There's nothing better than getting something for free. Apparently, that is what the Congressional Budget Office (CBO) says that we can do with green stimulus.

The basic story is simple. Suppose that we had a generous tax credit (30-40 percent) for homeowners and businesses who increased insulation, installed energy efficient windows or other energy conservation measures.

Suppose we also set up a pot of money for transit agencies that reduce fares for riders. The federal government meets their fare reductions dollar for dollar. This is effectively a tax credit for people who take mass transit.

CBO says these policies won't cost the federal government anything.

Its argument is that these policies are not stimulus because they take too long to implement. We can't know whether this is true or not in advance. (How long does it take desperate building contractors to find people who will take advantage of this tax credit?) But, we do know that if we pass time limited incentives (e.g. you have until March of 2009, or forget it) and no one takes advantage of the tax breaks, then it doesn't cost anything.

In other words, we can write these and other green stimulus measures into the law in a way that if they are not used, they don't cost anything. In short, it is a risk less proposition. If Congress took global warming seriously, these measures would be no brainers.