Hydrogen in the natural gas grid – can it be done?

There is no doubt that renewable energies are climate-friendly and available in unlimited quantities, thereby representing the future of our energy supply. And yet they have one major drawback: They are not geared toward our needs. With increasing frequency, this even leads to wind turbines or photovoltaic power plants having to be shut down if nobody wants the electricity they produce.

Researchers are working on turning this drawback to their advantage. In this regard, much revolves around the gas hydrogen. Advantage number one: The energy from the sun and wind that nobody wants can be taken and used to produce hydrogen. Advantage number two: Gas can be stored and easily transported. The two EnBW subsidiaries Netze BW and terranets bw (Independent Transmission Operator) are working on various projects to prepare the natural gas grid for hydrogen.

Can hydrogen be transported in natural gas pipelines?

Dr. Heike Grüner, project manager responsible for Hydrogen Island at Netze BW

Germany has a gas grid more than 500,000 kilometers long. Why not use the existing infrastructure and feed the hydrogen into the natural gas grid? “It’s not quite as easy as that. Not all gases are the same,” explains Dr. Heike Grüner, project manager at Netze BW. Natural gas and hydrogen differ in terms of their chemical composition, so natural gas cannot simply be replaced by hydrogen on a like-for-like basis. “But we are convinced that it is possible to add up to 30 percent hydrogen to natural gas without any reservations.” So convinced, in fact, that the company has set up a project that is unique in Germany: “Hydrogen Island Öhringen”.

Test under real conditions

The town of Öhringen provides ideal conditions for Hydrogen Island

In the town east of Heilbronn, part of the existing gas grid is being separated from the rest of the grid like an island and gradually supplied with up to 30 percent hydrogen. “The special thing about our project is that we are running it in the actual grid – without the households concerned being restricted in any way,” says Grüner. Nobody has to buy new appliances here. All the same, the households are one of the keystones of the project. That’s because people differ in terms of their consumption behavior and the built-in technology is never the same in two places. “The question for us is not whether it works, but how.”

Hydrogen Island Öhringen

Öhringen is getting itself fit for the future: Together with the town’s residents, Netze BW is delivering a solution to enable the storage of renewable energies. Since November 2021, a mixture of natural gas and hydrogen has been supplied to the company’s own site. In the summer of 2022, the aim of adding a 30 percent mix of hydrogen to the natural gas grid was achieved. Phase 2 then got under way, which involved also supplying the households in the area with the mixed gas. The initial findings will be presented in 2023.

New natural gas pipeline in Baden-Württemberg is H₂-ready.

The addition of hydrogen to the existing grid is an important part of the transition to green gases. EnBW’s long-distance gas subsidiary terranets bw is also conducting various tests in this regard. In December 2022, however, it commissioned a new natural gas pipeline that can do more. The roughly 28-kilometer-long Neckarenz Valley pipeline, or NET for short, transports gas in the Ludwigsburg area, thereby not only creating additional transmission capacity to cope with the growing demand for natural gas. Thanks to special welding processes and the use of hydrogen-compatible steel, the pipeline is also ready to transport green gases and hydrogen.

+++ Information supplied by the grid operators Netze BW and terranets +++