K-3.i

APPENDIX K-3. UPSTREAM EMISSION FACTORS 

FROM COAL AND NATURAL GAS PRODUCTION

TABLE OF CONTENTS

TABLE

Table K-3.1 Estimated Upstream Emission Factors and Relative Percentages 

To Direct Power Plant Combustion Emissions . . . . . . . . . . . . . . . . . . . . . . . K-3.2
K-3.1

APPENDIX K-3. UPSTREAM EMISSION FACTORS 

FROM COAL AND NATURAL GAS PRODUCTION

Tracking of pollutant emissions by NEMS-BRS is incomplete, with thorough treatment of

some aspects and scant treatment of others. The approach is also somewhat different between

emissions. Overall, carbon emissions are well covered because they are estimated based on

elemental carbon released as CO2 from all hydrocarbon combustion. However, some energy-use

effects of proposed standards are not tracked by NEMS-BRS so their effects on carbon emissions

are not counted. For example, the effect of lower residential electricity consumption on generation

is estimated, but not the second order effect on energy consumed in coal transportation to power

plants.

In other words, the amount of energy used to perform the upstream processes in coal and

natural gas production is not linked to the downstream consumption of these fuels. For this reason,

while total carbon emissions are counted, changes due to proposed standards are not. According to

M.A. DeLuchi, the amount of energy used to mine and clean the coal is minimal, amounting to less

than 1% of the energy available in the coal. The amount of energy required to transport the coal

using trains, trucks, and pipelines is approximately 0.156 EJ/yr (0.148 Quads/yr) as estimated for the

year 2020.1 Based on the AEO99 energy consumption of coal from electric generation, this

corresponds to 0.7% of the total energy required by electric generators. For natural gas production,

the amount of energy used to transport natural gas to the end-use consumer is 3.5% of the total

natural gas produced and made available to end-use customers as estimated for the year 2000. For

extraction of crude oil, the relative percentage is only 2.8%. Thus, the upstream losses are small

relative to the total amount of energy embodied in the coal, oil, and natural gas and, therefore,

changes due to proposed standards are also likely to be small.

NEMS-BRS tracks only NOx and SO2 emissions from power generation. Sources of these

emissions that may be affected by proposed standards are therefore missed. Two notable sources

of NOx and SO2 emissions not considered are household emissions from the combustion of natural

gas, liquefied petroleum gas (LPG), and heating fuel oil and emissions associated with fuel

extraction and delivery to the point of combustion. 

This analysis considers two uncounted emissions from coal and natural gas production and

delivery, SO2 and NOx. These emissions include those due to the mining of coal or extraction of

natural gas, the physical processes involved in preparing or cleaning the fossil fuel, and the

transportation of the fuel from the mine to the power plant. Household combustion effects of

proposed standards are explicitly included in the appliance energy-efficiency standards analysis and

the methods used are described in Appendix K-2.

Studies addressing upstream emissions are very limited. Thus, the reliability of the exact

measurements can be easily criticized. The values presented herre are only intended to provide a

coarse estimate of the magnitude of upstream emissions not accounted for in NEMS-BRS. In

general, emissions from mining, cleaning, or transporting fossil fuels are small compared to the

emissions that result from their combustion.
K-3.2

Upstream emissions estimates for carbon and NOx are taken from a thorough study done by

M.A. DeLuchi at Argonne National Laboratory in 1993. DeLuchi provides estimates of full fuelcycle emissions factors for emissions of CO2, methane (CH4), carbon monoxide (CO), non-methane

organic compounds (NMOC), and NOx from coal and natural gas production. The emission factor

for SO2 is taken from the Environmental Protection Agency (EPA) AP-42.2 This source notes that

coal cleaning is the primary source for upstream SO2 emissions from coal production, so the

emission factor for SO2 only reflects the coal cleaning process. Transportation is not addressed in

EPA’s study.

Emission factor estimates and corresponding percentage contributions of the upstream

emissions relative to power plant emissions are shown in Table K-3.1 for carbon, SO2, and NOx from

coal and natural gas production. The relative percentage to power plant emissions is provided so an

estimate of upstream emission savings based on the savings from the power plant could be easily

estimated. The values shown in Table K-3.1 represent emissions from upstream processes as mass

(g) per deliverable energy to end-use consumers.

Table K-3.1 Estimated Upstream Emission Factors and Relative Percentages To Direct

Power Plant Combustion Emissions

Coal Natural Gas

Emission

Factor 

(g/GJ)

% of

Combustion

Emissions

Emission

Factor 

(g/GJ)

% of

Combustion

Emissions

Carbon 2222 2.7 5456 11.9

SO2 29.2 0.9 0 0

NOx 41.7 5.8 153 40.0

DeLuchi’s analysis reveals that upstream processes in coal production relative to power plant

emissions account for 5.8% of NOx and 2.7% of carbon. The AP-42 indicates that less than one

percent of SO2 emissions result upstream relative to those from coal power plant emissions.

Upstream coal processes, therefore, account for at most 6% of relative power plant emissions for

carbon, SO2, and NOx.

For natural gas production, the upstream SO2 emissions are negligible. The upstream

emissions from NOx, however, are quite significant, accounting for 40.0% of emissions relative to

those from the power plant. Total natural gas combustion NOx emissions from the power plant are

only half those from coal, while emissions upstream processes are four times those of coal. Carbon

emissions are nearly 12% of power plant emissions with an emission factor of 5456 g/GJ of

deliverable energy; however, as noted above, changes to these emissions are counted by NEMSBRS.
K-3.3

Relative to the entire fuel cycle, DeLuchi estimates that approximately 8% by mass of all

emissions from coal production are due to mining, preparation, and transport from the mine to the

plant. Transportation emissions include those resulting from the use of fuel by the modes of

transportation used to move the fuel from the site of extraction to fuel production facilities. For

natural gas production, 14% of total emissions are estimated to result from upstream processes.

Based on Table K-3.1, this higher loss factor in natural gas production is likely due to the higher NOx

contribution. 

Thus, emissions factors and their relation to power plant emissions are provided to reveal the

relatively small proportion of energy losses attributable to upstream processes. With the exception

of NOx emissions from natural gas production, all emissions are less than 12% of power plant

emissions.
K-3.4

REFERENCES

1. DeLuchi, M. A., Emissions of Greenhouse Gases from the Use of Transportation Fuels and

Electricity, Volume 2: Appendixes A-S, November, 1993, Argonne National Laboratory.

Argonne, IL. Report No. ANL/ESD/TM-22-Vol.2. 

2. U.S. Environmental Protection Agency, Compilation of Air Pollutant Emission Factors, AP42, Fifth Edition, Volume I: Stationary Point and Area Sources, Chapter 11, Mineral

Products Industry,1995. November. < http://www.epa.gov/ttn/chief/ap42c11.html>