Connecticut has a pioneering plan to cut greenhouse gases by creating a cap on carbon emissions that decreases each year, then creating a market to buy and sell them. The theory is that the more emissions a power plant makes, the more it costs them, so it behooves to clean up their act and thus save money.
The Hartford Courant explains how this works, then points out a major flaw in the plan. There’s no allowance for power plants buying dirty power from outside their trading zone, then re-selling it. Also, a carbon credits market could easily just make power generation more expensive without any real lowering of emissions.
Instead, what’s needed are mandatory federally mandated (and enforced) emissions limits.