How to calculate the carbon dioxide equivalent for your HFC shipment

These resources explain how to make this calculation using an online tool, some of the technical terms, and how you use this calculation.

Global Warming Potential (GWP)

Many gases in the atmosphere have a warming effect as they capture energy from the sun and heat the Earth's atmosphere. This effect is natural and supports life on Earth.

However, climate change is now an issue because the proportion of these warming gases in our atmosphere has changed since the world became industrialised. Our atmosphere also now contains new, man-made gases which weren't present before, such as the HFCs.

Different gases heat the atmosphere at different rates. So that the heating effect of different gases can be compared, they are all compared against one gas – carbon dioxide. This is called the 'global warming potential' or GWP of a gas.

The ‘100-year global warming potential’ of a gas means the equivalent amount of carbon dioxide you would have to release into the atmosphere to have the same effect on the Earth’s temperature over 100 years.

Calculate the Carbon dioxide equivalent (CO2-e)

All hydrofluorocarbon gas (HFC) import and export permit applications require you to give us the carbon dioxide equivalent (CO2-e) in tonnes of your planned shipments. You may be more familiar with describing them by their mass (or weight). Use this formula to calculate this:

Carbon dioxide equivalent CO2-e of a gas (tonnes) = Amount of HFC gas (in tonnes) X GWP of the gas

Calculate the carbon dioxide equivalent of your HFC shipment (xlsx 30KB) (Updated 16 April 2019)

Calculate the carbon dioxide equivalent of your 2015, 2016 and 2017 HFC imports for a grandparented eligibility application (xlsx 30KB) (Updated 16 April 2019)

Note: These tools are for calculation purposes only to assist the preparation of your applications for grandparented eligibility or HFC permits. They are not indicative of the final amount of HFCs that you may be eligible to import.

Global warming potential of HFC gases

All HFC gases have different global warming potentials, and you will need to include this in your calculations. For example, HFC-152 has a 100-year GWP of 53, so it warms the atmosphere 53 times more then the same amount of carbon dioxide. On the other hand, HFC-23 has a GWP of 14,800, and therefore, a far greater atmospheric warming effect. The higher the GWP, the greater the atmospheric warming effect.

Table showing the GWPs for many of the HFC gases

Group Substance 100-Year Global Warming Potential
Group 1    
CHF2CHF2 HFC-134 1,100
CH2FCF3 HFC-134a 1,430 
HFC-143 353 
HFC-245fa 1,030 
CF3CH2CF2CH3  HFC-365mfc 794 
CF3CHFCF3 HFC-227ea 3,220 
CH2FCF2CF3 HFC-236cb 1,340 
CHF2CHFCF3  HFC-236ea 1,370 
CF3CH2CF3  HFC-236fa 9,810 
CH2FCF2CHF2  HFC-245ca 693 
CF3CHFCHFCF2CF3  HFC-43-10mee 1,640 
CH2F2  HFC-32  675 
CHF2CF3  HFC-125  3,500 
CH3CF3  HFC-143a  4,470 
CH3 HFC-41  92 
CH2FCH2 HFC-152  53 
CH3CHF2  HFC-152a  124 
Group 2    
CHF3 HCF-23  14,800 

What this means for you

If we issue an import permit for new bulk HFCs, the permit or notice will state the maximum carbon dioxide equivalent in tonnes of HFCs that you can bring into New Zealand for each calendar year, and any other import conditions. This allocation does not specify the type of HFC gas that you should import.

This means that you can choose to ship a greater volume of HFC gases with a lower GWP within your permit allocation. The lower the GWP of the gases in your shipment, the larger the weight you can ship, as long as their combined CO2 equivalent mass is within your permit allocation.

You will be required to report on your imports and exports annually, we will tell you more about this in early 2019.