Eliminating fossil fuel combustion in buildings – for space heating, water heating, cooking, and clothes drying – is a necessary step on the path to a stable climate. The International Energy Agency’s Net Zero 2050 report notes that “the direct use of low‐emissions electricity in place of fossil fuels is one of the most important drivers of emissions reductions.” Heat pumps meet this need. They are a proven, high-efficiency electric alternative to fossil fuels for both space and water heating, and because they move rather than create heat, even basic models are 3 to 4 times more energy efficient than combustion or electric resistance heating systems.
Heat pumps help by eliminating direct emissions, reducing methane leaks, and reducing air pollution all while saving people money on their energy bills. Methane has 86 times the global warming potential of CO2, so even small leaks have substantial climate impacts. These leaks occur at every point in the gas supply chain, from production, to transmission and distribution, and within the individual appliances in our homes. For example, a recent report from the Environmental Defense Fund found that the oil and gas industry in the US alone leaks more than 13 million metric tons of methane per year, enough to fuel more than 10 million homes. Another study from Stanford University found that the typical gas tankless water heater emits nearly 2.4 kg of methane per year due to leaks and incomplete combustion.
Indoor methane leaks and combustion emissions also pose a major health risk; researchers at the Rocky Mountain Institute found that compared to homes with electric stoves, homes with gas stoves have average NO2 concentrations that are well above indoor air quality guidelines issued by the World Health Organization.
For the benefit of our climate and our health, we must rapidly scale up deployment of electric heating. The IEA’s Net Zero Emissions scenario anticipates the need to deploy more than 1 billion new heat pumps for space and water heating in the coming decades, to bring the electrified share of total heating energy demand from %7 in 2020 to %55 by 2050.
Some of these heat pumps will be installed in new buildings, which should be fully electric from the start; all-electric new construction is already more cost-effective than building with mixed fuels in many places. For existing buildings, the challenges are more complex, and successful decarbonization will require smart strategies to replace fossil heating equipment across the full range of residential and commercial building types and climate zones. At CLASP we recently developed one such strategy for the US residential sector that holds the promise to deploy 45 million new heat pumps over 10 years and save nearly 50 MtCO2e annually by 2030, and we are now working to incorporate this into state-level decarbonization plans. We are also working together with our partners in the Crux Alliance to develop strategies to accelerate heat pump deployments in Europe, China, and the United States.
For these strategies to be successful, we’ll need strong commitments from national governments to phase out fossil heating and incentivize heat pump deployments. The UK, for example, has rolled out its Heat and Buildings Strategy ahead of COP26, with an aim to replace up to 1.7 million fossil fuel boilers per year by the mid2030-’s. We’ll also need to emphasize installer training and consumer awareness to ensure good market outcomes. Fortunately, cost-effective technical solutions for many buildings and climate zones are readily at hand. The stage is set for coordinated global action on heating decarbonization, and all we need to do is act.
Chief Research Officer, CLASP