In the small town of Öhringen, east of Heilbronn in Southwestern Germany, distribution network operator Netze BW is testing the future of gas supply by mixing an increasing amount of hydrogen into a small part of the natural gas network.
In the first phase of the BW-NETZlabor "Hydrogen Island", the Netze BW operating station in Öhringen was supplied with a natural gas-hydrogen mixture from October 2020. Currently, the hydrogen is still being purchased, but will soon come from the company's own electrolyzer on its premises, which is supplied with electricity from renewable energies.
Since July 2022, Netze BW, which belongs to the energy supplier EnBW, has also been supplying 30 neighboring test households with the natural gas-hydrogen mixture. They receive their gas from the previous pipelines, but these have been separated from the rest of the grid and now form an island network.
The hydrogen share is to be gradually increased to 30 percent, making it the highest admixture in existing natural gas pipelines to date. Nevertheless, the project manager responsible, Heike Grüner, does not anticipate any major difficulties. "By and large, it will work with the existing infrastructure," Grüner told SWR.
After all, because a hydrogen molecule with its two hydrogen atoms is much smaller and more volatile than, say, methane, the main component of natural gas, it is more difficult to seal off pipelines for hydrogen than for natural gas. But many of the appliances that run on gas also have to be adapted to handle the higher hydrogen content.
But in itself, hydrogen in urban gas pipelines is nothing unusual and has a long tradition. In Germany's first gas networks in Hanover and Berlin, it was not natural gas that flowed, but town gas obtained from coal gasification, which had a hydrogen content of up to 50 percent.
The triumphant advance of natural gas gradually displaced town gas from the pipelines. For reasons of independence, West Berlin relied on town gas until reunification in 1991, and it was not completely turned off until 1996.
Less than 20 years later, in 2014, Greenpeace Energy became the first energy supplier to start feeding green hydrogen into the gas grid. Since 2016, only surplus electricity from wind and PV power plants has been used for electrolysis