By Rory Carroll
SAN FRANCISCO, May 28 (Reuters) - California carbon permits covering emissions this year sold for$12.29 a tonne at the cap-and-trade program's May auction, up 8 cents from what they fetched at the previous auction in February, the program's regulators said on Thursday.
The auction, the state's third held in conjunction with its trading partner the Canadian province of Quebec, saw the partners sell all 77 million 2013 and 2015 permits put on the block.
They also sold 9.8 million permits covering 2018 emissions for the minimum price of $12.10 a tonne, regulators said.
Over 90 percent of all the permits sold at the auction were purchased by large-emitting companies required to participate in the program, the regulators said.
While they do not say how many permits individual companies purchased at the auction, the regulators released a list of qualified bidders that included oil giants Chevron, Exxon Mobil and Shell, utility companies Pacific Gas and Electric Company and Southern California Edison as well as banks, manufacturers and mining companies.
California and Quebec will announce how much revenue was generated from the auction on June 17.
California carbon revenue from its 10 quarterly auctions has already reached almost $1.6 billion, the California Air Resources Board said in March, money that must be spent on programs aimed at driving down the state's emissions of heat-trapping greenhouse gases.
This week California launched a $4.8 million pilot program funded by the revenue designed to help low-income residents replace their older cars and trucks with more fuel-efficient vehicles.
The next auction will be held on August 18. (Reporting by Rory Carroll; Editing by Jonathan Oatis and Alden Bentley)