The Greenhouse Gas Protocol, a crucial tool in the fight against the climate crisis, provides the most widely used method in the form of standards and guidance to measure and manage air emissions.
It offers a comprehensive framework for businesses, governments, and other entities, with specific standards for corporations, cities, corporate value chains, and products for their entire life cycle. It also provides guidance for industry sectors, such as agriculture, and specific use cases like carbon accounting. While both standards and guidance are essential components of the GHG Protocol, they serve different purposes and are used in distinct ways.
A GHG Protocol standard is a formal, comprehensive set of rules and criteria organizations must follow to measure and report their greenhouse gas emissions accurately. Standards are designed to ensure consistency, transparency, and comparability of GHG emissions data across different organizations and sectors. Guidance documents are supplementary materials the GHG Protocol provides that offer additional explanations, examples, best practices, and recommendations to help organizations implement the standards effectively. Guidance is intended to support the application of the standards but is not mandatory.
Scope 1, 2, and 3 greenhouse gas emissions refer to direct and indirect emissions from an organization’s activities, energy consumption, and supply chain.
When the news media refer to scope 1, 2, and 3 emissions, they use the classification method defined in the GHG Protocol Corporate Accounting and Reporting Standard, often called the corporate carbon footprint. The standard specifies how corporations must determine this footprint caused by their operations. Conversely, the Product Life Cycle Accounting and Reporting Standard provides a framework to measure the GHG emissions associated with individual products throughout their life cycle, often called the product carbon footprint. This helps identify hotspots in their product life cycles and develop strategies to reduce emissions.
Both reporting standards consider the seven most essential gases (CO2, CH4, N2O, NF3, HFCs, PFCs, and SF6). These gases have different effects on the earth’s warming. Two key ways in which these gases differ from each other are their ability to absorb energy (their “radiative efficiency”) and how long they stay in the atmosphere (also known as their “lifetime”). Global warming potential (GWP) measures how much energy the emissions of 1 ton of a gas will absorb over a given period relative to 1 ton of carbon dioxide (CO2) emissions. The larger the GWP, the more a gas warms the earth compared to CO2 over that period. The period usually used for GWPs is 100 years. GWPs provide a normalized unit of measure, which allows the addition, reduction, and comparison of emission estimates of different gases across sectors. That’s why methane and other GHGs are expressed in metric tons CO2eq.
Carbon dioxide, by definition, has a GWP of 1 regardless of the period used because it is the gas being used as the reference. CO2 remains in the climate system for a very long time and causes increases in atmospheric concentrations that will last thousands of years. CH4 emitted today lasts about a decade on average, much less than CO2, but it absorbs much more energy. The net effect of the shorter lifetime but higher energy absorption is reflected in a high GWP. Methane is estimated to have a GWP of 20-30 over 100 years.
The GHG Protocol Corporate Accounting and Reporting Standard classifies emissions for corporations into four categories, called scopes.
Scope 1 covers direct emissions from facilities or vehicles the reporting organization controls. These can come from stationary combustions like heating systems or production lines where natural gas gets burned, mobile combustions like propane-driven forklifts, process emissions from physical or chemical processes, or fugitive emissions like unintentional release of coolant from cooling systems.
Chemical production often involves complex reactions, energy-intensive processes, and diverse feedstocks. Emissions may occur from chemical reactions and by-products. Accurately quantifying GHG emissions in chemical manufacturing can be complex and requires detailed process-level data and emissions factors. However, organizations can very often use consumption data gathered from invoices or material provision processes to calculate GHG emissions in most other cases. Emission factors are available for almost all activities and energy carriers. The volume of the consumed energy carrier multiplied by the correct emission factor will translate directly into GHG emissions in metric tons CO2eq.
If a manufacturing plant, for example, is heated with natural gas, the consumed natural gas volume over time defines the activity data, which is multiplied by an emission factor. The result is a stationary combustion item in the company’s carbon inventory. Another example is the burning of propane to drive forklifts in warehouses. The provisioned volume of propane over time defines the activity data multiplied by an emission factor, which provides the result that accounts for a mobile combustion item in the same inventory.
Collecting consumption data is crucial for determining the GHG inventory for scope 1, and ClearStandard is designed to automate or streamline this process.
Scope 2 covers all indirect emissions created by producing purchased electricity, steam, heating, or cooling. The emissions are caused by the reporting organization but are emitted by others, such as a utility company’s power plant. Calculating GHG emissions is similar to the calculations used for scope 1. The consumed energy volume measured in kWh is multiplied by an emission factor, and the result accounts for an item in the corporate inventory.
The emission factors for scope 1 originate from scientific LCA databases. The emission factors for electricity represent the average emission per unit of electricity consumed from the power grid. They are calculated based on the overall energy mix of the grid, which includes various sources like coal, natural gas, nuclear, hydro, wind, and solar power. National or regional authorities and energy agencies usually provide the emission factors for grid electricity. For example:
- EPA’s eGRID in the United States: The Emissions & Generation Resource Integrated Database (eGRID) provides comprehensive emission factors for different regions in the U.S.
- IEA’s World Energy Outlook: The International Energy Agency (IEA) provides global and regional emission factors based on extensive energy data factors of the electricity grid in a defined network.
The Greenhouse Gas Protocol provides two methods for calculating scope 2 emissions: market-based and location-based.
The market-based approach reflects emissions from the electricity companies have purposefully chosen, which means it considers the specific electricity supply contracts and instruments that companies purchase. A company, for example, that buys 100% of its electricity from a supplier that guarantees the electricity generated from wind farms will use the emission factor associated with wind energy, which is typically close to zero. Renewable energy purchases are verified with so-called renewable energy certificates (RECs) to assure that the procured renewable energy exists and that someone else does not claim the same green energy.
The location-based approach reflects the average emissions intensity of grids on which energy consumption occurs without considering specific contractual arrangements for low-carbon energy. A company, for example, located in a region where the electricity grid is powered by a mix of coal (70%), natural gas (20%), and renewables (10%) will use the average emission factor calculated from this mix, resulting in higher scope 2 emissions compared to a market-based approach if they had purchased renewable energy certificates.
The challenge for sustainability teams remains the same. They must collect consumption data for all facilities and activities before calculating scope 2 GHG emissions. ClearStandard’s functionality will be valuable here.
The Greenhouse Gas Protocol has categorized all emissions created in the supply chain (upstream activities) or during distribution, sales, product usage, and end-of-life treatment (downstream activities) as Scope 3. Most of them are part of scope 1 and 2 emissions of vendors, retailers, and other partners in the supply chain. Utility data are as essential to determining these emissions as they are for the direct and indirect emissions. Still, because they are not under the direct control of the reporting organization, they will help only indirectly to determine scope 3 emissions.
Scope 4 GHG emissions, often called “avoided emissions,” are not officially part of the Greenhouse Gas Protocol’s standard scopes (scope 1, 2, and 3). However, they represent the emissions prevented by a company’s actions or products. These emissions reflect the positive impact of activities or technologies that reduce the need for higher-emission alternatives outside the organization’s control. A company, for example, which provides video-conferencing systems, avoids emissions because people have to travel less to meet and organize. The emissions from these trips would belong to the company’s inventory that causes these travels and not to the inventory of the video-conferencing provider. Even so, if the video-conferencing provider reduces emissions, it could not claim it in its carbon accounting because it never had it in its inventory.
The Product Life Cycle Accounting and Reporting Standard provides a framework for companies to measure the GHG emissions associated with individual products throughout their life cycle, from raw material extraction to disposal. This comprehensive approach helps companies identify hotspots in their product life cycles and develop strategies to reduce emissions.
