After three years, my laptop is set up with our Holy Cross Energy account. I can finally crunch numbers. First I pulled the electricity usage for the years 2019 through 2021. Monthly use peaks around December through February. With a daily peak of 27.72 kWh on Saturday, February 27, 2021. Other than it being winter and assumingly cold, I do not know why else usage was so high this particular day.
Zooming in on the interval October 14, 2020 through March 16, 2021, I correlated some lows and highs with events in my photo archive.
Min & Max: 2 – 30 kWh per day.
Avg Monthly Hi: 400 kWh in Jan & Feb – Lo: 200 kWh in June Jul Aug
I now go to the solar watts calculator from the national renewable energy lab’s website. (https://pvwatts.nrel.gov). You just put in the address draw the surface area on your roof and you get an estimate on what is possible to generate in photovoltaic energy per month:
Between 4000 – 6000kWh per year, We consume about 3000kWh
As proof of concept I have included a rendering of how 65″ x 39″ solar panels would fit on our roof. Regardless of which option the system would have a size between 3 to 5 kW.
How Net metering works:
source: Holy Cross Energy how net metering works (https://www.holycross.com/wp-content/uploads/2019/10/How-Net-Metering-Works-191021.pdf
Bank excess;
First use up any kWh in your bank;
Then annual payout:
@ AVERAGE WHOLESALE POWER COST FOR THE PRIOR YEAR.
= ???
The big question is: how much is that whole sale, less than the ¢11 or ¢12 Something which won’t go away: $12 a month flat fee.
Therefore the actual savings to use as a number on payback is around $250 a year, unless
I have to do the research but the key to working out the exact number is: “…average wholesale per power cost the prior year.”
COST OF SYSTEM (4-5kW)
Cost will be between $ 11K and $14K after at 26% sources to support that estimate:
at $300 a year savings it would take more that 50 years to pay back! at $650 a year in savings 23 years.
so the answer is:
No, not time to put solar panels on the roof, yet, unless something changes
We just don’t use enough electric…
With escalation of the natural gas price relying more on electric space heaters vs natural gas powered home heating. Also switching to electric to an electric vehicle could tip the balance.
At this moment I have no insight in communal Electricity and how these numbers can be tied into the equation. but would like to. For our block we would possibly be in the 15Kw range with $2500 a year in savings.
