Location: Bowdoin / Sustainability / Carbon Neutrality / 2010 Update

Annual Greenhouse Gas Emissions Inventory Update

Background and Overview

In fall 2009, Bowdoin College made a commitment to become carbon-neutral by the year 2020 and released a detailed implementation plan to achieve that goal.1

We are pleased to report that at the end of FY 2010, the College is on track to achieve carbon neutrality by 2020, as a result of campus-wide conservation efforts, specific initiatives in the implementation plan, and other factors.

Bowdoin's greenhouse gas emissions (GHG) were almost 7% lower in 2010 than the FY 2008 baseline total of 19,153 metric tons.

This Annual Greenhouse Gas Emissions Inventory Update summarizes key changes that contributed to Bowdoin's reduction in emissions. The College's GHG inventory accounts for the six greenhouse gases specified by the Kyoto Protocol and uses the global warming potential of each gas to present results in a common unit: carbon dioxide equivalent (CO2e).

Summary of 2010 Bowdoin College Greenhouse Gas Emissions

Bowdoin categorizes emissions into three scopes. Scope 1 includes onsite combustion of fuels, College vehicle use, and fugitive refrigerants. Scope 2 encompasses purchased electricity. Scope 3 includes travel by College faculty and staff, daily employee commuting, transmission line losses from electricity usage, and waste disposal.

The College has the most control over Scope 1 emissions and has made the greatest progress in this area as fuel-switching, green building standards for new construction, and weatherization programs for existing buildings increased campus-wide energy efficiencies.

Scope 1 Onsite fuel combustion, College vehicle use, and fugitive refrigerants

The College reduced its Scope 1 emissions by 5% in FY 2010, a 485 metric ton reduction.2

Lower fuel usage at the central heating plant was the largest factor in the Scope 1 reduction. The central heating plant used almost 11% (14,000 MMBtu) less natural gas in FY 2010 compared to FY 2008. Some of this reduction was weather related—warmer winter temperatures reduced demand in FY 2010—and some was associated with weatherization of campus buildings and the ongoing repair of the underground steam-distribution system. During this time, many of the College's satellite facilities were converted from No. 2 heating oil to natural gas, a conversion that typically reduces GHG emissions by about 30% per Btu consumed.

These advances were somewhat offset by an increase in GHG emissions due to increased College vehicle use and fugitive refrigerants. Vehicle use rose 14% (51 metric tons) compared to 2008 and refrigerants increased by 110%; however, the latter was due to a single incident and is not expected to persist into the future.

Scope 2 Purchased electricity

Scope 2 emissions were 6% lower in 2010 than in FY 2008, a 427 metric ton reduction.

The decrease in emissions includes a 2% drop in electricity usage, reflecting completed energy-efficiency projects, particularly lighting upgrades. Lowered electricity usage also reflects a higher level of awareness about conservation measures among students, faculty, and staff. One of the most visible of these initiatives was the ninth annual, month-long dorm energy-savings contest, which is estimated to have reduced electricity consumption by 16,893 kilowatt-hours in 2010.

A change in electricity-specific emissions factors published by the Environmental Protection Agency (EPA) and used in our emissions modeling contributed the remaining 4% of the Scope 2 reduction. Electric emissions factors are updated periodically by the EPA, and a gradual improvement is expected each year for Maine as a higher percentage of renewable energy is integrated into the state’s portfolio of power plants.3

It is worth noting, however, that Bowdoin has continued its practice of the past several years of purchasing renewable energy credits from Maine generators in the voluntary market to offset all of its Scope 2 emissions that are not already sourced from facilities that qualify as renewable under Maine's two Renewable Portfolio Standards.  Taken together, the voluntary market purchases and the compliance Renewable Portfolio Standard purchases offset 100% of Scope 2 emissions.

Scope 3 Travel by College faculty and staff, daily employee commuting, transmission line losses from electricity usage, and waste disposal

The College reduced its Scope 3 emissions by 13% in FY 2010, a 361 metric ton reduction.

Emissions associated with College travel were down 21%, a reduction of 113 metric tons of CO2e from FY 2008. Emissions related to employee commuting were down by 5% (94 metric tons) compared to FY 2008. Certain emission factor changes discussed in Scope 2 also reduced electricity line-loss related emissions by about 12% compared to FY 2008.

Total waste removed from Bowdoin decreased by 6% in FY 2010. At the same time, Bowdoin was able to increase recycling by 5%. Combined, these two trends lowered emissions associated with waste by about 100 metric tons of CO2e during FY 2010.

A breakdown of the estimated 17,881 metric tons of CO2e emissions for FY 2010 is shown by major category in the following chart.


1 This initiative was formally launched in 2007, when President Barry Mills signed the American College and University Presidents' Climate Commitment. To achieve this goal, the College developed a Carbon Neutrality Implementation Plan in 2009. As part of that plan, the College will track and report annually on its greenhouse gas (GHG) emissions relative to the Fiscal Year (FY) 2008 baseline year. The plan will be revisited and updated every two years (next update in fall 2011) so that Bowdoin community members can measure the effectiveness of strategies, evaluate the financial feasibility of specific projects, and incorporate new technological advances. The plan can be reviewed at http://www.bowdoin.edu/sustainability/carbon-neutrality/pdf/implementationplan.pdf

2 Emissions, previously reported in units of short tons, are now reported in metric tons. All historic data has been converted to metric tons. For reference, one metric ton is 1,000 kg or 2,205 lbs. while one short ton is 907 kg or 2,000 lbs.

3 In addition to the normal decline in electricity-associated emission factors, a new estimate of the specific N20 (nitrous oxide) factor associated with electricity generation in Maine was made available by the EPA. N20 is a potent greenhouse gas with a warming potential that is 300 times that of CO2e. N20 factors were not published by the EPA for Maine until the College’s most recent GHG inventory update. Given the magnitude of the impact (a reduction of about 2,500 metric tons or 26% of the Scope 2 emissions reported in 2008) we have revised the FY 2008 emission baseline as well as the current year emissions estimate so that a true measure can be made of the College’s progress over the past two years.