Transcript Slide 1

Greenhouse
Gas Inventory
1990-2003
2004
Sam Hummel
Matthew Barkley
Environmental Sustainability Coordinator
MEM ’05
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.
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Greenhouse Gas Inventory - Duke University
Sources of GHG Emissions Inventoried
•
Transportation
–
–
–
•
Fleet vehicles
Employee commuter trips
Athletic team travel (incomplete)
–
•
•
PFCs, HFCs, SF6
Solid Waste (negligible)
–
•
Coal, Fuel Oil, Natural Gas
Refrigerants (negligible)
–
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.
2004
• Steam Plant
Incinerated, Landfill gases
Offsets (negligible)
–
–
Duke Forest preservation
Composting
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.)
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Gas
Global Warming
Potential
Atmospheric
Lifetime
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
Sulfur
Hexafluoride
(SF6)
23900
3200
Greenhouse Gas Inventory - Duke University
Duke’s GHG emissions
(1990-2003)
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.
T otal Emissions (Metric T onnes eCO2)
450,000
eCO2 (Metric Tonnes)
400,000
350,000
36%
300,000
250,000
Kyoto Goal
200,000
64%
150,000
100,000
50,000
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
-
Year
T his graph is an example of your data to assist in choosing which years to display
2004
Greenhouse Gas Inventory - Duke University
Duke’s GHG Emissions: Contributions by Source
Total Emissions (Metric Tonnes eCO2 )
400,000
Refrigerants and other Chemicals
Solid Waste
Agriculture
Transportation
On-campus Stationary
Purchased Steam and Chilled w ater
Purchased Electricity
350,000
Transportation 22%
300,000
250,000
Steam Plant 25%
200,000
150,000
100,000
Purchased Electricity 53%
50,000
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
0
Year
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.
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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.
1,400,000
1,200,000
Recycled #2 Oil MMBtu
(0.136 MMbtu/gal)
1,000,000
Coal MMBtu
800,000
Natural Gas MMBtu
600,000
Distillate Oil
(#1 - #4) MMBtu
400,000
200,000
0
1
2004
3
5
7
9
11
13
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.
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Greenhouse Gas Inventory - Duke University
B ivari ate Fit of Gasol ine Usage (gal l ons) B y Fiscal Yea
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.
Gasoline Usage (gallons)
Source Details: Transportation
220000
200000
180000
160000
140000
120000
100000
80000
60000
40000
20000
0
1989 1991 1993 1995 1997 1999 2001 2003
Fiscal Year
•
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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Linear Fit
B ivari ate Fit of Di esel U sage (gal lon s) B y Fiscal Year
200000
180000
Diesel Usage (gallons)
•
160000
140000
120000
100000
80000
60000
40000
20000
0
1989 1991 1993 1995 1997 1999 2001 2003
Fiscal Year
Linear Fit
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.
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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.
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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.
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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.
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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.
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Greenhouse Gas Inventory - Duke University
Trends
These two charts
show that the
energy efficiency of
construction post1999 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
Bivariate Fit of eCO2 (metric tonnes) By Fiscal Year
400000
375000
Energy Management
350000
325000
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.
300000
eCO2 (metric tonnes)
•
plateau
275000
250000
225000
200000
175000
150000
125000
100000
75000
50000
25000
0
•
2004
The red line estimates where our
emissions would be now were the pre1996 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.
1990
1995
2000
2005
Fiscal Year
Linear Fit
Linear Fit
Linear Fit
Greenhouse Gas Inventory - Duke University