NARSTO Emission Inventory Workshop
October 14-17, Austin, Texas
Development of the API Compendium for Estimating Greenhouse Gas Emissions
Karin Ritter, APISusann Nordrum, ChevronTexacoTheresa Shires, URS
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Background
In response to continued interest by its member companies about consistency in greenhouse gas emissions estimation, the American Petroleum Institute (API) developed a Compendium of Greenhouse Gas Emissions Estimation Methodologies for the Oil and Gas Industry (API, 2001). Initially distributed in April 2001, the Compendium is a result of more than a year long effort by API to screen, evaluate and document a range of calculation techniques and emission factors that could be useful for developing greenhouse gas emissions inventories.
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In developing the Compendium, API reached out to sibling organizations and reviewed their guidance documents, along with emerging national and international protocols and internal company GHG estimation protocols. This paper provides a brief overview of the Compendium development and introduces the technical approach and techniques for estimating carbon dioxide (CO2) and methane (CH4) emissions. It also discusses the process undertaken to compare and reconcile different estimationmethodologies used by other organizations.
Through this work, API is expanding the dialogue among the global oil and gas industry and pursuing consistency in GHG emissions estimation to ensure comparability and the eventual fungibility of emission reductions. Findings from the pilot phase distribution of the Compendium are addressed in this paper, as well as enhancements planned for the 2003 update of the document.
Introduction
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Overview of API Compendium
l Issued in April 2001 for “road-testing” and “learning by doing”
l Main Attributes include:ü Consistent, standardized methodologies ü Compilation of recognized estimation approachesü Focussed on carbon dioxide (CO2) and methane
(CH4) emissionsü Combustion sources have broad industry
applicationü Non-combustion sources specific to oil and natural
gas industry
l Revised Compendium available by end of 2003.
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Greenhouse Gas Emissions Methodology Projectl Objectives –
ü Provide technical expertise on current methodologies and investigate improvements and streamlining options
ü Promote dissemination of consistent guidance for estimation of petroleum companies GHG emissions
l Mandate –ü Focus on Industry Sources and Emissionsü Concentrate mainly on CO2 and CH4
l Structure –ü Multi-sector petroleum industry participation to
ensure coordinated industry effort
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Methodology Approach
l Emission sources
l Preferred vs. alternative methods -ü Decision trees to guide method selectionü Sample calculations and Case Studies
l Data assumptions –ü Standard gas conditionsü SI units and units common to US practicesü Unit conversion factors
ü By source category u Combustion emissionsu Process emissionsu Fugitive emissions
ü By industry segmentu Exploration and Productionu Transportation and Distributionu Refining
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Typical Methods Hierarchy
Types of Approaches Hierarchy
Published emission factors
Equipment manufacturer emissionfactors
Engineering calculations
Monitoring over a range of conditionsand deriving emission factors
Periodic monitoring of emissions orparameters for calculating emissions
Continuous emission monitoring
Improved accuracyAdditional data requirements
Higher cost
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General Findings
l CO2 sources easier to generalize based on fuel carbon content and other properties -ü Uncertainty range of 5-15% if estimate is based on
heating values rather than carbon contentü Additional errors may be introduced in fuel volumes
data and in definitions of standard conditions
l CH4 estimates more complex -ü Device specific and can vary with operating practicesü Requires knowledge of specific emission sources
l Techniques presented have broader application to many other industriesü Particularly for combustion emissions
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Consistency and Comparability in Emission Estimates
Need for Consistency -ü Data aggregation, ü Performance
evaluation, and ü Identification of trends
Elements of Comparability -
ü Estimation approaches,
ü Organizational boundaries,
ü Emission sources included, and
ü Data presentation and report approach
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u Environmental Protection Agency (EPA) Emission Inventory Improvement Program (EIIP, 1999)
GHG Protocols Included in Quantitative Comparison
u Australian Petroleum Production and Exploration Association Greenhouse Challenge Report (APPEA, 2000)
u Canadian Association of Petroleum Producers, Global Climate Change Voluntary Challenge Guide (CAPP, 2000)
u Canadian Industrial Energy End-Use Data and Analysis Centre, “Guide for the Consumption of Energy Survey” (CIEEDAC, 2000)
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GHG Protocols Included in Quantitative Comparison
u Exploration and Production Forum, Methods for Estimating Atmospheric Emissions from E&P Operations (E&P Forum, 1994)
u Intergovernmental Panel on Climate Change, Guidelines for National Greenhouse Gas Inventories (IPCC, 1997; UNECE/EMEP, 1999; IPCC, 2001)
u Regional Association of Oil and Natural Gas Companies in Latin America and the Caribbean, Atmospheric Emissions Inventories Methodologies in the Petroleum Industry (ARPEL, 1998)
u World Resources Institute and World Business Council for Sustainable Development, The Greenhouse Gas Protocol (WRI/WBCSD, 2001)
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Emission Factors Comparison
l Qualitative comparisonü Identify scope, emission
sources, and application of emission factors
ü Determine root sources of the emission factorsu Ensure that references are
current
ü Ascertain transparency and documentation of derived emission factors
l Examine variability among
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0.06930.07030.07170.0692Aviation Gas
0.07890.07030.07750.07180.0788Residual
0.09870.10210.08790.10100.12600.102Petroleum Coke
0.05200.05310.05560.05320.05420.0531Natural Gas
0.06310.06150.06320.06260.0629LPG
0.07100.07030.06940.0712Gasoline
0.07320.07320.07420.07350.0742Diesel
0.07500.07320.07030.07180.0732Distillate
0.07030.07340.0743Crude Oil
0.09310.08790.08080.08510.081Bitumen
CIEEDACWRI/
WBCSDDEFRAIPCCAGOCompendiumFuel Types
Combustion Emission Factor Comparison
Tonnes CO2/MMBTU (HHV)
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Emission Factors Comparison
l Quantitative comparisonü 6 hypothetical facilities provided in case studies in
the Compendiumu Onshore oil field with high CO2 contentu Offshore production platformu Production gathering compressor stationu Natural gas processing facilityu Marketing terminalu Refinery
ü Emissions were estimated using methodologies and/or emission factors from each protocol.
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0
500
1000
1500
2000
2500
3000
APICompendium
ARPEL EIIP E&P Forum CAPP IPCC
Protocol
Non-combustion
Combustion
CH
4E
mis
sio
ns
(to
nn
es/y
r)
Onshore Oil Production Facility
High CO2 Content in Associated Gas
Comparative Emissions Estimate -Onshore Facility - CH4
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0
10,000
20,000
30,000
40,000
50,000
60,000
APICompendium
ARPEL EIIP E&P Forum CAPP IPCC WRI
Protocol
Non-combustionCombustion
CO
2E
mis
sio
ns
(to
nn
es/y
r)
Onshore Oil Production Facility
High CO2 Content in Associated Gas
Comparative Emissions Estimate -Onshore Facility - CO2
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CH
4E
mis
sio
ns
(to
nn
es/y
r)
Large Complex Refinery
0
100
200
300
400
500
600
700
AP ICompendium
ARPEL EIIP CAPP IPCC
P ro t o c o l
NoncombustionCombustion
Comparative Emissions Estimate -Refinery - CH4
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0
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
APICompendium
ARPEL EIIP CAPP IPCC WRI CIEEDAC
Protocol
Non-combustionCombustion
CO
2E
mis
sio
ns
(to
nn
es/y
r)
Large Complex Refinery
Comparative Emissions Estimate -Refinery - CO2
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Key Findings from Emission Factors Comparison - Combustion
l Variability of fuel-based factors due to different fuel specifications ü For high quality results need fuel specific data
(e.g. composition, heating value, density, etc.)
l Need to specify heating value conventionl Variation in CH4 emissions due to different
versions of EPA’s AP-42 ü Not significant for CO2
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Comparison Synopsis Report, 2002
Key Findings from Emission Factors Comparison - Non-combustion
l ARPEL quantified several sources not included in the Compendium
l Combining sources into one or two EFs makes it difficult to determine what sources are included
l Not all emission sources are addressed across protocols
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Attaining global consistency will ensure national and regional comparability in estimation techniquesand the eventual fungibility of emission reduction
credits among those nations with comparable crediting or trading regimes.
Outreach Efforts and Special Studies
l Dialogue among oil and gas associations worldwide
l Discussions with other protocols developers
l Protocols comparisons and emissions reduction studies
l New initiative for Global GHG Reporting Guidelines
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Conclusions
l Robust methods for calculating, reporting, and tracking emissions are essential for cost-effectively managing GHG emissions
l Consistent methodologies lend credibility to the estimates and enable aggregation and comparison
l Initial “road testing” of the API Compendium and special studies undertaken further support the pursuit of consistency
l These activities have spurred new initiatives to progress toward harmonization of methodologies and improved global compatibility emission estimates
