The Energy Department has a flawed system for documenting and tracking applications for taxpayer-backed loans, a weakness that could hinder oversight of federal investments in green-energy projects, congressional auditors said Monday.

The Government Accountability Office, in a new report, said it took Energy Department staff more than three months to provide data on the status of its loan guarantee applications.

“Because it took months to assemble the information required for our review, it is also clear that the [Energy Department’s loan office] could not be conducting timely oversight of the program,” the report says.