Here are some economics on the "Social Cost of Carbon" which is what the emissions of carbon dioxide actually cost us. As explained in the link below, EPA already uses these numbers as part of their estimates of the costs and benefits of various energy regulations. (Would WV ever consider doing so?)
Also, the "cost" is not a specific number, but one that varies largely depending on two factors: 1) the year in which emissions occur; and 2) the "discount rate" (roughly analogous to the interest rate or rate of inflation predicted to occur in the future, i.e., the future value of a dollar). EPA uses a range of rates to provide a range of predicted values for the benefits of damages avoided for a given amount of carbon emissions reductions.
http://www.epa.gov/climatechange/EPAactivities/economics/scc.html
The Union of Concerned Scientists has a recent editorial explaining some of the rationale and issues regarding the recent update to the SCC. http://blog.ucsusa.org/the-social-cost-of-carbon-setting-the-record-straight...
Compared to the values used by AEP and FE during the power plant transfer cases, these values from EPA are much higher.
Enjoy.
JBK