SOLAR POWER

SMA is so bloody expensive though. Buy Chinese either Ginlong or Sungrow. I’ve visited both their factories and their quality systems are great. I commissioned a full quality audit on Ginlong a few years back and they rated really highly and I only ever had one quality issue in dealing with them over 1000s of installs. (a weird clipping issue at maximum output that got solved in subsequent models)

If you have a difficult roof or shading issues, get SolarEdge.

I agree with Ed, Sungrow is good as well and SolarEdge is the best choice for shaded roofs - SMA won't work well with shade

I just *really* like the Secure Power Supply feature on SMA

also, Ed I would love to hear the gory details about that clipping issue if you are so inclined

We've got an ideal house and roof for a lot of this, so we'll see what the guy says tomorrow.

Just got off the phone with a good friend of mine who deals with these issues on a regular basis, and he is dubious about solar. Very bullish on geothermal though, because it's a constant. There's nothing to generate, no changing costs or production. It just does this thing. Vs. solar, which is beholden to myriad other factors.

He also, as Karl noted above, stressed the importance of simple shit, like insulation, to making sure your home is as efficient as possible. Doesn't matter where your power or heat or cooling is coming from if you lose half of it through your walls and windows.

Quick question: if I'm about to talk to this guy about solar, what specific questions do you think I should I ask him? What answers would be most useful for someone on the fence?

estimated payback time

price difference for different inverter options as Ed noted (Sungrow, Solar Edge, SMA if you want to spend a bit more for a backup outlet)

I dunno, what are your on-the-fence concerns? Like for example, this:

There's nothing to generate, no changing costs or production. It just does this thing. Vs. solar, which is beholden to myriad other factors.

I really don't agree with - solar is maintenance free, by design. set it and forget it. And the production is very consistent within seasonal variation. I've talked to people still getting 70% output from their Motorola panels made in the 1970s.

The guy I talked to was great, helped a lot. Estimated payback time with more efficient and reliable (which is to say, more expensive) panels could be about 7 years, which is not bad. And cost would in theory be reduced by 40% or so once you take into account tax rebates and SRECs and whatnot, with a lot of that coming back to you more or less the first year. Though it's still a *considerable* initial cash expenditure. Obviously a lower outright price would be better than a higher price with a promise of refunds, but that's not where we're at.

I think my friend's thing with geothermal is that the energy being generated is constant. It's not linked to sun or shade or snow or cloud cover or whatever, it's just there, year-round. There is no degradation of panels or reduction of panel efficiency, there is no fear of needing (or wanting) to upgrade in the near future, and it covers the biggest drag on a lot of homes, heating and cooling. Of course, it costs a lot more to install! But for example, solar, the Panasonic panels the guy prefers (with iirc solar edge inverter) have a 25 year warranty, which is great ... except who knows how things will look in 25 years, in terms of technology and options and the like. A similar consideration is that when it comes time for a new roof, the panels have to be removed and replaced, too, which could add thousands to the cost. And so on.

There is no degradation of panels or reduction of panel efficiency

this is not a thing that happens, panels have a 25-year output warranty for a reason, and work for even longer as noted above

no fear of needing (or wanting) to upgrade in the near future

also not an issue - don't replace existing panels to upgrade, just add more on a newer inverter.

the biggest drag on a lot of homes, heating and cooling

OK this I agree with.

fwiw my parents have had many painful and expensive difficulties with their geothermal system, they have had no issue with the solar at all.

sure there's an early-adopter price tag still. but as you have seen, the numbers are good in terms of IRR.

My mom has geothermal and loves it, but is not really a candidate for solar.

And panels absolutely do degrade, however slightly. So says the guy I just spoke with and everything I've seen. The cheaper the panel, the quicker (or more) they will start to degrade. The more expensive the panel (like the ones he was pitching), the better they work and the longer they work before any significantly reduced returns (plus better warranties). Granted, around 1% annual decline in productivity is not that big, but that still means 10% after 10 years, and so on, which is not nothing. If we were to, say, want to sell our house in ten years, solar may factor as a selling point, but esp. if we can say it offsets 100% of the house's consumption. It's still good to say 90%, or 85%, but it may not hit that magic psychological number, imo, to get the ideal ROI.

And adding to the system in the future obviously costs money, too. Just things to consider.

it's way less than 1% a year degradation, more like 1/4 of a %

there's a reason they guarantee >80% output for 25 years, 1% a year would be a lot more than that

and yeah you are correct that "100% coverage" is often not a good idea in terms of ROI

Just googling I saw something like an average of .5% annual degradation, and that's linked, like output and efficiency, to quality, which is to say, cost. But yeah, that's a relatively minor concern. Degradation, not cost, that is. A higher priced system here would go for around $22K. A lower cost system would go for around $18k. Both are huge numbers, and if you finance, obviously that number goes up.

fwiw that amount sounds just about right for installed cost on 5-6 KW

I just got his formal pitch, if you're curious, but it includes:

Panel degradation rate: 3% in year 1; 0.26% years 2-25 - 90% efficient @ yr 25

ah that's really interesting! thanks. I did not know that more degradation was assumed in year 1.

After saying my roof isn't great for solar I'm now starting to thing I should jump on this. The Roof is bad because it is flat and mainly taken up by my roof deck, but havingng Saturday up their a lot the shading on the exposed parts isn't actually as bad as I thought and now you can get a 400W standard size panel(SunPower), I could actually get some useful production out of it. There's an outside chance I could squeeze 6 on the eastern end of the roof and 2 on the western end, really its probably 4 and 2 but that could still be 2.4kW. Panels would probably have to be flat rather than on tilt frames or the homeowners association would flip and the shading means I'd have to have micro inverters (Enphase) or optimisers (SolarEdge) to get the best out of a system.

I've had the Enphase option priced out and it comes in at AU$3.74/W which makes me wince, especially as we won't qualify for the current VIC government rebate which would bring that down. I've got a mate going through the same process and his (much bigger) system is quoted out at $1.22/W or AU$1.08/W if he gets the rebate. Thats on a SolarEdge System with optimisers and and Longi 350W Mono PERC panels.

Not that it's really about payback but It would take me about 10 years to breakeven on that

26% solar tax credit extended for 2 years as part of the COVID bill, definitely a good thing

https://www.solarpowerworldonline.com/2020/12/solar-investment-tax-credit-extended-at-26-for-two-additional-years/

even better news

https://pv-magazine-usa.com/2022/07/28/solar-investment-tax-credit-to-be-extended-10-years-at-30/

Dunno if I mentioned it, but we did end up getting solar and have been very happy with it so far.

what inverter type, do you know?

also, Josh, note this key provision:

"The tax credit applies to residential adopters of solar technology. If the bill is passed, the 30% credit will be retroactively applied to anyone who installed their system since the beginning of 2022."

We had it done in 2020, so already got whatever rebates and whatnot we were expecting.

As for inverter type, I believe we have a Solar Edge Single Phase Inverter with HD-Wave.