Greenhouse Gas Inventory

Greenhouse Gas (GHG) Emissions

Duke's GHG inventory contains data back to 1990, but incorporates far more activity beginning in 2007.  Also beginning in 2007, emissions are broken out by University (which includes the School of Medicine and School of Nursing) and Health System. In total, Duke has achieved a 23 percent reduction in emissions as of 2013, based on a 2007 baseline. The graph below displays a reduction in overall emissions of the University and Health System since 2008.

The large reduction between 2012 and 2013 can in part be attributed to a change in methodology for the calculation of Duke's emissions due to air travel.  The methodology was updated based on access to new data that more accurately reflects actual air miles traveled.  Without this methodology change, Duke would still have a achieved a 15 percent reduction in emissions from the 2007 baseline in 2013.

2013 GHG

Duke's Climate Action Plan is specifically targeted for the University (including the School of Medicine and School of Nursing). The graph below displays a 28 percent reduction in University emissions in 2013, based on a 2007 baseline. 2013 GHG

As explained above, the 28 percent reduction in emissions is also a reflection of a new methodology for calculating air travel miles.  Absent this methodology change, University emissions have still achieved a 18 percent reduction from the 2007 baseline as of 2013.

This reduction can be partially attributed to energy conservation measures and an elimination of coal usage on campus, as well as the implementation of other Climate Action Plan measures.  Additional factors, such as economic conditions, also impact the University's emissions.  The graph below compares a Business as Usual (BAU) scenario to Climate Action Plan (CAP) projections and 2013 actual emissions.  The graph demonstrates that University emissions reductions are on target with the goals outlined in the Climate Action Plan.

CAP projections

Duke University's carbon emitting activities can be grouped into three major categories:

  • Electricity, which is purchased from Duke Energy;
  • Stationary fuel, which includes the two campus steam plants used for heating and hot water; and 
  • Transportation, which includes employee commuting, air travel paid for by the University, and the campus fleet.

The graph below displays the breakdown of emissions of the University (including the School of Medicine and School of Nursing) based on carbon emitting activity in 2013.  The "Other" category includes waste, refrigerants and fertilizers.

2013 GHG

Transportation Footprint

Duke's transportation footprint is comprised of three major sources which contribute the following percentages to Duke's overall GHG footprint:

  • Commuter travel (13%), employees commuting from their home to work;
  • Air travel (9%), faculty/staff work travel, sports team travel, and school-related student travel; and
  • Fleet (1%), all bus and university vehicles operated for directly work-related purposes.
In total, transportation comprises about 23 percent of Duke's greenhouse gas inventory, as displayed in the pie chart above.

Fleet emissions are down 10 percent compared to a 2007 baseline.  Overall, as of 2013, emissions from transportation have risen 15 percent compared to a 2007 baseline and will require significant attention in the coming years.

Energy Footprint 

Energy use at Duke has a significant impact on the environmental footprint of the University.  According to Duke's 2013 GHG inventory, energy comprises 76 percent of the University's GHG emissions. 

Formerly, on site energy emissions stemmed primarily from combustion of coal to produce steam in two campus steam plants.  In 2009, as part of the Climate Action Plan, Duke opened a newly renovated baseload natural gas East Campus steam plant, which cut coal consumption by 70% on campus.  In April 2011, Duke eliminated coal use from campus completely, and began renovations to its West Campus steam plant to convert it from a coal-burning plant to a natural gas facility like its sister plant on East Campus. Duke’s emissions from campus steam plants have decreased 36 percent as of 2013 compared to a 2007 baseline.

As of 2013, Duke's overall energy emissions are down 30 percent compared to a 2007 baseline.

The 2013 GHG inventory indicates that emissions from purchased electricity off site through Duke Energy make up 50 percent of the total campus GHG emissions (including emissions from transportation).