I learned some new things about solar last week. How it works in snow!
Pensacola has been renamed Pensacolda, Flurryday, at least for a few days. I live north of there, where it is a little colder still. It isn’t terribly unusual to get a flurry in winter. Sometimes, even enough to stick and make the kids go crazy. This time we got a doozy. The official tally was around 9 inches. That’s 3 times the record set in 1895. I had more than that on top of my wood-fired furnace.
I had seen picture’s of friend Bruce’s near vertical panels on his roof in Pennsylvania with snow on them. He says sometimes it falls off on its own. Down here in NW Florida, the panels are at a shallower angle and it takes some effort to get it off. I wish I had gone out to look at the nearby solar farms. Some of NextEra’s (FPL) panels are on trackers. Can trackers shake them clear? (I bet they wished they had batteries) I don’t know, but I do know that my panels were only putting out about 1% of what I would normally expect on a sunny day. Granted, when I checked we were still having a blizzard. I couldn’t check the solar farms because all the roads were impassable.
Day 2 of snowmageddon was bright and sunny and power output was still wimpy. My west-facing array is easiest to attack with a grass rake and broom. It came down as powder, but it was thick. I had not planned for snow when I set this array up, but there was sufficient clearance for the snow I raked down to not build up at the bottom. Lesson 1, give snow a place to go.
Another array, a “temporary” extension of the Solar Shed roof line ends maybe 8 inches from the ground. Not only did I have to drag the down the panels, I had to shovel the pile at the bottom to get it all off. More work! If you are in snow country, mount them a little higher.
The snow on the roof panels–solar shingles–was too high to get to. I figured I could get by with what I got from the lower array. That was all well and good until the roof snow started slumping down over the next 2 days. The western array saved the day.
Next lesson is to have plenty of battery. I recently added an extra 1600 amp hours of lithium batteries and they really held up well. Normally, it is often cloudy during the summer and we do like our air conditioning. This time of year, I have been getting back in touch with my heat pump. That’s easy on a clear day, but to run all night requires some serious battery. We get winter clouds, too, such as during snowstorms. My primary heat source is wood, but as I get older and lazier–and nights that go down to 6 degrees F really use the wood–I am embracing the heat pump, at least when it is warm enough outside for it to work.
Bruce in Pennsylvania texted me to watch out for an interesting effect snow can have on BOOSTING performance. Panel output is rated for a standard temperature and light level that is generally unobtainable during the summer in hot, cloudy Florida. However, when a panel is cooler it has a greater output. Also, when snow is on the ground, you not only get the direct sunshine, but you also get a reflected boost from the snow! So, even though many of my panels were totally or partially obscured, I was doing pretty well on power. In my system, one array is a little close to the edge on voltage, but all have plenty of room for a lot more amps. Most of my 8 charge controllers are rated for a peak of 160v, normal operation below 150v and 60 amps.
I’m clearing ground for a new array. You can bet it will be a little higher and the charge controllers will be set up in a safe range, mostly because there are things I’d rather do than buy and replace smoked equipment.
5 days later, the roads are open, though bridges and back roads still have some ice. The pipes are thawed and the solar water pump is pumping again. The first day was fun. It quickly turned to survival and hard work, but we learned things and got through it.
–Neal