A former employee is suing to force a Mississippi utility to repay $382 million that the federal government gave to build a failed coal-fueled power plant.

Kelli Williams, a former construction manager for Atlanta-based Southern Co., filed a whistleblower lawsuit against the company and its subsidiary Mississippi Power Co. in 2018. That lawsuit, unsealed Monday, alleges that the two firms defrauded the U.S. Department of Energy and state regulators in a failed quest to build a $7.5 billion power plant.