Campus sustainability and transportation: a case study of estimating green house gas (GHGs) emissions from commuter transportation choices at Yale University from a lifecycle perspective
Student name: Ms Ritika Tewari
Guide: Prof Bhavik R Bakshi
Year of completion: 2011
Host Organisation: Yale Office of Sustainability and Yale School of Forestry and Environmental Studies, Yale University
Supervisor (Host Organisation): Dr Matthew Eckelman
Abstract: The last few decades of alarming scientific revelations about anthropogenically enhanced
climate change have made environmental proactiveness a necessity than a choice for
organisations. Greenhouse Gas (GHG) accounting is a standard procedure for estimating the
environmental impacts of a product or service. While most of the existing protocols stress
only on accounting for direct emissions, they underestimate the environmental burdens
associated with the upstream and downstream processes and the supply chain. Lifecycle
assessment (LCA) methods track the entire lifecycle and hence provide a holistic estimation
of impacts.
The daily commute to and from the campus has significant environmental burdens. The
existing study calculates the total environmental impacts from the road transportation choices
available to commuters at Yale University from a lifecycle perspective for the year 2010.
Emissions of the three major GHGs i.e. CO2, N2O and CH4 have been calculated. Four
lifecycle stages, i.e. vehicle manufacturing, vehicle maintenance, fuel production and vehicle
operation have been taken into consideration. A tiered hybrid LCA has been done, with
significant impacts been modelled using GREET model, and the rest using Economic InputOutput
model (EIO-LCA).
The total GHG emissions for the year 2010 come out to be 19,831 tonnes CO2 eq. Of the four
modes considered in the study, passenger cars in driving alone state seem to have the
maximum impact while bicycling has the minimum. Annual lifecycle emissions of a bus and
a car commuting to Yale when normalised to the passenger miles travelled (PMTs) show that
the vehicle operational phase is responsible for only approximately 61% and 51% of total
emissions, for buses and cars (single passenger) respectively. This confirms that other
lifecycle stages have a sizeable share in total emissions. Three policy scenarios, discussed at
the end of the study, portray the scope of further improvements in the GHG profile of the
services provided by the university.
Key words: campus sustainability, transportation choices, GHGs, Tiered hybrid LCA,
GREET, EIO LCA
