Solar Tax Credit on a system expansion that came with the house

[wvlucas253]

Hello there!

To summarize. 

I bought my house in 2019. The owners at that time had installed a 3.6kW PV system earlier that year. I recently replaced the roof and before putting the old system back up I wanted to expand the system due to my energy needs being greater than theirs plus Colorado and Black Hills Energy increasing what you're allowed to install. After some time, it was determined that I'm going to replace the panels and inverter so a completely new 5.1kW system will be installed. Since I didn't originally install and therefore didn't claim the tax credit for the original system, can I claim this one? If that isn't possible, can I at least claim the difference in kW

[Opus 17]

You can claim the credit on new installation.    That would include adding new capacity, or ripping out the old system and installing a new one.  It would not include making repairs to the old system.