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9-11 year payback isn't bad based on the projections. You could probably goose it a bit with inflation of electrical prices (depends on how the electrical poli
by boringg 9mo ago
9-11 year payback isn't bad based on the projections. You could probably goose it a bit with inflation of electrical prices (depends on how the electrical policies change and what they pass through).
I'll also add theres some O&M coming down the line. Inverters @ year 10, small maintenance and Im assuming you re-did your roof before you installed. Anyone putting solar up make sure you do it at the same time as a roof because taking it down to redo a roof kills your economic value.
- toomuchtodo 9mo agoIt is essentially a bond return, with the caveat being that solar PV panels will last 25+ years with some degradation and reduction in output. To your point, the best arrangement (imho) is a standing seam metal roof (40-70 year lifetime) with the panels mounted via friction racking with no roof deck penetrations. This avoids the economic cost of pulling everything off the roof to re-roof, and should outlive any homeowner 40 years of age or older. I also expect labor willing to get on a roof becoming more scarce and expensive over time in the developed world, which I think should be taken into account. Your battery storage can be replaced 10-15 years from now at the end of its service life by anyone with a hand truck.
- systemtest 9mo ago-
- toomuchtodo 9mo agoThis is factually inaccurate. Solar PV panels will continue to produce power at 80-90% of rated output after 25 years, and battery storage will still have 80-90% capacity. I'm sure you can understand that as long as the system is storing and producing power at these levels, its value is not zero.
- systemtest 9mo agoCan you point out what part of what I said is factually inaccurate?
- toomuchtodo 9mo agohttps://magnifina.com/articles/rooftop-solar-yield/ https://magnifina.com/articles/rooftop-solar-yield/ explains it better than me attempting to write a wall of text.
- deleted 9mo ago[deleted]
- triceratops 9mo ago> while the initial principal of your bond investment will remain intact. As long as the bond issuer remains solvent. How much do you trust bonds that yield 9% to retain their full value for 25 years?
- systemtest 9mo agoDon't buy junk bonds. Why are you looking for bonds that yield 9%?
- triceratops 9mo agoFrom the article: "Another way to look at this is that the investment is returning ~9%/year."
- systemtest 9mo agoThat is without accounting for depreciation of the installation.
- triceratops 9mo agoHow do you measure the depreciation? The panels deliver at least 70%, but probably closer to 80%, output after 25 years. The batteries need replacing after maybe 15 years. Assuming that knocks a couple percent points off the return (batteries can only get cheaper and cheaper) that's still a solid 7% long term yield with no default risk. Share your math if you disagree. EDIT: Two more things that will juice the return 1. Grid electricity prices will go up over those 25 years, at the very least tracking inflation. 2. Unlike bond coupon payments, the "return" from a solar installation isn't taxable. Because you're saving money, not getting paid.
- specialist 9mo ago> essentially a bond return You reminded me: David Roberts' often states that a hurdle for electrification and decarbonization projects is connecting them to "slow capital". Stuff like residential, community, solar, battery, heat pumps, appliances, ground source heat, yadda yadda. I gather that there's plenty of "slow capital" perfectly happy with low risk long term modest returns. But these projects are too small to be worth the effort. Probably something about transaction costs. My impression is there's an opportunity to bundle up these projects for the larger/largest investors. Biden's IRA created a "green bank" (RIP); maybe that was its intended function. You're smart about money and finance, so you can probably explain what Roberts is talking about (to noobs like me). https://volts.wtf https://volts.wtf
- toomuchtodo 9mo agoStay tuned, I have an idea to soak up global capital for these projects.
- pjc50 9mo ago> I'm assuming you re-did your roof before you installed In the UK I would expect the roof to be tile, which lasts basically forever unless a storm hits hard enough. I did have to have my panels taken down and refitted, at a cost of well over £1000, because I hadn't bird-proofed underneath them (wasn't suggested by original installer). So watch out for that one.
- vasco 9mo agoAlmost all simulations I've done across 3 countries with 3 different payback models for selling back to grid (one of the three doesn’t allow selling back almost anything above your consumption), I could never make investing in Solar not being a gamble. You really need to gamble on odds of replacing equipment being very low for it to make sense. And in practice most people I anecdotally know that run it, after 5-7 years have already done additional purchases. The payback time keeps getting pushed back to the point that when payback will happen your panel will be worthless in efficiency compared to new ones. At industrial / commercial scale it makes sense, but humans like to move houses, and do stuff in the houses and that messes with the payback plans at the individual level. So either I was in the wrong countries or most people just gamble on the equipment lifetime, but for that I'd rather buy SPY calls, less drama.
- latchkey 9mo agoHaving power when your entire neighborhood is off, priceless. [edit: yes, I assume you also get batteries, I know that solar alone doesn't magically power your house.]
- mattmaroon 9mo agoWell there are other, far cheaper ways to get that.
- boringg 9mo agoWhats funny about that -- is you assume thats the case - but a lot of solar isn't installed to be backup power. With Storage yes, but straight up solar -> no.
- systemtest 9mo ago-
- thescriptkiddie 9mo agobattery life span is defined as when the reach 80% of their original capacity. it's possible that the decline will accelerate after that point but they aren't suddenly useless
- IAmBroom 9mo agoPresumably an exponential decay, as for most tool lifetimes.
- toomuchtodo 9mo agohttps://electrek.co/2026/01/06/catl-ev-batteries-significantly-outperform-rivals-degradation/ https://electrek.co/2026/01/06/catl-ev-batteries-significant... > For example, CATL is one of four LFP battery suppliers at the Zhangbei National Wind-Solar-Storage Demonstration Project in China. CATL’s batteries are the only ones that have never been replaced, retaining over 90% of residual capacity after 14 years. Batteries are not only not worthless after almost 15 years in service, they still have sufficient capacity to continue to operate. If you need that capacity back lost to degradation, add a battery ~15 years from now, they will only continue to get cheaper.
- n8m8 9mo agoIs an ETF simple? I get your point that in modern society, you can invest in an ETF in a few clicks, but in a way, owning your own infrastructure is simpler. Transform the sun into energy reserves with parts you can buy, understand, and install yourself from wholesalers. A power company is opaque, carries overhead, and requires complexity to serve at an institutional level. ETFs have a similar complexity/abstraction to their customers.
- deleted 9mo ago[deleted]
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- alberth 9mo agoWont you need to replace the batteries around Year 10 and then this becomes a wash?
- boplicity 9mo agoWhy would you need to replace the batteries? Do they fail outright at around 10 years, become unsafe, or do they just lose capacity? Curious! Even if they're at 50% capacity, they would still work, right? But if there are other considerations, especially safety ones, then that would definitely be a consideration. I'm not sure where to learn about this type of thing.
- mbesto 9mo ago> Do they fail outright at around 10 years, become unsafe, or do they just lose capacity? LiFePO4 generally degrades to 80% capacity after 10 years, that's it. Safety isn't an issue.
- lostapathy 9mo agoAt which point if you're short on capacity (but who knows how your demand might shift over a decade) it's not like you need to replace the original batteries to get that 20% back, you will probably be able to just expand the pack to bring the capacity up.
- HexPhantom 9mo agoThe payback math almost certainly improves if electricity prices keep rising faster than inflation