Saturday, January 13, 2024

How My First Full Year With Solar Panels Worked Out

My first full calendar year with the panels is in the books, and if nothing else, the numbers tell a mixed tale that emphasizes how important weather cycles are. 

First the top line numbers: The system produced a total of 8.55 MWh against total consumption of 7.82 MWh. Exports were 6.3 MWh, and I exported more power than I took from the grid in February, March, April, August, September, November, and December. 

Put simply, I ended the year having produced almost three-quarters of a megawatt more than I used, overall, and I consumed about 2.5 MWh directly from the panels. (The sum of the blue strips on the graphic to the left. Click to make it bigger.) 

By itself, it's good news, but when you compare it on a month-by-month basis, production was lower in CY23 than in the months of CY22 when the system was live. (Recall it first went live in June of '22.) Only November had higher production year-over-year, and then only by a whisker.

Weather was clearly a factor. It was a wet summer and a wet fall in the Northeast, so it wasn't a surprise that production came in below the prior year which was a pretty dry one, especially in the Hudson Valley.

Another factor was the weird production interference the system experienced from the "bad crimp" that was corrected over the summer

As luck would have it, 2024 is an El Niño year, which implies a warmer and wetter winter than the typical seasonal pattern. I'm not a big fan of snow, but the local creeks and rivers are already close to overflowing, so it would be great to see more sun if only to dry things out. If typical, the La Niña cycle that tends to follow will bring a drier summer, and perhaps a lot of sun with it.

So far the system tells me it has produced more than 16 megawatts in its 18 months of operation, and saved the atmosphere more than 25,000 pounds worth of carbon emissions, which according to SolarEdge, the manufacturer of my inverters, is the same as planting 190 trees. To give me that number it used the methodology created by the US Environmental Protection Agency. In perspective, the carbon savings equate to taking 2.6 gas-powered cars off the road for one year, or 1,292 gallons of gasoline consumed. By that logic, it's at least offsetting some of the gas I consume driving my car, but not all of it. We do drive a lot.

On the billing front, we've now had three billing periods come in with that minimal amount I first saw on my bill in May. So we are saving money, but because of the weird problems the local utility has experienced with its billing system, it's impossible to actually do the math and estimate the savings with any precision. Meanwhile, I'm still paying off the loan I took out to build the system, but it's a relatively painless amount every month. 

And obviously, we're still paying the utility for natural gas to heat our home and make hot water. Still ahead for us are questions about if and how to transition toward non-gas alternatives. I'd like a tankless electric water heater, and I'm curious about geothermal heat pumps, both of which qualify for tax credits under the Inflation Reduction Act. So while we're off to a good start on reducing our overall carbon footprint, there's a lot more work to do on that front, but it also has to make financial sense. 

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