3MWh and counting …

We hit 3MWh (that’s megawatt-hours) of solar PV production yesterday, a few weeks ahead of the 1-year anniversary of the install.  In that time, we:

  • Generated 3000 kWh
  • Pushed 1877 kWh onto the grid
  • Pulled 3278 kWh off the grid

So, that means we used (3000 – 1877 + 3278) = 4401 kWh in that time (for about 360kWh/month average), and we generated 3000 / 4401 = 68% of the electricity we used in our home.  A bit shy of the 75% I’d hoped for but not too bad!

The monetary value of those 3000MWh is about $300 here in MN, at about $0.10/kWh (my baseline for comparison is the cost for electricity with Windsource, since we have subscribed to that program for many years now.  It’s only slightly higher in cost, about $0.009/kWh, since the fuel charge gets removed for Windsource customers).

5 thoughts on “3MWh and counting …

  1. Congratulations! Thank you for being such a great advocate for solar and for greener, more efficient living. The best way to advocate for something is to live it — and you’re definitely doing it.

    P.S. — Wish we had the Enphase system you have. I think we’d have produced several hundred more kWh this year in Aurora, Colo., primarily due to snow melting (or lack thereof) issues. I also like the new 25-year warrant on the new Enphase micro-inverters.

    • Thanks Christof :)

      Enphase might have helped when you had that partially-snow-covered array, yes … but the clipping at 199W was tough to see here, on those beautiful spring days. Hard to say; you are clobbering me production-wise though with your larger array. :)

      That 25-year warranty is pretty sweet, isn’t it!

      Check out this map of public Enphase installs – it’s a fair bit of solar!

  2. Did you publish anywhere here what were the total expenses installing the system and what have the upkeep cost been so far? Any estimates of what the break-even point would be for you currently would be interesting.

    • I haven’t detailed the costs, but my final costs were a bit over $5000, after a tax credit, a utility payment/rebate for my SRECs, and a state rebate. I was somewhat lucky that all these incentives existed at the time.

      There have been no maintenance costs, really, other than a long pole I bought to remove some snow in the winter.

      Break-even is hard to guess since it depends in large part on what utility rates do over the next decade, opportunity cost for the money spent, etc. Break-even wasn’t my primary motivation, although I probably would not have done this if there were no hope of payback over the life of the array. OTOH, environmental payback was almost immediate (granted there is some embodied energy to pay off in the panels :) )

      This estimator could probably be used; entering zipcode 55116, a 2.5kWh array, $40/month bill, $6/watt cost (to make up for the expired state rebate which that calculator no longer shows), and “Pay cash” since that’s what I did, and the A01 net metering rate. With all that it tells me I have about a 6% ROI. The $6/watt is probably still a bit high, as it says my first-year cost would be $6700 with that, and that’s more than it did cost me.

      Interestingly, it seems my payback might have been better if I’d paid with a home equity loan (I guess that’s the opportunity cost factor) and the A02 time of use rate (I wonder if I can still switch to that… ). It also seems to assume something a bit different about whether the utility payment is taxable; I assumed that it was not and therefore took the 30% tax credit on a smaller amount. It was roughly a wash. (Yes, this stuff is too complicated…)

      With net metering rate A02 and a home equity loan it says 10% ROI. Shrug.

      • So, basically at current numbers the break-even point is at around 16 and a half years, possibly sliding up to 20 if some components wear out during that time, or sliding down as the energy prices go up. Pretty nice!

        I tend to ignore opportunity cost in such calculations, mainly because it is pretty clear that opportunity cost factor is linked to inflation, which nowadays is strongly tied to energy prices, so in this case we can assume that the effects are likely to cancel each other out. And it makes for a much simpler and easy to understand math.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.