Update. I just called the number back and let it ring until a person answered. He said they were "an outbound call center trying to help consumers lower their utility bills". He asked if I had given any consideration to adding solar panels.  I informed him I am on the national no call list and they should not be calling me. He apologized and said he would add my number to their no call list. He is uncertain why my number is still being called since they use scrubbers that remove the numbers on the no call list.