Mills College Greenhouse Gas Emissions Inventory – 2009-2010
Abstract
Mills College is a signatory of the American College & University Presidents Climate
Commitment (PCC) and as such has made a commitment to reduce and ameliorate the climactic
effects of college operations. A component of satisfying the PCC is performing a comprehensive
inventory of greenhouse gas (GHG) emissions. The inventory accounts for sources of emissions,
their quantities, and their contribution to anthropogenic GHGs as equivalent to the warming
potential of Carbon Dioxide (CO2). GHG totals are presented in metric tons of carbon dioxide
equivalent (MTCDE). In the fiscal year 2009-10, Mills College GHG emissions totaled 6,495.15
MTCDE. Of this, 3,149 was from natural gas use, 1,390 was from electricity use, 1,536 from
commuting by faculty, staff and students, 242 from air travel funded by the College, and 119
from direct fuel consumption (Campus Fleet). High waste stream diversion resulted in a
negative value for emissions from waste and is excluded from the total; though it is still included
in the report.
In comparison to the 2008 GHG inventory the College’s greenhouse gas emissions have
increased modestly, by 1.18%. However, there was a reduction in use per capita of -1.19% and
an additional reduction of -5.95% per square foot. These numbers indicate a net decrease in
emissions given that both the student body and building square footages have increased in the
past 2 years. Additional emissions reductions will come from more rigorous oversight of newly
established caps and from behavioral changes being instituted across the spectrum of campus
life.
Key Results
GHG Emissions by Source
Electricity
21%
Air Travel
4%
Natural Gas
49%
Commuting
24%
Campus Fleet
2%
Emissions by Source in MTCDE
3,500
3,149
3,000
2,500
2,000
1,500
1,536
1,390
1,000
500
242
119
0
Electricity
Natural Gas
Campus Fleet
-500
Commuting
Air Travel
Waste
-367
-1,000
Scope of Work and Inventory Process
Mills College developed a GHG emissions calculation tool tailored to Mills using the Greenhouse
Gas Protocol resources developed by the World Resources Institute (WRI). This tool is
structured based on the WRI’s Operational Control approach, setting guidelines for emissions
within the College’s control. The WRI’s boundaries are divided into three scopes, Direct GHG
Emissions, Purchased Electricity-Indirect Emissions, and Other Indirect Emissions, or scopes 1, 2,
and 3 respectively. While Mills used these guidelines to define scope and the extent of
information included in this report, some differences exist.
Direct GHG Emissions (Scope 1) includes any activities where GHGs are generated by combustion
or released physically on campus. This report includes the burning of natural gas for heating
and the consumption of fuel in campus vehicles and equipment. Currently, Mills does not
produce any electricity via combustion. Also, Mills has few air conditioning systems, making any
refrigerant leakage minimal relative to total GHG emissions and therefore is not included in this
report.
Purchased Electricity Indirect Emissions (Scope 2) includes electricity purchased by the college
and consumed on campus.
Other Indirect Emissions (Scope 3) is optional, and includes emissions that are a consequence of
campus operations, but are from sources not necessarily owned or controlled by the College.
Scope 3 sources in this report include commuting, travel on college business, and the production
of waste.
Establishing a baseline emissions level
For Mills to reduce GHG emissions, the College must first know how much it emits, which
necessitates setting a baseline measurement derived from a comprehensive inventory of GHG
sources. It reveals the areas with greatest potential for reductions and provides a starting point
for comparison with future inventories as progress is made. Additionally, the inventory process
itself helps in developing a culture of data collection. It demonstrates Mills’ commitment to
both environmental and fiscal sustainability in relation to energy and resource consumption.
Units and Conversions
Measurements in this report are of carbon dioxide equivalents (CO2e), a universal standard of
measurement for the impacts caused by the release of greenhouse gases. CO2e are calculated
using the global warming potentials (GWP) of each greenhouse gas per the World Resources
Institute’s calculation standards. CO2, methane (CH4), and Nitrous Oxide (N20) are the GHG’s
included in this report. The GWP of CO2 is set at a value of 1 because CO2 is the most prevalent
greenhouse gas. Methane and Nitrous Oxide have GWPs of 23 and 296 respectively.
Measurements are presented in metric tons of carbon dioxide equivalent (MTCDE).
All conversion factors are from government agencies such as the California Public Utilities
Commission and the US Environmental Protection Agency and more localized accurate factors
were used when available. Factors given in kilograms of CO2e per unit measurement include
methane (CH4) and Nitrous Oxide (N20).
Emissions by Source
Scope 1: Direct Emissions
Direct Fuel Consumption
A single gas pump exists at the Campus Facilities Corporation Yard on campus. Fuel usage from
this pump (in gallons) was totaled from supply purchase records. Credit Card receipts from staff
and invoices for diesel supplying the campus shuttle were used to total off-campus fuel
purchases.
Twenty thousand nineteen gallons of fuel was used in the fiscal year 2010, contributing nearly
119 MTCDE to the College’s total emissions, or 2%.
Conversion factors are from the California Climate Action Registry’s General Reporting Protocol,
2009 (GRP’09). Different fuel types were not isolated from gas/petrol records; however diesel
usage is small relative to petrol. Only the gas/petrol conversion factor was used in this
calculation. The factor is 8.87 kg CO2 e per gallon of petrol.
Purchased Natural Gas
Natural gas consumption data was collected from historical Commercial Energy records.
Mills College used 516,390 therms in the fiscal year 2009-2010, 3,149 MTCDE to the college’s
total emissions, or 48%.
The conversion factor is taken from PGE’s Climate Smart program and is approved by the
California Public Utilities Commission. Methane and Nitrous Oxide emission factors for
stationary combustion (as a weighted U.S. average) were taken from the GRP’09. The factor is
6.099 kg CO2e per Therm.
Scope 2: Purchased Electricity Indirect Emissions
Purchased Electricity
Mills College used 5,675,394 kWh of electricity in the fiscal year 2009, contributing 1,390 MTCDE
to the College’s total emissions, or 21%.
The conversion factor is taken from PGE’s Climate Smart program and is approved by the
California Public Utilities Commission. Methane and Nitrous Oxide emission factors for the
Californian eGRID sub region were taken from the GRP’09. The factor is 0.245 kg CO2e per kWh.
Scope 3: Other Indirect Emissions
Commuting
A survey of staff, commuting students, and faculty was used to establish travel patterns,
commute distance and means of transportation. Each group had the survey administrated
differently. Commuting students filled out a paper survey while picking up their commuting
parking permit. This group’s data collection spanned the first two weeks of the academic
session. Students commuting by other means of transportation are not included. Staff
completed paper surveys, distributed and collected by department managers. Staff had the
highest response rate of the groups. Faculty received the survey via email by the Provost office
and emailed responses to the Sustainability Coordinator. Each group was tallied as a separate
population.
Average roundtrip commute distance, percentage of population participating in each
transportation mode, and days commuted per week were determined from survey responses.
Population size for staff and faculty was provided by HR. Commuting students were determined
by the number of parking permits issued. Numbers of commuters in each transportation mode
totaled to more than total number of commuters due to mixed-mode transportation, such as
driving three days a week and biking two days a week.
The number of weeks in the academic year that require commuting by students begins with the
first day of instruction and ends the last day of final exams, for both Fall and Spring semesters.
Holidays and Spring Break are not included in student commuter days. There are 30 student
commuting weeks per year. The staff members of Mills commute throughout the year. Starting
with the full 52 weeks of the year, two weeks for holidays and two weeks for an average
vacation are subtracted. Commuting calculations for staff are based on a standard of 48 weeks.
In regards to faculty, 20% were determined to require year-round commuting because of
research labs on campus. The remaining 80% of faculty require commuting the 30 academic
calendar weeks in addition to three weeks of preparation for instruction.
For each group, the total annual distance commuted was calculated by multiplying the average
miles in a weekly roundtrip, by number of commuters in that transportation mode, by the weeks
commuted per year. According to the Bureau of Transportation Statistics, the average fuel
efficiency of American cars in 2008 is stated at 22.6 miles per gallon. This factor was multiplied
by total annual distances to obtain the total gallons of fuel annually spent commuting for all
populations. Since the surveys were administered once (in the Fall of 2010), held a modest
response rate, and extrapolate weekly estimates over the course of a year, the figures are fairly
approximate. Future data collection systems coinciding with parking permit issuance have the
potential to be more effective.
The average weekly, roundtrip commute distance was approximately 92 miles for faculty, 125
miles for full-time staff, 57miles for part-time staff, and 97 miles for students. Carpooling
weekly distances were lower for faculty and students, but high for staff. Roughly 8-10% of the
commuting population was found to carpool, both exclusively and as part of a mixed-mode
transportation routine. An estimated 173,000 gallons of petrol were spent commuting over the
course of the year. The estimated carbon footprint for a fiscal year from commutes is 1,536
MTCDE or 24% of total campus emissions.
The U.S. Energy Information Administration (EIA) conversion factor was again used to convert
gallons of gas/petrol into MTCDE. The factor is 8.87 kg CO2e per gallon petrol.
Air Travel
GHG emissions from air travel on college business were determined by checking grant travel
expense reports and credit card use for staff and faculty. Since the last evaluation the college
finance office placed all travel expenses into one account allowing a breakdown of travel
purchased by P-card compared to other means. Travel on ‘college business’ was defined as
travel paid for by the college and includes travel for prospective students, which is substantial.
Staff generally use Mills issued credit cards (“P” Cards) to purchase airfare. Purchases on these
cards are coded by purchase type so an expense report for flights in the FY 2009-2010 was
generated by the Controller’s Office, however flights may have been purchased by other means.
The P-cards do not show the destination city or distance traveled but hard copy faculty and staff
flight records were available showing the destination city. The miles were then calculated
assuming round trip flights. The recorded flight distances for faculty and staff was summed to
generate a grand total. Air travel contributed approximately 241.72 MTCDE to the College’s total
emissions totaling 4% which is equal to the 2007-2008 inventory.
Emissions factors came from the US EPA’s Greenhouse Gas Inventory Protocol Core Module
Guidance publication, May 2008: Emission Factors for Airline Business Travel. The emissions
factors (in kg CO2 per passenger-mile) are 0.185, 0.229, and 0.277 for long haul (>700 miles),
medium haul (300-700 miles), and short haul (<300 miles) flights respectively. The conversion
factor for unknown flight distances is 0.271 and was used in calculating staff emissions. CH4 and
N20 emission factors are 0.0104 and 0.0085 respectively (kg per passenger mile).
Waste
For the fiscal year 2009-2010 waste streams from Mills College were hauled away in a variety of
ways and consequently measured as such. Two 4 CY (cubic yard) and two 6 CY garbage
dumpsters are serviced weekly by Waste Management and hauled to the Davis Street Transfer
Station and ultimately to the Altamont Landfill in Livermore, CA. Actual garbage volume in these
dumpsters is estimated via site checks by the Mills Sustainability Coordinator and converted to
tonnage with a volume to weight factor based on estimated garbage ‘type’, or likely
composition. Mills facilities staff hauls any additional garbage to the Davis Street Transfer
Station where it is weighed directly. Special one-time dumpsters are used a few times a year,
are assumed full, and converted to tonnage by a volume to weight conversion factor.
Recycling is picked up by Civicorps Recycles! and weighed at their nearby Oakland, CA sorting
facility. Compost is hauled to the San Francisco transfer station and then onto Jepson Prairie
Organics in Vacaville by Recology. Compost volume was also estimated via site checks. Volume
to weight conversion factors by waste stream ‘type’ (estimated composition) were provided by
Recology and Recyclemania.org.
Mills College has implemented effective compost and recycling programs, which resulted in a
diversion rate that averaged 50% in FY2010. That is, 50% of waste that otherwise would have
been sent to a landfill was either composted or recycled. Materials directed off-campus are not
transported far, with compost being the furthest at 86 miles. Additionally, the Altamont landfill
uses methane capture for electricity generation.
According to the US Environmental Protection Agency’s Waste Reduction Model Calculation
Tool, the amount of recycling, composting and methane-capture done with Mills’ waste results
in a negative emissions value, equaling approximately 367 MTCDE in emission reductions.
Values below zero were not included in the emissions total.
Natural Gas – Electricity Consumption Comparison
Together, heating and electrifying the campus comprises almost 70% of total campus emissions,
presenting a productive starting point for reductions. Mills was able to moderately reduce both
its electricity and natural gas usage during FY 09/10 as compared to FY07/08. This was probably
due to a combination of increased campus awareness, better monitoring and installation of
more energy efficient appliances and lighting. We plan on continuing to focus in this area to
realize additional greenhouse gas emissions reductions as there are still significant improvement
opportunities.
The emissions factor for electricity in California are lower than many other places in the country
because of the high proportion of low-emission electricity generation from sources such as
hydroelectric and nuclear power. PG&E’s power mix is available online and shows the
percentage breakdown of sources for electricity generation delivered to retail customers.
Tracking Emissions and Trends and Tracking Inventory Quality
Tracking emissions has proven difficult, especially in identifying which departments and people
have the needed data and information. A goal of the Mills inventory is to establish a culture of
awareness and data collection so that the information needed for a GHG inventory is more
readily available. If new data for this base year emerges, figures may be edited accordingly.
Furthermore, it will be important to note improved but different data collection and calculation
methods in future reports when comparisons are made to previous surveys. Specifically, all
changes in conversion factors should be well documented.
Acknowledgments
The guidelines, standards and information for this inventory were adapted from The World
Resources Institute. The GHG Protocol (www.ghgprotocol.org) developed by World Resourced
Institute is “the most widely used international accounting framework for government and
business leaders to understand, quantify, and manage greenhouse gas emissions. It is a decadelong partnership between the World Resources Institute and the World Business Council for
Sustainable Development”.
Corporate Accounting and Reporting Standards (Corporate Standard): methodologies for
business and other organizations to inventory and report all of the GHG emissions they produce,
World Resources Institute
Designing a Customized GHG Calculation Tool, World Resources Institute
This report has been adapted from the 2008 GHG inventory. The following individuals
contributed to this report:
Janet Holmgren, President of Mills College
Renee Jadushlever, VP Operations
Linda Zitzner, AVP Planning and Facilities
Karen Fiene, Campus Architect
Britta Bullard, Recycling Manager
Niviece Robinson, Security and Transportation
Mike Lopez, Security and Transportation
Brian Harrington, Environmental Planner, Campus Facilities
Pat Ernesto, Campus Facilities
Alice Knudsen, College Records
Doug Gallagher, College Records
The Mills College Sustainability Committee