Typically when a new building technology is evaluated the
energy performance of a baseline building is compared to the
energy and life-cycle costs of alternatives to determine
cost-effectiveness. But what if the lowest energy or
life-cycle cost alternative is not the cleanest or lowest
environmental impact? By calculating environmental impact,
designers can compare alternatives not only in terms of their
energy performance but also their environmental
performance—working towards a more sustainable design (Liesen
1997; Stroot, Nemeth, and Fournier 1996). Environmental
impacts are quantified, in part, by modeling the amount of
emissions and in EnergyPlus this is done using the input
objects “EnvironmentalImpactFactors,” “FuelFactors,” and
“Output:EnvironmentalImpactFactors.”
Based on emissions factors entered by the user, EnergyPlus
calculates the mass or volume of thirteen different
pollutants: CO\(_{2}\)
(carbon dioxide), CO (carbon monoxide), CH\(_{4}\) (methane), NO\(_{x}\) (nitrogen oxides), N\(_{2}\)O (nitrous oxide), SO\(_{2}\) (sulphur dioxide), PM
(particulate matter), PM\(_{10}\) (particulate matter
10>PM\(_{10}\)>2.5
microns), PM\(_{2.5}\)
(particulate matter<2.5 microns), NH\(_{3}\) (ammonia), NMVOC
(non-methane volatile organic compounds), Hg (mercury), and Pb
(lead) as well as water consumed through evaporation in
thermo- and hydro-electric generation and high- and low-level
nuclear waste from nuclear electricity generation for on- and
off-site energy production. Note that while these comprise
the largest proportion of pollutants, more than one hundred
other pollutants are emitted from fossil fuel combustion or
electricity generation. Much of the information compiled here
for fossil fuel combustion comes from AP-42 Compilation of
Air Pollutant Emission Factors (EPA 1998a, 1998b, 1996).
For more information on pollutants, see the U.S. Environmental
Protection Agency (EPA) Clearinghouse for Inventories &
Emission Factors (www.epa.gov/ttn/chief/efinformation.html).
EnergyPlus models energy performance of on-site fossil
fuels and purchased electricity (generated from a variety of
fuels including natural gas, oil, gasoline, diesel, coal,
hydroelectric, nuclear, wind, solar power, and biomass). The
energy performance calculated by EnergyPlus is converted into
a mass or volume of pollutants emitted. From a baseline
building, alternative energy and pollution saving technologies
can be explored, and the energy savings and pollution
reduction can be calculated. Figure
and Figure
illustrate a comparison of two buildings simulated using
Chicago weather data in EnergyPlus and the calculated
pollutant levels (based on U.S. national average pollutants)
(Crawley 2003).
To calculate the mass or volume of each pollutant,
consumption is multiplied by an emissions factor for each fuel
(natural gas, electricity, fuel oil, diesel, or coal). In
future versions, users will be able to schedule how the
emissions factors by time of day, month, season and year. For
electricity, the mix of generation fuel sources—whether
utility, state or regional—is used to adjust the emission
factors. If a user has emissions factors specific to the
building site and equipment, these can be entered directly.
There are no default emissions factors.
EPA categorizes pollutants as either Criteria Pollutants or
Hazardous Pollutants. Criteria pollutants are the six
substances for which EPA has set health-based standards,
including carbon monoxide (CO), nitrogen oxides (NO\(_{x}\)), sulfur dioxide (SO\(_{2}\)), and particulate matter
(PM10 and PM2.5), ozone (O\(_{3}\)), and lead (Pb). Because
ozone is created in atmospheric photochemical reactions of
volatile organic compounds, ammonia, and other substances
rather than direct building-related energy emissions, we do
not calculated ozone emissions in EnergyPlus. But we do
include ozone precursors: methane (CH\(_{4}\)), non-methane volatile
organic compounds (NMVOC), and ammonia (NH\(_{3}\)). Hazardous pollutants are
substances that are known or suspected to cause serious health
problems such as cancer. We include typical hazardous
substances associated with energy production and use including
lead (Pb) and mercury (Hg). We also include CO\(_{2}\) (carbon dioxide) since it
is largest greenhouse gas in terms of impact.
Example Annual Atmospheric
Pollutants and Water Consumption
Example Annual Total Carbon
Equivalent for Major Greenhouse Gases
The Intergovernmental Panel on Climate Change has studied
the effects on the relative radiative forcing effects of
various greenhouse gases. This effect, called Global Warming
Potential (GWP), is described in terms of the Carbon
Equivalent of a particular greenhouse gas. This equivalent is
based on a factor of 1.0 for carbon. This group of gases
includes carbon dioxide (CO\(_{2}\)), carbon monoxide, nitrous
oxide, methane, halocarbon emission, hydrofluorocarbons (HFC),
perfluorocarbons (PFC), and chlorofluorocarbons (CFC). For
building energy use, the main gases of concern are carbon
dioxide, carbon monoxide, methane, and nitrous oxide.
Although carbon monoxide has a relatively short life, CO
emissions into the atmosphere may have a significant impact on
climate forcing due to chemical impact on CH\(_{4}\) lifetime, and tropospheric
O\(_{3}\) and CO\(_{2}\) photochemical production
normally reacts to produce carbon dioxide, but it can’t be
ignored since it is produced in incomplete combustion and the
carbon remains to interact as CO\(_{2}\) Yet there is no agreement
on its carbon equivalent (IPCC 2001). The carbon equivalent of
carbon dioxide, methane, and nitrous oxide are calculated and
then multiplied by their GWP on a 100 year time frame. The
Carbon Equivalents of the following gases have been determined
and used in the program are shown in the following table.
Carbon Equivalents (IPCC 2001)
Gas
Carbon Equivalent
NO
80.7272
CH
6.2727
CO
0.2727
The resulting carbon equivalents by fuel type are shown in
the output of the program along with the individual gas
pollutants.
Emission factors for on-site fossil fuel consumption are
based on Section 1.4 Natural Gas Combustion in EPA (1998a) Table shows
the greenhouse gas and precursors and criteria pollutant
emissions factors for natural gas. Similar emissions factors
are shown for residual fuel oil (No. 4 and No. 6 fuel oil) [Table{]},
distillates (No. 1 and No. 2 fuel oil) [Table{]},
residential oil furnace [Table{]},
LPG (butane and propane) [Table{]},
gasoline and diesel [Table{]},
and coal [Table{]} in the
indicated tables. Note that a zero for a pollutant in the
table may mean that no data were available, not that there are
no emissions of that pollutant.
Emission Factors for Natural Gas
Pollutant
Emission Factor (g/MJ)
Carbon Dioxide (CO )
50.23439
Carbon Monoxide (CO)
3.51641E-02
Methane (CH )
9.62826E-04
Nitrogen Oxides (NO )
4.18620E-02
Nitrous Oxide (N O)
9.20964E-04
Sulphur Dioxide (SO )
2.51172E-04
Particulate Matter (PM)
3.18151E-03
Particulate Matter (PM10)
2.38613E-03
Particulate Matter (PM2.5)
7.95378E-04
Ammonia (NH )
0
Volatile Organic Compounds
(NMVOC)
2.30241E-03
Mercury (Hg)
1.08841E-07
Lead (Pb)
2.09310E-07
a Based on data from Tables
1.4-1, 1.4.-2 and 1.4.4 in EPA (1998a), Natural gas heat
value of 1027 Btu/ft3 based on data for 2003 in Table A-4 in
DOE (2004)
b Values shown are for
uncontrolled burner. For controlled-low NO burner, use 0.64
lb/106 ft3, 0.000627 lb/MMBtu, 0.0002679 g/MJ
c Based on 100% conversion of
fuel sulfur to SO . Assumes sulfur content is natural gas of
2,000 grains/106 ft3. The SO2 emission factor can be converted
to other natural gas sulfur contents by multiplying the SO
emission factor by the ratio of the site-specific sulfur
content (grains/106 ft3) to 2,000 grains/106 ft3.
d PM is the sum of all
particulate matter including PM10 and PM2.5. PM10 and PM2.5
stand for particles smaller than 10 and 2.5 microns,
respectively.
e No data
Emission Factors for Residual Fuel Oil (No. 4 and
No. 6 Fuel Oil)
Pollutant
Emission Factor (g/MJ)
Carbon Dioxide (CO 2 )
50.23439
Carbon Monoxide (CO)
3.52E-002
Methane (CH 4 )
9.63E-004
Nitrogen Oxides (NO X )
4.19E-002
Nitrous Oxide (N 2 O)
9.21E-004
Sulphur Dioxide (SO 2 )
2.51E-004
Particulate Matter (PM)
3.18E-003
Particulate Matter (PM10)
2.39E-003
Particulate Matter (PM2.5)
7.95E-004
Ammonia (NH 3 )
0
Volatile Organic Compounds
(NMVOC)
2.30E-003
Mercury (Hg)
1.09E-007
Lead (Pb)
2.09E-007
Based on data from Tables 1.4-1,
1.4.-2 and 1.4.4 in EPA (1998a), Natural gas heat value of
1027 Btu/ft3 based on data for 2003 in Table A-4 in DOE
(2004)
Values shown are for
uncontrolled burner. For controlled-low NOX burner, use 0.64
lb/106 ft3, 0.000627 lb/MMBtu, 0.0002679 g/MJ
Based on 100% conversion of fuel
sulfur to SO2. Assumes sulfur content is natural gas of 2,000
contents by multiplying the SO2 emission factor by the ratio
of the site-specific sulfur content (grains/106 ft3) to 2,000
grains/106 ft3. grains/106 ft3. The SO2 emission factor can be
converted to other natural gas sulfur
PM is the sum of all particulate
matter including PM10 and PM2.5. PM10 and PM2.5 stand for
particles smaller than 10 and 2.5 microns, respectively.
No data.
Emission Factors for Distillates (No. 1 and No. 2
Fuel Oil)
Pollutant
No. 1 Fuel Oil Emission Factor
(g/MJ)
No. 2 Fuel Oil Emission Factor
(g/MJ)
Carbon Dioxide (CO )
66.0233
68.47998
Carbon Monoxide (CO)
1.54E-002
1.54E-002
Methane (CH )
6.63E-004
6.63E-004
Nitrogen Oxides (NO )
6.14E-002
7.37E-002
Nitrous Oxide (N O)
3.38E-004
3.38E-004
Sulphur Dioxide (SO )
4.36E-001
4.82E-001
Particulate Matter (PM)
6.14E-003
6.14E-003
Particulate Matter (PM10)
3.32E-003
3.32E-003
Particulate Matter (PM2.5)
2.55E-003
2.55E-003
Ammonia (NH )
0
0
Volatile Organic Compounds
(NMVOC)
1.04E-003
1.04E-003
Mercury (Hg)
3.47E-006
3.47E-006
Lead (Pb)
4.64E-006
4.64E-006
a Based on data from Tables
1.3-1, 1.3-3, 1-3.8, 1.3-10 and 1.3-12 in EPA (1998b).
b Based on 100% conversion of
fuel sulfur to SO . Assumes 1% sulfur content. The SO emission
factor in this table can be converted to other natural gas
sulfur contents by multiplying the SO emission factor by
percentage sulfur content.
c PM is the sum of all
particulate matter including PM10 and PM2.5. PM10 and PM2.5
stand for particles smaller than 10 and 2.5 microns,
respectively
d No data.
Emission Factors for Residential Oil Furnace
Pollutant
Emission Factor (g/MJ)
Carbon Dioxide (CO )
68.48237
Carbon Monoxide (CO)
1.53543E-02
Methane (CH )
5.46612E-02
Nitrogen Oxides (NO )
5.52753E-02
Nitrous Oxide (N O)
1.53543E-04
Sulphur Dioxide (SO )
4.36061E-01
Particulate Matter (PM)
2.14960E-02
Particulate Matter (PM10)
1.58763E-02
Particulate Matter (PM2.5)
5.89603E-03
Ammonia (NH )
0
Volatile Organic Compounds
(NMVOC)
2.18952E-03
Mercury (Hg)
3.47006E-06
Lead (Pb)
4.63699E-06
a Based on data from Tables
1.3-1, 1.3-3, 1.3-8, 1.3-10, and 1.3-12 in EPA (1998b).
b Based on 100% conversion of
fuel sulfur to SO . Assumes 1% sulfur content. The SO emission
factor in this table can be converted to other natural gas
sulfur contents by multiplying the SO emission factor by
percentage sulfur content.
c PM is the sum of all
particulate matter including PM10 and PM2.5. PM10 and PM2.5
stand for particles smaller than 10 and 2.5 microns,
respectively.
d No data.
Emission Factors for LPG (butane and propane)
Pollutant
LPG (butane) Emission Factor
(g/MJ)
Propane Emission Factor
(g/MJ)
Carbon Dioxide (CO )
66.0233
68.47998
Carbon Monoxide (CO)
1.54E-002
1.54E-002
Methane (CH )
6.63E-004
6.63E-004
Nitrogen Oxides (NO )
6.14E-002
7.37E-002
Nitrous Oxide (N O)
3.38E-004
3.38E-004
Sulphur Dioxide (SO )
4.36E-001
4.82E-001
Particulate Matter (PM)
6.14E-003
6.14E-003
Particulate Matter (PM10)
3.32E-003
3.32E-003
Particulate Matter (PM2.5)
2.55E-003
2.55E-003
Ammonia (NH )
0
0
Volatile Organic Compounds
(NMVOC)
1.04E-003
1.04E-003
Mercury (Hg)
3.47E-006
3.47E-006
Lead (Pb)
4.64E-006
4.64E-006
a Based on data from Table #
1.5-1 in EPA (1996); Higher Heating value of 1.02 MMBtu/gal
for butane and 0.915 MMBtu/gal for propane based on data in
EPA (1996).
b Based on 100% conversion of
fuel sulfur to SO . Assumes sulphur content is 0.18 gr/100
ft3.The SO emission factor can be converted to other LPG
sulphur contents by multiplying the SO emission factor by the
ratio of the site-specific sulphur content gr/100 ft3 to 0.18
gr/100 ft3.
c PM is the sum of all
particulate matter including PM10 and PM2.5. PM10 and PM2.5
stand for particles smaller than 10 and 2.5 microns;
respectively.
d No data.
Emission Factors for Gasoline and Diesel
Pollutant
Gasoline Emission Factor
(g/MJ)
Diesel Emission Factor
(g/MJ)
Carbon Dioxide (CO )
66.20808
70.50731
Carbon Monoxide (CO)
2.70E+001
4.08E-001
Methane (CH )
0
0
Nitrogen Oxides (NO )
7.01E-001
1.90E+000
Nitrous Oxide (N O)
0
0
Sulphur Dioxide (SO )
3.61E-002
1.25E-001
Particulate Matter (PM)
0
0
Particulate Matter (PM10)
4.30E-002
1.33E-001
Particulate Matter (PM2.5)
0
0
Ammonia (NH )
0
0
Volatile Organic Compounds
(NMVOC)
9.03E-001
1.50E-001
Mercury (Hg)
0
0
Lead (Pb)
0
0
a Based on data from Table #
3.3-1 in EPA (1996); Diesel higher heating value of 19300
Btu/lb and gasoline higher heating value of 20300 Btu/lb based
on data in EPA (1996).
b PM is the sum of all
particulate matter including PM10 and PM2.5. PM10 and PM2.5
stand for particles smaller than 10 and 2.5 microns;
respectively.
c No data.
Emission Factors for Coal
Pollutant
Bituminous Emission Factor
(g/MJ)
Anthracite Emission Factor
(g/MJ)
Lignite Emission Factor
(g/MJ)
Carbon Dioxide (CO )
91.11052
99.26669
152.12646
Carbon Monoxide (CO)
8.27E-003
1.05E-002
8.27E-003
Methane (CH )
6.61E-004
0
0
Nitrogen Oxides (NO )
1.98E-001
3.15E-001
2.35E-001
Nitrous Oxide (N O)
4.96E-004
0
0
Sulphur Dioxide (SO )
6.28E-001
6.82E-001
9.92E-001
Particulate Matter (PM)
1.65E-001
1.75E-001
2.18E-001
Particulate Matter (PM10)
3.80E-002
4.02E-002
7.61E-002
Particulate Matter (PM2.5)
9.92E-003
1.05E-002
2.18E-002
Ammonia (NH )
0
0
0
Volatile Organic Compounds
(NMVOC)
9.92E-004
2.15E-002
1.32E-003
Mercury (Hg)
6.94E-006
2.27E-006
2.74E-006
Lead (Pb)
1.37E-006
1.56E-004
1.39E-005
a Based on data on pulverized
coal from Tables 1.1-3, 1.1-6, 1.1-18, 1.1-19 in EPA (1998a),
Coal average higher heating value of 26.0 MMBtu/ton based on
EPA (1998a).
b Based on data on pulverized
coal from Tables 1.2-1, 1.2-2, 1.2-3, 1.2-4, 1.2-7 in EPA
(1996), Coal average higher heating value of 24.6 MMBtu/ton
based on EPA (1996).
c Based on data on pulverized
coal from Tables 1.7-1, 1.7-3, 1.7-7, 1.7-14 in EPA (1998b),
Coal average higher heating value of 13.0 MMBtu/ton based on
EPA (1998b).
d Based on 100% conversion of
fuel sulfur to SO . Assumes 1% sulfur content. The SO emission
factor in this table can be converted to other natural gas
sulfur contents by multiplying the SO emission factor by
percentage sulfur content.
e PM is the sum of all
particulate matter including PM10 and PM2.5. PM10 and PM2.5
are particles smaller than 10 and 2.5 microns, respectively.
Expressed in terms of coal ash content, assumes 1% ash
content. Multiply weight % ash content of coal (as fired) by
the value.
While estimating emissions from on-site fossil fuel
combustion can be fairly straight-forward, emissions from
off-site electricity is more challenging. How the electricity
is generated, i.e., from gas, oil, coal, nuclear, renewable
sources (wind, PV) or hydroelectric, and the mix of generation
determines the resulting level of emissions. While data are
available at utility and even power plant level (from the
sources cited), data are shown here for United States
national- and state-level average emissions from electricity
generation. Table
provides average greenhouse gas and precursors and criteria
pollutant emissions factors for the entire United States from
electricity generation. Table
provides average electricity emissions factors by state, for
greenhouse gas and precursors, and Table
for criteria pollutant emission factors. These two tables also
include a ratio of heat input to electric output (efficiency
of electricity generation) including distribution and
transmission losses to allow calculation of source energy.
As mentioned in the introduction to this section,
EnergyPlus also calculates water consumed through evaporation
in thermo-electric and hydro-electric generation. Torcellini,
Long, and Judkoff (2004) provide data on average water
consumption by generator type by state. These data are
summarized in units suitable for EnergyPlus in Table,
for national and state average water consumption for
thermal-electric, hydro-electric, and Table
for weighted total electricity generation.
United States National Average Emission Factors for
Electricity Generation
Efficiency Ratio (J/J)
Ratio of Heat Input to
Electricity Output
2.253
Pollutant
Emission Factor (g/MJ)
Carbon Dioxide (CO )
168.333168
Carbon Monoxide (CO)
4.20616E-02
Methane (CH )
1.39858E-03
Nitrogen Oxides (NO )
4.10753E-01
Nitrous Oxide (N O)
2.41916E-03
Sulphur Dioxide (SO )
8.65731E-01
Particulate Matter (PM)
2.95827E-02
Particulate Matter (PM10)
1.80450E-02
Particulate Matter (PM2.5)
1.15377E-02
Ammonia (NH )
1.10837E-03
Volatile Organic Compounds
(NMVOC)
3.72332E-03
Mercury (Hg)
3.36414E-06
Lead (Pb)
0
Data based on 1999 data from
*eGRID* version 2.01 (EPA 2003a).
Data based on 1998-2000 average
data in DOE (2002).
Data based on tier emissions
report for criteria air pollutants in EPA (2003b).
PM is the sum of all particulate
matter including PM10 and PM2.5. PM10 and PM2.5 stand for
particles smaller than 10 and 2.5 microns, respectively.
No data.
U. S. State Average Greenhouse Gas Emission Factors
for Electricity Generation, in g/MJ
Ratio of Heat Input to Electric
Output
Carbon Dioxide (CO 2 ) b
Carbon Monoxide (CO) c
Methane (CH4) b
Nitrogen Oxides (NO X ) a
Nitrous Oxide (N 2 O) b
Sulphur Dioxide (SO 2 ) a
Alabama
2.23
165.30922
1.45E+003
1.73E-003
4.02E-001
2.81E-003
1.14E+000
Alaska
2.734
173.87708
3.72E+002
8.57E-004
7.29E-001
1.12E-003
2.38E-001
Arizona
1.694
132.29777
8.27E+002
8.57E-004
2.74E-001
1.94E-003
2.28E-001
Arkansas
2.207
162.03327
6.42E+002
1.57E-003
2.87E-001
2.56E-003
4.25E-001
California
1.422
76.35472
2.91E+003
8.44E-004
6.56E-002
4.66E-004
3.05E-002
Colorado
3.101
242.67192
1.51E+003
1.60E-003
4.74E-001
3.64E-003
5.84E-001
Connecticut
1.72
118.69
3.21E+002
2.19E-003
1.82E-001
1.51E-003
3.79E-001
Delaware
2.736
230.57612
1.31E+002
1.55E-003
4.13E-001
2.86E-003
1.11E+000
District of Columbia
4.844
172.1131
8.95E+000
1.49E-003
7.30E-001
2.60E-003
1.62E+000
Florida
2.694
175.64105
6.13E+003
1.89E-003
4.73E-001
2.27E-003
1.01E+000
Georgia
2.119
172.1131
1.06E+003
1.63E-003
4.00E-001
2.85E-003
1.12E+000
Hawaii
2.95
209.40848
1.18E+002
2.70E-003
7.28E-001
2.31E-003
5.44E-001
Idaho
0.213
3.52794
0
1.01E-003
1.07E-002
4.16E-004
1.06E-002
Illinois
1.694
146.66153
1.85E+003
1.03E-003
4.42E-001
2.27E-003
1.12E+000
Indiana
3.281
261.5716
2.14E+003
1.80E-003
7.30E-001
4.07E-003
1.89E+000
Iowa
3.033
237.12801
7.58E+002
1.74E-003
5.61E-001
3.75E-003
1.05E+000
Kansas
2.826
212.18043
8.66E+002
1.41E-003
5.59E-001
3.20E-003
7.07E-001
Kentucky
3.234
253.00374
1.51E+003
1.76E-003
8.41E-001
4.04E-003
1.79E+000
Lousiana
2.624
148.4255
1.68E+004
1.18E-003
3.42E-001
1.41E-003
5.06E-001
Maine
2.191
107.35019
4.93E+002
7.12E-003
1.80E-001
3.40E-003
4.04E-001
Maryland
2.277
172.1131
4.90E+002
1.49E-003
5.38E-001
2.60E-003
1.39E+000
Massachusetts
2.729
161.02529
7.89E+002
2.19E-003
2.89E-001
2.00E-003
8.01E-001
Michigan
2.616
199.07665
1.69E+003
1.84E-003
4.92E-001
3.15E-003
9.77E-001
Minnesota
2.331
163.04126
6.96E+002
1.66E-003
5.02E-001
2.08E-003
5.07E-001
Mississippi
2.404
231.8361
2.18E+003
1.59E-003
4.67E-001
3.63E-003
8.98E-001
Missouri
2.857
192.02077
1.30E+003
1.98E-003
6.42E-001
3.11E-003
9.07E-001
Montana
1.936
180.68096
4.13E+002
1.36E-003
3.58E-001
2.86E-003
2.01E-001
Nebraska
2.195
176.39703
4.68E+002
1.20E-003
3.94E-001
2.76E-003
5.29E-001
Nevada
2.615
191.26478
3.82E+002
1.13E-003
4.02E-001
2.46E-003
4.03E-001
New Hampshire
1.394
85.93055
2.64E+002
2.17E-003
2.03E-001
1.78E-003
8.71E-001
New Jersey
1.451
88.9545
2.27E+003
9.70E-004
1.77E-001
9.95E-004
2.31E-001
New Mexico
3.307
254.26372
8.56E+002
1.65E-003
6.58E-001
3.73E-003
5.70E-001
New York
1.808
108.10618
1.94E+003
1.02E-003
1.69E-001
1.12E-003
4.68E-001
North Carolina
1.969
156.48937
1.10E+003
1.32E-003
4.69E-001
2.56E-003
1.00E+000
North Dakota
3.244
282.48725
9.01E+002
1.85E-003
6.45E-001
4.27E-003
1.53E+000
Ohio
2.736
226.79619
1.59E+003
1.64E-003
7.68E-001
3.63E-003
2.34E+000
Oklahoma
3.024
216.96835
1.67E+003
1.39E-003
5.11E-001
2.81E-003
5.11E-001
Oregon
0.526
35.5314
1.87E+002
4.16E-004
5.27E-002
4.28E-004
7.51E-002
Pennsylvania
1.827
159.26132
1.86E+003
1.35E-003
3.29E-001
2.56E-003
1.26E+000
Rhode Island
2.561
132.54977
1.68E+002
8.57E-004
6.21E-002
5.92E-004
4.54E-003
South Carolina
1.3
105.08223
8.39E+002
1.15E-003
2.54E-001
1.83E-003
6.05E-001
South Dakota
1.192
100.54631
9.79E+001
6.68E-004
5.45E-001
1.52E-003
5.81E-001
Tennessee
1.902
163.29325
9.10E+002
1.32E-003
5.10E-001
2.67E-003
1.18E+000
Texas
2.749
184.4609
9.63E+003
9.70E-004
3.28E-001
1.84E-003
4.91E-001
Utah
3.095
243.6799
5.13E+002
1.69E-003
5.27E-001
3.88E-003
2.13E-001
Vermont
0.306
3.52794
1.38E+002
1.21E-003
1.94E-002
4.91E-004
2.14E-003
Virginia
1.924
146.66153
9.13E+002
1.73E-003
3.65E-001
2.42E-003
7.87E-001
Washington
0.414
30.99548
4.30E+002
4.66E-004
5.30E-002
5.04E-004
1.90E-001
West Virginia
2.917
248.97181
1.28E+003
1.73E-003
7.78E-001
3.98E-003
1.87E+000
Wisconsin
2.68
206.88852
1.00E+003
1.74E-003
4.97E-001
3.28E-003
9.25E-001
Wyoming
3.534
270.39145
9.01E+002
1.85E-003
5.59E-001
4.26E-003
5.79E-001
a Data based on 1999 data from eGRID version 2.01 (EPA
2003a).
b Data based on 1998-2000 average data in DOE (2002).
c Data based on tier emissions report for criteria air
pollutants in EPA (2003b).
d PM is the sum of all particulate matter including PM10
and PM2.5. PM10 and PM2.5 stand for particles smaller than 10
and 2.5 microns, respectively.
e No data.
U. S. State Average Criteria Pollutant Emission
Factors for Electricity Generation, in g/MJ
Particulate Matter (PM)
Particulate Matter (PM10)
Particulate Matter (PM2.5)
Ammonia (NH )
Volatile Organic Compounds
(NMVOC)
Mercury (Hg)
Lead (Pb)
Alabama
7.91048E-03
7.86328E-03
4.72023E-05
3.55049E-05
4.66784E-03
5.14071E-06
0
Alaska
8.96502E-03
8.85977E-03
1.05247E-04
6.51454E-06
2.82297E-03
3.27594E-07
0
Arizona
1.70555E-02
1.69322E-02
1.23202E-04
1.80226E-04
2.27385E-03
1.88997E-06
0
Arkansas
9.27803E-03
9.19307E-03
8.49561E-05
4.59383E-04
3.46429E-03
2.73415E-06
0
California
7.16813E-03
7.07819E-03
8.99402E-05
4.02651E-03
2.62453E-03
1.38598E-07
0
Colorado
7.29822E-03
7.23699E-03
6.12291E-05
9.56430E-05
4.36770E-03
1.62537E-06
0
Connecticut
1.22734E-02
1.21694E-02
1.04033E-04
2.22944E-03
3.93896E-03
1.18438E-06
0
Delaware
1.39283E-02
1.38287E-02
9.96131E-05
1.54469E-03
4.74441E-03
3.62874E-06
0
District of Columbia
2.88269E-02
2.84861E-02
3.40760E-04
8.76496E-03
2.30080E-02
0
0
Florida
4.33040E-02
4.29055E-02
3.98460E-04
1.58386E-03
3.39110E-03
1.71357E-06
0
Georgia
2.05237E-02
2.03865E-02
1.37175E-04
7.51637E-05
2.16686E-03
3.20035E-06
0
Hawaii
5.97339E-03
5.90409E-03
6.92999E-05
3.55697E-03
7.01715E-03
1.77657E-06
0
Idaho
0
0
0
0
0
0
0
Illinois
1.53276E-01
1.52156E-01
1.12047E-03
5.93583E-03
2.77818E-02
4.62412E-06
0
Indiana
2.18862E-02
2.17008E-02
1.85453E-04
5.75861E-04
4.87283E-03
4.86352E-06
0
Iowa
2.34564E-02
2.32698E-02
1.86674E-04
9.09228E-05
4.78644E-03
6.19910E-06
0
Kansas
2.41783E-02
2.39535E-02
2.24799E-04
4.19292E-04
5.39089E-03
4.93912E-06
0
Kentucky
1.69397E-02
1.68139E-02
1.25825E-04
4.35029E-05
3.80922E-03
4.71232E-06
0
Lousiana
1.79917E-02
1.77843E-02
2.07304E-04
1.66720E-03
1.02357E-02
1.41118E-06
0
Maine
3.36399E-03
3.34131E-03
2.26813E-05
1.55132E-03
9.62614E-03
4.53592E-07
0
Maryland
2.13382E-02
2.12038E-02
1.34391E-04
7.21581E-04
2.78881E-03
4.88872E-06
0
Mass-achusetts
8.85244E-03
8.76617E-03
8.62772E-05
1.70282E-03
3.49171E-03
1.88997E-06
0
Michigan
9.08755E-03
9.00520E-03
8.23449E-05
2.22140E-04
2.79017E-03
3.67914E-06
0
Minnesota
4.04781E-02
4.01455E-02
3.32617E-04
6.74889E-05
4.13240E-03
3.30114E-06
0
Mississippi
5.44446E-02
5.37910E-02
6.53601E-04
4.06289E-02
1.54329E-02
2.45696E-06
0
Missouri
1.25537E-02
1.24368E-02
1.16929E-04
6.48638E-05
4.98085E-03
4.67452E-06
0
Montana
3.67504E-03
3.64126E-03
3.37798E-05
4.01020E-05
3.14400E-03
3.77994E-06
0
Nebraska
1.33751E-02
1.32829E-02
9.21636E-05
6.90470E-05
5.23031E-03
3.59094E-06
0
Nevada
2.09146E-02
2.07657E-02
1.48886E-04
3.79659E-04
3.33440E-03
1.36078E-06
0
New Hampshire
3.09503E-02
3.06487E-02
3.01568E-04
7.16019E-04
2.45937E-03
3.40194E-07
0
New Jersey
3.45712E-02
3.41460E-02
4.25200E-04
1.24216E-04
1.52830E-02
1.28518E-06
0
New Mexico
5.20754E-02
5.16748E-02
4.00653E-04
4.41665E-04
5.12951E-03
8.41666E-06
0
New York
5.35802E-03
5.31301E-03
4.50068E-05
2.22325E-03
4.26008E-03
1.33558E-06
0
North Carolina
3.40955E-02
3.38325E-02
2.62976E-04
3.00504E-05
1.73434E-03
3.33894E-06
0
North Dakota
5.17162E-02
5.13979E-02
3.18277E-04
6.41672E-05
6.88995E-03
8.71905E-06
0
Ohio
1.38722E-02
1.37957E-02
7.64501E-05
1.11541E-04
2.59201E-03
6.24949E-06
0
Oklahoma
1.83971E-02
1.82479E-02
1.49160E-04
9.73713E-04
4.68484E-03
3.88073E-06
0
Oregon
3.47911E-03
3.46199E-03
1.71186E-05
4.43277E-06
5.31933E-04
3.77994E-07
0
Pennsylvania
2.21604E-02
2.20060E-02
1.54356E-04
1.47657E-04
1.51542E-03
6.56449E-06
0
Rhode Island
1.03973E-03
1.02744E-03
1.22906E-05
0
2.25247E-03
0
0
South Carolina
2.45530E-02
2.43803E-02
1.72632E-04
2.51344E-05
1.16735E-03
1.54977E-06
0
South Dakota
4.67825E-03
4.63562E-03
4.26239E-05
8.82976E-05
4.63562E-03
1.22218E-06
0
Tennessee
2.51650E-02
2.48944E-02
2.70575E-04
2.70034E-05
2.88396E-03
2.98615E-06
0
Texas
1.73147E-02
1.71765E-02
1.38283E-04
1.26310E-03
4.32150E-03
3.52794E-06
0
Utah
1.47314E-02
1.46364E-02
9.50155E-05
9.59315E-05
2.48737E-03
9.70184E-07
0
Vermont
1.16247E-03
1.14873E-03
1.37415E-05
1.80704E-05
2.12073E-03
0
0
Virginia
1.22315E-02
1.21362E-02
9.53635E-05
2.93259E-04
2.50975E-03
2.21756E-06
0
Washington
5.37627E-04
5.32210E-04
5.41708E-06
6.46409E-06
6.87348E-04
5.92190E-07
0
West Virginia
2.39677E-03
2.38177E-03
1.50018E-05
4.25792E-05
3.09497E-03
6.55189E-06
0
Wisconsin
7.34187E-03
7.28252E-03
5.93472E-05
6.45613E-05
4.61829E-03
4.83832E-06
0
Wyoming
5.08215E-02
5.06042E-02
2.17349E-04
5.19787E-05
4.78782E-03
5.27931E-06
0
United States National Average Water Consumption
Factorssupa
ThermoElectric Generation
HydroElectric Generation
Weighted Total Water
Consumption
L/MJ
Percent of Total Generation
L/MJ
Percent of Total Generation
L/MJ
United States
0.4960
89.4%
19.2095
8.6%
2.1007
a Based on data from Torcellini, Long, and Judkoff
(2004).
U.S. State Average Water Consumption Factors for
Electricity Generationsupa
ThermoElectric Generation
HydroElectric Generation
Weighted Total Water
Consumption
State
L/MJ
Percent of Total Generation
L/MJ
Percent of Total Generation
L/MJ
Alabama
0.1503
89.80%
38.9053
6.4%
2.6274
Alaska
0.3295
86.20%
–
13.8%
0.2839
Arizona
0.3313
88.30%
68.1928
11.7%
8.2533
Arkansas
0.3
89.50%
–
5.7%
0.2684
California
0.0511
74.10%
21.943
22.0%
4.8739
Colorado
0.5368
96.00%
18.8333
4.0%
1.26
Connecticut
0.086
90.80%
–
1.5%
0.0781
Delaware
0.0132
99.90%
–
0.0%
0.0132
District of Columbia
1.6959
100.00%
–
0.0%
1.6959
Florida
0.1506
95.70%
–
0.1%
0.1441
Georgia
0.6267
93.60%
49.8599
2.3%
1.7339
Hawaii
0.044
92.40%
–
1.1%
0.0407
Idaho
0
2.70%
8.9528
92.2%
8.2501
Illinois
1.1093
99.40%
–
0.1%
1.1032
Indiana
0.435
99.60%
–
0.3%
0.4331
Iowa
0.1229
97.30%
–
2.5%
0.1196
Kansas
0.6099
100.00%
–
0.0%
0.6098
Kentucky
1.1521
97.20%
162.2884
2.8%
5.599
Louisiana
1.6411
94.20%
–
0.9%
1.5461
Maine
0.3049
40.40%
–
28.7%
0.1231
Maryland
0.0343
95.30%
7.0617
2.7%
0.2259
Massachusetts
0
92.40%
–
2.4%
0
Michigan
0.5221
95.80%
–
1.4%
0.4999
Minnesota
0.4657
93.40%
–
2.4%
0.4351
Mississippi
0.4145
94.40%
–
0.0%
0.3912
Missouri
0.3213
97.40%
–
2.5%
0.313
Montana
1.0051
55.80%
38.6619
44.1%
17.5997
Nebraska
0.202
94.50%
2.2888
5.5%
0.3165
Nevada
0.5936
90.60%
77.1023
9.2%
7.626
New Hampshire
0.1231
83.90%
–
8.6%
0.1033
New Jersey
0.0747
97.60%
–
0.0%
0.0729
New Mexico
0.6609
99.30%
71.507
0.7%
1.1886
New York
0.8951
81.30%
5.8535
16.7%
1.704
North Carolina
0.2445
95.50%
10.9089
3.1%
0.5751
North Dakota
0.3809
91.70%
60.773
8.3%
5.3968
Ohio
0.9972
99.10%
–
0.3%
0.9884
Oklahoma
0.5378
93.70%
144.0133
5.8%
8.8254
Oregon
0.8633
18.40%
4.6351
80.7%
3.899
Pennsylvania
0.57
97.60%
–
1.0%
0.5563
Rhode Island
0
98.20%
–
0.1%
0
South Carolina
0.2754
97.20%
–
1.9%
0.2677
South Dakota
0.0143
36.70%
120.7558
63.2%
76.3811
Tennessee
0.0026
90.80%
45.5853
8.3%
3.7833
Texas
0.4595
99.00%
–
0.3%
0.455
Utah
0.5959
96.60%
77.115
3.4%
3.209
Vermont
0.3642
71.50%
–
20.9%
0.2605
Virginia
0.0693
94.90%
–
0.9%
0.0657
Washington
0.3013
15.70%
3.3506
83.2%
2.8344
West Virginia
0.618
99.00%
–
1.0%
0.6119
Wisconsin
0.5199
93.60%
–
3.3%
0.4867
Wyoming
0.519
97.10%
144.0177
2.7%
4.3654
a Based on data from Torcellini, Long, and Judkoff
(2004).
Other
Energy-Related Pollutants and Sources of Other
Information[LINK]
EnergyPlus (with user entered-data) will also calculate
high- and low-level nuclear waste from electricity generation.
Few utilities now provide data on nuclear waste resulting from
electricity generation and no US national or state-level data
are yet available (this will be added as data become
available). Two Illinois utilities regularly report nuclear
waste in terms of pounds per kWh or MWh for high-level waste
and cubic feet per kWh or MWh for low-level waste. For these
two utilities, high level nuclear waste values range from
0.0042 to 0.01 lb/MWh (7000 to 16000 g/MJ); low-level nuclear
waste ranges from 0.0001 to 0.0002 ft\(^{3}\)/MWh (0.01 to 0.02 m\(^{3}\)/MJ) depending on relative
proportion of nuclear as compared with other electricity
generation sources.
IEA (2003) contains carbon dioxide (CO\(_{2}\)) emissions factors for
electricity generation by country and region. Carbon dioxide
(CO\(_{2}\)) is responsible
for over 60% of the anthropogenic greenhouse effect (UNEP
2002). Because only limited greenhouse gas emissions factors
and data (other than CO\(_{2}\)) is available for other
countries, an interim method for estimating emission factors
would be to compare the CO\(_{2}\) emission factor for the
particular country from IEA (2003) and match it to the state
with the closest CO\(_{2}\)
emission factor in Table—using
the other emissions factors for that state. Since the Kyoto
Protocol (UNFCCC 1997) requires each country to report
emissions of the major greenhouse gases [carbon dioxide
(CO\(_{2}\)), methane
(CH\(_{4}\)), and nitrous
oxide (N\(_{2}\)O)] as well
as ozone-depleting substances [hydrofluorocarbons (HFC),
perfluorocarbons (PFC), and sulphur hexafluoride (SF\(_{6}\))] and all energy
consumption in their annual ‘national communication’, more
complete emission factors for a larger number of countries
should become available over the next few years. More
information and other resources for calculating emissions
factors are available in IPCC (2000, 1997).
Crawley, Drury B. 2003. “Impact of Climate Change on
Buildings,” in Proceedings of the CIBSE/ASHRAE
International Conference 2003, September 2003, Edinburgh,
Scotland. London, England: CIBSE.
Intergovernmental Panel on Climate Change. 2001.
Climate Change 2001: The Scientific Basis.
Cambridge: Cambridge University Press.
Intergovernmental Panel on Climate Change. 2000. Good
Practice Guidance and Uncertainty Management in National
Greenhouse Gas Inventories, Paris, France:
IPCC/OECD/IEA.
Intergovernmental Panel on Climate Change. 1997.
Revised 1996 IPCC Guidelines for National Greenhouse Gas
Inventories, J.T. Houghton, L.G. Meira Filho, B. Lim, K.
Treanton, I. Mamaty, Y. Bonduki, D.J. Griggs and B.A.
Callender (editors). Paris, France: IPCC/OECD/IEA.
International Energy Agency. 2003. CO\(_{2}\) Emissions from Fuel
Combustion 1971-2001 (2003) – 2003 Edition. Paris,
France: IEA.
Liesen, Richard J. 1997. Atmospheric Pollution
Prediction in a Building
Energy Simulation Program, April 1997, BLAST Support
Office, Department of Mechanical Engineering. Champaign,
Illinois: University of Illinois.
Stroot, Peter J., Robert J. Nemeth, & Donald F.
Fournier. 1996. Pollution Reduction Through Energy
Conservation, REEP Model. Champaign, Illinois: U S Army
Construction
Engineering Research Laboratory.
Torcellini Paul A, Nicholas Long, and Ronald D. Judkoff.
2004. “Consumptive Water Use for U.S. Power Production,” in
ASHRAE Transactions, Volume 110, Part 1. Atlanta,
Georgia: ASHRAE.
United Nations Environment Programme. 2002. Climate
Change Information Kit. Châtelaine, Switzerland:
UNEP.
United Nations Framework Convention on Climate Change.
1997. KyotoProtocol to the United Nations
Framework Convention on Climate Change. Bonn, Germany:
UNFCCC.
U.S. Department of Energy. 2004. Monthly Energy
Review. Washington, DC: Energy Information
Administration, U S Department of Energy.
U.S. Department of Energy. 2002. Updated State-level
Greenhouse Gas Emission Coefficients for Electricity
Generation 1998-2000. April 2002, Energy Information
Administration, Office of Integrated Analysis and Forecasting,
Energy Information Administration. Washington, DC: U.S.
Department of Energy.
U.S. Environmental Protection Agency. 2003a. eGRID
Emissions and Generation Resource Integrated Database,
May 2003, Washington, DC: U.S. Environmental Protection
Agency.
U.S. Environmental Protection Agency. 2003b.
AirData, Tier Emissions Report - Criteria Air
Pollutants, 1999 data, May 2003. Washington, DC: U.S.
Environmental Protection Agency.
U.S. Environmental Protection Agency. 1998a.
Compilation of Air Pollutant Emission Factors, AP-42,
Fifth Edition, Volume I: Stationary Point and Area
Sources, Chapter 1 External Combustion Sources,
Supplement D, July 1998. Research Triangle Park, North
Carolina: U. S. Environmental Protection Agency.
U.S. Environmental Protection Agency. 1998b.
Compilation of Air Pollutant Emission Factors, AP-42,
Fifth Edition, Volume I: Stationary Point and Area
Sources, Chapter 1 External Combustion Sources,
Supplement E, September 1998. Research Triangle Park, North
Carolina: U. S. Environmental Protection Agency.
U.S. Environmental Protection Agency. 1996.
Compilation of Air Pollutant Emission Factors, AP-42,
Fifth Edition, Volume I: Stationary Point and Area
Sources, Chapter 1 External Combustion Sources,
Supplement B, October 1996. Research Triangle Park, North
Carolina: U. S. Environmental Protection Agency.
Environmental Impacts[LINK]
Typically when a new building technology is evaluated the energy performance of a baseline building is compared to the energy and life-cycle costs of alternatives to determine cost-effectiveness. But what if the lowest energy or life-cycle cost alternative is not the cleanest or lowest environmental impact? By calculating environmental impact, designers can compare alternatives not only in terms of their energy performance but also their environmental performance—working towards a more sustainable design (Liesen 1997; Stroot, Nemeth, and Fournier 1996). Environmental impacts are quantified, in part, by modeling the amount of emissions and in EnergyPlus this is done using the input objects “EnvironmentalImpactFactors,” “FuelFactors,” and “Output:EnvironmentalImpactFactors.”
Based on emissions factors entered by the user, EnergyPlus calculates the mass or volume of thirteen different pollutants: CO\(_{2}\) (carbon dioxide), CO (carbon monoxide), CH\(_{4}\) (methane), NO\(_{x}\) (nitrogen oxides), N\(_{2}\)O (nitrous oxide), SO\(_{2}\) (sulphur dioxide), PM (particulate matter), PM\(_{10}\) (particulate matter 10>PM\(_{10}\)>2.5 microns), PM\(_{2.5}\) (particulate matter<2.5 microns), NH\(_{3}\) (ammonia), NMVOC (non-methane volatile organic compounds), Hg (mercury), and Pb (lead) as well as water consumed through evaporation in thermo- and hydro-electric generation and high- and low-level nuclear waste from nuclear electricity generation for on- and off-site energy production. Note that while these comprise the largest proportion of pollutants, more than one hundred other pollutants are emitted from fossil fuel combustion or electricity generation. Much of the information compiled here for fossil fuel combustion comes from AP-42 Compilation of Air Pollutant Emission Factors (EPA 1998a, 1998b, 1996). For more information on pollutants, see the U.S. Environmental Protection Agency (EPA) Clearinghouse for Inventories & Emission Factors (www.epa.gov/ttn/chief/efinformation.html).
EnergyPlus models energy performance of on-site fossil fuels and purchased electricity (generated from a variety of fuels including natural gas, oil, gasoline, diesel, coal, hydroelectric, nuclear, wind, solar power, and biomass). The energy performance calculated by EnergyPlus is converted into a mass or volume of pollutants emitted. From a baseline building, alternative energy and pollution saving technologies can be explored, and the energy savings and pollution reduction can be calculated. Figure and Figure illustrate a comparison of two buildings simulated using Chicago weather data in EnergyPlus and the calculated pollutant levels (based on U.S. national average pollutants) (Crawley 2003).
To calculate the mass or volume of each pollutant, consumption is multiplied by an emissions factor for each fuel (natural gas, electricity, fuel oil, diesel, or coal). In future versions, users will be able to schedule how the emissions factors by time of day, month, season and year. For electricity, the mix of generation fuel sources—whether utility, state or regional—is used to adjust the emission factors. If a user has emissions factors specific to the building site and equipment, these can be entered directly. There are no default emissions factors.
Types of Pollutants[LINK]
EPA categorizes pollutants as either Criteria Pollutants or Hazardous Pollutants. Criteria pollutants are the six substances for which EPA has set health-based standards, including carbon monoxide (CO), nitrogen oxides (NO\(_{x}\)), sulfur dioxide (SO\(_{2}\)), and particulate matter (PM10 and PM2.5), ozone (O\(_{3}\)), and lead (Pb). Because ozone is created in atmospheric photochemical reactions of volatile organic compounds, ammonia, and other substances rather than direct building-related energy emissions, we do not calculated ozone emissions in EnergyPlus. But we do include ozone precursors: methane (CH\(_{4}\)), non-methane volatile organic compounds (NMVOC), and ammonia (NH\(_{3}\)). Hazardous pollutants are substances that are known or suspected to cause serious health problems such as cancer. We include typical hazardous substances associated with energy production and use including lead (Pb) and mercury (Hg). We also include CO\(_{2}\) (carbon dioxide) since it is largest greenhouse gas in terms of impact.
Carbon Equivalent[LINK]
The Intergovernmental Panel on Climate Change has studied the effects on the relative radiative forcing effects of various greenhouse gases. This effect, called Global Warming Potential (GWP), is described in terms of the Carbon Equivalent of a particular greenhouse gas. This equivalent is based on a factor of 1.0 for carbon. This group of gases includes carbon dioxide (CO\(_{2}\)), carbon monoxide, nitrous oxide, methane, halocarbon emission, hydrofluorocarbons (HFC), perfluorocarbons (PFC), and chlorofluorocarbons (CFC). For building energy use, the main gases of concern are carbon dioxide, carbon monoxide, methane, and nitrous oxide. Although carbon monoxide has a relatively short life, CO emissions into the atmosphere may have a significant impact on climate forcing due to chemical impact on CH\(_{4}\) lifetime, and tropospheric O\(_{3}\) and CO\(_{2}\) photochemical production normally reacts to produce carbon dioxide, but it can’t be ignored since it is produced in incomplete combustion and the carbon remains to interact as CO\(_{2}\) Yet there is no agreement on its carbon equivalent (IPCC 2001). The carbon equivalent of carbon dioxide, methane, and nitrous oxide are calculated and then multiplied by their GWP on a 100 year time frame. The Carbon Equivalents of the following gases have been determined and used in the program are shown in the following table.
The resulting carbon equivalents by fuel type are shown in the output of the program along with the individual gas pollutants.
Fossil Fuel Emissions Factors[LINK]
Emission factors for on-site fossil fuel consumption are based on Section 1.4 Natural Gas Combustion in EPA (1998a) Table shows the greenhouse gas and precursors and criteria pollutant emissions factors for natural gas. Similar emissions factors are shown for residual fuel oil (No. 4 and No. 6 fuel oil) [Table{]}, distillates (No. 1 and No. 2 fuel oil) [Table{]}, residential oil furnace [Table{]}, LPG (butane and propane) [Table{]}, gasoline and diesel [Table{]}, and coal [Table{]} in the indicated tables. Note that a zero for a pollutant in the table may mean that no data were available, not that there are no emissions of that pollutant.
Off-Site Electricity Generation Emissions[LINK]
While estimating emissions from on-site fossil fuel combustion can be fairly straight-forward, emissions from off-site electricity is more challenging. How the electricity is generated, i.e., from gas, oil, coal, nuclear, renewable sources (wind, PV) or hydroelectric, and the mix of generation determines the resulting level of emissions. While data are available at utility and even power plant level (from the sources cited), data are shown here for United States national- and state-level average emissions from electricity generation. Table provides average greenhouse gas and precursors and criteria pollutant emissions factors for the entire United States from electricity generation. Table provides average electricity emissions factors by state, for greenhouse gas and precursors, and Table for criteria pollutant emission factors. These two tables also include a ratio of heat input to electric output (efficiency of electricity generation) including distribution and transmission losses to allow calculation of source energy.
As mentioned in the introduction to this section, EnergyPlus also calculates water consumed through evaporation in thermo-electric and hydro-electric generation. Torcellini, Long, and Judkoff (2004) provide data on average water consumption by generator type by state. These data are summarized in units suitable for EnergyPlus in Table, for national and state average water consumption for thermal-electric, hydro-electric, and Table for weighted total electricity generation.
Other Energy-Related Pollutants and Sources of Other Information[LINK]
EnergyPlus (with user entered-data) will also calculate high- and low-level nuclear waste from electricity generation. Few utilities now provide data on nuclear waste resulting from electricity generation and no US national or state-level data are yet available (this will be added as data become available). Two Illinois utilities regularly report nuclear waste in terms of pounds per kWh or MWh for high-level waste and cubic feet per kWh or MWh for low-level waste. For these two utilities, high level nuclear waste values range from 0.0042 to 0.01 lb/MWh (7000 to 16000 g/MJ); low-level nuclear waste ranges from 0.0001 to 0.0002 ft\(^{3}\)/MWh (0.01 to 0.02 m\(^{3}\)/MJ) depending on relative proportion of nuclear as compared with other electricity generation sources.
IEA (2003) contains carbon dioxide (CO\(_{2}\)) emissions factors for electricity generation by country and region. Carbon dioxide (CO\(_{2}\)) is responsible for over 60% of the anthropogenic greenhouse effect (UNEP 2002). Because only limited greenhouse gas emissions factors and data (other than CO\(_{2}\)) is available for other countries, an interim method for estimating emission factors would be to compare the CO\(_{2}\) emission factor for the particular country from IEA (2003) and match it to the state with the closest CO\(_{2}\) emission factor in Table—using the other emissions factors for that state. Since the Kyoto Protocol (UNFCCC 1997) requires each country to report emissions of the major greenhouse gases [carbon dioxide (CO\(_{2}\)), methane (CH\(_{4}\)), and nitrous oxide (N\(_{2}\)O)] as well as ozone-depleting substances [hydrofluorocarbons (HFC), perfluorocarbons (PFC), and sulphur hexafluoride (SF\(_{6}\))] and all energy consumption in their annual ‘national communication’, more complete emission factors for a larger number of countries should become available over the next few years. More information and other resources for calculating emissions factors are available in IPCC (2000, 1997).
References[LINK]
Crawley, Drury B. 2003. “Impact of Climate Change on Buildings,” in Proceedings of the CIBSE/ASHRAE International Conference 2003, September 2003, Edinburgh, Scotland. London, England: CIBSE.
Intergovernmental Panel on Climate Change. 2001. Climate Change 2001: The Scientific Basis. Cambridge: Cambridge University Press.
Intergovernmental Panel on Climate Change. 2000. Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, Paris, France: IPCC/OECD/IEA.
Intergovernmental Panel on Climate Change. 1997. Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories, J.T. Houghton, L.G. Meira Filho, B. Lim, K. Treanton, I. Mamaty, Y. Bonduki, D.J. Griggs and B.A. Callender (editors). Paris, France: IPCC/OECD/IEA.
International Energy Agency. 2003. CO\(_{2}\) Emissions from Fuel Combustion 1971-2001 (2003) – 2003 Edition. Paris, France: IEA.
Liesen, Richard J. 1997. Atmospheric Pollution Prediction in a Building Energy Simulation Program, April 1997, BLAST Support Office, Department of Mechanical Engineering. Champaign, Illinois: University of Illinois.
Stroot, Peter J., Robert J. Nemeth, & Donald F. Fournier. 1996. Pollution Reduction Through Energy Conservation, REEP Model. Champaign, Illinois: U S Army Construction Engineering Research Laboratory.
Torcellini Paul A, Nicholas Long, and Ronald D. Judkoff. 2004. “Consumptive Water Use for U.S. Power Production,” in ASHRAE Transactions, Volume 110, Part 1. Atlanta, Georgia: ASHRAE.
United Nations Environment Programme. 2002. Climate Change Information Kit. Châtelaine, Switzerland: UNEP.
United Nations Framework Convention on Climate Change. 1997. Kyoto Protocol to the United Nations Framework Convention on Climate Change. Bonn, Germany: UNFCCC.
U.S. Department of Energy. 2004. Monthly Energy Review. Washington, DC: Energy Information Administration, U S Department of Energy.
U.S. Department of Energy. 2002. Updated State-level Greenhouse Gas Emission Coefficients for Electricity Generation 1998-2000. April 2002, Energy Information Administration, Office of Integrated Analysis and Forecasting, Energy Information Administration. Washington, DC: U.S. Department of Energy.
U.S. Environmental Protection Agency. 2003a. eGRID Emissions and Generation Resource Integrated Database, May 2003, Washington, DC: U.S. Environmental Protection Agency.
U.S. Environmental Protection Agency. 2003b. AirData, Tier Emissions Report - Criteria Air Pollutants, 1999 data, May 2003. Washington, DC: U.S. Environmental Protection Agency.
U.S. Environmental Protection Agency. 1998a. Compilation of Air Pollutant Emission Factors, AP-42, Fifth Edition, Volume I: Stationary Point and Area Sources, Chapter 1 External Combustion Sources, Supplement D, July 1998. Research Triangle Park, North Carolina: U. S. Environmental Protection Agency.
U.S. Environmental Protection Agency. 1998b. Compilation of Air Pollutant Emission Factors, AP-42, Fifth Edition, Volume I: Stationary Point and Area Sources, Chapter 1 External Combustion Sources, Supplement E, September 1998. Research Triangle Park, North Carolina: U. S. Environmental Protection Agency.
U.S. Environmental Protection Agency. 1996. Compilation of Air Pollutant Emission Factors, AP-42, Fifth Edition, Volume I: Stationary Point and Area Sources, Chapter 1 External Combustion Sources, Supplement B, October 1996. Research Triangle Park, North Carolina: U. S. Environmental Protection Agency.
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This documentation is made available under the EnergyPlus Open Source License v1.0.