@tax73 wrote:
If I stopped paying my federal taxes monthly would that allow me to use the solar credit once I file my taxes for that year?
No. The credit can only be applied to your tax liability, which is only loosely related to your tax due or refund.
Suppose you have $5000 of payments and withholding and get a $1000 refund. Your tax liability was $4000. Or, if you only paid $1000 into the system and owed $3000 when you filed, your tax liability is still $4000.
Your tax liability is on line 22 of form 1040. It sounds like your liability is already zero for 2020, if Turbotax won't let you use the credit. You might or might not have tax liability for 2021, depending on your income, kids credits, and so on, but your liability will be the same now matter how much you owe or pay in advance.
(If you are self-employed, your self-employment tax is separate from your income tax liability. The solar credit is applied against the income tax liability, not the SE tax liability, so even if you owe SE tax but no income tax, you can't use the credit.)
