What are Emission Factors?

Sumday Team
January 18, 2024
5 Minutes
Photo by Anne Nygård

What are emission factors?

Think of emission factors as the magic number that allows you to calculate your carbon emissions using the data you already have. They help quantify the impact of a given activity on the environment by providing a rate of GHG emissions. 🌍📈


You take $2M paid for food packaging x emissions factor (🪄) = 50t of C02-e. 

You take 1000 kWh of electricity x emissions factor (🪄) = 170 kg C02-e

They are also often referred to as conversion factors, emission intensity, or carbon intensity.

Sumday has a database full of emissions factors to help you perform these calculations in the absence of primary data from suppliers (More on this in a bit).

Where do the emission factors come from?

Emissions factors are published by a variety of sources. For the most part, Sumday uses publicly available emissions factor data published by reputable sources like governments, international organisations, universities, peer reviewed journal articles and primary emissions data disclosed by companies. We do this so we can transparently share every one of these numbers and their source with you in the Carbon General Ledger report. You can find a summary of key sources included in Sumday’s database here.

Companies and their accountants are not limited to the use of data within the Sumday database. Where organisations have licensed other data sources or have their own organisational specific emissions factors, these can be uploaded as custom emissions factors in Sumday and will only be available to your organisation.

Ok…but where do those databases get the information?

This is a great question. For the most part, emission factors come from studies or economic analysis to produce a very high level average for the carbon associated with your relevant activity or the goods and services you’re purchasing. This may seem extremely uncertain (it is) and yet every company in the world measuring their scope 3 emissions relies on methods that adopt these industry averages, because they don’t have actual data from suppliers (Sumday is on a mission to change that!).

These magical 🪄industry average emission factors don’t actually tell you the real emissions of your chosen supplier or investments. Say, for example you decided to gift more sustainably to your team this year, you’ve done your research, you found some cool shoes that are made from eco-friendly materials with minimal environmental impacts - if that supplier hasn’t accounted for their carbon, you’ll resort to using the industry average emission factor for shoes. You won’t be able to recognise your sustainable efforts when you do account for your carbon emissions. Your carbon footprint will be higher than what you might’ve actually contributed to - that’s not good enough right?

What’s a "Supplier-Specific Emissions Factor" or “Primary data from suppliers”?

Imagine, for every product and service out there, there's an associated carbon footprint e.g. For every litre of milk we purchase from this supplier, Milky Way Ltd, we know there's 2kg CO2e of carbon footprint associated with it. That's your supplier-specific emission factor (aka "Primary-Data Emissions Factor")

To get to that point, every business on the planet needs to be carbon accounting (and we all manage to get this done with financial accounting, so let's make carbon an extension).

Here’s the example of where we envision the world to be:

You take $2M paid for 4M food boxes x Compostable Packaging supplier’s missions factor (🪄) = 1t of C02-e

You take 1,000 tonnes of grain x supplier’s emissions factor (🪄) = 10t ofC02-e

...rather than the 'average' emissions from grain for a given country based on high level data or the average of packaging (especially where action have been taken to reduce emissions, you want this to be recognised in your accounting!)

Now, how do we do that?

It’s not as impossible as it may seem…

Step 1: Start carbon accounting!

But who can help? How can businesses afford this?

Well fortunately, every company, large and small, already has a climate hero that can make that happen…sometimes they’re called accountants 🦸‍♀️ And they’ve been doing it with financial accounting for centuries!

Sumday firmly believes the world of carbon accounting is on the cusp of change and we believe it will simply become an extension of normal accounting and reporting for all companies. In doing so, carbon accounting becomes meaningful and can fast track reduction efforts. This allows businesses to start understanding their impact and rely on their trusted advisors to guide them in making informed decisions regarding their impact, considering both financial and carbon returns. Importantly it becomes affordable and accessible to everyone.

Step 2: Engage with your suppliers

It takes one simple question, ask them “Are you carbon accounting?”

If they are, great! You’ve got your supplier-specific emission factor (as long as their carbon accounting is complete and audit ready, giving you comfort to replace an average). If they aren’t, we’re here to help you engage with your supply chain.

You may think, why bother reaching out to the supply chain and ask, as they are unlikely to have the data. We've also heard "I don't want to reach out until my own house is in order" - the emissions from your suppliers are actually 80-90% of your house! It’s known as Scope 3 emissions. Asking is one of the biggest impacts a business can have; it is a market signal that there is a growing expectation that businesses understand their emissions. And when you provide support, not just questions, you're starting to have a significant impact.

At Sumday, we’re on a mission to make this all possible - supporting every business to affordably embed carbon accounting - so we can all just...get on with it. We're leading with education, transparency and trust every step of the way.

Reach out for a chat with us or sign up for a free trial to look around. Getting started isn’t as overwhelming as you might think!