V2grid (Vehicle to Grid) and Tesla

[WannabeOwner]

If your socket shows voltage drops and your car has a temperature sensor feeling warm ambient air, there is a good chance the grid needs your power. If socket drops below say 118V, then "output". If it is above 120V, then "charge" cells. Doesn't need extreme amounts of smartgrid standards and protocols. I just charge my EV at night, 3am to 7am for the most part.

I could do a lot dumber than that even! We have off-peak electricity here 00:00-07:00, I could discharge Tesla from when I return home if the solar panels output is off/low (overcast days / later in Summer than Winter) provided some conditions are met e.g. SoC > 30% and time between 6PM and midnight, with the ability to say "don't do it" because I am planning to take the car out later.

We already have timers on white-goods and hot water immersion to run overnight so that they use spare generating capacity instead of peak. I'd be very happy to extend that to other things - such as discharging Car Battery into house - if the car had that facility

 

[Tedkidd]

So this question was brought up again today during the conference call, discussing the offer to acquire SolarCity. Elon reiterated the reasons listed above.

It seems like they're really not interested in doing this for the foreseeable future, but I would love to be able to use my Model 3 as a emergency backup.. not sure I'd want to use it more frequently than that.

So how much would you pay for this thing you wouldn't use much, if at all?

Would you pay $5000 for the car upgrade, inverter and all the wiring and interconnect?

Why not just get a powerwall and open the opportunity for getting paid for all types of grid services?

The car battery is for mobility. If you use it for your house, how will you get around? If you have extra capacity for traveling, you can potentially get "paid" by not charging during a grid peak event.

 

[bonaire]

The right solution is all public EVSEs eventually allow grid-operated signalling for some frequency-response technology, paying for the service of doing that. Say signalling superchargers to dip their charging speed 20% during a grid peak in CA, having a car at a workplace output at 2KW during 3pm-4pm as long as there is a full battery to start from, allowing cars parked at the movie theater to maybe even power the movie theater. There are all sorts of ways to make V2G and V2H work - not just for standby power. A smart grid and a set of algorithms and compliance payments would make it work. Now, how high a compliance payment? That's the thing - if we pay for the car features, then the payments should be high. I say make V2G and V2H free. Make the payment go to the technology company that builds that out instead. If all our cars (EVs and EREVs) were able to produce outbound power (either signaled by grid for payment or just on our own using an inverter at say a campsite, or other needed power situation) then having that extra value in cars makes them far more lucrative to a buyer who is moving from ICE than just "oh, it's just another car with slightly different fuel source".

V2G inclusion would draw in EV buyers in droves to have a car that could power your house. People buy Generac generators for the "very occasional" emergency and shell out $10k at a time for a whole home generator that is used maybe 4-6 short times a year, and once for a few days every decade. They will pay service fees to annually service the generator, burn fuel in "test-runs" and so on. EVs are a clean generator (a source of power) and thus are far more beneficial than buying a Generac. When you put your car on the regulated smart grid, then you also can take payments back from the distribution companies as well. If you want to consider EVs as "the future" this type of thinking really has to be part of it. I look at it as you won't have one EV and one powerwall. A family of four eventually will have four cars. At some point in time, someone is home. You aren't trading off a powerwall for a car as a battery-source - you have a fleet of EVs at home as the family car situation changes from ICE to EV. If one goes off to work and the other stays home, your standby battery is still there. If that person goes shopping for a few hours and the power goes out, then not a big deal, when they get home and plug in, power comes back on. If both are working and nobody home, then power could be out or supported by solar + power wall, whatever. But if the family of two is a two-worker household trying to pay for all the goodies of the house through dual incomes, maybe they need to think about what really they are doing. Are they living to work - or working to live.

 

[arnis]

But you have to buy a DC to 3-phase AC inverter instead of generator. Which cost more than generator itself per kW.
EVSE's can't send power back to grid.

 

[bonaire]

But you have to buy a DC to 3-phase AC inverter instead of generator. Which cost more than generator itself per kW.
EVSE's can't send power back to grid.

Maybe 3-phase in the Euro-region but here in the USA, the simplicity of two-way inverters is actually somewhat straight-forward. If a high-voltage powerwall can work with the Solar PV inverter from SolarEdge, a car could also. They are nearly the same voltage. Hybridized powerwall homes area already setup which offer instant standby-power after a grid failure with Solar PV power continuance which goes both into the home load and into the powerwall to charge. This can and should be extended to cars - whether Tesla does it or others. GM has been working with V2G and V2H solutions for a number of years (I hear from someone) and thus they may "lead" into this area once they get all the planning figured out. It's multi-faceted as the grid providers do need a way to signal downstream to do load management in this way. Grid and EVSE makers and Car makers and Solar PV inverter makers all have to "make it happen" as a group

 

[arnis]

It's not reasonable to care what GM is working on. Toyota has worked on hydrogen vehicle for years. So what?
Some people work on finding aliens.

No, car can not work like that. Charger is not the same.
Elon has mentioned many times Tesla cars will not be used as V2G V2H devices. I agree with his reasoning.
PS, it's even mentioned in the vehicle manual.

Oh and you also need a device that isolates grid from home.

 

[Drax]

So how much would you pay for this thing you wouldn't use much, if at all?

Would you pay $5000 for the car upgrade, inverter and all the wiring and interconnect?

Why not just get a powerwall and open the opportunity for getting paid for all types of grid services?

The car battery is for mobility. If you use it for your house, how will you get around? If you have extra capacity for traveling, you can potentially get "paid" by not charging during a grid peak event.

I’d easily pay $5K, maybe even $10K, simply because I would have no need for a powerwall since I’d have a 75-100kW portable equivalent in the garage already. Hook me up with some solar panels to power the rest of the house and charge the car, and we’d be golden.

 

[RandyS]

Why not just get a 12 volt to 120 volt DC to AC inverter and use that to power stuff in the home on an emergency basis? A thousand watts or maybe a couple thousand watts...For a couple of hundred bucks on Amazon, you can get a relatively high powered unit that you can use to get the job done. Assuming it's for emergency use, you wouldn't be using it that often. You'd have to pre-wire an easy method of connecting it to the 12 volt battery...Doesn't seem that difficult to do...

 

[eml2]

I don't understand why all the sudden people are interested in using their EV's battery to power their homes, but no one talks about adapting their ICE car to power their homes? Just because EV has a battery doesn't mean that it can be used to power the home easily, just as ICE has an engine and alternator doesn't mean it can be easily functioned as a home generator.

 

[bonaire]

Why not just get a 12 volt to 120 volt DC to AC inverter and use that to power stuff in the home on an emergency basis? A thousand watts or maybe a couple thousand watts...For a couple of hundred bucks on Amazon, you can get a relatively high powered unit that you can use to get the job done. Assuming it's for emergency use, you wouldn't be using it that often. You'd have to pre-wire an easy method of connecting it to the 12 volt battery...Doesn't seem that difficult to do...

Running a 1500W load off a 12V battery equal...125 Amps. A 12V just isn't meant for this. I have run a 900W load off my car's 12V before and it's fine - but what the real need is a balance load of say 1500-2500W running appliances and lights while re-loaded by a Solar PV array during the day. It's the way it should be - but won't for a few years until the car makers and solar PV inverter folks work together to make a standard. Then it will be commonplace and a very desired feature of EVs.

 

[bonaire]

I don't understand why all the sudden people are interested in using their EV's battery to power their homes, but no one talks about adapting their ICE car to power their homes? Just because EV has a battery doesn't mean that it can be used to power the home easily, just as ICE has an engine and alternator doesn't mean it can be easily functioned as a home generator.

Entirely different. Running a generator in a car produces gases and overheats engines. Not proper for close-proximity to a home. EV can be recharged by a local Solar PV array such as the wall with the SolarEdge inverters. This EV can act as the battery store for a Solar PV and can allow a house to run entirely off-grid (hybrid temporary or even fully). Drive to your mountain cabin, plug in car and you have a 24x7 power system. When done, unplug, and go home. Drive to a campground and power-up lights, cooking, etc. Come home and now your one or two EVs acts as a home's local smart-grid battery buffer and can react to grid signals to help out the grid by lowering the house's demand load. Lots of options you cannot do with a gas-gen car in place of.

 

[ItsNotAboutTheMoney]

I don't understand why all the sudden people are interested in using their EV's battery to power their homes, but no one talks about adapting their ICE car to power their homes? Just because EV has a battery doesn't mean that it can be used to power the home easily, just as ICE has an engine and alternator doesn't mean it can be easily functioned as a home generator.

There are several reasons:
- EVs don't have concerns about exhaust gases, so could be run in a garage.
- EVs are already plugged in and have high-power AC-DC conversion. The thought would be to reverse it so you can have DC to AC with reasonable output.
- ICEVs generally would be lower power since the alternator is just to power some 12V electrical systems. Perhaps when 48V becomes the ICEV standard voltage, and higher power demands are the norm it might be considered a bit more.
- Dedicated ICE generators aren't that expensive.
- EVs would be much more efficient as back-up since it'd just be a round trip. V2H wouldn't just have to be for emergencies.

 

[eml2]

Entirely different. Running a generator in a car produces gases and overheats engines. Not proper for close-proximity to a home. EV can be recharged by a local Solar PV array such as the wall with the SolarEdge inverters. This EV can act as the battery store for a Solar PV and can allow a house to run entirely off-grid (hybrid temporary or even fully). Drive to your mountain cabin, plug in car and you have a 24x7 power system. When done, unplug, and go home. Drive to a campground and power-up lights, cooking, etc. Come home and now your one or two EVs acts as a home's local smart-grid battery buffer and can react to grid signals to help out the grid by lowering the house's demand load. Lots of options you cannot do with a gas-gen car in place of.

That is exactly my point. Just because an ICE has an engine and can produce power doesn't mean it is suitable to work as a generator. The battery in the EV may not be suitable to power a home. Even though an EV already has a high-power AC-DC inverter, it is probably not suitable for home AC. You can always design some equipment to make it work. But then, why not use something that is probably designed for the job at hand. Powerwall for home and leave the battery in EV for the car.

 

[WannabeOwner]

why not use something that is probably designed for the job at hand

The first thing I wrestle with is "Why should everyone have two batteries", seems very wasteful / expensive to me.

If what we want is to time-shift the peak load then when I come home in the car early evening during Winter (max load here), discharge the car for a bit, and then recharge it overnight using spare load. Even if I have a house battery then House + Car is a much more significant resource to supplement the grid

That fits nicely with the fact that I have sized my battery big enough for regular longer trips I take, thus it has plenty of spare on a normal commute-day. Especially if I charge at work, as well as overnight at home.

But the flip sides that trouble me are:

My EV car isn't at home - Wife has taken it. I suppose that's actually not entirely correct. If each person in the house has a car, then anyone at home has an EV Battery available to be charging-from-solar or discharging to supply the house.

Here in the UK we have a good national grid, so I tend to think that batteries are not the solution (until we have an excess of Renewal Energy during the day that we need to store; we aren't there yet), so my solar panels can export to grid, and charge my car (e.g. at work)

But the killer for me is: I won't own a car in 5 years time, I'll just hail a ride, so no point putting all that infrastructure in for V2G (at home at least) 'coz there won't be a BEV parked in the drive / garage.

I've seen chatter that maybe Tesla are going to use the Semi batteries to "transport" power and discharge to grid at peak-load time ... if all the cars are Autonomous and have all gone somewhere to plug in when not in use then the whole fleet could collectively discharge during peak-load.

(where is that huge open parking/charging space? - maybe one of them will stop on each person's driveway to charge?!!)

 

[Schumpeter]

That is exactly my point. Just because an ICE has an engine and can produce power doesn't mean it is suitable to work as a generator. The battery in the EV may not be suitable to power a home. Even though an EV already has a high-power AC-DC inverter, it is probably not suitable for home AC. You can always design some equipment to make it work. But then, why not use something that is probably designed for the job at hand. Powerwall for home and leave the battery in EV for the car.

Agree with your point here. Off course there is some financial value in being able to also discharge, however it is often not worth all the hassle it takes to enable this.

I have seen a lot of examples from Nissan and Mitsubishi who support V2G and this always requires comprehensive DC based chargers which are very expensive....

 

[Tedkidd]

This seems a discussion between children and adults.

The children like shiny toys, possibly nearly useless and with no market appeal that justifies.

The adults suggest you have a car so it'll be a car. Using it as backup for your house takes the car part OUT OF SERVICE.

The car part means all the infrastructure lies useless when you use the car, so it's not earning its keep providing paid services to the grid.

So it sounds "neat" is not good enough value justification when it comes to spending real money. Some children will do it, but the early majority will have no interest, thus the cost of development can't be spread enough to make the product viable.

The economics simply don't work. And the battery portion of what is required is becoming so cheap that the main argument of avoiding battery cost becomes silly.

 

[bonaire]

This seems a discussion between children and adults.

The children like shiny toys, possibly nearly useless and with no market appeal that justifies.

The adults suggest you have a car so it'll be a car. Using it as backup for your house takes the car part OUT OF SERVICE.

The car part means all the infrastructure lies useless when you use the car, so it's not earning its keep providing paid services to the grid.

So it sounds "neat" is not good enough value justification when it comes to spending real money. Some children will do it, but the early majority will have no interest, thus the cost of development can't be spread enough to make the product viable.

The economics simply don't work. And the battery portion of what is required is becoming so cheap that the main argument of avoiding battery cost becomes silly.

The point for a family is to have multiple EVs. While one or more are plugged in they provide the two-way power solution for the home. One drives off to work, you still have the utility. The thinking has to go past "a family has one EV". We know of many EV "families" with multiple Teslas in their garage, correct? A home needs a lot of power and a Solar PV solution with multiple cars offers a pool of power solutions including Grid, Cars, Solar PV. No need to go "off grid" - because there will be times when you need the grid for backup on cloudy days where the cars all need to be charged, perhaps (a busy weekend or whatnot). Some have even called for "a pool of cars sharing their power to re-charge another car" such as how a parallel battery set works (they self-balance across the parallel set).

The idea here is this. If a family is going EV, then they will have 100s of kWh of battery in the cars in the driveway/garage. In this case, it dwarfs the battery capability of the 15kWh or 30kWh 1, or 2, powerwalls dedicated for power. Can a home live with 2 powerwalls? Maybe, but not enough to run larger McMansion 3000-5000+ sq ft homes, those with pool pumps, etc. Those need 200kWh of standby power to maintain lifestyle of multiple kids and so on. With enough cars in the mix, you could even run a home's AC off the cars during a short-term power outage (summer-time rolling-blackouts as PG&E suggests).

 

[Ampster]

With enough cars in the mix, you could even run a home's AC off the cars during a short-term power outage (summer-time rolling-blackouts as PG&E suggests).

I have mixed emotions about the benefits of V2G. The hardware to do that is not simple and of unknown cost at this point. I like the concept but I also plan on driving my Teslas for as much as 8 years and I don't know what using my car as V2G would do to the warranty or the life of the battery. Our situation may be unique in that we both may be gone during the day when I would want to get the benefits of a peak shifting solution. We don't have a Powerwall but a similar hybrid inverter that is powered by some used Nissan Leaf batteries.

I also understand that the chemistry is slightly different between the cells in a Tesla vehicle and the cells in a Powerwall. The vehicle batteries are optimized for driving that occasionally needs large surges of energy. The Powerwall doesn't need to produce that large a surge compared to its capacity so the chemistry in the electrolyte is different. That is why I can use some Nissan Leaf Modules that have no longer have usefulness in a vehicle but work in a stationary power application. I expect to get another year or two out of the Leaf modules and will replace them with Tesla modules which are increasingly becoming available. I realize my solution is more DIY than most people would want.

 

[bonaire]

The DC/AC inverter to do V2H is already within the PowerWall. It wouldn't be too hard to just take the battery source out of Powerwall and make it a stand alone "connector" to the car - an HPWC-2H.

Powerwall uses a high voltage battery set and presumably high enough that it "mimics" the voltage in the car, so it would be assumed that this isn't too hard to do. Mix in the SolarEdge PV inverters and you have V2H done well. By making your car a "PowerFloor" or whatever you could call it, it becomes more valuable. A used Tesla at $35k now is worth roughly $40k to 45k because it replaces a powerwall or a Generac generator in function. if you have a vacation home and a regular home, you could install the adapter in both locations allowing for standby power wherever you are. I don't see why people have a problem understanding this value-add a V2H offers. Probably because the grid is so-very reliable. The fear pushers who want to "get off the grid" are missing the point of the largest machine in the world - the national power grids of North America that are near 99.99% uptime to all locations, save for things like PG&E wiring-induced fires or lightning storm issues.

 

[Ampster]

I don't see why people have a problem understanding this value-add a V2H offers. Probably because the grid is so-very reliable.

It is not a problem understanding the value proposition that you see. In my case my grid is not reliable and I have have put more value in having a standalone Powerwall like solution that will power my home when i am away. I dont want to arrive home to find the food in my freezer has spoiled because my car wasn't plugged in.. As you mention the DC to DC converter and the modulating AC inverter that could control a grid tie inverter are already in the Powerwall. Most of the software is already written. Technically it is feasible. The real issue is that at this time, Elon Musk doesn't see the value. Perhaps he doesn't want to cannibalize sales of Powewalls or figure out the impact of V2G on the warrant of the vehicle battery. I think the length of the battery warranty is out of his control because the government dictates that.

I am sure he has a simple answer. Perhaps a third party will come up with a solution for 8 year old Tesla's that are already out of warranty. Used Tesla batteries from wrecked cars are finding their way into systems that emulate Powewalls but so far they are mostly DIY.