GHG Inventories

Syracuse University, in the course of its normal operations, is responsible for the emission of volumes of greenhouse gases (GHGs). Under the terms of the American College and University Presidents Climate Commitment, SU has agreed to eliminate its net GHG emissions by the year 2040. To estimate the amount (volume or weight) of GHGs that SU emits, several GHG inventories have¬† been conducted. GHGs are emitted as a result of a wide range of activities, both stationary and mobile. Thus, GHG emissions cannot be measured directly — means of estimating these emissions as accurately as possible are constantly evolving, both at SU and nationwide. Some GHG source activities (burning natural gas in the University’s Steam Station, for example) are fairly easy to estimate — the amount of natural gas burned and the GHGs created per unit of gas are both well known. Estimating GHGs emitted due to other source activities (e.g., commuting to campus by students and employees) are far more complicated — SU has no authoritative records of where every student or employee lives, by what mix of means they travel, or even how often they commute to campus each year. SU’s Sustainability Division continues to improve its estimating techniques in an effort both to understand how much GHG the university emits and how successful we are in reducing that amount. Thus, some perspective is necessary to understand the summary table of GHG inventories which follows. The table covers a period of 11 years, during which time there have been significant changes in both campus operations and GHG estimating techniques. Please review the explanatory notes which follow the table before relying on any of the numbers presented.

 Cropped GHG table

Notes:

  1. GHG emissions are conventionally accounted under three different categories, referred to as “scopes”.
    • Scope 1 emissions reflect GHGs generated by the direct combustion of fossil fuels on campus, proper.
    • Scope 2 emissions reflect GHGs emitted as a result of generating¬† utility services (electricity, steam, chilled water, etc.) consumed on campus; the activity which actually generates the GHGs is off-campus, but the demand which triggers that generating activity is campus-based.
    • Scope 3 emissions are generated by any other activity, often not under the control of the University, which takes place as a result of SU’s existence and normal operation — examples include commuting by members of the university community.
  2. GHG inventories for years 2001-2007 were prepared using a well-respected externally-provided GHG estimating tool. Because this tool was developed for use by any college or university campus, it necessarily contained a large number of factors and calculations based on national averages. Among these were factors for the efficiency of equipment for producing steam and chilled water. Since, during those years, SU purchased its steam and chilled water from an outside vendor, national average efficiency factors were the best information available to use. Subsequently, SU took over direct operation of the Steam Station, and our more recent estimates (particularly for 2010 and 2011) are based on improved information and simpler, more accurate algorithms. We now believe that the 2001-2007 estimates for GHG emissions embodied in purchased steam and chilled water were overstated.
  3. As a result of the Steam Station transition mentioned above, emissions which were previously included under the category of “steam and chilled water” are now accounted for as part of the emissions from direct combustion of natural gas.
  4. Campus shuttle service, while operated exclusively by Centro during years 2001-2007, was treated as a Scope 1 emission. Fuel burned by campus shuttle buses was, for estimating purposes, added to fuel consumed by the actual campus fleet of cars, vans, trucks and other equipment. After 2007, campus shuttle emissions were (more properly) treated as falling under Scope 3.
  5. Due both to the transfer of Steam Station operating responsibility and a change in GHG estimating tools, estimates for 2009 should be used with particular caution.