Natural gas pipelines become hydrogen pipelines

Cli­mate-neu­tral hydro­gen has an impor­tant role to play in Europe’s efforts to achieve its net zero green­house gas emis­sions tar­get by 2050. By then, hydro­gen will have replaced fos­sil fuels in many areas. The exist­ing nat­ur­al gas infra­struc­ture is key to suc­cess­ful­ly trans­port­ing hydro­gen. In the future, pipelines that were pre­vi­ous­ly used for nat­ur­al gas are to trans­port hydro­gen to con­sumers. The Euro­pean Hydro­gen Back­bone Ini­tia­tive has also devel­oped an imple­men­ta­tion con­cept for hydro­gen pipeline infra­struc­ture that relies large­ly on con­vert­ed nat­ur­al gas pipelines.

Since Octo­ber 2022, the “HyGrid2” project, sup­port­ed by the Aus­tri­an Research Pro­mo­tion Agency (FFG), has been con­duct­ing stud­ies to facil­i­tate the trans­port of pure hydro­gen using exist­ing nat­ur­al gas infra­struc­ture. A con­sor­tium con­sist­ing of the “Öster­re­ichis­che Vere­ini­gung für das Gas- und Wasser­fach” (Aus­tri­an Gas and Water Asso­ci­a­tion – ÖVGW), research insti­tu­tions and indus­tri­al ser­vices provider Bil­fin­ger, under the lead­er­ship of Energien­et­ze Steier­mark, aims to put the knowl­edge gained in “HyGrid2” to use in an effort to answer open ques­tions by 2025. The find­ings are expect­ed to make future con­ver­sions pos­si­ble. These include the inspec­tion and clean­ing of the pipelines, the qual­i­ty of the trans­port­ed hydro­gen, theap­pli­ca­tion-ori­ent­ed purifi­ca­tion of H2, and the H2 com­pat­i­bil­i­ty of the indi­vid­ual com­po­nents and mate­ri­als used.

In the course of the project, the first Aus­tri­an nat­ur­al gas steel pipeline sec­tion in the grid ter­ri­to­ry of Energien­et­ze Steier­mark will be con­vert­ed for hydro­gen trans­port and devel­oped into a demon­stra­tion plant with the help of Bilfinger’s Aus­tri­an sub­sidiary Bil­fin­ger Indus­tri­al Ser­vices. The for­mer nat­ur­al gas pipeline will be oper­at­ed with pure hydro­gen under real­is­tic con­di­tions in order to gath­er insights need­ed for prac­ti­cal application.

The spe­cial chal­lenge pre­sent­ed by the con­ver­sion lies, on the one hand, in the require­ments for the puri­ty of the pip­ing sys­tems. For exist­ing pipelines that are con­vert­ed to trans­port hydro­gen, the pre­vi­ous use is rel­e­vant and has an impact on the qual­i­ty. An addi­tion­al fac­tor in the “HyGrid2” pipeline con­ver­sion project is that the net­work sec­tion was oper­at­ed with odor­ized gas, which means that gas that was mixed with odor-inten­sive sub­stances: In Aus­tria as well as in some oth­er coun­tries such as France and Nor­way, the near­ly scent­less nat­ur­al gas is odor­ized with sul­fur-based com­pounds when it enters the gas dis­tri­b­u­tion net­work in order to make an unin­ten­tion­al gas leak detectable at an ear­ly stage. With­in the frame­work of HyGrid2, stud­ies to deter­mine what impact pip­ing sys­tems that were used for odor­ized gas could have on the qual­i­ty of trans­portable hydro­gen are there­fore essen­tial for the oper­a­tion of con­vert­ed pipelines.

As part of its “Green Gas 4 Grids” research pro­gram, ÖVGW has already con­duct­ed the “HyGrid” pilot study to inves­ti­gate which impu­ri­ties can occur in the hydro­gen when it flows through pipelines that have been repur­posed from nat­ur­al gas pipelines to pure hydro­gen pipelines. Such impu­ri­ties can include odor­ants or oth­er com­po­nents of nat­ur­al gas.Another chal­lenge is the mate­r­i­al suit­abil­i­ty of the exist­ing infra­struc­ture for hydro­gen trans­port. Here, in con­trast to nat­ur­al gas, so-called “hydro­gen embrit­tle­ment” can occur, i.e. dif­fu­sion and dis­so­lu­tion of hydro­gen in the microstruc­ture of met­al pipes. Over time, this can lead to pipeline dam­age and thus to the for­ma­tion of leaks. Bil­fin­ger intends to use the pipeline demon­stra­tor to test the exist­ing nat­ur­al gas infra­struc­ture for its suit­abil­i­ty for hydro­gen trans­port using var­i­ous non-destruc­tive test­ing meth­ods and to mod­i­fy it in what­ev­er way necessary.

“HyGrid2” fur­ther aims to put the results of the pipeline demon­stra­tor to use in order to cre­ate a man­u­al for suc­cess­ful nat­ur­al gas pipeline con­ver­sion. This man­u­al will cov­er the tech­ni­cal, eco­nom­ic and legal frame­work con­di­tions and will include the cur­rent state of sci­ence as well as the reg­u­la­to­ry require­ments and orga­ni­za­tion­al process­es. The ref­er­ence man­u­al will serve as a guide­line to accel­er­ate the con­ver­sion of nat­ur­al gas pipelines for H2 trans­port in the future, sothat green hydro­gen can real­ize its poten­tial for a ful­ly sus­tain­able and inde­pen­dent energy

sup­ply.

HyGrid² is a research project fund­ed by the Cli­mate and Ener­gy Fund and con­duct­ed as part of the “Mod­el Region Ener­gy” WIVA P&G program.

Project con­sor­tium: Bil­fin­ger Indus­tri­al Ser­vices, ÖVGW, DBI Gas- und Umwelt­tech­nik, Energien­et­ze Steier­mark, Mate­ri­als Cen­ter Leoben Forschung, HyCen­tA Research, Mon­ta­nuni­ver­sität Leoben — Chair of Gen­er­al and Ana­lyt­i­cal Chem­istry, WIVA P&G