We’ve noticed that certain questions come up repeatedly in discussions about emissions calculations. For many companies, emissions calculations and sustainability reporting are still relatively new practices. Therefore, established processes for data collection, calculation, and reporting may not yet be in place. In this blog, we answer some of the most frequently asked questions about emissions calculations.
Carbon footprint calculation – are there clear standards?
As you begin calculating and reporting emissions, you may notice that there are many different standards and guidelines available. However, there is no need to be overwhelmed by the variety. These standards and guidelines have been developed, and are needed, for different purposes. For example, the carbon footprints of companies and individual products are calculated using different standards.
The GHG Protocol standards are among the most widely recognized and widely used standards for greenhouse gas accounting. They provide the framework, for example, for calculating organisations’ Scope 1-3 emissions, as well as emissions and removals from the land sector. In addition to the standards themselves, the GHG Protocol has published a range of guidance documents. The guidance documents complement the standards and help organisations apply them in practice.
Another significant body that has developed emissions accounting standards is the International Organization for Standardization (ISO). For example, the ISO 14064 standard is a well-known standard for organizational-level greenhouse gas accounting. ISO 14067, on the other hand, is a standard for product-specific carbon footprint calculation and reporting.
However, significant changes to standards are expected in the coming years, as the GHG Protocol and ISO have announced that they will be aligning their emissions accounting standards. The new, harmonized organizational-level accounting standard is scheduled to be published by the end of 2028.
Is it necessary to calculate Scope 3 emissions?
Previously, company-level greenhouse gas accounting often included only certain Scope 3 emission categories. These were typically categories for which data was readily available, such as waste or business travel. However, this is rarely sufficient today, given that Scope 3 emissions can account for more than 90% of a company’s overall GHG emissions. If Scope 3 emissions are excluded entirely, or if only some categories are included, the GHG inventory will not provide a reliable overall picture of the company’s climate impacts. All emission sources identified as significant to the company’s operations should be included in the Scope 3 assessment. This applies where the required data can be obtained with a reasonable level of effort. If any emission sources are excluded from the calculation, the reasons for their exclusion must be carefully justified and documented.
Excluding Scope 3 emissions may be justified, for example, for SMEs that follow the Voluntary Standard (VS, formerly the VSME Standard). The VS is a voluntary sustainability reporting standard that only requires companies to report their Scope 1 emissions and location-based Scope 2 emissions. Read more about the standard and its requirements in our previously published blog.
How do I choose the right emission factor?
Emissions accounting standards recommend using primary data wherever possible. Primary emission factors are supplier-specific values that reflect the emissions associated with the supplier’s own products and services. In practice, however, such data is still relatively limited, and carbon footprint assessments often need to rely on secondary data, i.e., average emission factors. When using average emission factors, the most up-to-date factors available should be selected. Local and regional emission factors should be prioritized over country-specific or national factors whenever possible. Global average data may be used when more geographically specific data is not available.
In addition, emission factors should, wherever possible, be based on physical quantities such as mass or volume. When suitable physical quantity-based factors are not available, spend-based emission factors can be used instead. However, this approach should be considered a last resort, as spend-based calculations often produce less accurate results and often overestimate emissions compared to calculations based on physical activity data. Their reliability can also be affected by factors such as inflation between the reporting year and the year the emission factor was developed, as well as fluctuations arising from currency conversions. For more detailed guidance and an example comparing spend-based and physical quantity-based approaches, see our previously published blog post.
To support companies in their climate efforts, we have developed and maintain the OpenCO2 emissions database. The database contains more than 8,000 up-to-date, quality-rated emission factors. In addition to primary emission factors, the database includes both physical quantity-based and monetary emission factors from a wide range of reliable sources.
“How to start carbon footprint calculation?”
Carbon footprint calculation typically begins by defining the objective of the calculation and setting the calculation boundaries. If getting started feels challenging, for example, due to selecting the appropriate standard or finding up-to-date emission factors, you can contact us. We will help you get started!
We offer a range of training and support services to help organizations build their expertise in carbon accounting. For example, you can strengthen your understanding of greenhouse gas accounting through our trainings. Alternatively, you can have your first carbon footprint assessment conducted as a consulting project and then manage future calculations independently. Once the first calculation has been completed by our experts, future calculations become much easier. This is especially true when there are no significant changes to the calculation boundaries or emission sources. In practice, this often means simply updating the activity data for the new reporting year. The calculation template already includes reliable emission factors selected by our experts. We also offer a Calculate Yourself and Learn subscription for our carbon footprint platform. This allows you to carry out a standard-compliant assessment independently while receiving support from our experts. Explore our full range of services here.
OpenCO2net supports organizations in their data-driven climate efforts by providing tools, training, and consulting services for reliable, standard-based carbon footprint calculations. Our services cover both corporate and product carbon footprint calculations. In addition, we provide high-quality emission factors and customizable expert support tailored to your specific needs.
