An offer of US$2.2 billion from Toshiba Corporation to help pay for the two over-budget and overdue nuclear reactors its U.S. subsidiary had been building in South Carolina wasn’t enough to persuade fed-up investors to cancel the projects entirely yesterday.

The decision leaves the industry building only one new nuclear generating plant in the United States.

Santee Cooper, South Carolina’s state-owned electric and water utility, and private holding company SCANA Corporation, which respectively own 45 and 55% of the project, announced their separate decisions after costs for the two unfinished reactors soared from a little over $6 billion to $25 billion—dwarfing Toshiba’s last-minute offer. Begun in 2007 and originally scheduled to go online this year and next, the two 1.1-gigwatt generators at the Virgil C. Summer Nuclear Station were now not expected to produce power until 2022 after recurrent design problems.

SCANA CEO Kevin Marsh blamed the project’s failure squarely on Toshiba’s trouble subsidiary, Westinghouse, which declared bankruptcy in March. “[T]he bankruptcy of our primary construction contractor, Westinghouse, eliminated the benefits of the fixed-price contract to our customers, investors, and other stakeholders,” Marsh said in a statement. “Ultimately, Santee Cooper’s decision to suspend construction made clear that proceeding on our own would not be economically feasible.”

Utility Dive notes that “the decision leaves only one nuclear plant under construction in the United States—Southern Company’s Vogtle nuclear project” in neighbouring Georgia. It is also over-budget thanks to reactor design problems, and its owners “are expected to decide in August whether to terminate construction.”