I am trying to calculate my Utility Expenses related to my consulting work from my home. Can I include my loan payments for my solar panels?

No.  That's not utilities.

 

A second question would be can I deduct the loan interest.  Probably.  It would have to qualify as a 2nd mortgage.  Home improvement loans usually qualify. See rules at https://www.irs.gov/publications/p936

 

 

Other references:

https://www.rocketmortgage.com/learn/mortgage-interest-deduction#:~:text=What%20Is%20The%20Home%20Mortgage,amount%20of%20taxes%20they%20owe.

https://www.energysage.com/solar/financing/secured-or-unsecured-solar-loan/#:~:text=Many%20secured%20solar%20loan%20providers,secured%20loans%20is%20tax%2Ddeductible.