Energy Products

Big deltas between what PW2 and my utility report for power delivered to grid

edited November -1 in Energy Products

I wanted to put this out there to see if anyone else is running into the issue i'm seeing. I have a single PW2 with a 9KW solar system - both were installed by a local installation company which is a certified PW2 installer. After a few months of operation, i've noticed that what the PW2 says i've pushed back on the grid differs greatly with what my utility, Duke Energy, is giving me credit for. AFAIK i'm supposed to get 1:1 credit for the kHh I push back on the grid, but the numbers just don't line up. For example, one recent month I delivered 200kWh to the grid per my PW2's data, but Duke says it was 19kWh. This is way too big to be a measurement accuracy error. FWIW the PW2 reports almost the same value for solar generation as my SolarEdge inverter reports. Also, the last bill showed that the total from the grid was with 1% of what the PW2 reported. I suspect that Duke isn't measuring my meter correctly as its a CL320 meter (most houses are CL200) and doesn't appear to have the same radio in it as the rest of the neighborhood. When the meter read truck comes by each month, the dude has to get out of his truck and do a manual read - so i'm wondering if they are just not grabbing the proper parameters from the meter.

anyhow, wanted to see if anyone else may have run into this situation and where you might be with resolving it.



  • edited January 7
    Likely just a meter reader with a hangover - sounds like a new reading would be in order.
  • edited January 8
    I am always suspicious of Duke Energy meters. They claim our home consumption is WAY higher than anything that makes sense to me. That was one reason we purchased the Tesla solar system in November.

    Now that the Tesla solar and PW2 is operational, I am watching the Duke Energy bills like a hawk. If there is any case to be made for them ripping us off with "errors" in Duke's favor, I will likely file a lawsuit against Duke Energy for violation of Florida's Deceptive and Unfair Trade Practices Act (FDUTPA).

    I would do it pro se just for fun. I won't waste any money on a lawyer over the issue. But I will drag Duke Energy into court and make them spend some money over the issue.
  • edited January 8
    Haha, yeah i know what you mean regarding Duke. In this case, I really suspect that they are either measuring or reading incorrectly. The only reason I am not 100% confident is because my solar company initially setup the powerwall incorrectly, i.e. I was generating solar energy at night :). So, I can't rule out that they setup the CTs wrong again. I've sent them requests to review it as well, but I put my money on Duke.
  • edited January 8
    Duke Energy also has an arbitration agreement for customers.
    So you can file for arbitration for a mere $200.

    Per the arbitration rules, the company (Duke Energy) agrees to pay all arbitration fees.
    Filing fee $300, case management fee $1,400, hearing fee $500, arbitrator compensation $2,500.
    Total = $4,700
    And they are required to reimburse you the $200 filing fee that you paid.

    That is generally the situation on all arbitration agreements. In order for the company to force you to give up your right to file a lawsuit in court, the company has to agree to pay all arbitration fees.

    Mail a copy to the American Arbitration Association (AAA) with a check for $200. They will send a bill to Duke Energy for $4,700.

    Also mail off a copy of the arbitration filing form to Duke Energy, it is really simple and takes 2 minutes to fill out.
    Also include an offer to negotiate with Duke Energy if they would like to avoid paying the $4,700 in mandatory arbitration fees to the AAA.

    Trust me on this. You will get a phone call within days from the Duke Energy legal department (or any company you do this to) and they will basically do whatever you want to resolve the issue, as long as it costs them less than $4,700.

    It is quite easy to receive PREMIUM customer service, from any company that is giving you problem, with that simple process.
  • edited November -1
    Papa - is the Duke arbitration agreement part of their solar interconnection paperwork or is it more generally available to all customers? Our solar went online with Duke back in early 2016 and cant recall....
  • edited January 11
    @Patrick, it is available for everyone. Google 'Duke Energy arbitration"
  • edited February 14
    Hi - I'm a Tesla Solar panel customer and i'm seeing similar problem when Tesla App says i'm over producing , but Duke energy says i'm consuming more than what is produced from solar panel and sending bills. I'm seeing this from past 2 months.. Duke energy is claiming they are billing based on what they see on net metering and billing.. Tesla says panel are good and overproducing and no issue with system.. Both sides says they are good
    But i end up paying in both the sides.

    Is there a way to resolve this ..any help is welcome.

    Thank you in advance.
  • edited February 15
    Read the utility meter (U) and the figures on the front of the solar inverter (S, if available) yourself , and keep that data for evidence. It's the most accurate data you can get. You'll need to subtract the previous month numbers from the current month numbers to get data for the previous billing month. Understand that Duke's billing month isn't necessarily a calendar month.

    The utility meter figure (U) is your "net" usage, i.e. solar production (S) minus house consumption (C). Your house uses some, and what (if any) energy that's left over is exported to Duke.

    U = S - C

    If you produce more solar than your house consumes, U is positive, and Duke owes you.
    If you produce less solar than your house consumes, U is negative, and you owe Duke.

    (I realize you probably already know this, vlpraju, but there may be some lurkers who don't.)

    Consumption isn't typically measured directly, but can be derived from utility net (U) and solar production (S).

    C = S - U

    Note that net energy flow *in* from Duke gives "U" as a negative number, so house consumption (C) is what your solar produced (S), *plus* what you got from Duke (U), as the two negatives cancel.

    It's unlikely that the utility meter is in error. It's also unlikely that what the front of the inverter is reporting is in error. These are both revenue-grade measuring devices.

    Look at the figures for consumption that the Tesla app is reporting, versus what you measure and calculate yourself. They should be the same value. You may need to take measurements twice a month to get data to compare with the Tesla app on a calendar month and data to compare with Duke's bill for a billing month.

    Your calculations using the above *should* agree with with what Tesla and Duke are reporting. If not, you've got good data that can be used during a discussion with Duke and/or Tesla to try to figure out where the errors are. At a minimum, both Duke and Tesla customer service will probably escalate your issue to a higher-level tech, if you start throwing actual numbers at them, showing that you know what you're talking about. First-level techs typically don't get into the numerical details specific to your installation, but I've actually had some good conversations recently with Tesla first level on a PW question, that showed a pretty high level of understanding on their part.

    Good luck.
  • edited February 21
    I’m having similar issues with Dominion Energy in VA.
    For the last 8 months(since installation of 11.6kwH system + 2 powerwalls), Dominion energy says I’ve consumed 22,000KWh. I’ve been able to give back only 3500 to them during this time.
    Tesla claims my production has been 8100kwh during the 8 months.
    8100 vs. 3500 seems to be a very large delta.
    Any help?
  • edited February 21
    I’m having similar issues with Dominion Energy in VA.
    For the last 8 months(since installation of 11.6kwH system + 2 powerwalls), Dominion energy says I’ve consumed 22,000KWh. I’ve been able to give back only 3500 to them during this time.
    Tesla claims my production has been 8100kwh during the 8 months.
    8100 vs. 3500 seems to be a very large delta.
    Any help?
  • edited February 21
    Remember that the utility meter can only measure what goes through it. A portion (most?) of your solar production that's reported by the Tesla app is immediately consumed by your house, and does not pass through the utility meter.

    The utility figures are "net", in that they are the difference between what your solar produced and what your house consumed. See the long, explanatory post above yours...
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