Technical brief: transportation overtaking electricity generation as the largest source of US CO2 emissions
A technical brief by Dr. John DeCicco at the University of Michigan Energy Institute shows that transportation is overtaking electricity generation as the largest source of US CO2.
The average rate at which CO2 is emitted from vehicle tailpipes and other mobile sources has exceeded the rate of CO2 emissions from electric power plants over seven of the past eight months. Although efficiency gains are limiting transportation emissions growth, the gains are not enough to reduce the sector’s CO2 emissions in the face of increased travel and shipping, DeCicco writes. CO2 emissions from the transportation sector increased at an average rate of 1.8% per year over the past four years.
|12-month running averages for transportation and electricity generation since late 2014. These curves smooth over the seasonal variations in the monthly data. Data derived from US EIA. Source: John DeCicco. Click to enlarge.|
Further, electric sector CO2 emissions have dropped greatly in recent years, declining at an average rate of 2.8% per year over 2007-2015 due to the displacement of coal by natural gas, wind and solar for power production as well as energy efficiency gains.
On top of that, the Clean Power Plan will accelerate CO2 reductions in the electric sector, widening the gap by which transportation exceeds electricity in the years ahead unless additional steps are taken to reduce or offset the CO2 emitted by cars, trucks, aircraft and other mobile sources, DeCicco notes.
|Projected CO2 emissions from transportation and electricity generation with and without the Clean Power Plan. Source: John DeCicco. Click to enlarge.|
Stronger CAFE and GHG emissions standards for cars and trucks will help, but are not enough to put transportation sector CO2 emissions on a clearly declining trend. Additional measures, including ways to offset the CO2 emitted by liquid fuel use, will be needed to address the transportation-climate challenge.—John DeCicco