(Refiles to make headline read 'says' instead of 'say')
By Tom Hals
WILMINGTON, Del., June 15 (Reuters) - A clean energy group that has opposed a nuclear project in Georgia estimates the plant's cost has soared to $29 billion in the wake of the bankruptcy of half-finished plant's contractor, Westinghouse Electric Co, a unit of Toshiba Corp
Sara Barczak of the Southern Alliance for Clean Energy (SACE) said that the new estimate adds $9 billion to its projected cost of the Vogtle project, which has been beset by delays and billions of dollars of cost overruns.
Westinghouse and Southern Co, the utility that owns nearly half the project, did not immediately respond to a request for comment.
SACE based its latest estimate on a report last week by two utility consultants to the Georgia Public Service Commission, which regulates utilities including Southern Co's Georgia Power.
The report is based on a scenario in which the project comes online in 2022, three years behind its current schedule, and the bankruptcy layers on costs.
Southern Co, which is leading a consortium of utility owners of Vogtle, has said it is evaluating whether it will continue with construction of the project.
SACE's latest estimate puts increased pressure on Georgia's utility regulator to ensure Southern Co cannot pass along future cost overruns to ratepayers.
A spokesman for the Georgia PSC did not immediately respond to a request for comment.
SACE has warned since Vogtle was approved in 2009 that Southern Co was underestimating the time and cost of the project. Vogtle was originally expected to begin producing power in April 2016 and cost $14 billion.
Vogtle was meant to be a showcase for Westinghouse and part of a U.S. nuclear renaissance, by has been dogged by poor quality work and disputes with subcontractors, among other problems.
Toshiba has guaranteed Westinghouse's work on the project and on Saturday said it will begin making $3.68 billion in payments to the utility partners for failure to complete the contract.
The expert reports also spell out the failure of Westinghouse to improve productivity, despite hiring consultants in 2016 to speed up the project. Over the past year four core activities fell an average of 325 days further behind schedule, according to the report.
SACE's Barczak said she felt the Vogtle project would not be completed in wake of the latest expert reports. "But the unknown question is how long is it going to take for Southern Co to pull the plug," she said. (Reporting by Tom Hals in Wilmington, Delaware; Editing by Noeleen Walder and Grant McCool)