Winter blues got your solar panels down? Think again! This podcast reveals how cold weather can actually improve solar panel efficiency. Learn how to capture winter sunlight for maximum power. Stay warm and power up!
John Maher: Hi, I’m John Maher, and I’m here today with Brian Sadler. Brian is the Vice President at Solaris Renewables, a solar company in Massachusetts providing premium solar and storage technologies with exceptional customer service; and designing, installing and servicing solar systems in Massachusetts, Southern New Hampshire and Maine. Today we’re talking about solar power in the winter months. Welcome, Brian.
Brian Sadler: Hi John. Good to be with you today.
Solar Energy Production During the Winter
John: Yeah, you too. Brian, in the winter here in Massachusetts, the sun is pretty low in the sky and our daylight hours are reduced. How much energy production can I realistically expect on my solar panels during these months?
Brian: That’s a great question. We do get that a lot, right? So the little joke here in New England is you don’t like the weather, wait five minutes. So, we do get snow and we do have cloudy days in the winter, but we also have a lot of sunshine year round and in the winter.
But you’re absolutely right. The sun is lower in the 42nd parallel in the Northern Hemisphere in the winter time and the days are shorter. Once we get to November with daylight savings in particular, it shortens up those days. But we model that, right? So when we’re guiding customers and talking about their production for the year on an annual basis, on a monthly basis, we’re modeling that this house is exactly at this latitude and longitude. And then we’re also looking at the roof pitch and the shading and roofs, all the pieces that create the science of the site, to give us an indication of how much that site, with the given panels and all those pieces, will produce. And we know that that exact location has a certain amount of precipitation per year, a certain amount of sun hour potential, and all those pieces go in to give the calculations on what the production will be.
So, although, yes, production in our part of the country in the winter time is less, we know that, and it’s all modeled for that. Fortunately, through our incentive programs, one being the most basic incentive of going solar, “net metering”, when we overproduce for a given billing cycle on a monthly basis, we can get credits and those credits can help offset future electric bills. In the winter, for instance, is where we’re trying to do that.
So it’s really modeled for all those pieces. And although it is slower, the winter time, we also have some winters where we have relatively mild or low snowfall. And we’ve actually seen some Februarys, for instance, was more on the expectation of what March would’ve been. So, across our fleet, we’ve been surprised. I think it was partially this year and last year that we had almost no snow and we had a lot of those crisp bluebird days where solar panels love that weather. It’s cool. So they’re not heated, and heat actually is a big detractor in their efficiency of production. So it’s cool and they’re able to crank along, even though, yeah, shorter days, but still, they’re beginning to get longer. And then we typically see a significant jump in March where we could also get snow, but it tends to be the days are getting longer, we have more sunshine and more temperate weather where the panels are really productive.
John: Right. And like you said, you’re able to calculate that. So maybe if we were further south, maybe you wouldn’t have to have that extra panel or two on your roof or something like that. Maybe you’re having to install an extra panel or two up here in New England in order to reach the same goals for production of electricity. But you model all of that. You can figure it out based on your location and the angle that you’re facing towards south or whatever, or the pitch of the roof and all of those things. And then that goes into a calculation and it determines how many panels you need to have on your roof to get to a certain goal, right?
Brian: Absolutely. Yeah. So in other parts of the country, you get close to the equator, you get sun. A lot more sun opportunity, but it’s also a lot hotter, and therefore the panels…actually heat’s a problem. And then if we’re talking about the southwest, you’re getting a lot of dust and then soiling on the panels can be an issue. You’ve got to wash the panels.
John: They don’t have as much rain to keep the panels clean.
The Effect of Rain and Snow on Solar Panels
Brian: So that’s another thing people ask, do I need to clean that? And I was like, nope. Because the snow and the rain is going to take the pollen off. In our area, it’s just the big pollen blooms, and for a couple of days you might have the panels look yellow and then it rains and they’re all gone. But generally speaking, they’re maintenance free and it’s all modeled for the exact location of the home and we know what it’s going to produce. And our sun potential is not much less than it is further south on the east coast. So we still have really significant sun hour potential and solar makes a ton of sense here.
John: Right. Speaking of snow, does snow actually have a significant impact on panel production during the winter at all? Does the snow come down and then it covers up my panels for a few days or a week or something like that? Or does it tend to melt off?
Brian: It melts faster. So we’ve got to think that, right now, without solar on your roof, most folks have shingles that have an asphalt fiberglass composite and there’s some grit on it as well. So when snow falls on it, it has more things to grab onto and it tends to melt off the roof more slowly. And then we could potentially have issues with the ice damming as it’s slowly sloughing off, melting, freezing, and then that water’s building back up our roof.
With solar panels, now at this point they’re black cells and now most of the panels themselves are black, which, a) attracts more sun, and then they’re on the parts of our property that are getting more sunlight. So it’s the places that are going to get hit with more sun, therefore melt faster. And when snow melts on a roof from the heat loss of the home or the solar gain of the sun and the weight of the snow itself, it tends to melt on the bottom. So when it melts on the bottom on the shingles, it melts and waters down, then it freezes, and that’s what we’re talking about like ice damming and the like. But now it actually lubricates what the snow would slide off of, an all-glass panel. So now the snow melts faster in the places where we’re putting solar systems and for then the snow to be released is a lot faster because as soon as the panel is visible to the sun, so to speak, it’s actually accelerating that melting because it’s all black. So they’re heating up quicker and it’s attracting more sun, the snow is melting faster, and because that water is lubricating, the snow is coming off, the snow comes off much quicker.
So it is a concern to a certain extent, but again, we model for it. I think that 2015 was a record year for the Boston area for snow, and it was like, I think 11 Sundays in a row we got over a foot of snow or something like that.
John: Right. It was something crazy, yeah.
Brian: And so something like that, yeah, you’re probably going to do a little bit worse in the winter and the snow is going to take longer to come off. But typical snow, when we get a few inches, and if it’s light stuff, it’s going to be gone really quickly. If we get that dense, heavy stuff, four to six inches, it hangs around for a couple of days. If it stays overcast, it might hang around a little bit more. But as soon as the sun hits it, that snow is going to come off the panels quickly.
But we also, when there’s marginal levels of snow and partial melting and things like that, the technology of the panels means a lot too. So all the panels that we use, aside from being all black for aesthetic reasons, they also have technology built into them that are more shade and snow-resistant. Therefore, when less of the panel is available, they’re actually making electricity. And again, electricity causes heat which accelerates snow melting. So that’s an additional benefit.
But also, now that the customer maybe only has half their panel available, well they’re making electricity. So as opposed to most conventional solar technology, if that panel had any snow on it or any shade on it at all, either a third or the entire panel is shut down. Because we are using better equipment, our customers are getting more available productive time.
Net Metering to Offset the Winter Months
John: Okay, that’s good to know. You mentioned net metering earlier. Tell me a little bit more about that and how producing more electricity than you need during the summer can help to offset those winter months when maybe you’re not producing quite as much.
Brian: Absolutely. So, we start to see production jump up, usually in March. There starts to be a significant increase there all the time. So that’s the first real opportunity for customers to begin to net meter on a monthly basis. So net metering, like you just pointed out, that it’s basically anytime your solar system is producing more electricity than your home needs, you’re basically pushing electricity back onto the grid. Effectively spinning your meter backwards, which is lowering the demand that you have on the grid. And you’re doing that in real time every single day. But if you’re able to do it over the course of an entire month, you’re actually able to wipe out your electric bill for that month.
And if you produce more than…it never lands on net-zero, let’s face it, right? It’s either you owe them a little bit of money or they owe you a little bit of money, is what it comes down to. And you’re able to build up real dollar amount net metering credits on your electric bill. Those credits build up until you need them, and then they, basically, automatically debit it from that “account” of credits you have to pay your energy bills.
For instance, if we build up March, April, May, June, and then July, maybe it’s really hot and we use a lot of air conditioning, we have a pool pump running or whatnot. Maybe our solar system is at the peak of the production season, but so is that our peak of our usage time with all those heavy load items to keep us comfortable in the hot days. So we might have a delta that we’re not able to overcome with our solar system, when we owe money to the utility for our electric bill on that given month, but we’ve had these bank of credits we’ve built up. So now that bank of credits pays for that one bill, and we carry into, we’ll say, August, September, October. Now we’re building up those credits again.
So then we come into November and we have a significant bank of credits that we were able to build up over the course of the year during the peak season. And now we know winter’s going to be lower producing time, and depending on your heating source and your lifestyle and how many folks in your house and all those factors on how much you’re really using on those months. Nevertheless, we generally know that our solar system’s not going to cover our need and we’re going to rely on our net metering credits. And so now, automatically, we get a November bill. That’s going to be paid for by our net metering credits. It’s going to be debited directly out of our bank of credits.
Now it’s just a matter of how far can we go, and that’s all based on the site science and what the system size is in that relationship for what we can do for the customer based on their needs and maybe some of their goals for growth. But net metering is how we get energy savings. And fortunately for us in Massachusetts and most of the Northeast, we have strong net metering programs, and we’re able to realize real energy savings, in some cases eliminate our electric bill altogether.
Our family was able to not pay an electric bill over the past eight years. And it is great for us, but not every site and not every household can do that. But the more of your bill you’re able to fix, the better the economics are and the more that you’re able to control your energy costs.
John: Right. And even if you ended up having to pay a little bit for a couple of months over the winter, maybe, say, January and February or something like that, you’re still going to come out positive in the end. The rest of the year you’re not paying anything on your bill. And so you’re still making out in the end.
Brian: Absolutely. I mean, that’s what a lot of customers, their initial thought is, well, I’m not going to do it unless I can eliminate my bill. And I’m like, well, not everyone can do that. Right? And if you have a $300 a month bill and you’re able to fix 70% of that, that’s amazing, right? You’re controlling 70% of your energy costs for that one utility to run your household, and you’re able to withstand the constantly rising costs of that one utility, it is a big deal.
And some folks have… We’re seeing more and more electrification, more folks using heat pumps and getting EVs and building bigger homes and building homes with more smart home capabilities and electronics. And although these homes are really tight and energy efficient, people are adding more stuff to them that use electricity. And therefore, generally speaking, their cost of electricity per square foot is rising. And then the utility costs are going to always go up. So, if you’re able to fix a good portion of that, I mean, that’s a huge win and you’re going to be saving money. You’re going to have the same return on your investment if you’re owning the solar system. And if you are going about it with a different financing mechanism and you’re able to save, whatever, 30, 50% a month on that bill, I mean, that’s massive.
Installing Solar Panels in the Winter
John: Right. What about installing solar panels in the winter? Is that a good time to install solar panels? Are there any incentives for maybe installing solar panels over the winter?
Brian: That’s a great question, John, and we do talk about this a lot. So first of all, we do install year round. We are obviously mindful of extreme weather and we don’t want to be disrupting a homeowners’ roof or property that’s not doing so in a responsible manner. But we are able, with the equipment that we use, and our teams, to install year round. If it’s a lot of snow, we’ll clear roofs, we’ll let the sun get on it and melt it so that we can mount the system in our warranty fashion with our… We have an industry-leading penetration guarantee for all of our installations as well. So we’re mindful of that.
But in terms of the incentives, there’s not an incentive, per se, from a federal or state government to install in a certain time of year, but it makes a ton of sense. The incentive for installing, say late in the year, we’ll call it December, right? A customer that gets installed in December, unfortunately they’re getting installed in the lower production time, but they’re going to realize their tax credits and their tax benefit much quicker. So they’re getting that return turned around to them in a really quick fashion. And that helps the economics and it depends on how you’re going about acquiring the system.
But so, there’s the benefit to get installing late in the year, or in the winter time of year and late in the year, is you get the tax credit faster. The benefit of getting installed early in the year is that you’re ready to rock for the peak production time. So you’re able to hit that March time when we see that production jump up and have a full peak production season to build up those net metering credits and get that bank of credits going, so that you can come into the winter with a full bank and then get significant energy savings, or eliminate your electric bill all that first winter.
So the incentive for the customer to get installed the winter is twofold, right? It’s either to be ready for the peak production season and/or to get that tax credit as quickly as possible.
John: All right, well that’s really great advice. Brian, great to talk to you again.
Brian: Thanks John, appreciate it.
John: And for more information, you can visit the website at Solarisrenewables.com or call 781-270-6555.