Updated at 7:08 p.m. on Friday, Nov. 2, 2018, with more information.

A 1 megawatt solar energy farm in east Memphis officially began operating on Wednesday, April 11, 2012 in Memphis, Tenn. Hundreds of industry members gathered this week in Memphis for a solar energy symposium and the dedication of a 1 megawatt solar farm. Industry leaders also met in Stanton, where Tennessee's largest solar generating facility uses its more than 21,000 panels to harness the sun's energy to output 5 megawatts of power. (AP Photo/Adrian Sainz)

The Tennessee Valley Authority has contracted with two of the nation's biggest solar power developers to build the largest solar installations ever built in Tennessee and Alabama to power Facebook's new data center in Huntsville, Alabama with 100 percent renewable energy.

TVA said First Solar will erect a 227-megawatt solar farm in Colbert County, Alabama and NextEra Energy Resources will build a 150-megawatt solar farm in Lincoln County, Tennessee.

The 377-megawatt output from these facilities is part of a historic agreement that TVA made with the solar providers to supply Facebook with renewable power for the $750 million data center Facebook is building in Huntsville. The 970,00-square-foot facility Facebook is building will employ about 100 workers and, as a condition of locating in Alabama, Facebook wanted to all of its electricity generated from renewable sources.

"We are committed to supporting our operations with 100 percent renewable energy and look to partner with organizations like TVA who offer solutions to help meet that goal," said Bryce Dalley, energy manager for Facebook. "TVA has been a great, responsive partner, and we are looking forward to being a part of the community in Huntsville."

TVA spokesman Scott Fiedler said the new solar farms will nearly double the 500 megawatts of solar-generated power now purchased or generated by TVA or its distributors.

Last year, TVA asked for requests for proposals from solar companies to build the new renewable generation for Facebook. TVA has made similar commitments to Google for its data centers in Alabama and Tennessee.

TVA officials declined to discuss the rates it will pay for the solar generation, although TVA President Bill Johnson has previously said that building additional solar or wind power tends to be more expensive than existing generation, especially since such generators don't produce power when the sun doesn't shine or the wind doesn't blow.

But to recruit businesses demanding renewable energy, TVA is adding more renewable generation. Facebook has committed to support all of its data centers and offices with 100 percent renewable energy by 2020.

"This announcement demonstrates TVA's commitment to invest in renewable energy that attracts high-paying jobs to benefit the communities we serve," said Doug Perry, TVA vice president of commercial energy solutions. "This partnership aligns the core values of TVA's public power model with Facebook's mission to bring the world closer together – powered by renewable energy."

TVA generates nearly 10 percent of its power from its 29 hydroelectric dams, but only about 3 percent of its power comes from purchased or TVA-owned wind and solar generation at present. Johnson said the federal utility plans to spend $8 billion over the next two decades on renewable power, including hydro upgrades, solar, wind and geothermal energy generation.

"TVA's commitment to the environment and our diverse portfolio are among the top reasons why businesses choose to relocate to the Valley," said John Bradley, TVA's senior vice president of economic development, who helped recruit a record amount of business investment to TVA's 7-state region in fiscal 2018. "TVA's ability to deliver large amounts of renewable, reliable energy at competitive rates makes the Valley an attractive place to do business and recruit quality jobs."

Environmental groups which have criticized TVA for not doing more to promote solar and wind energy welcomed Friday's announcement.

"We applaud Facebook for having the vision and the leadership to push for a clean energy future and TVA for responding to this large customer's demand," said Stephen Smith, executive director of the Southern Alliance for Clean Energy. "We look forward to additional solar announcements. However, TVA will still need to scale up considerably over the next five years to keep pace with solar installations from other utilities in the Southeast and respond to all customer classes desire for more solar."

Smith noted that next door in the Carolinas, Duke Energy Corp. has outlined plans to add 4,300 megawatts of additional solar power in the next 15 years.