Gas as a bridge technology
By now it is clear to everyone that we have to get away from coal, oil and natural gas, otherwise we will destroy our own livelihood on this planet. It is ironic that gas has been classified as sustainable in the “EU Taxonomy for Sustainable Green Economic Activities” set of rules. According to the EU definition of sustainable investment, power plants whose greenhouse gas emissions remain below 100 grams of CO₂ per kilowatt hour are considered sustainable. Some of the gas-fired power plants can meet this benchmark under certain conditions. However, the calculation does not include the considerable methane emissions from upstream processes such as extraction and transport. The consequences could be subsidies for supposedly sustainable (and newly built!) plants that do not support Germany’s climate goals but will continue to operate for two or more decades for economic reasons. Can this be useful bridging technology? A current example shows that our political decision-makers have either not understood the issue of climate emergency or have not thought it through far enough: The municipality of Mauer (where one of our offices near Heidelberg is located) and six other municipalities on the Elsenz River have just signed a concession agreement with Netze BW for gas supply over 20 years. This means that new gas pipelines are still being built in Germany at the present time – right on our doorstep! It is doubtful that these will later be used to transport hydrogen.
Excursus: green hydrogen
Hydrogen is mainly produced from water using the electrolysis process. The term “green hydrogen” is used when the electricity for splitting the water into hydrogen and oxygen comes from renewable sources. In a second step, synthetic methane can also be produced from it.
These two gases are certainly important for the energy transition, for example to decarbonize the steel industry or air traffic. However, an enormous amount of energy is lost in the manufacturing process, which is why a lot of renewable electricity and thus land is needed. This means that hydrogen is not available in unlimited quantities. Using it to heat buildings would be a waste. Fortunately, there are more efficient and less expensive renewable alternatives in the building sector.
Justifying new gas pipelines or even CHP plants on the grounds that they could later run on hydrogen is misleading greenwashing.
Oil and gas are fossil fuels and are finite. The fact that reserves are not running out after all is due to the fact that new methods, such as fracking, have been developed to access deeper deposits. What sounds positive at first is a disaster because fracking brings numerous undesirable side effects – see natural gas chart.
District heating is heat that is not generated in one’s own home, but comes from a power or heating plant in the surrounding area. Usually, water is heated there by combustion, which is then piped to the consumers through insulated (usually underground) pipes. Once in the residential building, hospital or office building, the energy is transferred to the building’s heating circuit in a transfer station, where it provides space heating and hot water.
In over 80 percent of cases, district heating in Germany comes from combined heat and power (CHP) plants. This means that not only heat is generated here, but also electricity at the same time, which saves around 40 percent of primary energy and thus protects the environment. But there is a huge downer:
Especially in densely populated areas, district heating could make a valuable contribution to decarbonization. If you look at the statistics above, however, you can clearly see that Germany is still a long way from this, because virtually only fossil fuels are used. With district heating, you can’t choose your supplier the way you can with electricity. You have to take the one that operates on site.