Since 2019, several dozen U.S. cities — beginning with Berkeley, Calif., and expanding to other liberal strongholds — have prohibited natural gas hookups in new residential (and some commercial) construction. Instead, these cities are mandating the use of electricity for heating.
This shift is part of a larger push to phase out fossil fuels in the residential energy consumption sector. Since 2000, the residential energy consumption sector has also seen the smallest drop in its carbon emissions, especially compared to the sharp lowering of emissions in the electricity generation sector.
While proposing the elimination of natural gas may seem environmentally sound, it will likely lead to an increase in carbon emissions in most jurisdictions and — counterintuitively — it will increase in natural gas consumption.
Heating homes with natural gas is straightforward and efficient. The gas is piped into the house and then burned in a furnace with efficiency exceeding 90 percent in modern models. This means that 90 percent of the energy contained in the natural gas ends as useful heat for the home’s residents. However, that use — as all fossil fuels — produces carbon dioxide emissions.
An electric heater can be just as efficient and produces no emissions. But what about the electricity used to run it? When natural gas is being burned in a power plant, only about 45 percent of the energy contained in it will be converted into electricity. As that electricity is transported and distributed, additional 6 to 10 percent is lost; and the amount of electrical energy delivered to a house is typically just one-third of the energy contained in the natural gas fuel. Consequently, the overall efficiency of a gas heater is almost three times as high than that of its all-electric counterpart.
Of course, electricity can be produced from sources other than natural gas, including emission-free wind, solar, hydro or nuclear power. But the U.S. is not doing that at scale today. As the price of natural gas plummeted during the fracking revolution, it became a dominant player in U.S. electricity production. According to the New York Times, it provides 38 percent of all electricity in the U.S., 39 percent in California, 53 percent in Texas and almost 90 percent in Delaware. In fact, the overall lowering of carbon dioxide emissions in the electricity generation sector has less to do with renewables and more with the switch from coal to natural gas: per unit of energy, natural gas emits just half the carbon dioxide from coal. The reason why residential carbon emissions have not dropped much is twofold. First, the sizes and amenities of the newly built houses are continuously increasing. Second, while natural gas could displace coal in electricity generation, it could not in residential heating — since it was already established in that sector decades ago.
With the current state of electricity generation, increasing electricity consumption means increasing natural gas consumption, which is ill-advised when using electricity for heating. Making electricity is hard and using it for heating is a waste akin to carving a beautiful wooden sculpture and then burning it to boil water for soup.
A broader lesson behind these policies is that politicization of energy leads to bad decisions — both on the political left and right. Energy issues are always complex and the two-party U.S. political landscape tends to treat most choices as binary. They are not — and nowhere is that clearer than in the case of natural gas. It is a carbon-emitting fossil fuel, on one hand. On the other hand, it is cheap, much cleaner than coal and produced domestically. It has evolved into the transitional fuel of our time, allowing the U.S. to quickly ditch coal while giving renewables time to expand to the scale needed to power the entire electricity-hungry country. Once those renewables have reached that scale, banning natural gas in residential construction starts making environmental sense. Until then, these proposals are ultimately increasing our carbon footprint.
Ognjen Miljanić is a professor of chemistry at the University of Houston, where he teaches about energy and sustainability.