The state Air Resource Board on Tuesday is auctioning about 22 million tons of carbon permits, called allowances.
The results are expected Friday, according to the Sacramento Bee (http://bit.ly/VtNBD3).
California's cap-and-trade program sets a limit on the amount of carbon that can be released annually from the biggest industrial polluters, a cap that will decline over time.
Right now companies are receiving most of their allowances for free, but can purchase the remainder through the auction or on the open market.
If a company reduces its emissions below the cap, it can sell extra allowances.
The California Chamber of Commerce has sued to halt the program, calling it an illegal tax.
Information from: The Sacramento Bee, http://www.sacbee.com