Oglethorpe Power Corp., a partner in Georgia Power's Vogtle Units 3 and 4 nuclear expansion project, has asked the Department of Energy (DOE) for as much as $1.6 billion in additional support to help finish the reactors.

In a quarterly conference call, Oglethorpe officials said that its 30 percent share of project costs had risen from $5 billion to a range of $6.5 to $7.3 billion, including financing costs and contingency.

"We expect Southern Nuclear will manage the project toward the low end of this range, but we are planning around the upper end of the range," the company said.

A recommendation from Georgia Power to state regulators on the project's future is expected by the end of August.

In late July, SCANA and its project partners decided to end work on a two-unit nuclear project at the VC Summer station in South Carolina. Both Summer and Vogtle have been affected by the Chapter 11 bankruptcy reorganization filing of Toshiba nuclear unit Westinghouse.

The DOE amended its loan agreement with the Vogtle project partners in late July. Under the amendment, loan advancements were suspended until the partners determined to move ahead with construction, adopt a new budget and timetable and finalize agreements with contractors.

If the owners scrap the project or fail to meet the amended loan agreement's terms, then the DOE will have the discretion to require a five-year payback of its loan. More than $3 billion in loan guarantees were issued by the DOE. To date, the project partners have drawn more than $1.7 billion of that. Another $1.3 billion remains to be tapped.