Airport Greenhouse Gas Emissions Inventory: A Primer (2024)
Chapter: 4. Monitor Progress Over Time
4. Monitor Progress Over Time
Effectively monitoring emissions using consistent and reliable inventory methods will help you:
- Evaluate trends that can inform emission reduction measures,
- Quantify the benefit of investments made to reduce emissions, and
- Report progress made toward achieving emission reduction goals.
While there are different options available to monitor progress ranging from using internally developed calculators and tools to using commercially available software, one key component of an effective monitoring program is to develop and maintain an inventory management plan.
4.1 Prepare an Inventory Management Plan
Airport operators can use an inventory management plan to complete a consistent, accurate, and reliable GHG emission inventory year after year. Inventory management plans help:
- Institutionalize GHG inventory practices to ensure that they remain consistent even if the individuals responsible for preparing the inventory change over time.
- Document key inventory decisions, assumptions, methods, factors, and contributors.
- Provide transparency to support review by inventory verifiers and assurance providers.
The below checklist describes the basic elements of an inventory management plan.
For more information, visit the EPA Center for Corporate Climate Leadership’s Inventory Management Plan Guidance page.
4.2 Example Airport Inventory Management Plan
The subsequent subsections include example information for an airport inventory management plan, following the checklist below.
This checklist describes the basic elements of an inventory management plan.
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Organizational Information |
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Include your airport’s name and address and the contact information of the GHG inventory manager. |
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Boundary Conditions |
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Describe your airport’s organizational and operational boundaries used in the inventory. |
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Emissions Quantification |
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Describe the emissions calculation methods, emission factors, assumptions, limitations, and emissions calculation results. |
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Data Management |
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Identify your data sources, describe your data collection process and quality assurance measures taken during data collection. |
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Base Year |
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Identify your GHG inventory base year and present the base year’s emissions by source. Describe any adjustments, structural changes, or methodology changes made to the base year made in subsequent inventory years. |
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Management Tools |
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Describe the GHG accounting management roles and responsibilities of those involved in the inventory development. Describe any trainings and file maintenance undertaken by the inventory team. |
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Auditing and Verification |
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Describe any internal or external audit processes used during the GHG inventory, senior management reviews, and corrective actions taken for any identified errors. |
EXAMPLE AIRPORT INVENTORY MANAGEMENT PLAN
Organizational Information
Airport:
XYZ International Airport
GHG Manager Contact Information:
John Smith (John.Smith@XYZAirport.com)
Boundary Conditions
Airport XYZ uses the operational control approach to consolidation emissions. The facilities included in this inventory under this emissions consolidation approach are Facility A, Facility B, and Facility C.
Airport XYZ’s inventory includes CO2, CH4, N2O, and hydrofluorocarbons (HFCs). The inventory uses global warming potentials from IPCC’s Fifth Assessment Report (AR5).
Airport XYZ’s inventory includes emissions from the following sources:
Scope 1
GSE, on-site waste and wastewater management, on-site power generation, firefighting exercises, boilers, furnaces, de-icing substances, refrigerant losses
Scope 2
Purchased electricity and steam
Scope 3
Category 1: Purchased Goods and Services
Category 2: Capital Goods
Category 3: Fuel- and Energy-Related Activities (Not Included in Scopes 1 and 2)
Category 5: Waste Generated in Operations,
Category 6: Business Travel
Category 7: Employee Commuting,
Category 11: Use of Sold Products and Services
Category 13: Downstream Leased Assets
Airport Inventory Management Plan 1
Emissions Quantification
Emissions for Airport XYZ’s inventory were calculated following Scope 1, 2, and 3 methodologies from the Greenhouse Gas Protocol Corporate Standard and Corporate Value Chain (Scope 3) Accounting and Reporting Standard.
Emission calculations used emission factors from the EPA Center for Corporate Climate Leadership Emission Factors Hub and ACERT.
Data gaps were filled using national average proxy data when missing.
Inventory results are presented in Table 4-1. Emissions are presented by constituent gas, emissions by gas in the common unit of CO2e, and all emissions aggregated into MT CO2e.
Data Management
Airport XYZ’s GHG inventory team collects the previous year’s data at the beginning of the calendar year and completes emissions calculations when all data has been collected and reviewed for quality assurance.
Airport XYZ’s data was collected from the sources presented in Table 4-2.
Base Year
Airport XYZ selected 2018 for its base year emissions. Airport XYZ has not made any adjustments to its base year during this inventory cycle.
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Management Tools |
Auditing and Verification |
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Airport XYZ’s sustainability team is responsible for preparing the annual GHG inventory. New members to the sustainability team participate in GHG accounting training provided by the inventory coordinator. |
Airport XYZ prepares its inventory internally and currently does not use a third-party auditor to verify the inventory results. |
Airport Inventory Management Plan 2
Table 4-1: Example Airport XYZ GHG Inventory Results
| Emissions by Constituent Gas | Emissions by Gas in Common Unit of MT CO2e Using AR5 100-Year GWPs | Aggregated Emissions Using AR5 100-Year GWPs | |||||
| Emission Source | MT CO2 | MT CH4 | MT N2O | MT CO2e of CO2 | MT CO2e of CH4 | MT CO2e of N2O | MT CO2e |
| Scope 1 | 1,482.0 | 0.2 | 0.1 | 1,482.0 | 6.6 | 28.1 | 1,516.7 |
| Scope 2 (Location-Based) | 3,040.0 | 0.3 | 0.0 | 3,040.0 | 8.4 | 5.6 | 3,054.0 |
| Scope 2 (Market-Based) (Informational Item) | 2,800.0 | 0.2 | 0.0 | 2,800.0 | 5.6 | 0.3 | 2,805.9 |
| Scope 3 | 123,129.0 | 12.0 | 8.4 | 123,129.0 | 336.5 | 2,234.5 | 125,699.9 |
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Category 1: Purchased Goods and Services |
16,000.0 | 0.4 | 0.2 | 16,000.0 | 9.8 | 53.0 | 16,062.8 |
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Category 2: Capital Goods |
8,000.0 | 0.2 | 0.1 | 8,000.0 | 4.9 | 26.5 | 8,031.4 |
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Category 3: Fuel- and Energy-Related Activities (Not Included in Scopes 1 and 2) |
200.0 | 0.3 | 0.1 | 200.0 | 7.0 | 21.2 | 228.2 |
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Category 4: Upstream Transportation and Distribution |
Not applicable | ||||||
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Category 5: Waste Generated in Operations |
100.0 | 0.1 | 0.0 | 100.0 | 2.2 | 0.3 | 102.5 |
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Category 6: Business Travel |
200.0 | 0.1 | 0.0 | 200.0 | 1.7 | 0.3 | 201.9 |
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Category 7: Employee Commuting |
500.0 | 0.1 | 0.0 | 500.0 | 2.5 | 0.3 | 502.8 |
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Category 8: Upstream Leased Assets |
Not applicable | ||||||
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Category 9: Downstream Transportation and Distribution |
Not applicable | ||||||
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Category 10: Processing of Sold Products |
Not applicable | ||||||
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Category 11: Use of Sold Products and Services |
96,329.0 | 10.9 | 8.0 | 96,329.0 | 305.4 | 2,128.9 | 98,763.3 |
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Category 12: End-of-Life Treatment of Sold Products |
Not applicable | ||||||
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Category 13: Downstream Leased Assets |
1,800.0 | 0.1 | 0.0 | 1,800.0 | 2.9 | 4.1 | 1,807.0 |
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Category 14: Franchises |
Not applicable | ||||||
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Category 15: Investments |
Not applicable | ||||||
| Total Emissions | 127,651.0 | 12.6 | 8.6 | 127,651.0 | 351.5 | 2,268.1 | 130,270.6 |
| Airport Inventory Management Plan | 3 | ||||||
Table 4-2: Example Airport XYZ GHG Inventory Data Sources
| Emission Source | Data Source |
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| Scope 1 | Utility bills, fuel purchase receipts, de-icing substance use records, firefighting exercise records, refrigeration/air conditioning maintenance records |
| Scope 2 | Utility bills |
| Scope 3 | |
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Category 1: Purchased Goods and Services |
Procurement records |
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Category 2: Capital Goods |
Procurement records |
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Category 3: Fuel- and Energy-Related Activities (Not Included in Scopes 1 and 2) |
Utility bills, fuel purchase receipts |
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Category 4: Upstream Transportation and Distribution |
Not applicable |
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Category 5: Waste Generated in Operations |
Waste hauling receipts |
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Category 6: Business Travel |
Business travel records |
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Category 7: Employee Commuting |
Employee commuting survey results |
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Category 8: Upstream Leased Assets |
Not applicable |
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Category 9: Downstream Transportation and Distribution |
Not applicable |
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Category 10: Processing of Sold Products |
Not applicable |
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Category 11: Use of Sold Products and Services |
Aircraft movement records, aircraft MOR records, tenant fuel receipts, tenant refrigeration/air conditioning maintenance records public ground access survey |
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Category 12: End-of-Life Treatment of Sold Products |
Not applicable |
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Category 13: Downstream Leased Assets |
Tenant utility bills |
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Category 14: Franchises |
Not applicable |
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Category 15: Investments |
Not applicable |
| Airport Inventory Management Plan | 4 |
