Green hydrogen (H2) is widely considered to be our best hope for replacing fossil fuels as we progress towards CO2-free energy supply. But moving this volatile gas from producer to consumer poses considerable challenges and so far no purpose-built distribution network exists.

The HYPOS initiative was set up to solve this dilemma, under the direction of Fraunhofer Institute for Ceramic Technologies and Systems IKTS and with input from commercial partners including Leipzig-based DBI Gas- und Umwelttechnik GmbH. The researchers are primarily looking at transporting the H2 alongside natural gas.

The gases are separated by carbon membrane technology: nano-porous ceramic substrates are coated with a custom polymer, which when heated up and starved of oxygen, deposits an ultrathin layer of carbon. The carbon acts as the filter in the tubular structures, separating the methane from the hydrogen; the smaller H2 molecules are forced through and come out of the other side as gas, while the bigger CH4 molecules are held back.

“This gives us hydrogen with an 80 percent degree of purity. We then filter the residual natural gas in a second separation step. The end result is a purity of over 90 percent,” explains Dr Adrian Simon, group manager at Fraunhofer IKTS in a press release. The H2 produced is pure enough to replace fossil fuels in steel production plants and can also heat buildings when burned in Combined Heat and Power systems. The team at IKTS are currently working on scaling up the technology.

“The advantage of this infrastructure is that it allows hydrogen to be fed into the natural gas grid as well. The two substances can be transported together in one line. Once they arrive at the destination, we can separate them from one another again as needed”, explains Simon in the release.