According to the US Environmental Protection Agency (EPA), Greenhouse Gases (GHG) forms a barrier in the atmospheric layer that traps heat and prevents it from being released into space. Excessive trapped heat can lead to global warming. Some examples of common GHGs include, Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O).
The GHG Inventory is a reporting tool that helps keep track of GHG emissions by an entity in its daily operations. GHG emissions are categorized into 3 scopes as defined by the EPA:
Scope 1 emissions are direct GHG emissions from sources that are owned or controlled by the entity. Scope 1 can include emissions from fossil fuels burned on site, emissions from entity-owned or entity-leased vehicles, and other direct sources.
Scope 2 emissions are indirect GHG emissions resulting from the generation of electricity, heating and cooling, or steam generated off site but purchased by the entity, and the transmission and distribution (T&D) losses associated with some purchased utilities (e.g., chilled water, steam, and high temperature hot water).
Scope 3 emissions include indirect GHG emissions from sources not owned or directly controlled by the entity but related to the entity’s activities. This can include commuting, air travel, waste emissions, etc.
UNL GHG Inventory
UNL recently conducted its Scope 1 and Scope 2 greenhouse gas emissions inventory for the year 2009 to 2014 using University of New Hampshire’s web-based Campus Carbon Calculator Version 2.0. Data for the inventory was collected from multiple University departments and compiled by the Office of Sustainability. Here is the list of personnel involved in the process:
Rhett Zeplin - FM&O Utilities Services for Campus co-generation
Jerry Welch - Procurement Services for fertilizer use
Greg Turner - Building Systems Maintenance
Bruce Effle - Utility and Energy Management for refrigerant use
Kelly Heath - Institutional Animal Care Program for livestock
The CACP Campus Carbon Calculator v7.0 was used to find equivalent CO2 emissions from each inventory source.
|UNL GHG Inventory|
|GHG Measured||Carbon-Dioxide, Methane, Nitrous-Oxide|
|Scope 1+2 Total Gross C02 Equivalent||234,191.17 Metric Tons|
|Per Campus Square Foot||0.018 Metric Tons|
|Per Capita Full Time Equivalent Student||10.37 Metric Tons|
Campus GHG Emissions over the Years
The University of Nebraska-Lincoln has been consistently putting engineering and conservation efforts to lower our carbon footprint. Based on the recent Scope 1 and Scope 2 emissions calculations conducted by the Office of Sustainability, UNL’s CO2 equivalent of the GHG is reduced by 33 percent from the baseline of 2009 per Full Time student Enrollment. The reduction of GHG is 38 percent from the baseline of 2009 per Gross Square Feet. Both of these numbers are significant because the university saw a 3 percent increase in enrollment of students (full time equivalent) and 12 percent increase in the building gross square feet. The findings lends credence to the highly efficient resource use and conservation techniques implemented by the Facilities Management department of the University in conjunction with several conservation strategies implemented by the University community.
Metric Tons CO2 Equivalent/Full Time Equivalent
The inventory tracks the Scope 1 sources of on-campus co-generation, university fleet activity, refrigerants and other chemical use, fertilizer use, and campus livestock. The inventory also tracks the Scope 2 source of purchased electricity. Scope 3, or indirect sources related to university operations (commuting, travel, waste emissions, etc), are not included in this submission.
The inventory shows that the majority of our emissions come from Scope 2 purchased electricity. This is largely explained by the fact that the University does not generate its own electricity on site. UNL produces only steam and chilled water for heating and cooling while other universities additionally produce their own electricity. This partially accounts for the lower levels of CO2 in comparison to other universities.
UNL purchases all electricity from Lincoln Electric System (LES) and Western Area Power Administration (WAPA). The university's fuel mix has a large amount of electricity derived from hydroelectric sources. This custom fuel mix differs from the regional electrical average and contributes to our smaller carbon footprint as hydroelectric systems result in far lower emission rates than fossil fuel-based electric systems.