Preoperative tests of intermittent power plants would be suspended along with other measures to increase the reliability of the national electrical system, Cenace said in a statement released Friday. Tests that haven’t yet started will also be suspended.

The agency said that it will apply the “actions and operational strategies to strengthen the reliability of the electrical supply.”

Critics worry that the new measures, which don’t mention older non-renewable plants operated by Mexico’s state-owned utility Comision Federal de Electricidad (CFE), will hurt renewable producers at the expense of their state-run rival. Calls to Cenace outside of normal business were not answered.

“This is not in line with the care that one should take of consumers and markets,” said Eduardo Perez Motta, the former head of Mexico’s antitrust regulator in an interview. “A company with market power — the CFE — is probably trying to take care of and protect itself through these measures.”

Clean-energy producers may have a case to make before regulators as the new guidelines displace competition, Perez Motta said. “It creates enormous uncertainty for these operators, because at any moment they can cut off the possibility of power distribution,” he said.

Tensions between the clean-energy industry and the administration of President Andres Manuel Lopez Obrador came to a head in December after an Energy Ministry decision to grant old, government-run plants credits that were designed to spur new development. In the end, a judge granted a full suspension of the rule change.