@kendra-lee-19 - the solar credit is what is called a "non-refundable' credit - it can reduce Line 18 of Form 1040, but it can go no lower than zero; I suspect that is what occured to you in 2021. The Solar credit can be 'rolled over' to 2022 (and as many years forward as nececssary to consume it).
But again, the same thing will occur in 2022....whatever tax credit you had leftover from 2021 can be used to reduce Line 18 on Form 1040 for 2022, but it can't go below zero.
