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Vermont replacing power plants with home batteries

389 points · 304 comments · devonnull

  1. beaviskhan · · focus · HN ↗
    This article is all over the place, but the principle is pretty simple - rather than adding more generation for peak usage times, batteries store energy generated off peak and smooth out the macro usage trends.

    Our local utility in NC has a program where they'll pay you ~$50/battery/month to enroll in their virtual power plant program. In exchange, they can take control of your battery up to 36 times per year for a period of a couple hours. Summer events are typically early evening during peak air conditioning times. Winter events are typically early morning during peak heating times.

    In practice this means one of two things:

    * They make your battery charge to full capacity in advance of the event, and then you run your home off the battery and don't take any power from the grid during that time * Sometimes you'll also return power to the grid beyond that used by your house - they pay you the contracted rate for the power you deliver

    We've paired our batteries with solar panels, so generally we have a full charge going into the summer VPP events. We have gas heat, but I expect we'll pay for at least some grid energy to charge batteries during the winter events. Regardless, it's been a good program for us - even without solar, we would not pay for any more power than we used, and the monthly rebate from the utility makes the economics of the system a lot more favorable, especially here in the land of relatively cheap coal power.

    1. bluGill · · focus · HN ↗
      Ideally for people with a battery they would take charge to manage your battery between 50%-80% full, paying you for anything you send to the grid. 36x a year means major peak events only (one assumes with a limit of 36 they will try to be under that just in case the last day of the year has a problem). However a 50-80% policy is nice to batteries and means they can use it for even tiny local peak events. Ideally there would be enough home batteries that between all the renewables (Parts of NC are part of the TVA with plenty of hydro) they go months between using a fossil fuel plant.
      1. Clent · · focus · HN ↗
        I would assume they do not use every enrolled home's 36 allotment on the same 36 days.
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