Editor’s Note: The following remarks were made regarding the “A Mid-year Update on HVAC Refrigerants” article by Peter Powell.

Reduction in Greenhouse Gas Emissions

Hydrofluorcarbons, or HFCs, have enabled an 83 percent reduction in U.S. direct greenhouse gas emissions since 1990 as a substitute for ozone depleting substances that were also very potent contributors to climate change. HFCs are used primarily as refrigerants or cooling agents for air conditioners, supermarket refrigeration systems, and insulating foam expansion agents for energy-efficient appliances and buildings. HFCs have zero ozone depletion potential, but they do have a climate impact, although not as strong as the chlorofluorocarbons (CFCs) they replaced. Overall, HFCs represent about 2 percent of the world’s greenhouse gas emissions.

We applaud the U.S. Environmental Protection Agency’s (EPA’s) efforts to further reduce greenhouse gas emissions. In releasing the annual U.S. greenhouse gas emissions report in April, however, the U.S. Environmental Protection Agency [EPA] concluded that HFC emissions increased “by 309 percent” since 1990. Unfortunately, this conclusion does not consider the beneficial impact of previous EPA regulations in that an important transition occurred during that period, with HFCs replacing CFCs. In fact, on a direct global warming basis, the transition to HFCs enabled a 1,747 teragram reduction in CO2 equivalent emissions. That’s equivalent to removing 368 million passenger vehicles from the road for one year, or more than all the automobiles in the U.S.

While HFCs have achieved tremendous climate gains, they remain greenhouse gases. Fortunately, a great deal of work is being done to identify and commercialize new, safe, and economically viable low-global warming potential (GWP) options for certain HFC applications. For example, HFOs, or hydrofluoro-olefins, are currently being commercialized for certain air-conditioning and refrigeration applications, including in automobiles. More than 1 million vehicles in the world today, growing to over 2 million by the end of 2014, contain air conditioning systems using an HFO. In other applications, HFO/HFC blends are showing great promise as reduced GWP alternatives to HFCs that provide the required safety and performance while dramatically reducing the global warming impact. According to the latest United Nations assessment report, HFOs offer global warming potentials that are 1 or less than 1. CO2 itself (this greenhouse gas can be an effective refrigerant when operated under high pressure), with a global warming potential of just 1, is making significant strides in supermarket refrigeration, marine container refrigeration, and other applications.

While much work still needs to be done to address climate change, HFCs have already played an important role. Today, HFCs are part of an ongoing international and domestic policy discussion to reduce greenhouse gas emissions. It’s important for the data to be transparent and complete to tell the full story to inform the best policy decisions. When statements are made that HFCs have increased “by 309 percent” without noting the 83 percent reduction in climate emissions they actually enabled, policy makers may jump to imperfect conclusions without all the facts. Context and balance will lead to the best outcomes as we seek effective ways to reduce greenhouse gas emissions.

William F. Walter, codes and standards fellow, United Technologies, Hartford, Connecticut; and Rajiv Banavali, CTO, Honeywell Fluorine Products, Morristown, New Jersey

Publication date: 12/29/2014

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