The price of solar power just fell 50% in 16 months

Spending $40,000 of that on "clean energy" so that they can "feel better" is well outside of the typical person's price range. Even $7000 would be cost-prohibitive, especially if they're paying or saving up for their kids.

A cold can of beer also makes you feel better. Its a hell of a lot cheaper too. The answer for the typical American is to wait for utility-scale to build Solar out for them.

When the city as a whole notices that solar is cheaper than running peaker plants or whatever, then the city / municipality can purchase an entire field of solar (AND the energy storage needed to make it useful) and give it out for the whole town.

And in the mean time, you can drink your beer on the porch while you wait for progress to be made.

by the same token, price reductions in solar power cost leads to battery storage systems (or other storage systems) being even more desirable and cost-competitive, in turn leading to them being installed in preference over other types of power plants.

First, I work from a baseline cost of $19K, even though the list price was closer to $40K I didn't pay that for the system so I use the actual cost in my calculations.

Second there is the point where the money you've saved is equal to the money you paid, we hit that point about 10 years in. And then, depending on the life of your system (which has "positive cashflow" at that point) determines your overall rate of return. The replacment inverter (which is actually going to replace both inverters) is $2K ("upgrade" pricing from the manufacturer) And as the inverter was failing our system was under performing (so not generating as much power). The question will be how much longer am I willing to run the panels. The warranty is 25 years, so in theory another 10 years but the manufacturer (Sharp) no longer makes them and cannot replace them under warranty (they can only offer to repay you to buy a panel from some other vendor with equivalent specs and size).

So from a money perspective, had I used the $19K and put it into an S&P 500 ETF in 2003, it would have doubled by now (SPX was 1,008 in 2003, its over 2,016 today). So "bad investment" comparatively. If the panels continue for an additional 8 years and PG&E's costs stay about the same then I'll have generated about $20K in value from them so that would pencil out to a ARR of about 3.5%. Initially I funded the panels with a refinance of the house loan and that was at 6% but that has since been refinanced even lower. However had it not been, at my original purchase I'd still be running a deficit trying to both pay back the house and generate cash from the solar.

Interestingly for me, with the $7K it would cost to re-implement that system today, and 4% mortgage rates, it would have a rate of return of closer to 14% (10% if you subtract 4% as the cost of capital for a mortgage refi) and pay for itself in a bit more than 3 years and have doubled the return in 6. The challenge is additional regulatory changes which get incorporated into new installations versus the regulation regime I operate under based on my 2003 install date. I wonder sometimes what the trigger is for resetting the project's origin date.