[mrsmith]

Perhaps it is the 1990 metric that accounts for the great difference.
Only emissions greater than those in 1990 contribute to the revenue so a small overall reduction could have a large impact on the revenue.

not a very informative article IMHO, does contribute some but could have done better.

[KarlInOhio]

Also they are auctioning a fixed amount of a product that is above the current inelastic demand. Normally they are doing the equivalent of auctioning water in a desert and are able to get any price they want. Now they are auctioning it in a lake and practically have to give it away.