According to a recent U.S. Energy Information Administration (EIA) news release, preliminary estimates of U.S. carbon dioxide emissions from burning fossil fuels increased by 1.6 percent in 2007. 

The economy, as measured by Gross Domestic Product (GDP), grew by 2.2 percent and energy demand rose by 1.7 percent indicating that energy intensity (energy use per unit of GDP) fell by 0.5 percent.  Carbon dioxide intensity (carbon dioxide emissions per unit of GDP) also fell by about 0.5 percent.  

Factors that drove the emissions increase included weather conditions that increased the demand for heating and cooling services and a higher carbon intensity of electricity supply.

Total U.S. energy-related carbon dioxide emissions have grown by 19.4 percent since 1990.   Energy-related carbon dioxide emissions account for over 80 percent of U.S. greenhouse gas emissions.

Preliminary fossil fuel consumption data indicate that:

• Carbon dioxide emissions from the residential and commercial sectors increased by 4.4 percent and 4.3 percent respectively in 2007, as heating degree-days rose by 6.7 percent and cooling degree-days rose by 2.6 percent.  The commercial sector includes all non-residential, non-industrial buildings, such as stores, office buildings, schools, hospitals, and government buildings.

• Industrial carbon dioxide emissions fell by 0.1 percent in 2007, continuing a trend of falling emissions since 2004. 

• Transportation-related emissions, which account for about a third of total energy-related carbon dioxide emissions, increased by 0.1 percent in 2007. 

• With combined industrial and transportation emissions essentially flat, all the growth in emissions came from the residential and commercial sectors.
  • Emissions from the direct use of natural gas in the residential sector grew by 8.3 percent, while growth in residential electricity use and changes in the generation mix caused emissions associated with the production of electricity used in residences to grow by 3.9 percent.
  • Emissions from the direct use of natural gas in the commercial sector grew by 6.1 percent, while growth in commercial electricity use and changes in the generation mix caused emissions associated with the production of electricity used in the commercial sector to grow by 4.2 percent.

• When electric power sector emissions are considered as a whole rather than being attributed to the end-use sectors that consume electricity, they are the largest single source of U.S. carbon dioxide emissions, representing 40 percent of total emissions.   In 2007, emissions from the electric power sector increased by about 3 percent, while power generation increased by 2.5 percent.  The increase in the emissions intensity of generation of 0.5 percent reflects, among other factors, a decline in non-fossil-fueled generation, as increased generation from wind and nuclear power of 6 and 19 billion kilowatthours, respectively, did not offset a drop in hydro-generation of 40 billion kilowatthours (kWh).

From 1990 to 2007, the carbon dioxide intensity of the economy fell by 26.6 percent or 1.8 percent per year.  By 2006 (the latest year of data for all greenhouse gases), carbon dioxide intensity had fallen by 26.2 percent and emissions of total greenhouse gases per dollar of GDP had fallen by 27.7 percent. 

EIA will continue to refine its estimates of 2007 carbon dioxide emissions as more complete energy data become available. A full inventory of 2007 emissions of all greenhouse gases to be issued in November 2008 will present revised energy data and provide a further analysis of trends.

The preliminary estimates are on EIA's web site at:
http://www.eia.doe.gov/oiaf/1605/flash/flash.html


Source: EIA-2008-05