best-known greenhouse gas (GHG) emissions trading initiative in the U.S. is the Regional Greenhouse Gas Initiative (RGGI). As of October 2007, a group of 10 states in the northeastern U.S. have agreed to begin an emissions trading system on 1 January 2009. This proposed system covers the electricity energy sector; more specifically generators with power plants in the RGGI region with over 25 MW of nameplate capacity, totalling approximately 810 facilities in the participating states.1 Although RGGI is a sub-national regional initiative,