Yes, according the the instructions for Form 5695, Residential Energy Credit:
If you can't use all of the credit because of the tax liability limit (that is, line 14 is less than line 13), you can carry the unused portion of the credit to 2020..
You should not include the cost of financing the solar panels in the solar panel cost entered in your tax return. So only include the total before interest.
[Edited 03.18.20 | 11:01 ]