VRS Cert GHG Inventory & Calculation Tools
VRS Cert tools empower companies and cities to develop comprehensive and reliable inventories of their greenhouse gas (GHG) emissions and support countries and municipalities in tracking progress toward climate goals.
Calculating emissions is a multi-step process. A precise and useful inventory must be developed with careful attention to quality control and activity data requirements before emissions are estimated. Organizations should consult the GHG Protocol Corporate Accounting and Reporting Standard for complete guidance.
The following tools are aligned with GHG Protocol best practices. Many tools include detailed guidance documents providing step-by-step instructions. Most organizations will need to apply multiple tools to fully account for their emissions.
Types of GHG Accounting Tools
- Cross-sector tools: Applicable across multiple industries.
- Country-specific tools: Designed for specific national contexts.
- Sector-specific tools: Tailored to particular industries.
- City and country tools: Support climate goal tracking at municipal and national levels.
How to Calculate Your Organization’s Greenhouse Gas Emissions
Developing a complete corporate GHG inventory — including Scope 1, Scope 2, and Scope 3 emissions — enables organizations to understand their total impact across the value chain and focus reduction efforts effectively.
Understanding Scope 1, 2, and 3 Emissions
GHG emissions mainly result from fossil fuel combustion for energy and transportation.
- Scope 1: Direct emissions from sources owned or controlled by the organization (e.g., fuel combustion in boilers).
- Scope 2: Indirect emissions from purchased electricity, steam, heating, or cooling.
- Scope 3: Other indirect emissions across upstream and downstream value chain activities.
Steps to Compute GHG Emissions
Step 1: Define Scope and Boundaries
1a. Select a Reporting Standard
Choose a recognized standard such as:
- GHG Protocol
- The Climate Registry
1b. Set Organizational Boundaries
Define included gases, emission sources, geographic boundaries, and reporting period.
1c. Identify Scope 1 Sources
- Stationary combustion (boilers, furnaces, turbines)
- Mobile combustion (vehicles, aircraft, ships)
- Process emissions (cement production, chemical processes)
- Fugitive emissions (equipment leaks, refrigeration systems)
1d. Identify Scope 2 Sources
- Purchased electricity
- Purchased steam or heating
1e. Identify Scope 3 Sources
- Upstream supply chain activities
- Downstream product use and disposal
- Leased assets and outsourced operations
Step 2: Collect Activity Data
Activity data represents the level of activity causing emissions.
- Scope 1: Fuel consumption (diesel, gasoline, natural gas)
- Scope 2: Metered electricity or steam consumption
- Scope 3: Transportation data, fuel usage, supplier data
Organizations should implement structured data collection systems and maintain continuous tracking for year-over-year comparison.
Step 3: Identify Emission Factors
Emission factors convert activity data into emissions values.
Examples:
- X kg CO2e per kWh
- X kg CO2e per mile
- X kg CO2e per gallon
Source-specific emission factors are preferred over generic factors where available.
Step 4: Calculate Emissions
Emissions are often expressed as carbon dioxide equivalent (CO2e) using Global Warming Potentials (GWP) established by the IPCC.
Basic Equations
- Activity Data × Emission Factor = Gas Emissions
- Activity Data × Emission Factor × GWP = CO2e Emissions
Example Calculation
Company A used 5,000 gallons of diesel in 2022.
- CO2 factor: 10.21 kg CO2/gallon (GWP 1)
- CH4 factor: 0.41 g/gallon (GWP 28)
- N2O factor: 0.08 g/gallon (GWP 265)
Total emissions calculated:
- CO2 = 51.05 metric tons CO2e
- CH4 = 0.0574 metric tons CO2e
- N2O = 0.106 metric tons CO2e
Total Emissions = 51.2134 metric tons CO2e
Handling Data Gaps & Quality Management
If data gaps exist, assumptions and estimates should be documented clearly. Organizations are encouraged to maintain an Inventory Management Plan (IMP) outlining procedures for:
- Data collection
- Calculation methodologies
- Quality control measures
- Record-keeping
This ensures transparency, consistency, and improved reporting accuracy over time.
Conclusion
A structured GHG inventory process enables organizations to institutionalize emissions tracking and reporting. With investors increasingly focusing on ESG performance, reliable GHG accounting systems are essential for risk management, compliance, and sustainability leadership.