Payback time in Scotland is 6-ish years. Same seems to be true in Massachusetts. Solar Panels have a lifespan of around 25 years. Inverters may need to be replaced sooner than that, but still last at least a decade.
There is no way that is true unless those solar panels are very subsidized. The energy needed to make a PV is 2x what that panel would harvest over its entire lifetime in Scotland for example. Scotland is a terrible place for PV. The numbers you give are probably accurate for central Mexico though. Also, the mean lifetime of a PV panel is 20 years.
We spend billions every year in gas subsidies. We spend billions every year in food subsidies. For energy independence and the carbon reduction alone, this is a worthwhile investment even if the upfront costs are substantial.
There are other reasons though. Whole house backup is a game changer. Battery always holding about twice our daily usage (or thrice a reduced, emergency usage) means I don’t really care about blackouts or midnight electrical company maintenance power cuts.
Direct to EV DC charging means I don’t buy gas, either. Planning for induction range and heat pump someday too. Not paying for energy about 3/4 of the year feels awesome.
Panels are cheap. Cheap to replace too. The newer ones have even better efficiency. My whole (unsubsidized) sistem cost around $15k here in Eastern Europe and amortization was never a consideration. Money well spent.
Finally, giving the finger to another crappy government-granted monopoly and proving once again that there is no such thing as a “natural” monopoly: priceless.
Approximately 3 times during the course of your life assuming you receive them when you're born and live for 100 years. They're roughly equivalent to wood siding or an asphalt shingle roof.
How long would you say a properly installed panel from 2000 made it in practice? How long would the modern equivalent installed in 2025 be expected to make it? And how many replacement events does each of those make for over the course of your life?
Do you contest my earlier claim that solar is roughly equivalent to wood siding or an asphalt shingle roof?
Using 30 years as a lifetime for solar panels is risky as there are no solar panels running for 30 years, not even close. Never mind the lifetime of the power wall battery and the inverters.
I bought a 40 year "premium" asphalt roof. It barely made it to 20. A regular asphalt roof, perhaps 10 years. Now I have a metal roof.
All the results I've seen indicate that solar panels will keep producing electricity long after those 30 years, just at a reduced rate (but seemingly still >50%).
I'm not sure what kind of answer you expect here. Your initial objection further up was:
> By the time the "free" electricity has paid for the installation, you'll need to replace it.
Since you won't need to replace it, I'd say that this whole thing couldn't work out better: the panels are literally just generating electricity for free! And that's not even taking into account that 30yo panels generate more than "only half the power" (the study I linked measured ~80%).
Imagine someone offered to give you their 30 year old panels and install them on your property for free. Unless every eligible surface is already taken up by more efficient solar panels, who would say no?
Not when you're paying people to coat their properties in solar panels. As you noted, that would cost plenty.
Solar panels also degrade over time. By the time the "free" electricity has paid for the installation, you'll need to replace it.