Hydrogen in the gas grid: what DVGW G 260 and G 655 mean for installers

Feeding hydrogen produced from renewable sources into the natural gas grid is permitted under the Energy Industry Act (Energiewirtschaftsgesetz). How much hydrogen a gas may contain and what this means for pipes and appliances is governed by the DVGW's technical rules. Two documents are particularly important for installers.

G 260: gas quality

Worksheet G 260 specifies the properties that gases in the public supply must have. With the 2021 edition, the 2nd gas family, i.e. natural gas, was extended to include mixtures with up to 20 per cent hydrogen by volume. At the same time, a new 5th gas family for hydrogen was introduced.

One sticking point was the relative density. Depending on the base gas, it falls below its lower limit of 0.55 at the latest at around 20 per cent hydrogen. A compatibility check with infrastructure and gas applications is then required. In 2023, the DVGW announced that it would adjust the limit. Since August 2025, supplement G 260-B1 "Relative density in the 2nd gas family" has been available on this.

G 655: H2-ready gas applications guide

Information sheet G 655 supplements the TRGI (G 600) and the rules for pipes on industrial premises with the requirements for natural gas with up to 20 per cent hydrogen and for pure hydrogen. The 2025 version replaces the 2021 edition. New features include requirements for gas pressure regulation and gas metering in domestic installations, further developed testing and installation requirements and sizing diagrams for hydrogen.

According to the DVGW's research findings, feeding in 10 per cent hydrogen is possible without restrictions, and for the majority of domestic and commercial gas appliances 20 per cent as well. In the pilot project run by the DVGW and Avacon with up to 20 per cent hydrogen, around 350 household appliances continued to operate without any change to their settings. Separate limits apply to industrial applications and power stations, and a maximum of 2 per cent to natural gas filling stations because of vehicle tanks.

Conversion to pure hydrogen

In the DVGW's assessment, existing gas installation pipes can generally also be used for hydrogen. The gas meter may need to be replaced with a larger one because of the higher volume flow. Gas appliances, on the other hand, must in principle be replaced with H2-ready appliances. The DVGW points out that this changeover can take place within the normal replacement cycle of the appliances.

For businesses, this means that anyone installing gas appliances today should pay attention to the manufacturer's information on hydrogen compatibility and advise customers accordingly.