There’s a “down side” to almost everything.
One angle, I think, is government subsidies.
Another, for the companies who call around, is whatever cut they get.
The companies who do “free” contracts are doing it for free. The one I talked to had a contract, where if my situation matched their model well enough, then there were some options but mainly they’d “take over” my electric bill from the utility company until they had made enough money to pay off their costs in building it, plus whatever margin they’re asking for. Until then, they were essentially selling the generated electricity (calculated to be more than my household needed) to the electric company.
So the basic idea is they will eventually pay for themselves and more.
If you can afford to get someone to build them for you in advance, then that might have you come out ahead in the end, but it’s going to take years to pay for itself.
.
In my case, I didn’t do it with that company because it turned out they found out they weren’t yet able to do work where I am. But I am still interested in having solar panels – I just need to research who in my area it’d work well to do it with,