The "American Clean Energy and Security Act" is a complex proposal. Lawmakers who weren't crazy about the "cap and trade" idea to begin with today complained about seeing the 932 page proposal first time late Friday, ahead of this afternoon's mark-up. The big change is that utilities and other large emitters of carbon will no longer pay for their initial pollution permits, but be given them for free.

Public Citizen's Tyson Slocum says it's a "huge mistake to make radical, major revisions to the bill behind closed doors." Both Congressman Ed Markey and Henry Waxman hailed the compromise. The key reason for the change was to build industry support for the bill.

Now that the debate is out in the open, people are beginning to evaluate what it means. Deloitte consultant Branko Terzic says by giving away the initial permits, the private sector, rather than government will be the ones to decide how the allocations are used, and the profit motive can be an incentive to innovate. But environmental groups are wary. Most still support the bill, but are now calling for it to be "strengthened". David Hamilton of the Sierra Club says we shouldn't repeat the mistakes the Europeans made with their cap and trade proposal. In that case, many firms treated their free allocations as if they had paid for them and passed the "costs" to consumers.