I overheard one of my students ask a classmate today, “Why are they doing so much solar in Vermont, when it’s so much cloudier here than in other parts of the country?” This was on my mind when it occurred to me that that her comment might be more meaningful if rephrased— “Since solar is working in Vermont (and Germany), where it’s relatively cloudy, imagine how it would work even better in other states?” Because, solar does work here in Vermont, and the data so far from my net-zero project is bearing witness to that fact, here in my little corner of the state.
When I last wrote about the project, as I was just finishing the barn panels (post: “Just in the Nick of Time“), the snow had arrived and the days were near their shortest. The snow is mostly gone now, though, the days are getting longer, and the solar production is ramping steadily up. The image above is from my March report from Enphase (the company tracks the performance of each individual invertor and panel via the internet, and sends these nifty monthly reports). The panels on the barn, according to Enphase, have offset nearly a ton of carbon emissions, and have produced well over a megawatt hour of clean, renewable power, in the month of March alone.
Eventually I’ll get the whole system online, and I’ll work up the numbers for the system’s performance over the course of a whole year. But for now, it appears that my preliminary cost projections are working out as planned— the monthly savings from the project (in propane, generator fuel, electricity to charge the electric cars, and, in a side benefit, cheaper internet due to the coax we ran in with the underground power) nearly completely offset the loan payment. So it still looks like the project will pay for itself in 11 or 12 years, and then provide a large savings every month after that.
As for the net-zero aspect, my goal was to completely power the house, AND the two electric cars, with solar. I can’t quite tell on this one, but I believe we’re close to this goal. I’ll need a few more months of data—our usage for the cars will be higher in the winter months (due to using the heaters, having snow tires on, and the lower efficiency of the batteries in cold weather), while the solar production will be higher in the summer. I’m also not quite finished putting all the panels back on-line; the new ones on the barn roof are finished, but I need to reinstall all the panels we were using when we were off-grid. This should bump up the solar production another 20 or 30 percent.
So, it’s too soon for me to do a complete report, but the results so far are good. We are net-zero, we’re driving 90 miles or more every day on mostly solar power, and we’re going to save money in the long run. It’s time for everyone to jump on this bandwagon.