The U.S. Department of Energy (DOE) has denied an Energy Transfer LP affiliate’s request to again extend the deadline for starting exports from its proposed Lake Charles LNG facility in Louisiana. 

In an order denying the application for an “unprecedented second extension,” DOE said Friday that the project had failed to show good cause for it. The agency sided with environmental groups that oppose the plant, finding the company’s arguments for the project’s stalled development were generalized.

In a policy statement issued the same day, DOE reaffirmed its expectations that LNG projects should be able to start exporting the super-chilled fuel within seven years of receiving export authorization. DOE also said it would not consider applications for extending the...