Switching from natural gas to electric cooking and heating could cut the carbon footprint of Munich’s Oktoberfest festival by 87%, according to a new study.
The dramatic difference is in part due to leakage and incomplete combustion of natural gas by appliances, which releases the powerful greenhouse gas methane into the atmosphere. Still, similar gas-to-electric switches would not have as great a benefit at a global scale – yet – because the carbon footprint of electricity varies from place to place, the researchers found.
“Gas leakages and the share of renewable electricity are critical to understand the climate impact of gas and electrical powered cooking and heating appliances,” says study team member Jia Chen, an engineer studying air pollution and climate change at the Technical University of Munich in Germany. “We need to keep these in mind when comparing gas-powered with electricity-powered end-use equipment and when making decisions” about the best way to reduce the carbon emissions of everyday activities.
Chen and her colleagues used the Munich Oktoberfest as a case study to examine how these two factors affect the balance of whether gas or electric appliances are more climate-efficient. The festival, which draws more than 6 million visitors a year, has used an increasing share of renewable electricity over time. But it’s also a hotspot of natural gas use. The fossil fuel accounts for about 40 percent of energy use at the outdoor festival, mainly to power heaters and cooking appliances.
The researchers first used a mobile gas analyzer to sample the air around the festival and determine the rate of methane leakage from appliances used there: about 1.4%. That’s roughly half the total leakage rate estimated for the entire U.S. natural gas supply chain, which highlights the fact that end-user appliances account for a pretty significant proportion of methane leakage. So one easy way to reduce the climate impact of natural-gas appliances would be to reduce methane leakage from these devices.
The researchers then folded this estimate of methane leakage into a comparison of the total carbon footprint of gas versus electric cooking and heating appliances. These calculations revealed that when the share of renewable energy reaches 58%, electricity becomes the more climate-friendly source of power for Oktoberfest, the researchers report in the journal Earth’s Future.
The Munich Oktoberfest reached this renewable energy benchmark in 2005. Today, the festival uses 100% renewable electricity. Swapping all natural gas appliances used at the festival out for electric ones would have saved the equivalent of up to 450 tons of carbon dioxide emissions in 2019 alone, the researchers calculated.
The researchers next used the calculations they developed for Oktoberfest to assess the gas-versus-electricity break-even points for 25 countries around the world that account for 74% of global natural gas consumption.
The researchers found only five countries – Brazil, France, Canada, Belgium, and Venezuela – in which electricity is almost certainly a more climate-friendly energy source than natural gas for cooking and heating appliances, even if the methane leakage rate is very low. Actual methane leakage rates are notoriously difficult to pin down in practice, but assuming an average methane leakage rate means that two more countries, the United Kingdom and Spain, join the group.
In the other 18 countries, lower shares of renewable electricity generation mean that natural gas appliances may still be the more climate-friendly option – or in some cases maybe not, depending on the methane leakage rate. Still, electricity will become the more climate-friendly option in more countries as the share of renewable electricity increases in the future, the researchers say.
A key assumption behind the researchers’ calculations is that electric and gas appliances are roughly equally energy efficient, says study team member Florian Dietrich, who conducted the work as a graduate student at the Technical University of Munich. This reflects practices at Oktoberfest, where either gas or electric radiation heaters are generally used to provide heat.
“If much more efficient appliances, such as heat pumps, were included in the comparison, electrical appliances would become more climate-friendly, so that more countries would already have reached the break-even point,” he says. This, in turn, would be consistent with past research suggesting that heat pumps beat fossil heating systems from a climate perspective, even in many countries with lots of fossil fuel-generated electricity, as well as with findings that the cloimate benefits of gasoline versus electric cars depend on the particular conditions of their use.
Source: Dietrich F. et al. “Climate Impact Comparison of Electric and Gas-Powered End-User Appliances.” Earth’s Future 2023
Image: © Anthropocene Magazine
