Thank you @Opus 17 for responding and asking the follow-up questions. Here are more details:
I will need to install a total of 50 solar panels on my home in Massachusetts. The net metering cap in Mass was legislatively increased last year, but the utilities are waiting for new regs and so the present cap of 34 panels is still in place. My solar company advised me to install the first batch of 30 panels this year, and to install the other 20 next year after the new regs are released (and I can be assured to fall within the net metering cap without relying on grandfathering).
This is one system for my house, and I have installed and am operating the first 30 panels. I will likely install the other 20 panels on this present system next year after the regulations are updated.
I had planned on claiming the 30% credit each tax year (30 panels for this year and then 20 panels for next year), but worried that I could only claim once per system. This didn't make sense to me though because if someone wanted to add more panels to an operating system (e.g., because they later bought an EV), I would imagine they would get the 30% credit on the incremental new panels as well.
I suppose I could also wait until after 50 panels are installed and then claim the FTC for that year (which would be next year), but I also thought you had to file the credit in the year in which you first installed (as opposed to finished) the system.
I also suppose I could treat the 30 panels as one system and the 20 panels as another system, and that would also allow me to file the FTC for each system when installed. I know the solar company will have to do another round of permitting and likely another Permission to Operate (PTO) for the second 20 panels as well (that would then get up to my total of 50 panels, with two different PTOs for 30 and then another 20 panels).
Thank you again for taking the time to try and help me get my head around this.
