The Mississippi Sierra Club is warning that regulators may give Mississippi Power the ability to spend more money building its coal-fired Kemper County power plant.
Mississippi Power Co., a unit of Atlanta-based Southern Co., is building what is supposed to be a $2.4 billion plant.
In March, the Mississippi Supreme Court ruled the commission failed to adequately explain reasons for easing financial restrictions.
But March 30, the PSC gave temporary approval to keep building, citing financial losses if construction stopped.
Critics said that approval exceeded the PSC's authority to give temporary permissions.
The Sierra Club said Monday that it expects the PSC to give new final permission to Mississippi Power Tuesday.
The group says the company is trying to get the PSC to lift the current $2.88 billion cost cap.
The Sierra Club said again Monday that the project is foolhardy, considering how low natural gas prices have fallen as drillers have unlocked new supplies in recent years.
The group says the commission should consider how those economics have changed since
it approved the project in 2010.