The tasks of grid operators include, on the one hand, the safety-oriented design of the gas infrastructure and, on the other hand, guaranteeing the proper functioning and operational reliability of the gas networks over their lifetime of use. Network operators ensure this by adhering to the requirements in the technical regulations of the DVGW, the German association for gas and water standards (Deutscher Verein des Gas- und Wasserfaches e.V.), for all gases in accordance with reference sheet (Arbeitsblatt) G 260. Which now also includes hydrogen. With the publishing of the new Energiewirtschaftsgesetz (German energy industry law, EnWG) in August 2021, the DVGW also became responsible for establishing the technical rules and requirements for the supply of hydrogen by pipeline to the general public. On the one hand, this is a leap of trust in the expertise of the gas industry and, on the other, an impetus to further develop the regulatory framework especially for hydrogen.
The requirements for the quality of fuel gases of the public gas supply are specified in Arbeitsblatt G 260 “Gasbeschaffenheit” (“G 260 Technical Rule ‘Gas quality’”). Since the version from May 2021, it also includes a gas family for hydrogen. This so-called 5th gas family includes two different purity levels. Group A requires an H2 content in the gas of at least 98 percent and group D of more than 99.97 percent.
With the publishing of G 260, Arbeitsblatt G 262 “Nutzung von Gasen aus regenerativen Quellen in der öffentlichen Gasversorgung” (use of gases from regenerative sources in public gas supply), which had specified the quality of renewable gases fed into the grid, was withdrawn. Users, however, still need to comply with the ordinance for entry into the German gas network (Gasnetzzugangsverordnung, GasNZV). It requires that biogas, which legally includes hydrogen from regenerative sources, comply at the feed-in point and during feed-in with the conditions laid out in the 2007 version of DVGW reference sheets G 260 und G 262. As a result, the regenerative gases fed into the network, to date, must still adhere to the standards set out in these earlier reference sheets.
The new G 260 reference sheet does not set a concentration limit for the hydrogen content of methane-rich gases of the 2nd gas family. However, this content is indirectly limited by the ranges of permissible combustion characteristics that must be adhered to. Furthermore, the gas infrastructure and applications concerned must be demonstrably suitable for the given H2 content. In the evaluation of the combustion characteristics, it should be taken into account that the composition of the methane-rich gas strongly influences the combustion characteristics of a methane-hydrogen mixture.[…]
… Read this article to the end in the latest H2-International
Author: Dr. Klaus Steiner – Erdgas & Verwandtes, Bochum