I have a similar situation.
I got my solar in 2018. But I was not able to use all 30% credit in the 2018 tax year. So turbo tax carryover for me automatically.
In 2019, I purchased a plugin vehicle, so I got $ 7500 credit in the 2019 tax year. Since this credit can not be carryover I will use it or lose it. Turbo tax automatic use $7500 credit for 2019 and push my 2018 credit to 2020 (another carryover).
Hope this helps you.
