Georgia regulators on Thursday approved a revised Georgia Power plan that will increase the utility's use of solar and wind but also allow it to charge customers $99 million to investigate the feasibility and then license a new nuclear plant.

The Georgia Public Service Commission passed both measures 4-1.

"Adding renewables and nuclear together makes sense," said Commissioner Tim Echols in a prepared statement. "I am committed to keeping rates low and energy plentiful, diverse and clean."

The approved plan includes an additional 1,600 megawatts of renewable energy by 2021. That's nearly triple what the company initially proposed and is enough to power about 250,000 homes.

The Southern Alliance for Clean Energy and other experts testified that the utility could have added at least 2000 MW of renewable energy without causing any upward pressure on rates. The commission considered, but ultimately rejected that further expansion.

Still, environmental groups including SACE were pleased with the added renewables.

"As we've seen across the country and here in Georgia with the first solar programs approved in 2013, more renewable energy means more savings for customers," said Stephen A. Smith, SACE executive director in a prepared statement. "These projects cost less than the projected cost of generating power. This plan will set Georgia on a new path forward to grow jobs and compete."

Lisa Bianchi-Fossati, director of Policy at Southface Energy Institute, said her organization was pleased with the expansion of renewable energy, but regretted a missed opportunity to provide better compensation for rooftop solar.

"Rooftop solar customers in Georgia who send some of the power they generate to the grid are not currently fairly compensated for the valuable and clean energy they produce," she said in a prepared statement. "We appreciate the effort of Commissioners McDonald and Echols to support such a program under this IRP and look forward to addressing this issue in the future."

Green groups were less welcoming of the new nuclear plant, to be explored for a site in Stewart County along the Chattahoochee River. SACE labeled the decision "bad news for the state," and noted that under-construction reactors at Plant Vogtle along the Savannah River are already behind schedule and over budget. Commissioner Bubba McDonald was the sole vote against the nuclear motion, which includes a provision to recover the costs from ratepayers in the future.

Commissioner Stan Wise advocated for nuclear, saying it is "among the lowest cost energy source, with a 92 percent reliability rating and it is carbon free."

On the company's transition from coal, the Sierra Club supporting phasing out the Hammond and McIntosh coal plants over the next several years. The final plan caps the amount of money Georgia Power can spend on maintaining these plants and also establishes a process for the utility to work with the PSC staff to address retiring them. The new process will start within the next six months and will conclude in early 2018.

"We're glad to see that Georgia Power won't continue to sink more of its customers' hard-earned money into propping up old, inefficient coal plants like Hammond and McIntosh, and will instead build on the momentum for Georgia's growing clean energy economy," said Ian Karra, organizing representative for the Beyond Coal campaign in Georgia.