From 2010 to 2011, CO2 emissions from fossil fuel combustion decreased by 2.5 % due to: (1) a decrease in coal consumption, with increased natural gas consumption and a significant increase in hydropower used; (2) a decrease in transportation - related energy consumption due to higher fuel costs, improvements in fuel efficiency, and a
reduction in miles travelled; and (3)
relatively mild winter conditions resulting in an overall decrease in energy demand in most sectors.