Your first carbon footprint is ready, and soon someone will check it: a customer, an auditor or a verifier. One wrong unit can change a result by a factor of a thousand. A missing source can hide a large part of your Scope 1. In the footprints we review, the same six mistakes come back again and again.
- Carbon footprint calculation mistakes: six errors that we often see when companies calculate their footprint.
- Scope 1: refrigerant leaks and process emissions are the items most often left out.
- Data: wrong units and unsuitable emission factors distort the result.
- Scope 2 and boundaries: report both Scope 2 methods and explain every site you leave out.
1. Leaving out refrigerant top-ups in air conditioning
When they calculate Scope 1, many people forget leaks of refrigerants from cooling and air-conditioning systems. Gases such as HFCs have a very strong effect on the climate, so you must include them. This matters most for companies with many air-conditioning units, including those in cars. To avoid this mistake, collect data on refrigerant top-ups and use it in the calculation.
2. Missing emissions from industrial processes and maintenance
Another common mistake is to forget emissions from processes and maintenance. Companies often focus on production and energy use. But they forget other processes, such as chemical reactions or transport inside the site. Maintenance also creates emissions, for example exhaust gases from machines or vehicles. Collect data on all these processes and include them in the calculation.
3. Wrong units for consumption data
Wrong units are a simple mistake, but they are very hard to notice. Before you publish your results, check three or even four times that you converted the units correctly. A common error is a factor per kWh used with data in MWh, or the other way round. The result is then wrong by a factor of a thousand. Copying data by hand is the main cause of wrong results. To avoid this, ask a person who did not take part in the calculation to check everything.
4. Using only one method for electricity: location-based or market-based
Another frequent mistake is to report electricity with only one of two methods: location-based or market-based. The GHG Protocol asks for both.
The location-based method uses the average emission factor for a region or a whole country. It depends on where you take power from the grid.
The market-based method uses emission factors from your electricity supplier. Each supplier has its own mix of sources, with its own level of emissions. As a rule, with some exceptions, the more renewable sources a supplier has in its portfolio, the lower its emissions.
Include these factors correctly in your corporate carbon footprint. Electricity is often the largest part of an organisation's Scope 1 and 2 emissions.
5. No description or reason for excluded sites
Sometimes a company decides to leave some sites out of the calculation, for example because their impact is small. Then give a clear reason for each site that you left out. This protects you from claims that you changed the results on purpose. It also keeps your data credible.
6. Unsuitable emission factors
The last mistake is to choose unsuitable emission factors. Factors that are too general lead to wrong results. Choose factors that match the sector and the type of activity of your company. For example, a fuel producer may need different factors than a clothing maker. So research the factors before you use them.
What to do after you find the mistakes?
A correct calculation is the first step to cutting greenhouse gas emissions. With a reliable footprint, you can plan real measures to reduce your company's carbon footprint.