Investments in natural gas pipeline infrastructure should be viewed as a way to transport  increasingly low-carbon molecules, according to a report from US research body the Columbia Center on Global Energy Policy.

Some campaigners oppose investment in the US pipeline infrastructure for fear it will lock fossil fuels into the US energy mix. But the same pipelines can be repurposed to carry a blend of natural gas, hydrogen and biomethane, Erin Blanton, one of the authors of the report, tells Hydrogen Economist.

"Pipelines could be seen as a network that carries increasingly ‘green’ molecules" Blanton, CCGEP

“In the same way you can view an electricity grid as a network that carries increasingly ‘green’ electrons, pipelines could be seen a network that carries increasingly green’ molecules,” she says.

Even the most ambitious decarbonisation scenarios see natural gas forming a part of the US energy mix for some time, and much of the 2.5mn miles of natural gas pipelines in the US will need to undergo routine maintenance over the next few years.

That maintenance could be extended at little extra cost to improve the network to carry hydrogen. This would involve the replacement of cast-iron pipelines. These sections constitute a small percentage of the network but are responsible for an disproportionate amount of methane leakage. They are also incompatible with transporting hydrogen.

Polyethylene (PE) natural gas pipes are much less likely to leak and are also better suited to carrying low-carbon fuels.

Hydrogen blend

Currently, the report authors believe most of the US natural gas pipeline system could safely carry a 20pc blend of hydrogen. But this percentage could increase as the pipeline network is repurposed and more hydrogen production comes online.

To enable this, US states should adopt state-level methane reduction targets for gas utilities, federal authorities should updated pipeline standards, and inventories should be made of the composition of pipeline infrastructure in each state, the report says.

2.5mn miles – US pipeline network

Industrial firms and utilities operating in closed-loop clusters could also start testing increasing concentrations of hydrogen in purpose-built pipeline infrastructure.

This infrastructure will operate alongside the existing pipeline infrastructure rather than growing to replace it, according to Blanton.

“I don’t think there will eventually be two parallel networks, apart from in the industrial clusters,” she says. “We will just see increasing concentrations of low-carbon molecules in this existing system—but that will require certain upgrades and changes.”

The report is titled Investing in the US natural gas pipeline system to support net-zero targets.

---

Author: Tom Young