When it comes to calculating your emissions, navigating the various methods offered by suppliers can be overwhelming. What do they all mean? In this article, we’ll explore the three primary methods for calculating emissions, highlighting their advantages and disadvantages.
The Spend Method
The Spend Method, often known as Carbon Accounting, is the simplest way to estimate your emissions. However, this simplicity often comes at the expense of accuracy, typically yielding only rough estimates. In the most basic form of the spend method, emissions can be calculated by multiplying your annual spend by a factor relating to the company SIC code.
For a more detailed approach, businesses can calculate emissions by analysing spending across various items, applying specific factors to each. While this method allows for quick assessments, it can also encourage practices like switching suppliers or renegotiating contracts to reduce emissions, rather than pursuing genuine efficiency improvements.
One notable limitation is that the spend factors are derived from US Dollar values, as the UK Government does not provide its own conversion factors, further compromising accuracy. In summary, while the Spend Method is user-friendly, it lacks precision. As we want you to know your emissions, we have decided not to offer this method of calculating your emissions at Attain Zero.
Average Values
In contrast, using Average Values significantly enhances accuracy because it bases calculations on actual weights, mileage, and usage. By multiplying the weight of an item or the mileage travelled by the relevant UK government-issued Carbon Conversion Factor, you get a more realistic picture of your emissions. These detailed factors are updated annually to reflect the emissions associated with specific products and services during that time.
With the wide range of available factors, this method allows you to calculate nearly all of the 15 Scope 3 emissions—except for investments, like pensions, which currently lack available conversion factors as these vary massively between suppliers. While the Average Values method provides a more accurate assessment, it does require more complex data collection. This is why Attain Zero offers this form of calculation, and support businesses in simplifying this process.
Industry Figures and Hybrid Methods
While Average Values improve accuracy, there’s an even more precise option: Industry Figures. This method relies on data provided by suppliers regarding the carbon emissions linked to the production or transportation of goods. To effectively use industry figures, it’s crucial to verify their accuracy by reviewing the underlying data yourself.
The downside? Industry figures are currently limited in availability. However, as the push for Net Zero intensifies, we expect to see an increase in these figures, especially as suppliers adopt greener production methods. You can also adopt a Hybrid Method, by using the average values method and incorporating industry figures, where these are available, to yield the most accurate emissions calculations at this point in time.
At Attain Zero, we currently don’t support the input of industry figures, but we’re excited to work on this feature for release during 2025!
We hope this overview has shed light on the main methods for calculating your business’s emissions. If you have any questions or need further information, don’t hesitate to reach out!
A really interesting article.
I hadn’t realised there are different calculation methods all with different accuracies.
Thank you.