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Transcript of 2004Greenhouse Gas Inventory - Duke University Greenhouse Gas Inventory 1990-2003 Sam Hummel...
2004 Greenhouse Gas Inventory - Duke University
Greenhouse Gas Inventory
1990-2003
Sam Hummel Environmental Sustainability Coordinator
Matthew BarkleyMEM ’05
2004 Greenhouse Gas Inventory - Duke University
Methodology
• The inventory was performed during the summer of 2004 using software distributed by Clean-Air Cool-Planet, a non-profit organization out of Portsmouth, NH. (www.cleanair-coolplanet.org/)
• The goals of the inventory were to determine how much greenhouse gas (GHG) emissions Duke is responsible for today, characterize the major sources and examine trends in emissions over the last 14 years. These pieces of information will be instrumental in forming any action plan for reducing Duke’s emissions.
• The inventory includes all campus operations, meaning it includes the medical center as well as the University. The decision to put the two together was driven by the difficulty in parsing energy, waste and transportation expenditures between the two entities that share a common campus.
2004 Greenhouse Gas Inventory - Duke University
Why 1990 to 2003?
• The motivation for beginning the inventory in 1990 came from the Kyoto Protocol, which has become the primary benchmark for environmental stewardship with regards to global climate change.
• The Protocol is an international treaty negotiated in 1997 that calls on industrialized nations to decrease their emissions of six greenhouse gases…carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, HFCs and PFCs.
• The protocol sets national reduction targets which range from 8% reductions below 1990 levels for the European Union to 7% for the US, 6% for Japan, 0% for Russia, and permitted increases of 8% for Australia and 10% for Iceland.
• The United States has not ratified the Kyoto Protocol treaty and is therefore not legally bound to meet the Kyoto reduction target. However, institutions, and municipalities within the US have made commitments to reduce their own emissions in accordance with the Kyoto goal.
• Cornell University, Lewis & Clark University, College of the Atlantic have all made a commitment to meeting the Kyoto Protocol.
2004 Greenhouse Gas Inventory - Duke University
• Transportation– Fleet vehicles– Employee commuter trips– Athletic team travel (incomplete)
• Purchased Electricity – Duke Power – The GHG emissions factor used
was reported by the Southeastern Electric Reliability Council (SERC). The SERC region is made of Virginia and the Carolina’s. Power plants in SERC are responsible for 21% of the GHG emissions emitted by power plants in the US every year.
• Steam Plant– Coal, Fuel Oil, Natural Gas
• Refrigerants (negligible)– PFCs, HFCs, SF6
• Solid Waste (negligible)– Incinerated, Landfill gases
• Offsets (negligible)– Duke Forest preservation– Composting
Sources of GHG Emissions Inventoried
2004 Greenhouse Gas Inventory - Duke University
Carbon Dioxide Equivalency (eCO2)
• All results are reported in carbon dioxide equivalents (eCO2).
• This is necessary in order to compare the global warming effect of the six greenhouse gases because each of them have very different heat trapping potentials.
• Measurements of non-carbon-dioxide greenhouse gases were converted into CO2 equivalents (eCO2) based on their relative heat trapping potential.
• As can be seen in the table at right, carbon dioxide actually has the lowest global warming potential of the six gases measured. (However, CO2 makes up a majority of the emissions.)
Gas Global WarmingPotential
AtmosphericLifetime
Every 100 Years Years
Carbon Dioxide(CO2)
1 50-200
Methane (CH4) 21 9-15
Nitrous Oxide(N2O)
310 120
HFC-134a 1300 15
HFC-404a 3260 48
SulfurHexafluoride
(SF6)
23900 3200
2004 Greenhouse Gas Inventory - Duke University
This graph is an example of your data to assist in choosing which years to display
Total Emissions (Metric Tonnes eCO2)
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450,00019
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2001
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2003
Year
eCO
2 (M
etri
c T
onne
s)Duke’s GHG emissions (1990-2003)
36%
64%
Kyoto Goal
In 2003, Duke’s emissions were 31% above its 1990 emissions, and 36% above the goal of 7% below 1990 established by the Kyoto Protocol.
2004 Greenhouse Gas Inventory - Duke University
Duke’s GHG Emissions: Contributions by Source
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400,00019
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Tot
al E
mis
sion
s (M
etri
c T
onn
es e
CO
2)
Refrigerants and other ChemicalsSolid WasteAgricultureTransportationOn-campus StationaryPurchased Steam and Chilled waterPurchased Electricity
Purchased Electricity 53%
Steam Plant 25%
Transportation 22%
2004 Greenhouse Gas Inventory - Duke University
Source Details: Purchased Electricity
• Duke’s electricity purchase was responsible for 53% of the university’s GHG emissions in 2003.
• Duke used 375,903 MWh generated by Duke Power.
• The generation of Duke’s 2003 electricity purchase produced 198,639 metric tonnes of eCO2 emissions.
• That is equivalent to the average emissions of 43,792 cars in a year.
• Or, it is the amount absorbed in a year by 59,732 acres of mature trees.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Steam Generation
• Duke’s steam plant was responsible for 25% of the university’s GHG emissions in 2003.
• The generation of Duke’s steam produced 93,019 metric tonnes of eCO2 emissions.
• That is equivalent to the average emissions of 20,507 cars in a year.
• Or, it is the amount absorbed in a year by 27,972 acres of mature trees.
0
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1 3 5 7 9 11 13
Recycled #2 Oil MMBtu(0.136 MMbtu/gal)
Coal MMBtu
Natural Gas MMBtu
Distillate Oil(#1 - #4) MMBtu
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
• Transportation was responsible for 22% of the university’s GHG emissions in 2003.
• The inventory measured emissions from Duke’s fleet vehicles, employee commuter trips and athletic team travel.
• The emissions from Duke’s transportation related activities in 2003 produced 88,495 metric tonnes of eCO2.
• That is equivalent to the average emissions of 19,510 cars in a year.
• Or, it is the amount absorbed in a year by 26,611 acres of mature trees.
• Note: An undetermined amount of transportation related emissions have fallen under the steam plant and purchased electricity totals in the inventory. This is because natural gas purchased for use in Facilities Management’s compressed natural gas (CNG) vehicles was not separated out from that purchased for use in the steam plant. This is also true for the energy used in any electric vehicles, including John Deere Gators and golf carts.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
Incomplete Data
• The pre-1999 fleet fuel usage is likely overestimated in the inventory. This is because exact data was not available for 1990 to 1999.
• There was a rapidly increasing trend in both diesel and gasoline fuel usage from 1999 to 2003. If that rate were used in regression analysis to estimate 1990 fuel usage, the fuel usage would have been approximately zero. The improbability of that scenario lead the inventory team to decide that the fuel usage from 1990 should not be estimated through regression.
• Instead, the measured fuel usage for 1999 was simply used for the years 1990 to 1999, with the recognition that this was likely an overestimate.
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Gas
olin
e U
sage
(ga
llons
)
1989 1991 1993 1995 1997 1999 2001 2003
Fiscal Year
Linear Fit
Bivariate Fit of Gasoline Usage (gallons) By Fiscal Year
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Die
sel U
sage
(ga
llons
)
1989 1991 1993 1995 1997 1999 2001 2003
Fiscal Year
Linear Fit
Bivariate Fit of Diesel Usage (gallons) By Fiscal Year
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
Biodiesel
• Because Duke only began using biodiesel in
its diesel fleet at the tail end of fiscal year
2003, the mitigation benefits of biodiesel are
not evident in the current inventory.
• When the 2004 fiscal year closes, it is
expected that Duke’s use of a 20% biodiesel
blend will contribute a 35% reduction in GHG
emissions from the diesel fleet, which
represents a 10% reduction in the entire fleet’s
emissions.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
Employee commuter miles
• Commuter emissions are by far the largest source of Duke’s transportation related emissions measured in this inventory.
• Using an anonymous list of employee addresses and Geographic Information Systems software, we were able to determine the straight-line distance from home to campus for each employee. The average distance was 15 miles. We multiplied that distance by 2 trips a day and 225 work days in the year.
• Human Resources was only able to provide a list of employee addresses for the 2003 fiscal year. HR said it would be highly difficult if not impossible to provide a list for each year from 1990. Unfortunately, that means our inventory was unable to capture the effects of suburbanization on commute distances that have been measured at area institutions, such as UNC-CH.
• The straight-line nature of our travel distances represents a large underestimate of the actual road miles and driving conditions that would effect fuel economy.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
Employee commuter miles - Continued
• Measured mode share data is not available at Duke. (Mode share indicates what percentage of
commuters use various modes of transportation: cars, bus, carpool, bike, walk)
• In place of measured mode share data we used estimates based on common mode shares at
other campuses and area institutions. We assumed that 95% of faculty and 85% of staff either
drive their own car to campus or are dropped off and picked up by a friend or family member.
That leaves a small percentage of bicyclists, carpoolers and bus riders.
• The lack of mode share data is a major source
of inaccuracy in our inventory and must be
resolved with a combination of commuter
surveys and travel journals.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
Student commuter miles
• No data was entered into the inventory for student travel
habits because no reliable analysis of student travel
habits exists. Factors would be short and extended trips
off-campus for work, pleasure or school.
This could perhaps be estimated through
a combination of surveys and travel
journals.
• It may be possible to inventory the
emissions related to travel between a
student’s family home and school at the start and end of
each semester. This would be very difficult to do for
past years, but perhaps should be done for each fiscal
year moving forward.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
Air Travel
• Air travel is the most greenhouse gas intensive form of
transportation because it releases large amounts of gas
into the upper atmosphere where it is unlikely to be
readily absorbed.
• The only air travel captured by the inventory is athletic
team travel, which was available beginning in 2003.
• Faculty and staff air travel was not available because
flight bookings are done individually with no central data
collection repository.
2004 Greenhouse Gas Inventory - Duke University
Source Details: Transportation
2004 Greenhouse Gas Inventory - Duke University
Source Details: Duke Forest
• With the help of the Nicholas School, it was
estimated that the Duke Forest absorbs
approximately 8,000 metric tons of CO2 each year.
• Considering Duke Forest is 7,900 acres, that is
essentially means the each acre of the Duke Forest
absorbs 1 metric ton each year.
• Interestingly, the EPA estimates that it only takes 1/3
of an acre of forest to absorb 1 metric ton each year.
The discrepancy may result from a difference in the
biological make-up of the forests studied or reflect
newer science.
• Assuming our estimation is correct, the Duke Forest
absorbs an amount of CO2 equivalent to the average
emissions of 1,746 cars in a year.
2004 Greenhouse Gas Inventory - Duke University
Trends
These two charts show that the energy efficiency of construction post-1999 slightly reduced the whole University’s emissions per square foot. This would be a good trend to continue.
2004 Greenhouse Gas Inventory - Duke University
Trends
Energy Management
• Beginning in 1996, Facilities
Management Department’s Energy
Management Team implemented 46
energy efficiency projects. The
reduction in energy use generated by
those projects can be seen in the
inventory where the emissions plateau
from 1995 to 2000 before resuming their
upward trend.
• The red line estimates where our
emissions would be now were the pre-
1996 trend to have continued. The blue
line represents the trend over the whole
13 year period, and the green line
represents the trend post-2000.
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eCO2
(metr
ic ton
nes)
1990 1995 2000 2005
Fiscal Year
Linear Fit
Linear Fit
Linear Fit
Bivariate Fit of eCO2 (metric tonnes) By Fiscal Year
plateau