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The More Heat Pumps the Merrier

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Senior Fellow Emeritus, E Source

Jay Stein, a Senior Fellow Emeritus affiliated with E Source, is one of America's leading energy technologists. Over the course of his over 40-year career he has played numerous roles, including...

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  • May 4, 2022

The number of cities moving to ban natural gas heating in new buildings, and encourage builders to install heat pumps instead, keeps growing. Early leaders include New York and Seattle. In California alone, 54 jurisdictions adopted codes that either restrict natural gas usage or outright require heat pumps in new construction.

Following their lead, policymakers and environmental advocates responding to Russia’s Ukraine invasion, advanced heat-pump-boosting plans to lessen Europe’s dependence on Russian natural gas. One of the most prominent proposals came from the journalist and environmentalist Bill McKibben, who in an article titled Heat Pumps for Peace and Freedom, implored President Biden to “immediately invoke the Defense Production Act to get American manufacturers to start producing electric heat pumps in quantity, so we can ship them to Europe…” Biden hasn’t commented publicly on McKibben’s proposal, but separately, the White House did release a statement announcing support for the European Commission's plan to increase heat pump deployments.

Some critics of amplifying heat pump installations noted that the vast majority of heat pumps currently produced in the US are charged with refrigerants that are potent greenhouse gases, and those refrigerants leak. As a result, or so they claim, turbocharging heat pump production and installation is bound to increase climate change.

While it is correct that the leaking refrigerant problem is serious, let’s not let the perfect be the enemy of the good. Research shows that the potential benefits to be gained by installing heat pumps instead of gas furnaces far outweigh the drawbacks of leaking refrigerants. Also, more climate-friendly refrigerants are on the way. Federal regulations, expected to take effect in 2025, will drive manufacturers to produce new climate-friendlier heat pumps. The push to install more heat pumps is a good thing that needn’t be slowed down over refrigerant concerns.

A new study that settles the question

For years now, leaders at the Natural Resources Defense Council, a US-based legal and scientific environmental advocacy group, heard concerns about the heat pump refrigerant problem. To investigate to what extent leaking refrigerants undermine the climate benefits of replacing natural gas furnaces with heat pumps, the organization funded a study by researchers working at the University of California, Davis.

The UC researchers used computer simulation to project the hour-by-hour energy consumption of an average US home in 99 US cities, first with a high-efficiency natural gas furnace, and then with a high-efficiency heat pump. Next, they used a database from the National Renewable Energy Laboratory to convert that energy consumption into carbon dioxide emissions. They also added in the leakage of natural gas and refrigerants, from gas pipes and heat pumps.

What they found was that for a weighted average of the US population, over a 15-year equipment lifetime, installing electric heat pumps instead of gas furnaces would reduce equivalent carbon dioxide emissions by a bit more than half. That projection assumes current refrigerants and starting out with the current mix of electric generation on the grid. The researchers expected savings to increase in the future as the grid gets cleaner and refrigerants are more climate friendly. The UC researchers also found that the savings would have been greater had there been no heat pump refrigerant leakage, but that leakage only reduced savings for current units by about 10%. As time goes on, that penalty decreases to just a few percentage points.

Given these findings, the researchers concluded “…policies to expand heat pump deployment will only modestly impact refrigerant emissions from the residential sector, a change that is far outweighed by the significant reductions in carbon dioxide and methane emissions gained by deploying increasing numbers of heat pumps.”

More climate-friendly refrigerants are on the way

The US EPA is currently preparing new regulations that will essentially ban the refrigerant (R-410A) that is currently used in the vast majority of heat pumps and air conditioners sold in the US, and only allow newly manufactured equipment to be charged with a new generation of relatively climate-friendly refrigerants. It’s widely expected that those regulations will be released this summer, that they will only allow refrigerants that exhibit a bit less than about 40% of the climate warming impact of the current standard refrigerant, and that they will go into effect January 1, 2025.

Although the allowed refrigerants will be more climate friendly and efficient than the current standard, most of them are classified as "mildly flammable." They can be ignited, but not easily. For example, they’re about as flammable as ammonia, which you may be storing under your kitchen sink.

To enable mildly flammable refrigerants to be used safely, industry researchers developed new sensors, controls, and piping techniques, but there’s still a lot of work left to do to incorporate them into standard practice. For one, designers and installers are being trained to work with this equipment. For another, the nation’s building codes need to be amended to include standards for the new safety equipment and techniques.

For the last century, virtually all US building codes explicitly outlawed flammable refrigerants inside buildings. In the US, there are thousands of building code jurisdictions, at the state, county, and municipal government level. Amending the codes for all these jurisdictions is a major undertaking.

Leading the effort is the Air Conditioning, Heating, and Refrigeration Institute, a trade association which represents more than 300 companies. AHRI is advocating both statewide code amendments and state legislation, that empowers building code officials to accept the new slightly flammable refrigerants. According to Helen Walter-Terrinoni, AHRI’s vice-president for regulatory affairs, “Either code amendments or legislation is in place for markets representing one-third of annual sales. We expect to get to two-thirds by the end of next year.”

Of the remaining code jurisdictions, there could well be some laggards. According to Elizabeth Ortlieb, a director with Alpyne Strategy, “I've seen recent reports that say it is unlikely that building codes in all 50 states will accommodate mildly flammable refrigerants by 2025.”

As states and other jurisdictions get ready, manufacturers will follow by shipping products with refrigerants that can meet the new regulations. Daikin, the world’s largest air conditioner and heat pump manufacturer, is already shipping products charged with the new refrigerants to a few states, including Florida, Oregon, and Washington. By late 2024, it’s likely that products from virtually all the major manufacturers will be widely available.

Let’s do the tighten up

In addition to advocating for climate-friendly refrigerants, both environmentalists and industry leaders are looking to prod installers and service people to take a more active role in preventing leaks. As Kristen Taddonio, a senior climate and energy advisor at the Institute for Governance and Sustainable Development, puts it, "What matters is the lifecycle climate performance of the system, including efficiency. If leaks are minimized, and the refrigerant is reclaimed at end-of-life, refrigerant should not contribute much to climate change.”

By law, contractors are not allowed to intentionally vent refrigerant to the atmosphere and are required to reclaim refrigerant from retired equipment for reuse or destruction. However, far less refrigerant is being reclaimed then should be in theory, so it’s assumed that the missing refrigerant is being released.

Recovering refrigerant from decommissioned systems is hard and expensive work, and when contractors go to sell what they’ve recovered, they find that it’s not all that valuable. Probably, if the economics were more attractive, more would be recovered. Both the policy makers and environmental advocates that I spoke with called for government action, including paying incentives to contractors to recover refrigerant, as well as more rigorous law enforcement. Furthermore, as more EPA regulations kick in, prices will likely go up, which should also make recovery more profitable.

It’s getting better all the time

It’s clear that the climate change benefits of greater heat pump utilization far outweigh the impacts of their leaking refrigerants. Furthermore, as regulations come online, and new heat pumps come charged with climate-friendlier refrigerants, the net benefits of installing heat pumps will grow ever greater. In the event governments come up with the right means to motivate greater adherence to refrigerant recovery laws, that will be icing on the cake.

In the meantime, the refrigerant problem isn’t being ignored. To put it into context, according to Project Drawdown, a nonprofit organization that conducts rigorous assessments of climate solutions, the combined benefits of its Refrigerant Management and Alternative Refrigerants solutions are 25 times greater than those of its High Efficiency Heat Pumps solution.

Given the results of the UC California study, how can that be? Refrigerants are used in many more applications than heat pumps, including transportation, refrigeration, and industrial food processing. There are also plenty of homes out there that incorporate air conditioners but not heat pumps.

While the problem of climate-warming refrigerants isn’t yet solved, we are making progress. The vast majority of refrigeration sectors have either already transitioned to climate-friendlier refrigerants, as the automotive sector has done, or the EPA is well underway developing new regulations that will be released over the course of the next few years. Lastly, this is just the world’s third wave of climate-driven refrigerant re-regulation. It’s unlikely to be the last.

This article originally appeared on the Energy Technology Revolution website.


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