have lots of 2 to 7kW chargers at places like train station carparks. The owner of the chargers would be able to turn them on and off to offer grid stability services and receive payment for offering those services.
Because the charge rate wouldn’t be guaranteed, you couldn’t charge much for the service to EV owners unless they say, opt for a guaranteed charge over the course of the day.
Yes, we need some sort of monetary incentive so that everyone benefits:
1. car park/ shopping centre/ office building owners
2. EV Charger owners
3. Grid/ electricity retailer/ network owners
4. EV owners
5. Software/ app developers etc to tie it all together.
Bringing this disparate and self interest groups together is a big task.
We need Governments (Federal/ State/ Territory and Local) to come together and set the laws, regulations, standards etc for Industry to make this happen.
Yep.
Given the amount of parking lots the previous federal government was famous for installing in key electorates.
It shouldn’t be beyond the scope of the current government to go and put a lot of EV charging stations in those same parking lots – where vehicles are parked all day while their owners have taken public transport to work.
Yep this is a no brainier I have been saying for a while now. Get the rules changed so that DNSPs can roll out out power pole.mounted Chargers and Chargers in industrial estates and car parks near transport hubs – limit them to only 2.4kw output and mandate they can only charge the FIT price + (say) 30%.
The slow charging speed stops them cannibalising fast charging companies and the additional revenue can go to decreasing the daily connection charge for households in that area with a small allowance for increase on RROR
If they CEFC gave them a low Interest loan of $500M that would go a long way to getting this off the ground.
Further down the track as statistics show the uptake increasing they could then come up with a plan to slowly relocate the one way chargers to another location and selectively roll-out V2G so people could opt in to support the grid and get a payback as well in times of need
Craig
What is being suggested here was seen in the film: “Who killed the electric car?” many years back. It showed Californian parking areas with roofs and solar panels keeping the cars cooler and charged.
This is true.
I want to go V2G but a bi directional charger is $6500.
For the same money with the current Gov subsidy I can get another 20kwh on the home battery.
Being retired my EV is often at home during the day so I charge it only when the sun is shining. My 12Kw of panels can run the house, recharge the home battery and charge the car between 9am and 3pm on a fine day. I live in the tropics so have plenty of daylight hours all year. We get plenty of wet days too but I only need to charge the car about once a week so can choose a sunny one.
I agree with the sentiments of this article and it is happening in a few places like a local leagues club which has built some covered parking with solar panels on top and EV charging below. But places like train stations where commuters could park undercover for the day with solar on top and slow charging outlets below could work out very well.
If there’s something EV owners love, it’s FREE EV CHARGING.
It’s the “free beer” of the EV world. There are charging points on PlugShare with low ratings, not because they’re bad, but because they were free for a long time, now their owners had the temerity to start billing people.
So in the spirit of Phase Shift’s “let’s look at this different” focus, I offer this idea: all these daytime public chargers will only work if you get compliance. And nothing drives compliance like FREE.
(Make it paywalled: you can plug in and get FREE but at minimum power. And only enough to soak up excess solar. If you do the log-in-via-the-app-and-scan-the-code dance, it turns to a regular full-power commercial charger. Would be better if we had plug-and-charge tech for L2 charging…)
Yep couldn’t agree more. V2G is to late and to expensive.
My next vehicle will likely be an EV. My commute is a round trip of 180km. Having destination charging during the day would be perfect.
(An electric motorcycle with a range of 300km would be better).
We have a car park at work filling with EVs at an ever increasing pace, with electricity everywhere but almost nowhere to charge. The building owner, a very prominent player in the industry and who promotes its EV charging chops does provide electric scooter EV charging but only car charging on a case by case basis.
They could be waiting for numbers to hit a level where the work of an electrical study and procurement and pricing makes sense, but charging infrastructure seems to be a “build it and they will come” type phenomenon. I can see pricing based on what I know they will be paying which will be a very attractive price at which to charge and which would see a positive return on investment after just a few years.
Workers might even choose to pay for the installation of a charger at work rather than at home. That would actually make more sense for them.
Makes a lot of sense. Solar FIT is routinely negative now, and even occasionally negative to buy. Adding more already worthless solar to the grid without batteries to soak it up is pointless. Furthermore, a car might then manage a few days use when the weather goes bad – a better option than grid batteries that last a handful of minutes.
DC chargers take input (pretty much….) directly from the PV arrays and dont tax your inverter on the way through to the car. For most people a 7kw AC charger doesn’t leave much left over from the solar inverter for the house to use while its doing its thing flat out in the middle of the day when the sun is shining. for me, with a BYD shark I can also do V2G (sigenergy stack) should I need to and the car has the ability to charge itself via petrol motor if it needs to.
For a repeat of QLD Alfred type event that gives a fair bit of flexibility that an AC charger alone does not. When Alfred was close to shore then most PV solar systems that would delivery normally 10’s of kw of PV panel power struggled to produce 1kw of power… building redundancy costs $, always has, always will, to me growing potential avail battery capacity at home by 30kwh of self charging battery was worth the extra few $k.
The BYD charger that came with the shark is only capable of 1300w…that’s a travesty!!!
My take on this is a little different. I agree that we should soak up as much energy during the middle of the day, but I feel V2G is also a resource.
I live on a rural property, so V2G could be an important backup for times of crises (such as the ´22 floods in Lismore). Personally, I am waiting for a reasonably priced V2G charger, which I feel should be $1500>$2K. All these chargers are is a hybrid inverter & interface electronics + local compliance. There is even a project on Open-Inverter where one was built in Germany (not
applicable to Australia except possibly for off-grid)
Another application I can see is small business: a V2G backup would suit this application & could also be used for Maximum demand control.
So, my take is that V2G might not be economical as a VPP (where the price will reduce as the peaks are eventually flattened so the Generators gaming might stop) but as a backup, better value. Batteries will need to
reduce in price to be competitive to Batts on wheels!
Spot on, Finn!
It would seem to be a growing experience. Of the 9 MWh produced here in the last 18 months, 2.9 MWh went into the BEV.
It’s as I wrote in Issue 170 of Renew magazine (Jan-Mar 2025): ‘Even a modest MG4, doing only 15,000 km per year, “exports” around 2.5 MWh per annum in 100% fossil fuel displacement, and therefore CO₂ reduction.’
That was an underestimate, overlooking charger losses and the amount of highway driving I’m doing, with just 13,200 km consuming the 2.9 MWh of pure photon energy.
Grid migration to renewables is exponential, commuting not. One brother’s family drives 5 ICE cars, no BEV. Swap just 1 to BEV in 10 million families,
& national emissions drop. Mine are negative. (See the article.)
Before too long, my 46 kWh battery will be middling. Even off-grid, V2H is not needed here. On-grid; very dubious.
BEVs & chargers are the most urgent area for moving from endless talk to acute action. Both drivers & governments are asleep at the wheel.
Hi Eric,
These engineer types might catch up with the electricians one day. So far they’re only two years behind.
We’ll have to talk to these characters and get them up to speed 😉
Schools seem to me to be an obvious place to install panels and chargers. High ratio of roof area to cars. Typically moderate commutes. Just for staff. Lots of schools to get economies of scale. Help to retain staff.
Yeah there is electricity infrastructure everywhere in cities. Retrofit chargers into power poles etc. charge anywhere.
Be careful when people talk of spot electricity prices being negative in the middle of the day. While it is true that they are in “essential energy” country if you partake of those negative prices you get the electricity for say a 2c credit to you, but then you get to pay for all the other entities that want a piece of the action…your credit quickly turns into a substantial debit.
For me i get to pay essential energy about 7c per kWh consumed, no matter the spot price. There’s also gov environmental levies per kWh… localvolta gets a piece of the action wethwer buying or selling…
Never have i paid so.much for something that was supposed to.pay me….
..
I’m still having trouble visualising how this would work. Are we saying that parking stations should have EV chargers in every parking space? Or would there be a limited number and first come, first served (and hopefully an ICE car wouldn’t take that valuable parking space).
“Put chargers where cars sit during daylight hours” – it’s a nice idea but wouldn’t that then lock up that charging space for the whole day while the owner is at work.
I’m interested to hear more details about how this might be organised.
Hi Alan,
If you talk to people in cold countries like Canada, they have been plugging cars in for years.
At low temperatures oil thickens & makes cars hard to start. When it’s well below zero the coolant in a combustion engine can freeze and literally tear the engine block apart.
To prevent this they run a heating element inside the engine, which is plugged into a standard 110Vac outlet.
Car parks are full of them.
Unlike the peasants of North America, we can have 10a @ 230Vac for 2kW charging, enough for 100km of driving after 8 hours plugged in.
I love this comment. There is so much expectation that “industry” rolls out charging. And they should, but wiring for 2kW isn’t asking for anything much more than a standard GPO is it?
Consider a factory with parking for 120 cars in 6 rows of 20 parking spaces. Free charging for all staff and visitors via a post between 2 rows able to serve 4 cars with 4 GPOs. 30 charge posts each on their own 40amp circuit serving 4 vehicles. 100 metres of standard 40 amp 230 volt cable plus a distribution board would cover 20 cars for the first row and repeat for each of the next 5 rows as demand requires. CHEAP.
A similar outdoor council or railway car park same infrastructure cost but energy cost recovery would be included with parking fees.
Businesses that don’t have problem finding employees might charge for parking and energy. It would probably be fairer to supply each row in turn every 30 minutes or so to equalise supply if energy is varied due to supply or conditions.
OK, thanks for the clarification. I was imagining big charging stations like you get on the road. But if we are talking more like a bunch of GPOs then I can see it being quite feasible.
It was good discussion. Rather than holding out for something that isn’t here, let’s just make good use of what is here
We have just ordered a large home battery and at 48kWhr it is larger than the one in our electric car. We won’t have or need V2G, although we could have used it if the car supported it (Mini Cooper e) and chargers were available (none approved in SA yet).
V2G, rechargable batteries and thus EVs have a life measured in charging/discharging cycles. Why would I increase the cycles of my EV without being paid for it?
Help save the world perhaps? A kWh at a time? Why is it always about money? Show some community spirit.
Yes, V2G always sounded useless as EVs come home after sunset needing to be charged.
Unless you can charge at work and come home and charge the house. 60kWh battery using 10 to get home, 10 to charge it through a ToU peak 50c/kWh tariff, 10 to get back to work, repeat. Using otherwise often curtailed daytime renewables to fuel an otherwise fossil fueled car to delete some evening peak demand while saving someone money.
Not my circumstance, nor yours by the sound of it, but for those who can, it is all part of the puzzle.
Finn’s thrust doesn’t devalue V2G, it just makes a point that V2G futurism mostly leapfrogs. We have daytime utility renewables being curtailed that could charge the entire current EV fleet, which is an entirely doable challenge of today. And Anthony Bennett’s (knowledgeable SolarQuotes author) comment here points out the technical feasibility. It doesn’t need to be much more than basic powerpoints wherever cars are in the day. Ubiquitous 2kW charging (like a kettle might draw) would do it.
I’m banging out a whole article about it OB 😉
Can you point me towards supporting evidence that Home batteries are getting cheaper? I can buy a BYD for $60k and a 60kwh battery. 60 kwh of home battery would cost me $60k ??… Using V2G seems the winner in that equation even if i just parked it permenantly at home.
A) You wouldn’t get a 60kWh home battery; and B) even if you went for a beefy 30kWh, it is currently around $500/kWh installed (and not $1,000 as per your estimate which was about correct about a year ago – I could point to my own recently paid invoice for supporting evidence).
Currently the price drop is mostly about the government rebate, but the consequence is also huge volumes of sales and confidence that this will bring unsubsidised prices down such that we should see $500/kWh or less even as the subsidy per kWh decreases over the next 5 years.
That said, your point about the relative low cost of batteries in EVs still stands. Putting cells with prices of perhaps $150/kWh into EV batteries that come out at maybe $250/kWh is at the leading edge of battery innovation and competition. And it has been an annoyingly long wait to see that innovation cross over into home batteries. But it is on the way.
V2G makes sense when the overall cost of the EV and V2G infrastructure is less than a equivalent sized stationary battery.
Instead of lowering the price of a home battery, the market response is to increase the V2G component.
Even basic EV AC charger units are over the top price wise, the electronics from the charger is there to set up the top limit of power to pull from the connection, possibly with connect and disconnect the AC power.
A smart wall outlet power meter is under $20 a unit.
A portable EV charger is $250 from Bunnings.
Both plug into the regular wall outlet, both have micro controlers and both support a 10A load.
The difference is the programming knowledge to communicate with the car and the the connection on the car.
The discussion on EV and home batteries always ends up with where the money goes when buying. It’s good when China buys lithium and iron from Australian mines but if we buy the cars they make from them, it’s not?
Where is the Australian built EV?
Finn, if you were trying to make us think, with the pointed understatement; “they don’t even have to be particularly fast chargers.”, it’s slowly percolating here that a 7.2 kW Level 2 charger is a tiny fraction of the cost of a fast charger, so can be lamp-post-proliferated, to serve multitudes, hands-off during the day, when the cars are unused, PV overflows, & the grid needs load.
A phased joint venture with city parking could begin with a row or two of L2s, charging the customer & pocketting any negative tariff, to speed expansion. And a generous employer tax break could put a row of L2s in corporate car parks, with the modest charge rate lowering cabling & switchboard costs.
In a decade, at +2°C, it will likely become mandatory impending-crisis amelioration. Pro-active effort is cheaper, and normalises behaviour by degrees, before decrees are needed.
A silicon foundry is a longer term good. Mass grid-friendly EV charging can yield now & help fund the vital transition.
Yes I agree V2G is just a distraction in general. Sure, there are some valid use cases but it won’t become widely adopted for the many reasons already mentioned.
The question is how do you get those cars parked at workspaces to suck up the excess solar from the grid during the day? Drivers who can’t charge at home will be grateful for the opportunity, but those with chargers at home will only plug in at their workspace if the price is lower than at home.
So if you’re going to provide very low cost charging at workspaces, what’s the incentive for the property owner to install and maintain the chargers? Sure you can subsidise or even fully underwrite the initial capital outlay, but I wonder if that’s sufficient? The property owner still has to operate the chargers without making a loss.
None of this is helpful to the grid when the sun isn’t shining – isn’t that ultimately the point of V2G?
It should be pretty cheap to set up a line of 10amp car chargers that slow charge for the daylight hours at 2Kw/hr.
Could be at workplaces or railway stations etc. Anywhere EV’s are likely to be parked all day.
Maybe users could pay a small fee eg $5 for a covered all day parking spot which also tops up your car.
I bloody love it, G2V as a hype acronym, hope it catches on (and putting it in Saul’s head and your platform may well do that).
As we enter spring especially, it looks a lot to me that the charging requirements of the nation’s entire EV fleet is currently being dwarfed by curtailed utility RE.
Maybe we could add “G2B”, open up the battery rebate to non-solar homes and let them disappear from peak demand using cheap daytime solar?
Are home battery prices “dropping fast”?
Ignoring the subsidy I’ve not noticed any dramatic drop in prices
A Question.. (not sure whether this has been answered before…)
Does, say, 10 Kwh of electricity generated by Solar input into a solar battery as 10 Kwh or is there some loss in the conversion from the current generated depending on your string or micro inverter for that conversion?
If there is a loss from generation to input to the battery, what is the percentage of loss?
Hi Christopher,
Round trip efficiency is the term you’re looking for. A battery that’s charged with 10kWh of DC solar might only return 9.5kWh due to heat and chemical action.
Once fed through a 95% efficient inverter to power your house, there’s another 5% conversion loss, plus heat in the wiring & the appliance efficiency itself.
Any time you convert from DC to AC or vice versa, there will be losses, but seeing as the energy is free, it’s not a big deal.
Have a look here for more and remember that AC coupled systems aren’t always as efficient but some losses can’t be avoided.
I’ve always figured on an average 5% loss in each conversion, just as Anthony does. But for fun, I’ve just looked at the history on my battery’s smartshunt, and over the last 18 months, 2558.9 kWh went in, and 2334.6 kWh came out. That’s a battery round trip efficiency of 91.2%, 4.4% loss each way. Add 5% MPPT/charger loss and 5% inverter loss, then around 81% of the photons hitting the roof get to warm my toes via the RCAC at night.
That’s not as efficient as running appliances straight off the AC during daytime, but no known energy storage is 100% efficient. Consumption here is 74% direct use, with no battery loss, so it’s insignificant, really.
My 46 kWh battery is big enough to supply night demand despite a few losses, and the fuel is cost and emissions free, so battery capacity is the only critical measure, given 27 kW of arrays. Losses do warm the equipment room a bit – handy in winter. YMMV
My BEV charging is AC-coupled, daylight charged, so only BEV battery loss involved.
P.S. Apropos vehicular stored energy efficiency; an ICE car has around 70% losses, utilising only 30% of the fuel energy – rather like a coal-fired power station’s global average of 33%.
That’s why the world only needs one third of the wind and solar energy, compared to the fossil Scheiße inefficiently burnt now, to power the planet.
Why have we not evolved to live longer? Quicker turnover should help us adapt, discarding fossilised thinking a bit faster, perhaps. (Just not remotely fast enough this time round, the evidence shows.)
The real interest I have with my EV is to be able to power my house without the grid. I’ve got 64kwhs of power in my garage that I can’t give back to power my 20kwh of daily use (2019 Kona) I don’t know how the logistics work doing this.
But of course this will put grid infrastructure at risk of not existing anymore. So that’s never going to work.
Given that we now cannot even get quotes for the bigger behind the meter BESS’s, the feral government should be adding BEV’s with V2G and V2L with capacity of at least 3.6kW, o the SRES scheme, the same as for the household behind the meter BESS’s.
And, given that, if a single phase household has a behind the meter BESS, instead of demanding free public BEV chargers, when the 7kW single phase chargers are not appropriate for single phase households, why are these people not advocating increasing the capacity on all of the electricity grids, for single phase hybrid inverters to match the electricity grid fuse for single phase grid connections – instead of the 40A inverter capacity, why is it not 63A? If a single phase 10kW inverter is supplying power for the household load, and, charging a behind the meter BESS, there is no point in having a BEV charger with capacity more than 3.6kW; a 15A plug in charger. Where is the extra capacity, to charge a BEV at 7kW, a BESS, and the house load?
Ok, so the following applies to those who have an EV. Better if you have an EV and a home battery.
As soon as I take delivery of my first EV soon, I’m going to have OVO (AGL owned) as my retailer.
They have THE BEST G2V rate on offer NOW!!! $0.00/kWh between 1100 and 1400 daily – rain, hail, clouds or shine. (Yes, I know there are other retailers, that offer the same, which is GREAT) OVO also offer 8c/kWh between 0000 and 0600 daily, in case you need cheap grid power to top up your battery or batteries or for wanter you want to power from the grid during that period.
So G2V IS a ‘thing’ and as all EV manufacturers are very hesitant to offer the full V2X from their batteries (I can understand their hesitation – never meant to use the EV’s battery in that way), I decided to install a fairly large home battery (25kW/48kWh) as my primary and only battery to power my home.
They usually charge $20 an hour for 50 KW, $2 to $3 an hour here in Canada for 7 KW, and nothing for 125 volt x 12 amp. Or about 60 cents per KW-h for higher rate DC fast charging.
A third of Canadians live in apartments without access to plugins, nearly another third park on a street and can’t legally string a cord to their car.
People aren’t going to pay the extra cost for an EV and be happy about paying as much or more than fuel, for electricity. Solar + daytime charging ay work will do the job here at 51 degrees latitude for 8 and sometimes even nine months of the year.
Randy you have my sympathy,
It must be difficult being tied to the US. I see switchboards the yanks proudly install for “200Amp power upgrade” on houses, and marvel that it looks state of the art for the twenties… they get upset when you clarify it’s the 1920s. O.o
Electrification is going to be difficult with 110Vac. It’s glorified garden lighting compared to the 2.3kW rating of every outlet in Australia.
The majority of EV owners here manage with a standard home power point, but we need many more of them accessible from the street during the day.
Every North American pamel is 240 volt (mine showed 253 when the Sun was up and the panels had no snow. That’s 50 KW.
The supply is also center tapped, with the center tap connection grounded at the house panel, so a pair of 125 volt strips of opposite phase. Which is for historical reasons that relate to lighting bills and sewing machines in the 1800s.
Kitchen plugs are often 20 amp breakers x 125 volt, so 2.5 KW, 2 KW continuous. Stove plugs are 40 A x 250 V, so 10 KW.
There’s enough capacity in our panel to tap 60Ax250 V for an EV plug. But I’m waiting to see what the solar installer needs for 15 KW on the roof. In other words, I’m too cheap to bother, the 1.4 KW plug works and thete’s a 50 KW plug 1 KM away.
I work at a number of hospitals and several years ago they all banned charging from the GPOs which already exist in their carparks. Most have de-energized them and others padlocked them. I particularly miss them now I have moved out of town and my round trip commute exceeds my BEV range – a few hours at 2kW would get me home. It would be no great technological feat to create a smart plug with OCPP which billed me for the power consumed – preferably at the rate I would be paying at home – and enabled smart curtailment when required. @Rather Not Say identifies the major impediment: lack of policy.
Hospitals in Alberta, Canada charge $2.50 per half hour for parking to a $15.00 daily max.
It shouldn’t take much planning to have EV stalls that cost $3.50 or $4.00 per half hour in an EV section. And if people park there without charging, just pocket the extra.
7 KW charging here is usually $2.00 to $3.00 per hour if you’re plugged in. Some avoid that by just parking without plugging in, so I think it’d be better to charge by the slot.