Climate balance of electricity or natural gas as a heat supplier


In terms of emissions, gas heating in Germany is slightly more climate-friendly than heating with electricity. © Axel Bueckert/ iStock

Many people around the world use either a gas stove or an electric stove for cooking, and both energy suppliers are also used for heating. Which method is more climate-friendly depends on various factors, including the amount of methane that escapes unburned and the electricity mix. A research team has now examined the carbon footprint for heating and cooking with gas or electricity and what would be cheaper for 25 countries. The result: In five countries, including France, Brazil and Canada, electric heating and cooking is more climate-friendly due to the high proportion of non-fossil electricity. In eleven countries, including Germany, the two forms of energy are still balanced. And in eight countries, including China and India, the high proportion of coal used in power generation makes natural gas a more climate-friendly alternative – at least temporarily.

Because the combustion of natural gas causes fewer climate-damaging emissions than coal, it was long considered a bridging technology in climate protection. Although this has changed in Europe as a result of the Ukraine war, the conflict with Russia and the lack of gas supplies, this is still the case in other regions of the world. However, the relative climate advantage for gas only applies if the natural gas is completely burned and as little methane as possible escapes into the atmosphere unburned. Because methane is a highly potent greenhouse gas that has a far greater greenhouse effect than carbon dioxide. Studies show, however, that leaks in pipelines, at distribution stations or through insufficient combustion during cooking and heating can lead to uncontrolled methane leakage from 0.1 to over five percent of consumption. So far, however, these releases have often only been partially included in the climate balance for the use of natural gas.

Natural gas or electricity?

There is also a second aspect: although natural gas is generally more climate-friendly than coal, how does it compare to cooking and heating with electricity? "We wanted to know whether it is more climate-friendly to use gas for heating and cooking or electricity - also taking into account the gas leaks," explains first author Florian Dietrich from the Technical University of Munich. It is clear that this depends crucially on which energy mix is ​​used in a country or region to generate electricity. For example, if you primarily use electricity from coal, the carbon footprint of electric cooking and heating can be worse than that of gas. With a high proportion of "green" electricity from renewable energies, the situation is reversed, especially if there are also significant leaks in the natural gas system. Then cooking and heating with electricity can be the more climate-friendly alternative - as long as enough "green" electricity is available.

Dietrich and his team have now examined for 25 countries which energy source for cooking and heating is the more climate-friendly there today. They selected the countries that contribute at least 0.5 percent to annual natural gas consumption and where renewable energies already contribute at least ten percent to the electricity mix. "Because in this study we primarily wanted to investigate how and from when an increasing proportion of renewable energies will make the use of electricity more climate-friendly than natural gas," explains the team. As a result, many countries in the Near and Middle East fell out, leaving 25 countries, including Germany. “These 25 countries together are responsible for 75 percent of global natural gas consumption,” report Dietrich and his colleagues. "The USA alone accounts for 21.7 percent of natural gas consumption, followed by Russia with 12.4 percent and China with 5.4 percent." Using country-specific data on the electricity mix, leaks and emissions, the scientists determined a comprehensive one for each country Emission factor for using natural gas or electricity for cooking and heating.

In Germany there is still no clear advantage for electricity

The evaluations showed that if you include the leaks in the gas network and on the gas burners, heating and cooking with natural gas is often more harmful to the climate than previously thought. It also means that the bridging technology benefits of natural gas over electricity are diminishing – and in some countries are already non-existent. "By including the leaks and incomplete combustion, a lower proportion of renewable energy sources is required in the electricity mix than previously assumed," says co-author Jia Chen from the Technical University of Munich. Based on a range of gas leaks between 0.2 and 5.35 percent, heating and cooking with electricity is already more climate-friendly than using gas burners in five countries. This applies to Canada and Brazil, for example, because hydropower and other renewable energies account for a large proportion of the electricity mix there. France and Belgium are also among these countries because they cover a high percentage of their electricity needs with nuclear energy.

Germany, on the other hand, belongs to a second group of twelve countries in which the climate balances of gas and electricity are still roughly balanced. Cooking and heating with electricity would only be significantly more climate-friendly if the share of renewable energies such as sun and wind in the electricity mix was increased by around 15 percent. Also in Italy, the USA, Russia, Turkey or the Netherlands there is currently no clear advantage for the end use of electricity instead of gas. However, this would change as soon as the proportion of "green" electricity increases. In the other eight countries, including India, China, Poland and Australia, natural gas is clearly the more climate-friendly source of energy for cooking and heating. Because there, electricity is still generated to a large extent from coal, which means that electricity there is "dirtier" than natural gas even if you include leaks in the gas network, as Dietrich and his team determined. "For the countries in this third group, the use of natural gas could remain more climate-friendly than the use of electricity even in the more distant future," say the scientists.

Source: Florian Dietrich (Technical University of Munich) et al., Earth's Future, doi: 10.1029/2022EF002877

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