“Electricity consumption falls within an organisation’s Scope 2 emissions,” Brian says. “So, as part of our organisation’s GHG emissions report, we must use electricity emissions factors to calculate our total electricity emissions.”
Brian is the Head of Sustainability at a manufacturing facility. Right now, he’s explaining how to calculate electricity emissions to the larger finance team who will be helping his team calculate the company's greenhouse gas emissions. This team plays a crucial role in this process because they have the skills needed to carry out complex calculations, and they hold the organisation’s financial bills and records.
Are you struggling to understand the process of calculating your electricity emissions? Are you finding it difficult to locate the right electricity emissions factors that apply to your organisation’s region? We’ve got you covered!
Keep reading to uncover how to:
- Gather the right data pertaining to your organisation’s electricity consumption
- Collect the right electricity emissions factors and global warming potentials
- Make the necessary calculations
Gather the right data pertaining to your organisation's electricity consumption
The first step in this process is to gather information on your organisation’s electricity consumption. Depending on the information you have at your disposal, you can choose one of the following three avenues:
1. Electricity meters
The first method of capturing your electricity consumption is using electricity metres on site. To get a certain month’s value, you must subtract the previous month’s reading from the current month’s reading. You will then get a value which will be in kilowatt hour (kWh), which is the standard unit used for electricity consumption. You can use this method for various time periods and quarters.
2. Electricity invoices or bills
Another method is collecting your organisation’s electricity bills or invoices for the specific interval of time you’re looking for. These will be sent to the finance department, the building’s landlord, or you can download them from your electricity supplier’s website. Within the bill, the respective entity will have already done the calculation for you with an area labelled consumption amount.
3. Neither of the above
If you don’t have access to either of the above two pieces of information, it’s still possible to estimate your electricity consumption value! How? All you need to do is measure the size of your organisation in square metres or square feet, depending on your location, and apply an electricity intensity assumption.
These can be found according to the Chartered Institution of Building Services Engineers (CIBSE) and Better Buildings Partnership (BBP) in the UK, and the Commercial Buildings Energy Consumption Survey (CBECS) in the US.
For all of the above methods, don’t forget to include all your organisation’s locations when calculating your total electricity emissions.
Collect the right electricity emissions factors and global warming potentials
Now that you have your electricity consumption value in kWh, you might be wondering where to find the correct emissions factor. You’ll be happy to know this is unnecessary if you use our software because these numbers are already set according to location (that’s one less calculation you have to worry about!).
On a national level, regions have their own electricity emissions factors by country (or even for individual states/provinces). To get the right value, you need to find your country-specific grid average electricity emissions factor. Where can you find this? This depends on where you are in the world.
If you are in the United Kingdom for example, you can find this within the conversion factors provided by the UK Department for Energy Security and Net Zero. If you are in the United States, you can find your grid electricity carbon factor from the US Environmental Protection Agency, and these vary depending on where in the country your organisation is located. These values will be in kg CO2 per kWh, but you will also need to include the emissions associated with the other relevant GHGs. This means finding values for kg CH4 per kWh and kg N2O per kWh.
Once you find the right emission factor for electricity, you’ll also need to find the right Global Warming Potential (GWP) values for the non-CO2 gases. This measures the warming impact that different gases have in the atmosphere. For example, carbon dioxide has a value of 1 because all other greenhouse gases are in reference to it. Methane has a value of around 25 (depending on the publication reference), signifying it is 25 times more warming than carbon dioxide.
You can find the most recent global warming potentials within the Intergovernmental Panel on Climate Change (IPCC) 6th assessment.
Make the necessary calculations
With your total electricity consumption value, electricity emissions factors, and global warming potentials, you’re ready to start making some calculations (this is where the finance team comes in!).
Let’s take the following example (these values are demonstration numbers only and are not the correct emission factors for UK electricity):
You are a manufacturing facility in the United Kingdom, and these are the values you have collected:
- Total electricity consumption value is 1000 kWh
- Emissions factor for CO2 is 0.300 kg CO2 per kWh
- Emissions factor for CH4 is 0.000003 kg CH4 per kWh
- Emissions factor for N2O is 0.0000005 kg N2O per kWh
- GWP for CO2 is 1
- GWP for CH4 is 25
- GWP for N2O is 298
You may have noticed that some of the values above are in different units. The first thing you need to do, is convert them to a carbon equivalent or CO2e value since we are measuring the value of total greenhouse gas emissions from electricity, not just carbon dioxide.
It’s important to note that carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are all released during the combustion of fossil fuels, which are typically used in the generation of electricity, so you will need to get the values of each of these gases, as seen above.
Let’s break down the calculations you’ll need to make into steps:
Step 1: First you need to multiply your total electricity consumption value by each electricity emissions factor so you can get a value in kg for each relevant greenhouse gas.
1000 kWh x 0.3 kg CO2 per kWh = 300 kgCO2
1000 kWh x 0.000003 kg CH4 per kWh = 0.003 kg CH4
1000 kWh x 0.0000005 N2O per kWh = 0.0005 kg N2O
Step 2: As you can see, we have 3 different values, all for a different gas. So, we need to multiply the non-CO2 values by their Global Warming Potentials so they’re all in a value of CO2e or carbon equivalent, as mentioned earlier.
300 kgCO2 x 1 (GWP of CO2) = 300 kgCO2e
0.003 kgCH4 x 25 (GWP of CH4)= 0.075 kgCO2e
0.0005 kg N2O x 298 (GWP of N2O) = 0.149 kgCO2e
Step 3: Now that all the values are in the same unit, we can simply add them together to get our total electricity emissions value as a carbon dioxide equivalent for that specific location.
total CO2e = 300 + 0.075 +0.149 = 300.224 kgCO2e
Step 4: Finally, add the values you obtain for every location together to get the total electricity emissions value for your organisation.
Wishing there were a simpler way?
We know that this process can be time-consuming and prone to human error, so we want to help. Since 2012, our internal sustainability experts have been sourcing global electricity emissions factors and supplying them to organisations all over the world to simplify this process.
What’s more, our sustainability reporting software can help simplify your GHG reporting through automatic calculations and robust insight, so you can make more sustainable decisions. Ready to check it out?