GWP (Global Warming Potential) is a unit of measurement that indicates the extent to which a given gas contributes to global warming relative to carbon dioxide (CO₂). The reference value for carbon dioxide is always 1, while the GWP values of other gases use this baseline as a reference.
How is GWP measured?
GWP takes into account a gas's heat retention capacity and its atmospheric lifetime. The calculation examines how much impact the given gas has on global warming over a certain period (e.g., 20, 100, or 500 years) compared to CO₂.
Example:
If a gas has a GWP of 1000, it means that the given gas contributes 1000 times more to global warming than the same amount of carbon dioxide over the same period.
GWP and Refrigerants
GWP plays a key role in the classification of refrigerants, as these substances can be significant greenhouse gases.
CFCs (chlorofluorocarbons): Very high GWP values (between 5000 and 10,000). Their use has almost entirely ceased due to their harmful effects on the ozone layer and climate change.
HCFCs (hydrochlorofluorocarbons): Their GWP is lower than that of CFCs (between 1000 and 4000). They are being phased out because they still have a significant environmental impact.
HFCs (hydrofluorocarbons): Widely used refrigerants, but their GWP values are still high (between 150 and 4000).
HFOs (hydrofluoroolefins): The new generation of synthetic refrigerants with low GWP values (typically below 20).
Natural refrigerants:
- CO₂ (R744): GWP value is 1 (carbon dioxide).
- Ammonia (R717): GWP is close to 0.
- Propane (R290): GWP is approximately 3.
- Comparison of GWP types
- Refrigerant type Example GWP value Notes
- CFCs R12 8500 High environmental impact, phased out.
- HCFCs R22 1800 Under gradual phase-out.
- HFCs R410a 2088 Under regulation, replacement in progress.
- HFOs R1234yf <1 Low GWP, new generation refrigerant.
- Natural gases CO₂, Ammonia 1 or close to 0 Environmentally friendly alternative.
Why is GWP important?
Environmental protection: The use of materials with lower GWP values reduces the impact on climate change.
Regulatory requirements: The EU F-Gas Regulation and the Kigali Amendment restrict the use of refrigerants with high GWP values.
Sustainability: Low GWP refrigerants encourage the adoption of sustainable technologies.
Summary
GWP is a key metric for evaluating the environmental impact of refrigerants and other greenhouse gases. The use of low GWP materials helps mitigate global warming and promotes the spread of sustainable technologies. Industries and regulators must pay close attention to introducing alternatives and increasing energy efficiency to protect the environment.