Jimmy Carter has supported not only solar energy, but also domestic fossil fuel production and encouraged both of them. The policy of Carter administration never was to go 100% renewable.

"Our Nation's energy problem is very serious—and it's getting worse. We're wasting too much energy, we're buying far too much oil from foreign countries, and we are not producing enough oil, gas, or coal in the United States."

Energy Address to the Nation. April 05, 1979 https://www.presidency.ucsb.edu/documents/energy-address-the...