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Scope 1 Emissions: An Explainer Guide

Article Overview

With accelerating climate change and increasing regulatory pressures, understanding and managing greenhouse gas (GHG) emissions has never been more critical. This guide is designed to help you understand your organization’s scope 1 emissions — the direct emissions from sources that an organization owns or controls. Covering aspects from identifying emission sources to calculating, reporting, and ultimately reducing these emissions, this comprehensive guide equips your organization to make substantial progress toward sustainability, bolstered regulatory compliance, and heightened corporate responsibility.

What are Scope 1 Emissions?

According to the GHG Protocol, a global standardized framework to measure and manage greenhouse gas emissions, scope 1 encompasses direct emissions from owned or controlled sources. These represent the most immediate form of emissions that an entity can influence. Understanding and managing these emissions constitute the initial steps toward sustainability and regulatory compliance.

Below are four key types of scope 1 emissions.

1. Stationary Combustion

Stationary combustion refers to emissions resulting from burning fuels in stationary equipment such as boilers, furnaces, or generators. These are typically found in heating, power generation facilities, or specific industrial processes. For example, a manufacturing plant may utilize a natural gas boiler to generate steam, thereby combusting a fuel and emitting carbon dioxide, methane, and nitrous oxide.

2. Fugitive Emissions

Fugitive emissions involve leaks and irregular releases of gases, often stemming from refrigeration and air conditioning equipment, as well as from the production, processing, transmission, storage, and use of fuels and chemicals. A supermarket chain, for instance, might experience significant fugitive emissions from refrigeration systems, leaking hydrofluorocarbons (HFCs), and potent greenhouse gases.

3. Mobile Combustion

Mobile combustion encompasses emissions from fuel combustion in company-owned or controlled vehicles, including cars, trucks, ships, airplanes, and other forms of transport. Whether it's a delivery fleet emitting carbon dioxide from diesel or a company car using gasoline, these emissions are direct and controllable by the organization. Another common example of mobile combustion would be a forklift that uses propane.

4. Process Emissions

Process emissions are the greenhouse gas emissions released during industrial processes unrelated to energy consumption. This includes emissions from chemical reactions necessary to produce goods from raw materials. For example, the carbon dioxide released during the calcination step in cement production constitutes a process emission.

scope 1 emissions

Stationary Combustion Emissions: Sources, Data Collection, and Calculation Methods

Stationary combustion is a critical component of an organization's greenhouse gas inventory. It refers to the emissions from burning fuels in stationary sources such as power plants, boilers, furnaces, and other industrial facilities that generate heat or electricity. 


The most common stationary combustion sources are the equipment that burns fuel to generate energy or heat. This includes boilers that produce steam for heating or industrial processes, furnaces for metal smelting or glass production, and generators for electricity. 

To assess and manage emissions, it is crucial to compile data on fuel consumption for each piece of equipment within your facilities.

Collecting Data on Fuel Consumption

The cornerstone of calculating your stationary combustion emissions is understanding the fuel consumption of your equipment. This data is typically recorded in purchase records or centralized billing systems. For comprehensive and accurate emissions reporting, organizations must collect data on the type and quantity of fuel consumed by each piece of equipment.

Who might have this data? It’s usually sourced from the Facilities Manager, Energy Manager, or the broader Operations Team. Finance Departments, Sustainability Departments, or Building Management System (BMS) teams might also hold relevant information. If your organization leases facilities or equipment, it’s essential to coordinate with the Facility Landlord or Procurement team.

Additional Guidance for Data Collection

Sometimes, fuel consumption records may not be readily available. Organizations might need to estimate fuel consumption in such cases. Estimations can be based on the type of equipment and standard operating times, applying average fuel consumption rates for similar machinery. While less precise than actual consumption data, these estimates can provide a baseline for your emissions calculations.

Calculation Method: Fuel Consumption

Calculating emissions from stationary combustion requires applying specific emissions factors to the quantity of fuel consumed. These factors vary by fuel type and are based on the carbon content of the fuel. They reflect the amount of greenhouse gases, primarily CO2, released per unit of fuel consumed. The GHG Protocol offers a comprehensive set of emission factors for various fuel types and combustion technologies.

Considerations for Accurate Emissions Calculation

When calculating direct emissions from stationary combustion, several considerations are crucial for accuracy:

  • Type of Fuel: Different fuels have different carbon contents and thus different emission factors. It's important to distinguish between natural gas, coal, oil, and other fuels. 
  • Combustion Technology: The efficiency and technology of combustion equipment influence the completeness of fuel combustion, thereby impacting emission factors. While CO2 factors per volume of fuel remain consistent across fuel types, the presence of CH4 and N2O varies depending on equipment type.
  • Operational Conditions: How equipment is operated can affect efficiency and emissions. Regular maintenance and operational efficiencies can lead to lower emissions. And while this is true, this isn't reflected in the emission factors - short of consuming less fuel.
  • Regulatory Requirements: Ensure your calculations comply with local, national, and international reporting requirements and standards.
  • Verification: Consider third-party verification for your emissions data to ensure accuracy and credibility in your reporting.

Mobile Combustion Emissions: Sources, Data Collection, and Calculation Methods

Mobile combustion refers to the emissions from burning fuels in vehicles, airplanes, ships, and other forms of transportation. These emissions are a significant part of an organization's carbon footprint, especially for companies that own or control their transportation and logistics. Understanding and managing these emissions is crucial for reducing an organization's environmental impact. 

Sources: Vehicles

The vehicles used for transportation and logistics are the primary sources of mobile combustion emissions. This includes everything from company cars, delivery trucks, and forklifts to ships and airplanes. Essentially, any vehicle your organization operates, whether owned, leased, or rented for business purposes, contributes to your mobile combustion footprint.

Collecting Data on Fuel Consumption

To calculate emissions from mobile combustion, you need detailed data on the quantity and type of fuel consumed by each vehicle. This data can typically be sourced from:

  • Fuel Receipts: Direct records of fuel purchases.
  • Employee Reporting: Logs or reports from drivers or operators.
  • Fleet Management Software: Centralized systems tracking fuel use across all vehicles.

The key personnel likely to have access to this data include Facility Managers, Fleet Managers, and members of the Operations or Finance departments. Accurate and comprehensive data collection is foundational for credible emissions reporting and reduction strategies.

Additional Guidance for Data Collection

In situations where direct fuel consumption data isn't available, you may need to rely on secondary data sources:

  • Odometer Readings or Distance Traveled: You can estimate fuel consumption by knowing the distance traveled and the vehicle's fuel efficiency.
  • Vehicle Specifications: Manufacturer data on fuel efficiency can be used to estimate fuel use based on operational hours or distance.

While actual fuel consumption data is preferable for accuracy, these estimation methods can provide a useful approximation for your emissions calculations.

Calculation Method: Fuel Consumption

Calculating emissions from mobile combustion involves applying emissions factors to the fuel consumption data. These factors vary depending on the type of fuel used (gasoline, diesel, biofuels, etc.) and are based on the typical amount of CO2 emitted per unit of fuel. The GHG Protocol provides detailed emissions factors for various types of vehicles and fuels.

Considerations for Accurate Emissions Calculation

When calculating emissions from mobile combustion, it's important to consider:

  • Type of Vehicle and Fuel: Different vehicles and fuels have different emissions profiles. For example, diesel engines typically have different emissions factors than gasoline engines.
  • Efficiency and Maintenance: Vehicles' age, condition, and maintenance can significantly affect their fuel efficiency and emissions.
  • Usage Patterns: How vehicles are used (e.g., city vs. highway driving) can also impact fuel consumption and emissions.
  • Regulations and Standards: Ensure that your calculations are aligned with relevant regulatory requirements and international standards for emissions reporting.

Process Emissions: Sources, Data Collection, and Calculation Methods

Process emissions are a category of direct greenhouse gases released during various industrial and chemical processes. They are integral to understanding and managing the full spectrum of an organization's environmental impact, particularly in the manufacturing, chemical processing, or mineral production industries. 

Process emissions occur from chemical reactions or physical changes during industrial operations. Process emissions can involve a variety of greenhouse gases, including higher concentrations of methane, nitrous oxide, and a range of fluorinated gases. They are often specific to certain industrial processes or product uses.

Common examples include:

  • Calcination in Cement Production: The transformation of limestone into lime and CO2 in cement manufacturing.
  • Aluminum Smelting: The use of carbon anodes in the production of aluminum leads to CO2 emissions.
  • Chemical Production: Various chemical manufacturing processes release greenhouse gases, depending on the substances produced or used.


Identifying the sources of process emissions within an organization depends largely on the industry and specific operational activities. Common sources include:

  • Manufacturing Equipment and Processes: Look at the specific equipment or processes unique to your industry that might involve chemical reactions or material transformations.
  • Product Use: Some products, such as certain types of insulation or refrigerants, release greenhouse gases when used or disposed of.
  • Waste Handling and Treatment: Some waste treatment processes, particularly biological treatment of organic waste, can release methane or nitrous oxide.

Calculation Methods and Reporting

Calculating process emissions typically involves understanding the specific chemical or physical processes occurring and applying appropriate emission factors that relate the activity data (e.g., quantity of material processed, or product used) to greenhouse gas emissions. The GHG Protocol provides sector-specific guidance for various industries, outlining the methodologies for calculating process emissions.

Key aspects include:

  • Activity Data: Collect data on the amount and type of material processed or product used that leads to process emissions. This might involve production volumes, throughput, or usage rates.
  • Emission Factors: Apply specific emission factors relevant to the particular chemical or physical process. These factors are typically based on the material or substance type and the process's nature.
  • Tiered Approach: The GHG Protocol and other standards often provide a tiered approach for calculating emissions, ranging from basic methods based on general assumptions to more detailed methods requiring specific data and calculations.

Considerations for Accurate Emission Reporting

When reporting process emissions, it's crucial to consider:

  • Industry-Specific Factors: Understand the unique aspects of your industry's processes that contribute to emissions. This might involve specialized knowledge of chemical reactions, material properties, or operational practices.
  • Data Availability and Quality: Ensure you have access to reliable and accurate data for your calculations. This might involve direct measurement, supplier information, or industry studies.
  • Regulatory Requirements: Be aware of and comply with specific reporting requirements or regulations for your industry or region.

Fugitive Emissions: Sources, Data Collection, and Calculation Methods

Fugitive emissions are the unintentional releases of greenhouse gases, typically from leaks, equipment malfunctions, or other irregular releases during the production, processing, storage, transport, or use of fuels and other substances. Understanding and controlling these emissions are critical for organizations committed to reducing their environmental impact. 

Sources and Types of Fugitive Emissions

Fugitive emissions are diverse and can arise from multiple sources within an organization:

  • Refrigeration Systems: Air conditioning, refrigeration, or heat pump systems leakages. These systems use various refrigerants, which, when leaked, can have a high global warming potential*.
    *Global Warming Potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific period, usually 100 years, compared to carbon dioxide (CO2). It helps quantify the impact of different gases on global warming, enabling comparison and prioritization of emission reduction efforts.
  • Industrial Processes: Leakage of gases used in manufacturing or processing, including nitrogen, methane, or carbon dioxide.
  • Oil and Gas Operations: Releases from extraction, refining, storage, and distribution systems, including wellheads, pipelines, and tanks.
  • Chemical and Petrochemical Plants: Emissions from the handling and processing of volatile substances lead to leaks from piping, vessels, and other equipment.
  • Waste Management: Releases of methane and carbon dioxide from the decomposition of organic waste in landfills and other treatment facilities.
  • Agriculture: Methane emissions from the digestive processes of livestock, especially ruminants like cattle.

Data Collection and Calculation Methods

The calculation of fugitive emissions relies on understanding the quantity and type of substances that have the potential for leakage. This might involve collecting data on the amount of refrigerant or industrial gas purchased and used within the organization's operations. Fugitive leaks can be calculated using the difference between what remained at the end of a reporting period and what was purchased to “top off” that source. The key sources for this data include:

  • Facility Managers and HVAC/Refrigeration Engineers: Individuals responsible for operating and maintaining equipment and systems.
  • Maintenance Departments and Equipment Manufacturers: Those who service or supply the equipment and can provide specifications or leakage rates.
  • Building Management System (BMS) Teams: Personnel responsible for the integrated management of building systems, including climate control and refrigeration.

In cases where direct measurement or precise data is not available, organizations may estimate emissions based on typical leakage rates for the type of equipment or systems they use. This requires understanding the equipment specifications and applying average or industry-standard leakage rates.

Calculation Method: Purchased Amount

The most common approach for calculating fugitive emissions is based on the amount of substance purchased and the estimated leakage rate. This involves:

  • Collecting Purchase Records: Gathering detailed records of all substances purchased that have the potential for fugitive emissions.
  • Estimating Leakage: Applying typical leakage rates to the total amount purchased to estimate emissions. This might involve industry standards or manufacturer specifications.
  • Adjusting for Recovery and Recycling: Accounting for any substances that are captured, recovered, or recycled, reducing the net emissions.

Considerations for Accurate Emissions Calculation

When addressing fugitive emissions, organizations should consider:

  • Regular Inspections and Maintenance: Implementing a robust inspection and maintenance schedule for all equipment and systems that might leak GHGs.
  • Upgrading Equipment: Investing in newer, more efficient, and less leak-prone equipment and systems.
  • Employee Training: Ensuring that all relevant personnel are trained in operating, maintaining, and monitoring systems to minimize leaks.
  • Record Keeping: Maintaining accurate and comprehensive records of all substances purchased, systems in use, and any incidents of leakage or repair.
  • Regulatory Compliance: Understanding and complying with any legal requirements or industry standards related to managing and reporting fugitive emissions.

Getting Started with Scope 1 Accounting

Embarking on a journey to understand and reduce your organization's Scope 1 emissions is a critical step toward sustainability and regulatory compliance. Scope 1 accounting involves a systematic approach to identify, calculate, and manage direct emissions from owned or controlled sources. 

Step 1: Identify Scope 1 Sources

The first step is to list all direct emissions sources your organization owns or controls. This includes all combustion activities in your organization's boilers, furnaces, vehicles, and other equipment. Don't forget to consider process emissions that arise from industrial processes and fugitive emissions from leaks or irregular releases.

Once all sources are listed, classify them for easier management and understanding. Typical categories include:

  • Stationary Combustion: Emissions from burning fuel in boilers, heaters, or furnaces.
  • Mobile Combustion: Emissions from burning fuel in company-owned or controlled vehicles.
  • Process Emissions: Emissions from physical or chemical processes.
  • Fugitive Emissions: Emissions that are not physically controlled. They result from the intentional or unintentional releases of greenhouse gases.

Step 2: Determine Emission Factors

Emission factors are crucial for converting activity data into greenhouse gas emissions data. They represent the amount of emissions produced per unit of activity (e.g., per liter of fuel burned). Obtain these factors from reputable sources like the GHG Protocol, the Environmental Protection Agency (EPA), or other relevant industry or regulatory sources. Ensure they are specific to the types of fuels and processes your organization uses.

Step 3: Measure Activity Data

In this step, you’ll need to collect detailed data on the quantity and types of fuels used, encompassing all fossil fuels such as gasoline, diesel, and natural gas. For organizations with substantial fuel consumption, the adoption of fuel tracking systems or software can streamline this data collection process, enhancing accuracy and efficiency.

For process emissions, identify and measure relevant parameters that contribute to emissions. This may involve tracking variables such as the quantity of raw materials processed, the types of chemical reactions taking place, or the operational throughput of specific equipment.

Step 4: Calculate Emissions

Apply the relevant emission factors to the activity data associated with each emission source. This entails conducting detailed calculations for various elements, such as the types of fuel used, vehicles operated, or processes conducted within your organization.

Following this, total the calculated emissions from all individual sources to get the total Scope 1 emissions for your organization. It's important to maintain accuracy and consistency throughout these calculations by using standardized units and methodologies.

Step 5: Document and Report

When creating an inventory report for Scope 1 emissions, thorough documentation is key. This involves detailing every aspect of the calculation process, from the methodology and data sources to the emission factors utilized and the resulting outcomes. The inventory report should be comprehensive, transparent, and tailored to suit both internal needs and external reporting standards.

Sharing data on Scope 1 emissions is essential for fostering transparency and accountability within your organization. It's important to communicate this information to relevant stakeholders, including employees, shareholders, regulatory bodies, and industry platforms. Moreover, ensure that your reporting aligns with any regional or sector-specific requirements.

Step 6: Set Reduction Targets and Implement Strategies

Set realistic yet ambitious targets, informed by your organization's emissions data. This process should consider your operational context, industry benchmarks, and overarching sustainability objectives, ensuring that the targets align with your broader vision.

Following the establishment of reduction targets, the next step involves actively implementing strategies to achieve them. This could entail a range of measures, such as upgrading to more energy-efficient equipment, transitioning to lower-carbon fuels, and/or optimizing operational processes. The key is to tailor these strategies to your organization's specific circumstances and goals, considering both the immediate impact and long-term sustainability. By aligning targets with actionable strategies, your organization can make meaningful strides toward reducing its Scope 1 emissions.

Step 7: Monitor and Review

For this last step, it’s essential to stay informed about your organization's emissions. This involves regularly collecting and analyzing data to track your progress toward reduction targets. This ongoing monitoring is vital for understanding how the strategies you've implemented are impacting overall emissions.

Additionally, it's important to conduct regular assessments of the effectiveness of your emission reduction strategies. This involves being prepared to adjust or enhance strategies based on their performance, incorporating new technological advancements, or adapting to changes in regulatory requirements. This proactive review process ensures that your organization remains responsive to evolving conditions, helping to optimize and refine strategies in line with your sustainability goals.

Scope 1 Emission Management: A Path Forward

Having navigated the complexities of calculating scope 1 emissions, you are now equipped with the knowledge and tools to effectively measure, manage, and reduce your organization's direct emissions. While the journey towards significantly reducing emissions is ongoing and evolving, initiating robust scope 1 accounting practices is crucial. By continuously monitoring, reviewing, and adapting your strategies, your organization can comply with evolving regulations and demonstrate corporate responsibility and environmental stewardship leadership. 

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