Heat Pumps: A Climate Solution with Hidden Challenges
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Chapter 1: The Promise of Heat Pumps
In recent years, air conditioning has shifted from being a luxury to a necessity for many northern cities, largely due to the escalating frequency of heat waves attributed to climate change. Heat pumps, which provide both cooling and heating, have emerged as a viable solution, transferring heat from the outside in a way that is more energy-efficient than traditional natural gas heating systems. Theoretically, this presents a significant advantage for the environment. However, the reality is much more complicated.
Decades ago, global leaders recognized the urgent need to address the depletion of the ozone layer, primarily caused by chlorofluorocarbons (CFCs), commonly found in refrigerants, air conditioners, and aerosol products. In response, the Montreal Protocol was established in 1987, successfully initiating the recovery of the ozone layer after nearly 40 years.
The crux of the issue, however, lies in the replacement substances. Hydrofluorocarbons (HFCs) became the primary alternative to CFCs. While HFCs do not harm the ozone layer, they possess greenhouse gas properties that are significantly more potent than carbon dioxide. It’s perplexing that, despite the growing awareness of greenhouse gas effects during the late 1980s, this potential drawback was overlooked.
In 2016, following the Paris Accord, a new agreement was reached in Kigali, Rwanda, which aimed to include the greenhouse gas impacts of HFCs in the global strategy against climate change. Today, around three-quarters of countries, including the major economies of the USA, China, and the EU, are committed to this initiative.
Section 1.1: Alternatives to HFCs
Fortunately, there are effective alternatives available, such as propane, which is both affordable and has a minimal global warming potential. This refrigerant is already utilized in various air source heat pumps across Europe. Additionally, carbon dioxide is being employed as a refrigerant in certain hot water heat pumps, such as those manufactured by Sanden.
These alternatives represent an inexpensive and straightforward solution to mitigate climate change, ranking as the top action on Project Drawdown's cost-benefit list for climate interventions.
Section 1.2: The Challenge of Transition
Despite these promising alternatives, the global market for air conditioning and refrigeration continues to expand rapidly. Many existing cooling systems, such as wine refrigerators and commercial freezers, still rely on HFCs, and manufacturers have been slow to transition away from these substances. Compounding the issue, many of these appliances leak refrigerants annually—approximately 3% for commercial systems and around 4% for popular mini-split heat pumps. Given that some HFCs are thousands of times more potent than CO2, even minimal leakage can contribute significantly to global warming.
When mini-split systems are in use, the annual leakage can equate to roughly a quarter of a ton of greenhouse gases. Furthermore, these potent gases can linger in the atmosphere for extended periods. While replacing natural gas heating systems with heat pumps can yield a net positive climate benefit, doing so in conjunction with adding air conditioning can inadvertently increase emissions.
Chapter 2: Regional Disparities and Solutions
In locations like Vancouver, British Columbia, where climate initiatives are strong, the transition to eco-friendly heat pumps faces obstacles. Despite city efforts to promote heat pumps and ban new natural gas connections, the market still predominantly offers mini-split systems that utilize climate-damaging refrigerants. A report from a year ago outlined potential solutions, but even a city with significant resources like Vancouver struggles against the inertia of national supply chains.
Canada's reliance on the USA for imports complicates matters, especially since the U.S. only ratified the Kigali Amendment after the 2020 elections. Although the U.S. is beginning to phase out harmful refrigerants, they are not being replaced with genuinely low-global-warming-potential alternatives.
In contrast, the European Union has taken decisive steps to phase out HFCs and other problematic refrigerants, implementing a schedule that includes hydrofluoroolefins (HFOs) as well. The EU's carbon pricing scheme, set to commence in 2026, will also encompass HFCs, impacting imports through a carbon border adjustment mechanism.
The push to eliminate harmful refrigerants is crucial for climate action, as the world navigates a complex transition away from natural gas while facing its own climate challenges.
As a reminder, here’s a concise list of effective climate actions:
- Electrify everything
- Overbuild renewable generation
- Construct continent-scale electrical grids and markets
- Develop pumped hydro and other storage solutions
- Increase tree planting
- Revise agricultural practices
- Enhance concrete, steel, and industrial processes
- Implement aggressive carbon pricing
- Rapidly phase out coal and gas energy
- Cease financing and subsidies for fossil fuels
- Eliminate HFCs in refrigeration
- Stay focused on the core issues