Mills College Greenhouse Gas Emissions Inventory – 2011-2012
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 ACUPCC 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
2011-12, Mills College GHG emissions totaled 6,166 MTCDE. Of this, 2,874 was from natural gas use,
1,304 was from electricity use, 1,566 from commuting by faculty, staff and students, 241 from air travel
funded by the College, and 181 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 decreased by
3.17%. Deeper savings are seen in a decrease of 5.12% per square foot and a decrease of 8.94% per
capita. These numbers indicate that though the overall decrease is modest, a significant decrease can be
seen when taking into account the increase in student body and square footage since 2008. In the past
two years, Mills has established programs to reduce natural gas and electricity use on campus. These
programs are continuing to develop and we anticipate further savings. There was a slight increase in
resource usage in commuting and the campus fleet, making them likely targets for program
development over the next two years.
Key Results
GHG Emissions by Source
Electricity
21%
Air Travel
4%
Natural Gas
47%
Commuting
25%
Campus Fleet
3%
Emissions by Source in MTCDE
3,500
2,874
3,000
2,500
2,000
1,566
1,500
1,304
1,000
500
241
182
0
Electricity
Natural Gas
Campus Fleet
-500
Commuting
Air Travel
Waste
-293
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, four hundred and seventy-four gallons of fuel was used in the fiscal year 2012,
contributing nearly 182 MTCDE to the College’s total emissions, or 3%.
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 Commercial Energy records.
Mills College used 471,176 therms in the fiscal year 2011-2012, 2,874 MTCDE to the college’s total
emissions, or 47%.
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 5,321,958 kWh of electricity in the fiscal year 2012, contributing 1,304 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 commuting students, staff and faculty established frequency of trips, commute distance and
means of transportation. During the months of August and September 2012, all Mills College community
members registering for their yearly parking permit completed an electronic survey attached to
registration. We looked at commutes by car alone, by carpool, and by transit. Commuting by other
means of transportation were not included. Students, faculty and staff were tallied as separate
populations.
Survey respondents entered their commuting data, including roundtrip miles, days per week, weeks per
year, and their mpg. Typical weeks commuted per year include 48, 42, and 33. Population size for staff
and faculty was provided by HR. Commuting students were determined by an estimate of the number of
parking permits issued.
For each group, the total annual distance commuted was calculated by multiplying the daily roundtrip
miles, the days per week, and the weeks per year. For the current inventory, we asked for the
respondents to indicate their miles per gallon. For instances when we missed data for the miles per
gallon but had the other information, we averaged MPG for the data set (students, faculty, staff) and
filled in the missing MPG. For each response, we divided the miles per year by the MPG to obtain the
total gallons of fuel for the year.
The survey had a high response rate that resulted in a good base of known gallons of fuel per year. To
calculate the remaining commuters’ gallons of fuel for the year, we extrapolated based on existing data.
A histogram for each group was created, each following an exponential decay pattern. The missing data
was predicted by sampling from an exponential distribution built with the original data.
An estimated 175,200 gallons of petrol and 1,188 gallons of diesel were spent commuting over the
course of the year. The estimated carbon footprint for a fiscal year from commutes is 1,566 MTCDE or
25% 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 and 10.15 kg CO2e per gallon of
diesel.
Air Travel
For the fiscal year 2011-2012 Mills looked for a correlation between air miles flown and the expended
budget for air travel. For this report Mills looked only at air miles expenditures and found that the
departments with highest frequency of flying actually decreased expenditures but the overall campus
expenditures slightly increased (less than 2%). In the final analysis we assume air miles travel to remain
flat at 241.72 MTCDE compared with the 2009-2010 report. Mills plans on consolidating the process for
tracking air travel miles and expenditures which will improve out data collection methods.
For the 2009-2010 report 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 2007-2008
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 2011-2012 waste streams from Mills College were hauled away in a variety of ways
and consequently measured as such. Mills facilities staff hauls most campus garbage to the Davis Street
Transfer Station, where it is weighed, and ultimately goes to the Altamont Landfill in Livermore, CA. One
4 cubic yard dumpster is serviced weekly by Waste Management and hauled to the Davis Street Transfer
Station. Actual garbage volume in this dumpster is estimated via site checks and converted to tonnage
with a volume to weight factor based on estimated garbage ‘type’, or likely composition. Special onetime dumpsters are used a few times a year, are assumed full unless checked, 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.
Recology collects and hauls the campus compost to the Berkeley, CA transfer station and then onto
Jepson Prairie Organics in Vacaville. Compost volume was also estimated via site checks. Volume to
weight conversion factors by waste stream ‘type’ (estimated composition) were provided by Recology,
an internal compost audit, and Recyclemania.org.
Mills College has implemented effective compost and recycling programs, which resulted in a diversion
rate that averaged 54% in FY2012. That is, 54% 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 62 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 293 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 68% of total campus emissions,
presenting a productive starting point for reductions. Mills was able to reduce electricity usage and
reduce natural gas usage by 15% during FY 11/12 as compared to FY07/08. This was due to a
combination of boiler upgrades, increased campus awareness and behavioral campaigns, 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.
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 decade-long 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:
Alecia DeCoudreaux, President of Mills College
Renee Jadushlever, VP for Operations
Linda Zitzner, AVP for Operations
Karen Fiene, Campus Architect
Britta Bullard, Sustainability Coordinator
Niviece Robinson, Public Safety and Transportation
Mahmud Rahman, Director of Enterprise Information Services
Mark Henderson, Ph.D. Assistant Professor of Public Policy
Jessica Blakemore, MA student in Public Policy
Pedro Reynoso Mora, Ph.D. candidate in Mechanical Engineering
Carolyn Sherwood Call, Ph.D. Visiting Assistant Professor of Economics
Brian Harrington, Environmental Planner
Pat Ernesto, Campus Facilities
Alice Knudsen, College Records
The Mills College Sustainability Committee