I have a friend who is an engineer for a power company. We discuss solar energy vs on the grid. Solar energy, at this point, is not cost effective. My friend was responsible for integrating two large solar farms into the power grid. If you want it fine but you won’t recoup your costs.
Your friend and I would probably agree on a lot. Especially if he has as much disdain as I do about making the grid depend on solar farms. The grid should be based on dependable power.
Another thing we'd agree on is, as you put it, "We discuss solar energy vs on the grid", assuming I'm interpreting what you mean by that. In virtually every scenario it'd be cost prohibitive to make a comfortable home be completely solar powered (go off-grid). My goal is not to be so energy independent that I'm off-grid. My goal is to win most of the battle on energy costs by producing most (not all) of the power we need. In other words, finding the sweet spot between taking advantage of the economies of scale, but not try to fight the law of diminishing returns.
As far as not recouping costs....it depends...on a lot. You have to do your homework, lots of it, to make sure it's good for you. And then you have to do more homework on how to tweak it to make it even more beneficial without trying to go too far and it be a money drain with little return on investment. I'm a software engineer with more experience on the back-end data side than the front-end. I'll never claim to know as much about power as an electrical engineer, nor as much about any other field of study as a (whatever)-engineer (except IT, obviously). But I am good at looking at the real-world numbers for whatever client/functional user I work for in whatever industry I work for. I used those skills to give my family's finances some protection from the warmageddon cult Democrats' stupid energy polices and their attempts to use energy price increases to slowly control us more and more (like slow boiling a frog).
My personal energy project as it's been running for the past year and a half (when I upgraded it after studying the original for a year and a half) looks at paying for itself 8 years from now (10 years after the upgrade). That includes the cost of solar (parts and labor), the cost of doing other energy projects to the house (mainly replacing my old AC and nat gas furnace with a variable speed heat pump and var speed air handler and electric heat strips, and replacing nat gas water heater with a hybrid water heater), and the cost of getting an EV (vs getting another ICE car since it was time to replace my wife's old ICE car anyway). That also includes putting the tax credits into paying down the HELOC. I hate the tax credits, but it is what it is so it's part of the math.
This 10 year pay back projection assumes only a reasonable 3% inflation rate in the energy costs I avoid (obviously if the Dims spike energy costs past that then my payback time is sooner). And it assumes a 1.2% degradation rate of my solar equipment (based on the solar panels having 25-year warranties guaranteed to still be operating at 70% in the final year, and my batteries having 19-year/50% warranties). It also assumes paying off the HELOC I took out with a fixed low interest rate, to pay most of the up front costs. (Basically I now pay a small power bill + HELOC payment, in place of sky high power bill + high natural gas bill + tons of money at the gasoline pump).
If I hadn't gone with the other energy improvements to my home and gotten an EV, (just did solar), the payback period I was projecting was about 12 years. This was after Phase I of the solar project had run for a while (before the solar upgrade and before the other energy improvements). This was when I was trying to decide if Phase II would be just the full solar upgrade I originally wanted (but experimenting with Phase I smaller system first to make sure it worked before spending more money on it in Phase II). At that point I decided to make Phase II include replacing my wife's ICE car not with another ICE car, but with an EV. Again, real world data on your own situation helps make wise decisions.
But again, you have to do tons of research on your own power consumption needs, the amount of sunlight that radiates in your area on average per day, how much that changes in the seasons, how much your power consumption changes across the seasons, etc. For example, for my Phase II upgrade I originally expected to triple my solar panel capacity and double my battery capacity. But studying the data my inverters tracked (in 5-minute candles) showed me the opposite -- I doubled my solar capacity and tripled my battery capacity. (Some of that extra was to handle the extra power consumption of charging an EV, but even that is not such a burden if you're home a lot in the day like my retired wife and my quasi-retired-working-from-home self is.) That was also the point in time that I confirmed that it was unfeasible to try to be 100% energy independent. 80% energy self-reliant is the sweet spot for us (invest enough to take advantage of economies of scale to increase your ROI, but not so much that you're fighting the law of diminishing returns and lowering your ROI).
And to add a little pessimism in my predictions, in none of the payback calculation do I figure out how much I'm gaining in my Roth IRA's by not having to pay sky high energy prices. Thus, by keeping more money in my Roth IRA's (by not having to pay high energy bills and price at the pump) our investments grow more than just the sum of the energy costs I avoid. But again, I don't track that. I just keep it in the back of my mind as the main reason I did this project anyway (protecting our retirement financial planning from the Dims' energy policies).
I do have to make a HELOC payment (because of the solar project), but it's predictable. I know how much it'll be next year and the year after -- unlike the energy costs I'm mostly avoiding. And the HELOC's minimum payment is always based on the balance, which is payed down. In other words, next year's HELOC payments will be lower than this years (unlike probably the energy prices). And the year after that my cost of saving on energy (the HELOC payment) will be even lower, while the energy costs I avoid will be higher (saving more money next year). Thus next year's ROI will increase (cost me less next year to save more next year). And more ROI the year after that. And the year after that. Obviously, this increase in ROI each year is not linear (i.e. Brandon lowered the price of gas during an election year, and Trump may win to lower energy for 4 years). But it is an overall increase across years. And in my budget my energy costs (including the HELOC) feels like it's year 2019 (what I was paying for energy back then before solar and EV and when Trump was in office, but before covid messed up energy prices, so I don't like using 2020 as a standard). Next year, if my power bill goes down a little more (again if Trump lowers energy costs), I'll put the difference into paying down the HELOC more (again keeping the energy portion of my budget like it's still year 2019 so I don't "feel" in my budget the changes in energy costs). When the HELOC is paid off I'll keep making my energy budget feel like it's year 2019 by putting the excess into an investment account. That'll pay for future solar/EV repairs and replacements (i.e. replacing the EV's battery at about the 10-year anniversary of owning it, replacing or repairing my hybrid water heater, etc.)