Our legislature passes laws, but agency beaureaucrats write the actual regulations to implement said laws. These buereaucrats are typically 60's hippies, envirowhacko's or recent mid eastern immigrants.
It's going to be interesting in deciding who gets what caps.
Essentially the big guys are going to eat up the little guys, forcing them with lower caps, paying more political contributions to get higher caps so they can continue the same emissions, or lobbying for higher caps so they can get freebie carbon credits to play the market with. The bigger guys will also have better ability to fake their stats.