Profile: Solar PV in Wayland

Hello, it’s Kaat, the Wayland Solar Coach. My husband and I have both solar photovoltaic (PV) and solar hot water (SHW) on our roof.  I’ll share some details about the PV system here. More about the SHW here.

We turned on our PV array in August 2011. You can follow the production of this array in real-time, here.

Now, I offer this tale as a way of demonstrating a few things. Here’s the summary in case you don’t want to read through all the specs below 🙂

  1. Cost. I want to show how much better the market for solar is now. You’ll see in the details that some of the incentives that we enjoyed in 2011 went away, but you’ll also see how, even so, the cost of these arrays has gone down — while the efficiency of the panels has gone up. So while our system’s break-even point (the moment when it is paid off and after which it starts generating income) is 8.5 years, due to lower prices and higher efficiency, typical pay-back times nowadays are half that! 
  2. Sizing. Another lesson is that we sized our system to our consumption in 2011, and  for a couple of years it produced as much as we consumed. But then more people joined our household, and we got our beloved Nissan LEAF, a plug-in electric vehicle that we charge at home. Result: we under-produce (because we want our electricity to be 100% renewable, we now pay extra on the difference through Make the Switch). The lesson: when you are talking with your SolarFlair rep about the size of your system, keep any future electrical loads in mind! You get a credit on your electricity bill for whatever you over-produce, and you can sell or donate this credit to neighbors in the same load zone, so sizing a little larger (or however much larger you want) doesn’t hurt.
  3. Maintenance. Lastly, we’ve had two micro-inverters break on us, but they were replaced by our installer at no cost as they were/still are under warranty.  For the rest, the system has been maintenance-free. It just sits on my roof making electricity, and money.

So, on to the details, with the caveat that the system, though only six years old, is now somewhat outdated. But it works great and will keep working for decades to come.

Equipment

SolarFlair has a couple of offers through our Solarize program so you can pick and choose equipment manufacturers and panels with different efficiency. Their sales rep will explain all the options and the implications of choosing one over another.

Ours (2011):

  • 24 panels: SANYO HIT Power Modules | 100% of maximum power (Pmax) = 215.0 Watts / DC rate per panel 210 Watts / Total = 5040 Watt system. The efficiency of even the base model is higher than this now!
  • 24 inverters: Enphase D380 module-direct inverters. Due to some shading we went with individual microinverters instead of one central inverterA new technology is the solar optimizer, and SolarFlair offers any of these technologies. The sales rep can explain the difference and pros and cons of each.

Estimates

Each homeowner gets these as part of the quote. These estimates are researched and in many cases subject to industry and state rules, so they are reliable.

Ours (2011):

  • Estimated first year production in KWh: 4,735. This estimation takes into account historical weather data, the orientation and the tilt of the roof.
  • At this production rate, our “solar fraction” would be around 87% of our 2010 electrical consumption which translates to avoided utility costs of approximately $899 per year (this value was based on then-current utility rate of $0.18 per KWh).
  • At that rate, the estimated dollar value of solar energy harvested over project life would be $50,922.89.
  • Carbon savings estimate7,103 pounds of carbon saved in the first year | Pounds saved over the project lifetime: 187,469.

And how did it actually do?

  • First year production: 4,790 kWh
  • Yearly: 2011: 1,617 | 2012: 5,348 |2013: 5,056 | 2014: 4,940 | 2015: 4,718 | 2016: 5,150 | 2017 (to date): 1,402.1 KWh = 28.2 MWh = 107% of the estimate, so far. Not bad!

Cost

Beware, these are 2011 prices and 2011 incentives – some of which, however, still exist for you to take advantage of – but not for long!

  • Base system cost: $35,558.00
  • 2011 Commonwealth Solar rebate: $8,000.00 (this rebate no longer exists)
  • = Invoice cost: $ 27,558.00
  • Federal Tax Credit (30% of remaining cost): $8,260
  • State Personal Tax Credit: 15% of remaining, up to $1000
  • = Cost after installation: $18,290
  • = $3.62/kW

For comparison, SolarFlair’s base offer (after all incentives are taken into account) is $2.91 per kW installed.

Ownership/investment

We paid for full ownership. Currently, SolarFlair also offers leases, but if you want full ownership, there is also a great Solar LOAN program. Their sales rep will explain all of this to you in detail.

These systems are investments in that they pay for themselves over a certain time, then start making money. We enjoyed the following yearly deductions, beginning in year 1:

  1. savings on electricity bill per year: $900/year at our current utility rate of $0.18 per kWh > assuming prices don’t change, with just this, the system would pay for itself in approx. 20 years.
  2. The 28.2 MWh we produced has so far translated into 28.2 SRECs that were sold on the market for a total of $7,698.
  3. Add this to the calculation, and the system will break even/be paid for approx. 8.5 years from the time of installation. Typical pay-back times nowadays are half that!

After that, any SRECS sold and $$ saved will be profit. Not a bad investment for a system that makes all our electricity clean and renewable, or as they say, “decarbonized” our electricity.

No doubt you have questions. We have Q&A here. If your question is not answered there, don’t hesitate to comment here, or to email, and we’ll find an answer.

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