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To Charge or not to charge- that is my question

Discussion in 'Prime Fuel Economy & EV Range' started by Mark Schneider, Apr 15, 2019.

  1. fuzzy1

    fuzzy1 Senior Member

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    None of that is known to apply to the OP in New Jersey. NJ appears to have a very consumer-friendly net metering system, with production back into the grid credited at full retail price.
     
  2. mr88cet

    mr88cet Senior Member

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    My information may be specific to Austin, and is second-hand. However, it’s probably fair to say that net-metering, and grid-tying, a system are not synonymous.

    Grid-tying just means that you use power from the utility when you system isn’t producing power, and sell power to the utility when you have surplus.

    Net metering, as far as I know at least, means that the utility tallies up your total usage and charges you, or pays you, for the entire sum usage, positive or negative.

    As I understand it, at least here in Austin, all systems that they subsidize the purchase of (and possibly all systems they allow to be grid-tied; not sure) are grid-tied but not net metered. In return for subsidizing the cost of your system, they pay you less than they charge you. They then offer all in most of their service area a “Green Choice” energy option, which is partly powered from nearby solar.

    Anyway, if the OP’s system is not only grid-tied, but also net-metered as I understand it, then, true, it wouldn’t matter.
     
    #42 mr88cet, Apr 20, 2019
    Last edited: Apr 20, 2019
  3. fuzzy1

    fuzzy1 Senior Member

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    OK, this is where the difference lies. Austin doesn't use a standard simple net metering system, but instead created something called VOST, which I haven't adequately digested yet:
    How Does Austin Energy Net Metering Work in 2019? | EnergySage
    In fact, they aren't even the same topic. One refers to the electrical and physical architecture, while the other refers to the financial aspect of energy exchange.

    Grid-tie is simply the opposite of off-grid. The former is electrically connected to the local utility grid, the other is disconnected and isolated. The term says nothing about how energy is bought or sold.

    Net metering is just one of several methods of buying and selling energy between the utility and the grid-tied customer/home-energy-producer. It is generally used in the most PV-friendly areas, while hostile areas generally have other systems. While Austin's system is derived from net metering, apparently the VOST variation makes it different than the common basic net metering systems used in many other places.
     
    #43 fuzzy1, Apr 20, 2019
    Last edited: Apr 20, 2019
  4. bruceha_2000

    bruceha_2000 Senior Member

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    I know, my point was only that one can't generalize with regard to net metering, there are many different systems.
     
  5. fuzzy1

    fuzzy1 Senior Member

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    The other systems are not simple or basic net metering.
     
  6. mr88cet

    mr88cet Senior Member

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    In short, grid-tying a system doesn’t necessarily imply that it uses net-metering, nor any other particular billing system.
     
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  7. Mark Schneider

    Mark Schneider Junior Member

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    Enjoyed reading all the replies I wish I had better answers to some of the questions but I believe Net metering is our setup - but on next months bill I’ll find out for sure.

    But to be honest since starting this post I think I will continue to charge daily unless it gets to a point where we aren’t producing enough solar to keep the house 100% green and have to start pulling from the grid.

    But it’s still an interesting thought experiment
     
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  8. jb in NE

    jb in NE Senior Member

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    But even if your solar can't keep up with the demand including charging the car, wouldn't you still want to pull from the grid to charge the car and not run the car on gas?
     
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  9. mr88cet

    mr88cet Senior Member

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    I personally agree that there are other, equally-good reasons, not related to finances, to drive on electric, such as reduced pollution and noise, both for you and the people and other creatures around you. Better responsiveness too.

    However, just for the record, I gather the OP’s concern is not with the capacity of their home-solar, but with the economics of using that power directly vs. selling to the utility.
     
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  10. jb in NE

    jb in NE Senior Member

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    I was looking at the 100% green line. But, if the cost to run the car on electric exceeds the cost to run on gas, it's a more complicated decision.
     
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  11. bruceha_2000

    bruceha_2000 Senior Member

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    I think the OP will find that his wife is incorrect about how much the electric company is paying for their electricity.
     
  12. Peng Xiao

    Peng Xiao Junior Member

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    Base on today's price,
    EV 25 miles need, 6.5 kWh x $0.18/kWh = $1.17
    HV 25 miles need, 25 / (59 mpg) x $2.74/g = $1.16
     
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  13. Roy2001

    Roy2001 Active Member

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    For me right now, EV 25 miles need 6.3 kWh x $0.28/kWh = $1.76
    HV 25 miles need, 25 / (55 mpg) x $3.74/g = $1.70

    My electricity price is 22c for tier 1, and 28c for charging vehicle since I used all tier 1 quota. Fortunately I have solar installed.
     
  14. bruceha_2000

    bruceha_2000 Senior Member

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    EV 25 miles need, 6.5 kWh x $0.17/kWh = $1.105
    HV 25 miles need, 25 / (59 mpg) x $2.89/g = $1.225
    But like Roy, my actual electric cost is $0.0 since my solar array produces more than the house uses.
     
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  15. jb in NE

    jb in NE Senior Member

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    Are there no costs of the solar arrays that are being recaptured?
     
  16. fuzzy1

    fuzzy1 Senior Member

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    He is probably counting that as a sunk cost.
     
  17. bruceha_2000

    bruceha_2000 Senior Member

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    Yep. I've paid for them and they are generating more than the house uses. Our net meter credits expire a year from the month they are accrued. The capital cost per kWh generated/used is the same whether I put some in my car or give the utility free electricity. Some places will pay real cash money for excess net metering credits. In that case there would be an opportunity cost to using the extra in the car.
     
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