OT: solar panels

[reuben]

I've read all I can handle from Ye Olde Internete, and a couple of Paceline threads on the subject as well. I'm looking for up to date info.

1. Northern hemisphere. Midatlantic US.
2. 2600 square foot house (oof! too big!).
3. Typical kWh/month is unknown since I've only been here for about 4 months. Looks like it may vary from 600 to 1500 kWh/month over the course of a year, but that's before...
4. I have other energy efficient things in the works - sealing the basement rim bands, adding insulation to the attic, etc., which will reduce the kWh/month, but probably not by more than 10%. Maybe 5%?
5. I'm looking at maybe ~12 kW system - TBD.
6. Panels (maybe Canadian Solar), inverter (maybe SolarEdge) - TBD.
7. I might cut down a couple of trees, but they provide shade to the back of the house in the afternoon, which would make a difference in the summer (more sun for the panels, countered by more heat onto/into the house), and no real difference in the winter (deciduous). Can't have everything, right?
8. Upfront cost might be $35k USD or thereabouts - TBD.
9. HVAC is geothermal.
10. 99% chance of going with net metering rather than a battery.
11. I'm looking to substantially reduce my electric bill, but not necessarily eliminate it.

As a (former) engineer, I've been collecting data during my short tenure here. It looks like I should keep my thermostat at a constant temperature in the winter, rather than lower it at night and raise it again in the morning. Raising it in the morning asks the system to do the most work at the coldest time of day during the winter, and that early morning spike would often exceed the kW generated by the solar panels. This works for my geothermal system. If you have oil, gas, propane, air source heat pump, or other, well... YMMV and all that.

I find all sorts of conflicting (and sometimes outright WRONG) information out there, so I figured I'd ask the most knowledgeable solar experts I've ever (not) known - Paceline cyclists.

Thoughts? Recommendations? The roofs (rooves?) are relatively shallow, 2:12, so I probably don't need to splurge on hydraulic disc brakes. Rim brakes should be fine.

[mdeth1313]

While not an expert, my understanding is if you're using geothermal (ground source), temp setbacks are not as big of an issue as the ground maintains a constant temp as opposed to the outside air temp.

[MikeD]

Why don't you get some quotes on a solar system rather than trying to figure it out yourself? I think they all use the program PVWatts to provide estimates. What you pay for power where you live is a factor (the more that is the better the argument is for solar and the shorter the payback period is). You've got net metering, which is an important consideration too. Geographical location (number of sunny days), orientation of your home (South facing roof is best), and shading from trees, chimney, etc. is a big factor too. Roof condition is a factor (don't put them on an old roof). My system is a 7.5 KW with Solar Edge optimizers. I generate more more power than I use over the year so, other than a small monthly bill, I don't pay for electricity. I have a/c and use it a lot in the summer, but have gas heat and hot water. I think batteries are a rip off unless you need them for emergency power. They like double the cost of the system and will have to be replaced at some point, well before the panels wear out. Anyway, you probably know all this stuff.

[reuben]

Originally Posted by MikeD

Why don't you get some quotes on a solar system rather than trying to figure it out yourself?

I did. So far they range from $35-75k USD for my cost, with production of 11-23kWh per year (23 kWh is way more than I need). While those gross numbers are comparable, when I try to dig down deeper their numbers don't lead to any sort of apples to apples comparison. And not all are forthcoming about the panels or inverters they plan to use.

I know the orientation of the house, trees, roof condition, etc.

[prototoast]

I am an economist, not an engineer, so I will say that you are missing a few pieces of puzzle to figure out what the financial return of this will be. How much is your monthly electric bill now? Does your electric company Do full net metering? How much do you get paid for extra generated electricity?

Unless you are baseline, electric bills are particularly high, the ROI on your solar panels seems considerably worse than where I've seen elsewhere.

[benb]

Not sure I can find it right now but I read an article recently that is something to watch for.

Apparently a whole bunch of the Solar companies that lease you panels are in major hot water due to not running their finances intelligently and now they are at risk of folding due to interest rate issues.

It's like they are extremely leveraged on all the panels they put on everyone's houses.. they wrote contracts to the homeowners but on the back end they have loans that increased rates.

If you're financing/buying them yourself this isn't an issue.

[Shane4XC]

Originally Posted by benb

Not sure I can find it right now but I read an article recently that is something to watch for.

Apparently a whole bunch of the Solar companies that lease you panels are in major hot water due to not running their finances intelligently and now they are at risk of folding due to interest rate issues.

It's like they are extremely leveraged on all the panels they put on everyone's houses.. they wrote contracts to the homeowners but on the back end they have loans that increased rates.

If you're financing/buying them yourself this isn't an issue.

If they go under, what happens to the panels? Are the contracts voided and they’re ripped off the homes? That sounds awful.

[deluz]

Did you factor in the federal 30% tax credit?
Our system was about $12K before credits, but it’s a smaller size system and meets ours needs. Last year our bill for the whole year was $45.
Normally would have paid $1200 or more.
Since they changed the net metering rules here in California, the solar industry is pretty much dead. My daughter’s fiancé works for a solar company that did our installation and he said they are laying off and eventually might go out of business. There is now a proposal in California to charge a flat rate for electricity. The rate varies with income level. If it goes through our solar panel investment would actually end up being a financial loss.

[prototoast]

Originally Posted by benb

Not sure I can find it right now but I read an article recently that is something to watch for.

Apparently a whole bunch of the Solar companies that lease you panels are in major hot water due to not running their finances intelligently and now they are at risk of folding due to interest rate issues.

It's like they are extremely leveraged on all the panels they put on everyone's houses.. they wrote contracts to the homeowners but on the back end they have loans that increased rates.

If you're financing/buying them yourself this isn't an issue.

When I looked into solar, leasing panels was just a horrible deal even if the companies remained solvent.

[C40_guy]

You've probably seen my comments in old threads...we put on a 37 panel, 12.5KwH system eight years ago. Breakeven for us was over a year ago...but Massachusetts is very generous with production credits.

I would do it again in a heartbeat..with one variation. I'd also cover our second roof with 8 more panels. Seems you can't add to a system once it's been installed and permitted, at least in Mass. I'd have to add a second system, which makes things a bit more complex.

Right now we're covering about 110% of our needs (annually), and that is slightly creeping down as we add more electric hungry goodies. With an EV or using our minisplits for heating, we'd end up using more than we generate annually.

So...plan for overproduction...it's cheap now to add a few panels, difficult and expensive later.

Also, from a federal credit standpoint, site prep is part of your overall cost. So if you spend $10K taking down trees that block panels, potentially you get $3K back. Not tax advice, just saying. I might know a guy who did that.

You are on the right path...reduce, reuse (insulate first, etc.) You might also need an HRV if your house is tight.

By the way, here's a pro tip: shift any elective electrical use to daytime, sunny days. Up until recently I always ran our dishwasher and laundry at night, now I'm doing it during the day. I also have to season a set of cast iron pans, which will mean an hour or two of oven baking.

Using electricity at night means I'm buying it retail, and selling it back to the grid during the day wholesale. If I use more during the day, I use just a bit of the excess generated. Consumer version of electron arbitrage?

[MikeD]

I'd get a few quotes and pick a reliable company that's been in business for a while and has a good reputation and probably does roofing too so they know not to screw up your roof in the process. My system was not trouble free (an inverter and an optimizer had to be replaced which were repaired under warranty). I guess my system is about 5 years or so old. In all three bids, I was told what type of system it was, etc.

[dustyrider]

It would take me so many years to pay back even federally subsidized solar panels that it’s basically a no start for me. I wish it were cheaper to be environmentally conscious but it seems so far out of reach. All I can add is to contact some local solar installers as many of them around here are happy to chat with you about all the nitty gritty.

[C40_guy]

Originally Posted by MikeD

I'd get a few quotes and pick a reliable company that's been in business for a while and has a good reputation and probably does roofing too so they know not to screw up your roof in the process.

Good solar installers know not to screw up roofing. It's not rocket science. It's the basics of using good mounting components and techniques.

On the other hand, the skills necessary to scrape and replace roofing tiles is nothing like what's needed for mounting, installing and wiring large electronic components. I would be worried about a company that tried to do both.

[glepore]

I had a nominally 18kw system in Va and was very disappointed. Needed the kw in the winter (electric aux heat) and its grey here for our shortish winter. System was sized to do approx half my actual load, and never really seemed to make a financial dent.
And the tax credit? Great if you're working and pulling down 150k/year. Living on retirement income I've never been able to use more than $500/annually and have 11k of 12.5 remaining, and I'm out of the house and into a new property. It carries over but is a joke.

[bigbill]

Many of my neighbors have had solar installed, which makes sense in NW Arizona. The power from the utility is mostly generated by wind and solar. Salesmen go door to door, with at least one a week knocking on my door right next to the no soliciting sign. The last guy was on a segway the whole time he was talking to me. His biggest selling point is all the money I'll make selling power back to the cooperative.

It's sunny here with very few cloudy days; it's the Mohave Desert, or Mojave, across the state line in California. The big non-starter for me is our snowbird status. We aren't here when it is really hot. Before we take off with the travel trailer and horse trailer, I set the thermostat at 82 degrees and all our windows have sunshade screens and heavy wooden blinds inside. While we're gone, the electric bill is <$80 a month. We have gas heat in the winter, so our winter electric bill is <$60. I don't think the payback would occur in my lifetime.