RGGI is the Regional Greenhouse Gas Initiative, a consortium of 10 states in the Northeast that has been planning the nation's first cap-and-trade system designed to reduce greenhouse gas emissions. I wrote about it in March.

The first auction, of 12,565,387 carbon allowances, is tomorrow, Sept. 25. Ed Coletta of the state Department of Environmental Protection says that, in RGGI, each allowance is for a ton of CO2, about how much is produced when burning 100 gallons of gasoline. The allowances are sold in blocs of a thousand and are good for a year.

According to John Atcheson, writing at Climate Progress...

Initially RGGI will cap emissions from 233 electricity plants at no more than 188 million short tons a year between January 1, 2009 and 2014. Thereafter, it will lower the cap by 2.5 percent a year, each year until 2018, for a total of 10 percent.

An issue that Atcheson raises is whether the limits will have any effect at first.

The target cap of 188 million tons was based on estimates made in 2004 and 2005, but recent data indicates that total emissions in RGGI states in 2009 — the first compliance year — will be lower. The New York Times reports that emissions fell to 164.5 million tons in 2006 (the last year with complete data), and estimates suggest that when data is finalized, 2007 emissions will come in at about 172.4 million tons.

If producers burn everything they want and don't approach the limits, then there aren't really limits, are there? True, the ceiling drops 2.5 percent a year, but that doesn't start until 2015.

In the meantime, at least, the money raised by the auction is earmarked for programs to promote sustainability and efficiency. At least there's that.