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What ever happened to V2G tech?

Discussion in 'Technical' started by deckofficer, Feb 18, 2015.

  1. deckofficer

    deckofficer Member

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    I've always wondered why the original Alan Cocconi inverter speed controller used on the Tzero that had vehicle to grid interface wasn't used in the Roadster and future offerings. This AC Propulsion controller that was developed for California's Zero Emissions Mandate was rated at 150 kW, more than enough to handle household loads during a power outage.

    Any insight from the excellent knowledge pool here at TMC?

    Wouldn't it be comforting that as long as your Tesla is plugged in at home your immune from power outages? Just view it as a UPS for your home.
     
  2. Saghost

    Saghost Active Member

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    If I remember right, they moved away from the integrated architecture after the very early roadsters for safety reasons - the original didn't have as much isolation between the low and high voltage sides?

    Safety and isolation is the reason you can't have the second vision you described, either. If you allow the car to feed power back to a standard household wiring setup, it will push the power back out onto the grid, to the neighbor's house and the local transformer - and through the transformer to the power line they are trying to fix.

    V2G isn't dead, and I think it may become common in the future, but it needs dedicated controls to work safely, and in your house you would need wiring changes to build a protected subpanel behind an anti-islanding transfer switch (so that when the grid dies, the switch automatically opens and you are only powering the things on the protected subpanel.)
    Walter
     
  3. deckofficer

    deckofficer Member

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    Wouldn't the basic transfer relay switch that is used for standby generators handle this? Cocconi had everything packaged as one unit, inverter, speed control, and supercharger. Beef up your home charging circuit and Cocconi's design would also give home Supercharging.
     
  4. rabar10

    rabar10 FFE until Model 3

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    #4 rabar10, Feb 18, 2015
    Last edited: Feb 18, 2015
    The AC Propulsion AC-150 drive system i.e. Alan Cocconi's design includes a 'reductive' charger with 18kW power. This was better than any other in-car charging solution, till the Model S and dual chargers pushed it to 20kW, but it's hardly Supercharging (90-120kW). And no home's electrical connection could provide 90-120kW of power anyways.

    ---

    There's a difference between supporting V2G and being able to power a home as an "island" that is disconnected from the grid. The two are related in that in both cases, AC power flows out of the vehicle. But there are big differences: the former requires signalling and control between the grid and the car, but the grid still supplies a consistent voltage and AC frequency. The latter not only requires an anti-islanding transfer switch (as Saghost mentioned) but also the ability of the car to maintain its own 60Hz signal and consistent voltage level, in the face of highly-irregular loads (refrigerator or AC kicking on/off for example).
     
  5. doug

    doug Administrator / Head Moderator

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    Tom Gage, former CEO of AC Propulsion, spoke about V2G at TMC Connect 2014. He's now the founder and CEO of EVGrid, which I suppose should have the latest on what's going on.
     
  6. deckofficer

    deckofficer Member

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    #6 deckofficer, Feb 18, 2015
    Last edited: Feb 18, 2015
    Doug, thanks for that link, I wondered what Tom Gage was up to. He and I share the same vision that wide spread adoption of EVs could be beneficial to the grid instead of taxing it. I've always believed if power demands was a flat line throughout a 24 hour period instead of the peaks and valleys we have now, electricity would be cheaper for the consumer at the same time being more profitable for the producers. With Internet controlled charging and peak shaving (power from EV's batteries back to the grid), the power companies could create this straight line demand when there are enough EVs.

    Do you know what Alan Cocconi is up to? I always felt he was the brains behind the development of that drive system.

    On the EVgrid web site......

    WHEN DRIVING IT'S A CAR, WHEN PARKED IT'S A POWER PLANT. THIS IS V2G.

    Can electric transportation take us from the oil age to the sun age?
     
  7. TEG

    TEG TMC Moderator

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    #7 TEG, Feb 18, 2015
    Last edited: Feb 18, 2015
    Grid-tie inverters (including V2G) are expected to monitor the grid power and immediately shut off if they sense the grid is being disconnected.
    Power companies value the safety of people working on their lines and ( also in the case of downed power lines) want to be able to turn off the power and have it stay off. Something that fed power into grid lines when the grid was down would be unacceptable.

    If you want to have a static storage or vehicle inverter power your house, then, yeah, it needs to be set up so that you are an "island" and there is no chance you are energizing the lines leaving your property.

    (Much of this is already mentioned here, I am just stating it a different way.)

    ---

    Just noticed a related thread:

    AC coupling 'using grid-tie array during utility failure'

    ---

    Do a forum search on 'Grid' and you will find a lot of threads.
     
  8. deckofficer

    deckofficer Member

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    TEG,

    As a former and disgruntled oil exploration worker, my desire is for the wide spread use of EVs in such a way that it bolsters the grid instead of taxing it.
     
  9. TEG

    TEG TMC Moderator

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    I think there are a lot of reasons why V2G hasn't become mainstream. Many of them are political, protecting business model, etc.
     
  10. mitch672

    mitch672 Active Member

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    the issue of delivering power to the grid is relativly simple; the poco can on demand disable it, via communications, they have advanced powerline coms and of course the internet. It could be made to work "safely". Of course the biggest issue is Tesla doesn't allow it for obvious reasons right now (extra cycles when they are providing the warranty)
     
  11. TEG

    TEG TMC Moderator

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    I think grid-tie inverters just piggyback on top of the AC waveform coming from the grid. So if the grid stops oscillating the power, then the inverter just doesn't add to it.

    Standalone "Island" inverters generate their own AC waveform so it would conflict with the grid if you attempted to join them together.

    "There can only be one!"
     
  12. Saghost

    Saghost Active Member

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    Well, there are battery backup inverters that can also grid-tie safely, like the Schneider/Xantrex XW series.
     
  13. TEG

    TEG TMC Moderator

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    Yeah, I think they call that "grid-interactive". Traditional style would have a transfer switch so you could disconnect your grid tie inverter, and switch to an off-grid inverter (that generates it own AC wave) when you need to run off-grid, usuall from a battery bank. I gather that there are some "hybrid" smart inverters that can act as grid tie, or switch to "island mode" when needed. My point was to just mention that these things need to have two distinct modes depending if they are grid tied or off-grid. Many devices are only for one purpose or the other. Some people assume that if you have solar and and inverter that you can operate off grid, but that is usually not the case.
     
  14. psps

    psps New Member

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  15. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    I just don't see it that way.
    To be worth it, you need lots of electric cars.
    If you have lots of electric cars, you have lots of cheap batteries.
    If you have lots of cheap batteries why repurpose batteries that you can't guarantee will be hooked up, when you can have dedicated batteries you can put wherever you need?
    From the utility point of view, a lot of the benefits could be gained just with controlled charging (no feed in) and their own batteries.
     
  16. EVenthusiast

    EVenthusiast Member

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    Didn't see anyone mentioning University of Delaware's V2G efforts, worth checking out.

    One interesting angle I didn't even think of is using electric trucks & busses with V2G, especially vehicles which don't get used all day, such as school busses.
     
  17. rolosrevenge

    rolosrevenge Dr. EVS

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    Honestly, what happened is that no one wanted to work with me to get it done. Large groups of Model S could have been doing all sorts of cool things for years now, but no one seemed to care and I don't know how to write the necessary apps. It breaks my heart every time I think about it.
     
  18. Seattle

    Seattle Member

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    What do you actually need help with? There are zillions of software engineers here like me, and this could be something fun. Explain what you need in terms of programming.
     
  19. rolosrevenge

    rolosrevenge Dr. EVS

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    I need a server that has the same functionality of the Tesla app, but aggregates many cars into it, and can then send charge start and stop signals to any of those cars if they are plugged in.
     
  20. EVenthusiast

    EVenthusiast Member

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    In case anyone else has an interest in V2G, a new report has been published detailing the state of V2G, but it's a $2,500 report. If anyone has access to it, would love to hear your thoughts.

    Here is a press release about it, which gives you an idea of what is in the report:

     

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