June 21 (Reuters) - California's only functioning nuclear power plant will close by 2025 and be replaced by renewables, energy efficiency and storage under an agreement announced on Tuesday by its owner, PG&E Corp, labor unions and environmental groups.

PG&E said it would not seek to relicense the two reactors at the Diablo Canyon nuclear power plant beyond their current operating licenses, which expire in 2024 and 2025. The company cited California's goal of producing 50 percent of its power from renewables by 2030 and ambitious energy efficiency targets for the move, saying those policies had reduced the need for electricity from Diablo Canyon.

ADVERTISEMENT

The announcement is the latest in a series from nuclear operators moving to shut reactors. U.S. power prices have collapsed due to low gas prices, making it uneconomic to keep running or make needed repairs to the nuclear units . The owners of California's San Onofre nuclear power plant announced its retirement in 2013 following the detection of a leak in a steam generator tube.

Replacing Diablo Canyon with renewable power will cost less than relicensing the nuclear plant and operating it through 2044, PG&E said, citing the decline in the cost of renewables.

"California's energy landscape is changing dramatically," PG&E Chief Executive Tony Earley said in a statement. He added that nuclear power was "an important bridge strategy to help ensure that power remains affordable and reliable and that we do not increase the use of fossil fuels while supporting California's vision for the future."

PG&E also said it would make a voluntary commitment to source 55 percent of its power supplies from renewables by 2031.

ADVERTISEMENT

Groups that said they support PG&E's plan include the International Brotherhood of Electrical Workers Local 1245, Coalition of California Utility Employees, Friends of the Earth, Natural Resources Defense Council, Environment California and Alliance for Nuclear Responsibility.

There are currently 100 operating reactors in the United States, with a total capacity near 100,000 megawatts, generating about 20 percent of the nation's total power. Nuclear power provided about 8.5 percent of California's power mix in 2014. (Reporting by Nichola Groom; Editing by Dan Grebler)