Southern Company announced to state regulators Thursday it plans to carry on with its much-delayed plan to build two new nuclear reactors at Plant Vogtle in eastern Georgia.

Georgia Power, a subsidiary of Southern Company, thought Plant Vogtle would be a leading component of a wave of new nuclear power plants opening in the U.S. to supplement an aging fleet.

But in March, Westinghouse — the lead contractor on the project that designed the reactor — went bankrupt, imperiling the future of Plant Vogtle.

The recommendation from Georgia Power to the Georgia Public Service Commission to move forward with Plant Vogtle means it will remain the only nuclear reactor under construction in the U.S.

Last month, South Carolina utilities announced they would cancel a separate plan for two nuclear reactors in the state due to cost overruns after Westinghouse, also designing the reactor for that project, went bankrupt.

Nuclear advocates praised Southern Company's decision to press ahead with Plant Vogtle, considering it a signal of a commitment to clean nuclear power, which has zero emissions and proponents say is more reliable than wind and solar energy.

"What the Southern Company has done is courageous," said Rich Powell, executive director Clear Path Action, in an interview with the Washington Examiner. "They are standing up to say this technology has national significance and is important, and they won't give up on nuclear even though so much of the rest of the country has. They are making sure the big national investment we made in nuclear in the interest of remaining a nuclear competitive country won't go to waste."

Georgia Power estimates it will complete one of the new units at the Plant Vogtle by November 2021, and the other a year later.

The filing with the Georgia Public Service Commission begins a review process by Georgia regulators, who will decide whether to approve additional spending on the Vogtle nuclear project. A decision is expected by February 2018.

In 2009, Southern Company estimated the new Vogtle reactors would cost $4.4 billion. But, Southern later revised the cost estimate to $5.7 billion if both reactors were completed by 2020. Earlier this month, Southern said the cost could grow to $7.4 billion if the reactors were built after 2020.

Powell says this investment is worthy because it represents progress towards a "nuclear renaissance" promised in the George W. Bush administration.

But that promise never came to fruition. There has been only one nuclear reactor completed in the U.S. since the early 1980s.

The Obama administration was less friendly to the nuclear industry, Powell said, charging companies more for loan guarantees.

And competition over recent years from cheap natural gas produced by the hydraulic fracturing boom reduced the demand for nuclear power.

Today, 60 percent of the carbon-neutral energy produced in the U.S. comes from the nation's existing 99 nuclear power plants.

"Nuclear is already our most important source of clean energy," Powell said. "And don't forget about the national security angle to this: If we don't maintain a thriving domestic fleet of nuclear reactors, we won't be competitive globally. That means Russia and China will be the global nuclear players, and they don't have same commitment to nonproliferation that the U.S. does."