The California Air Resources Board tested August 30 the allowance auction designed for the state’s greenhouse gas emissions cap and trade program. The trial run provided the state’s major greenhouse gas emission sources an opportunity to learn how the system will work and gave regulators a chance to test the system. About 150 participants registered for the practice session to bid on 60 million vintage 2013 and 2015 allowances, though neither the total number of allowances sold nor the settlement price will be made public.