The harm to the solar industry is already being done, said assistant professor Jacquelyn Pless. The constant back and forth over policy, she said, makes it extremely difficult for companies to plan ahead. "Policy volatility is really my bigger concern," Pless said. "Policy uncertainty alone can start to freeze investment, raise costs, and damage market confidence."

"This opens the floodgates," research scientist Christian Catalini said. "You'll see entry by many issuers. Consumers will all have more choices. This will bring more competition and innovation in payments."