The US Department of Energy (DOE) has awarded $48m across 16 hydrogen research and development projects — with a particular focus on improving liquid H2 storage and fuelling for vehicles.

Stay ahead on hydrogen with our free newsletter
Keep up with the latest developments in the international hydrogen industry with the free Accelerate Hydrogen newsletter. Sign up now for an unbiased, clear-sighted view of the fast-growing hydrogen sector.

The biggest chunk of funding — $17.7m — went towards three projects studying liquid hydrogen fuelling and transfer systems.

Illinois-based GTI Energy was given $6m to develop a mobile liquid H2 fuelling station, while industrial gases firm Linde received $5.7m for “high-rate” liquid hydrogen fuelling for rail.

The Colorado School of Mines also received $6m to develop and deploy a solid-state hydrogen loss recovery system, with the aim of capturing 80% of “boil-off” during liquid H2 transfers.

While liquid hydrogen offers a higher energy density compared to gaseous H2 — which could give fuel cell electric vehicles (FCEVs) a greater range — the molecules have to be kept at temperatures below minus 253°C, just 20°C above absolute zero.

And while liquid hydrogen can be cryogenically stored — passively maintaining extremely cold temperatures without needing extra energy input — there is still a risk of hotspots forming, either within the tank or during refuelling, leading to H2 “boiling off” as a gas.

If this happens inside the tank, this can lead to pressure building up and a risk of explosion, requiring the hydrogen — an indirect greenhouse gas — to be vented, usually into the atmosphere.

Estimates vary on exactly how much hydrogen is lost as a result of boil-off, with Rio Tinto’s chief scientist last year putting the figure at 1% per day lost from storage tanks.

The next largest tranche of DOE cash — $11.7m — went towards onboard liquid H2 storage systems, funding three research projects by engineering giant GE, defense contractor Raytheon, and Japanese multinational Komatsu, each focused on developing high-capacity storage tanks for heavy-duty vehicles.

The DOE also awarded $6.9m to seven projects developing new hydrogen carriers, including $1m towards University of Southern California-led research into chemicals that can be used for “agricultural purposes” when dehydrogenated.

And $11.3m went towards research and development into high-performing and durable membrane electrode assemblies — a key component of permeable-exchange membrane fuel cells and electrolysers.

In a separate round of grants towards clean energy research and development by small businesses, a project to develop an ultra-low-NOx-emission hydrogen burner by Tulsa-based ClearSign Technologies Corporation and Californian utility SoCalGas was awarded $1.6m.

SoCalGas has also pledged to stump up $500,000 for the project and field-test the technology in southern California.

Updated to include additional funding awarded to ClearSign Technologies and SoCalGas.