V2grid (Vehicle to Grid) and Tesla

[ThosEM]

The forum contains not a single reference to V2grid so I'm starting a thread on this. Can anyone answer my question as to why Tesla doesn't support the use of car traction batteries to power a home or external gear on an emergency basis? Let's not focus on the temptation this would create to shop power from a free supercharger and bring it home. That would be quickly eliminated if Tesla charged for supercharging at power cost. What is the bigger picture here and what are Tesla's main considerations?

 

[miimura]

In my mind, Vehicle to Grid is inherently not an emergency situation and is usually used for grid stabilization or peak shaving. The separate term Vehicle to Home is usually understood to be applicable to emergency outages.

Tesla is understandably not interested in V2G since it is addressed by Tesla Energy. Tesla will probably only do grid interactive charging, which reduces charging current to relieve stress on the grid as needed.

 

[Tezlah]

At the 2016 Shareholder's meeting, JB and Elon explained why Tesla isn't focused on this problem. According to Elon, the early Roadster prototypes used to have this capability, but Tesla decided no to continue the feature. The main reasons they gave for not offering V2grid:

(1) the car is designed to cycle weekly, more or less. Cycling daily is what the powerwall is designed for
(2) "If there's unexpected back driving of power from the car, it can create electricution risks do things that people aren't expecting"
(3) Regulatory issues with the car being a power source to a home.. Permits and regs. differ depending on jurisdiction
(4) unhappy family members when you want to take your car for a drive, but your car is the house's primary power source.

Have a listen for yourself:

See 2:46:15 of the shareholder's meeting:

 

[Ludus]

If Solar City is integrated into Tesla I wonder if this will be reconsidered.

Solar City would be free to redesign the wiring as needed to address safety and code issues. Tesla's software would cooperate.

When plugged into the home charger the car battery pack could function as an emergency backup with about 10x the capacity of a powerwall.

Tesla Energy dropped the backup only version of the Powerwall so there's no direct conflict.

Dealing with local code variations and utilities is what Solar City does anyway.

This would be a software update for a fee in addition to home hardware installation charges.

For a lot of people it may be a desirable feature.

 

[Tezlah]

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.

 

[montreid]

OP: would suggest you alter to say V2H instead V2G. V2G has much broader systemwide conversations at Public utility level instead of the home "microgrid" which is what you're really pushing for in the conversation

All nonsense explanations by Tesla IMHO.
These batteries are the exact same as Powerwall. It maybe in the charge programming, but I doubt there's any significant difference between the Powerwall and the S battery packs in cycling tolerance or whatever safety parameters they spout.

It's more this: If we can sell you 2 batteries to use at 50%, why should we sell you only 1 battery that you can leverage fully?

Regulatory reasons -- probably nothing more than the Powerwall has to do.

Take this scenario with Powerwall Solar system --
800AM: sun shining: Tesla leaves home 100% charged overnight and PV solar making energy and netmetering to grid
12noon: sun shining: PV netmetering nicely to grid and all is good - stable home, stable grid
500pm: sun shininig: AC kicks in anticipation of home arrival to cool home, near net neutral - minimal grid demand
600pm: sunsetting,: AC in high gear, TV/Computers, cooking, and full house -- High demand Tesla Powerall engaged and starts draining to support all family activities. average two units needed to support = 5kWH and drained by 1000pm by time family settles down
1200mn: super off peak: tesla recharges at night to start all over again.

Goal: peak shaving is accomplished. Home grid is stable and minimized costs. Grid gains since evening duckbill is resolved.

Take V2H scenario with EV Car 80KwH battery + PV System
800AM: sun shining: Tesla leaves home 100% charged overnight and PV solar making energy and netmetering to grid
12noon: sun shining: PV netmetering nicely to grid and all is good - stable home, stable grid
500pm: sun shininig: AC kicks in anticipation of home arrival to cool home, near net neutral - minimal grid demand
600pm: sunsetting,: AC in high gear, TV/Computers, cooking, and full house -- High demand Tesla EV engaged and starts draining to support all family activities. average two units needed to support = 5kWH drained from battery
1200mn: super off peak: tesla recharges at night to start all over again at 100%

Goal: same achieved; 5kwH used from battery -- if you're even close to a 20% of battery charge on the Tesla car when pulling into the driveway, you're good to go. If you have two EVs, then even better.

The point --- fully leverage the battery you already paid for that's sitting on four wheels before buying another battery. Tesla (nor any other battery energy company) has NO FINANCIAL benefit to allow for this. This will only come about when Congress forces companies to open up their programming to allow for EV car batteries to discharge via their ports -- eg a large earthquake happens in Bay Area and some hacks show that connecting their EVs worked while their neighbors floundered with SDGE/PGE

 

[nwdiver]

V2G is a bit premature; Smart Charging would be more than sufficient for a LONG time... most places don't even have that yet.

 

[PaulusdB]

In Tesla-speak V2G is a four letter word.
That's why the integrated solution (closed Tesla architecture) will have to be called something else, possibly V2Home, containing car and home energy storage plus solar panels.
For this to happen Tesla just needs to acquire a solar panel distributor/manifacturerer/installer.

Oh wait...

 

[rolosrevenge]

The forum contains not a single reference to V2grid so I'm starting a thread on this. Can anyone answer my question as to why Tesla doesn't support the use of car traction batteries to power a home or external gear on an emergency basis? Let's not focus on the temptation this would create to shop power from a free supercharger and bring it home. That would be quickly eliminated if Tesla charged for supercharging at power cost. What is the bigger picture here and what are Tesla's main considerations?

That's because it's called V2G, not V2grid, and also there's tons of references to it. I got my PhD in V2G and have explained in many places on the forum about it, I even spoke about it at Teslive and TMC Connect. Bidirectional flow isn't going to happen and the responses have summed it up well. Unidirectional V2G could happen but everyone is too lazy to build an app to do it because of ... reasons, I'm sure. But someday it will. Tesla won't probably want some upstart aggregating all the EVs for even unidirectional V2G because then it undercuts a key value stream of Tesla Energy, but that's just short sighted on their part.

 

[ThosEM]

Thanks for all the perspectives and thoughts, and links to shareholder meetings! They clarify the picture a great deal. Can't figure out how to edit the OP but would if I could...

 

[Ben W]

The main reasons they gave for not offering V2grid:

(1) the car is designed to cycle weekly, more or less. Cycling daily is what the powerwall is designed for
(2) "If there's unexpected back driving of power from the car, it can create electricution risks do things that people aren't expecting"
(3) Regulatory issues with the car being a power source to a home.. Permits and regs. differ depending on jurisdiction
(4) unhappy family members when you want to take your car for a drive, but your car is the house's primary power source.

The thing is, none of these "reasons" is remotely valid, if the V2G is only used as an emergency backup in conjunction with a PowerWall.

(1) Emergency backups aren't used very often. Far less often than Supercharger use during roadtrips, which cycles the car battery every few hours, and Tesla doesn't seem to mind that.
(2) So use the car battery only to trickle charge the PowerWall; and not to power the home directly. Even if this requires two PowerWalls (trickle-charge one while powering the home from the other, then switch), it's still much better than needing ten PowerWalls to match the capacity of the car.
(3) Same answer: don't power the home directly, just trickle-charge the PowerWall. The permits and regs of powering the home from the PowerWall have obviously already been worked out.
(4) The PowerWall still works fine for a few hours while you're out driving around. There is no problem here.

The only legitimate reason I can think of to avoid V2G (oddly not mentioned on the call) is one of arbitrage, where users could go fill up at a SC for free, then come home and power their house from the car. Also, the associated wear and tear on the battery pack. Given that Tesla will likely implement pay-per-minute SC billing in the near future as an option for the Model 3, they could trivially also implement pay-per-minute V2G, at say $0.10/minute with a 6kW limit. (That works out to $1.00/kWh.) This would prevent arbitrage and makes it too expensive for daily use, but the whole purpose is only for emergencies, not daily use. And it would cover the cost of wear and tear on the battery, though vanishingly few users would use it often enough to make a significant difference. But in an emergency, it would be a wonderful option to have.[/QUOTE]

 

[Tezlah]

Another video where JB discusses this, for those interested:
See 26:32 of this video from May 2016.

 

[Ben W]

Another video where JB discusses this, for those interested:

Sure, but his objections all have to do with the complications powering the grid/house directly from the Tesla battery. If the Tesla battery is only used to trickle-charge a PowerWall at a fixed rate, but doesn't feed its own power through to the grid, all of those objections go away. I hope to get a chance to meet JB at the next Tesla event [that I get invited to] and ask him directly.

 

[TheTalkingMule]

That's because it's called V2G, not V2grid, and also there's tons of references to it. I got my PhD in V2G and have explained in many places on the forum about it, I even spoke about it at Teslive and TMC Connect. Bidirectional flow isn't going to happen and the responses have summed it up well. Unidirectional V2G could happen but everyone is too lazy to build an app to do it because of ... reasons, I'm sure. But someday it will. Tesla won't probably want some upstart aggregating all the EVs for even unidirectional V2G because then it undercuts a key value stream of Tesla Energy, but that's just short sighted on their part.

I always bring up Hawaii when people talk V2G and would be interested in your thoughts. Given the obscene electricity and gasoline prices in HI, I always thought it would make great sense to go 100% solar/wind on Oahu with a massive rental/share car fleet as perhaps half of the required storage. The other half could be up north on the military base.

By flipping around some of the economic incentive(pay only while unplugged) you could take the evening hours to charge the entire fleet and balance wind load. Peak electricity demand would be turned to massive overproduction by solar meaning cheap industrial daytime juice. You'd also likely knock car ownership low enough to halve traffic on the island. Of course you'd need to overbuild, but I have to think you'd end up with such massive efficiencies you'd save money.

Once the TSLA/SCTY merger is in place they could likely provide an end-to-end solution. Throwing out all the obvious disincentive to set up a system this efficient, would it be logical?

 

[callmesam]

Here's a 2007 V2G project from Tesla Motors but just smart charging:



PG&E and Tesla Motors Co-Pilot Vehicle-to-Grid Research

 

[Tiberius]

This was brought up (under different terminology) in the Model 3 section. Don't waste your time looking for it, TL;DR: most people were not interested.

Assuming they could do it without adding extra hardware/weight/cost, I would be a proponent but since at least one of those factors would go up, you can count me out.

 

[efxjim]

Wear and tear on a warrantied battery with no financial benefit to Tesla would be reason one. The Chademo spec supports bidirectional power flow. Has anyone checked to see if it is enabled on the Tesla?

 

[montreid]

Sure, but his objections all have to do with the complications powering the grid/house directly from the Tesla battery. If the Tesla battery is only used to trickle-charge a PowerWall at a fixed rate, but doesn't feed its own power through to the grid, all of those objections go away. I hope to get a chance to meet JB at the next Tesla event [that I get invited to] and ask him directly.

I don't buy their explanation. Powerwall batteries appear no different than the tesla car batteries coming off the same line. They don't suddenly NOT handle discharges and cycling well. BMW and Nissan are secondary marketing their 3 year old batteries for home grid support, so their batteries better than Tesla's (no, they're not)? Yes, arbitrage is a risk for Tesla, though can be mitigated at the user ID level. The real risk to Tesla and Battery companies---they can't sell their powerwalls if this occurs.


If one is truly green, then one should maximize utilization and balance with existing options. Letting 50kW sit idle in the driveway during demand draw makes no sense.

There is a solution already developed by Solar companies that support Powerwall and the likes. It's a matter of 1: developing connector between Car to that developed solution, 2: forcing car companies to allow this (Federal carrot intervention probably needed: Rec renewal of Fed EV incentives another 100k vehicles to power Micro/SmartGrid solution). Chademo already has a bidirectional solution that Honda leverages. Any DC has the ability to do this easily, it just needs to be deployed and adopted.

 

[Ben W]

Powerwall batteries appear no different than the tesla car batteries coming off the same line.

The battery chemistry is different: the PowerWall cells are optimized for daily cycling, while the Tesla cells are optimized for weekly cycling. However: (1) this hasn't prevented Tesla from operating Superchargers that provide near-hourly cycling to the car batteries during roadtrips, and (2) this actually dovetails nicely if e.g. a 90kWh Tesla is used to trickle-charge a 7.5kWh PowerWall. The PowerWall will cycle about 12 times more often than the car when used this way, which is perfectly in line with how the cells were designed. E.g. if the house is drawing ~2kW, then the PowerWall will cycle every 3.5 hours, and the Tesla can keep it charged for about 48 hours before needing to recharge itself.

 

[bonaire]

Some coverage of Chinese activity in the area with a story that has fairly little substance.

Vehicle-to-Grid And Vehicle-To-Home Tech Ready For Prime Time