It’s a fact of life in industrial processing that in order to accomplish “good” things you must sometimes have to work with potentially “bad” things. Such is the case with liquid hydrogen, or LH2. For example, as the industrial world continues to look for new ways to move away from the use of traditional fossil fuels to power vehicles and industrial processes, a number of alternatives have begun to rise to the fore. For the most part, this quest to expand the energy pool via “green” clean-energy alternatives is being driven by environmental, social and governance (ESG) initiatives that are aimed at reducing the high carbon footprint, greenhouse gas emissions and ozone depletion potential that are implicit in fossil fuel usage, which many argue are at the forefront of global climate change.

While propane and liquid natural gas have traditionally been the most popular among the new wave of clean-energy fuels – with Europe, China and India at the forefront of their use – hydrogen has begun to gain additional attention and traction as another promising alternative. In fact, in 2021 the US Department of Energy announced the creation of the Regional Clean Hydrogen Hubs program, which offered $7 billion in grants to companies that would like to develop more hydrogen liquefaction plants, with many traditional oil-and-gas producers showing interest in expanding their horizons into the LH2 universe. In late 2023, seven hub projects were selected for funding through the program, with a network of new liquefaction facilities that will eventually span the country from the mid-Atlantic to Pacific Northwest and Gulf Coast to upper midwest. Additionally, besides all the controversies around the electric vehicle market and applications, electrification alone can’t solve the road to zero emissions given its interconnectivity with the grid and battery technology limitations.

The simple truth is that a clean-energy future is coming, but it can only be realized once an infrastructure is in place that makes the use of alternative fuels economically viable – and unquestionably safe to dispense. This condensed white paper focuses on the challenges that are inherent in the dispensing of LH2 and how they must be overcome before the fuel can assume a prominent place in the world’s motor fuel pool.

The Challenge

While LH2 has the potential to power all motor vehicles, it is increasingly being viewed as a top choice for long-haul transport, including trucks, planes, and ships. However, the challenge lies in transporting the fuel in the massive quantities required. LH2's carbon-neutral status and its clean emissions of water and air make it an attractive energy source, but its volatile nature creates difficulties in harvesting, refining, transporting and dispensing. Ensuring safety throughout its production and supply chain is essential, regardless of the quantities handled.

One of the main challenges with LH2 is its working temperature of -423 ºF (-253 ºC), which is close to absolute zero. This makes it one of the most demanding cryogenic gases to work with, requiring dispensing equipment to include heavy thermal insulation to prevent significant losses from evaporation. Another concern is hydrogen embrittlement, a phenomenon where exposure to hydrogen weakens metals, causing a reduction in tensile strength, ductility and fracture toughness. In extreme cases, this can lead to the catastrophic failure of components. To reduce this risk, more resistant materials, such as high-quality stainless steel, should be used in LH2-dispensing nozzles. Additionally, the precision engineering of moving parts and seals is vital for ensuring safety. PCTFE is recommended for seals due to its high tensile strength and ability to remain stable at ultralow temperatures.

Beyond material concerns, the nozzle must be designed to prevent leaks, with the ability to immediately stop the flow if a leak occurs, to avoid dangerous situations. Automated flow control systems are also necessary to allow the operator to remain at a safe distance during refueling. Finally, LH2 systems must address the risk of liquid air buildup, which can result in highly combustible liquid oxygen forming on the nozzle during refueling. To prevent this, the dispensing system should be jacketed and maintain an extremely high vacuum to keep outer surfaces at ambient temperature, eliminating the possibility of liquid air accumulation.

The Solution

RegO^® Products, part of OPW Clean Energy Solutions, has introduced the HydrOMac^® LH2 refueling nozzle to tackle the unique challenges of LH2 handling. This nozzle is designed to offer a safe and reliable refueling experience that mirrors the familiar process of traditional diesel fueling, ensuring ease of use for consumers.

The HydrOMac nozzle reduces complexity in LH2, dispensing with a streamlined design. It features built-in leak detection and automated fuel control, allowing operators to refuel from a safe, remote location. A three-stage, thermally isolated operation enhances both efficiency and performance, while the jacketing is engineered to meet the low temperature requirements of LH2 and prevent the dangerous buildup of liquid air. Additionally, the nozzle is lighter than competing models, making it easier to handle during refueling.

These safety-focused and user-friendly features make the HydrOMac nozzle intuitive for consumers, removing any ambiguity during operation. This ease of use helps LH2 sellers replicate the traditional vehicle fueling experience, addressing any consumer concerns about handling an unfamiliar fuel. The HydrOMac nozzle is the latest in RegO’s line of hydrogen-handling products, which includes valves, regulators and other critical components.

There’s no getting around it – the clean-energy future is coming, and in order to optimize its potential from a production, supply, financial and safety aspect it must be outfitted with equipment and systems that are able to meet the unique handling characteristics of the growing roster of clean-energy fuels. In that vein, LH2 stands poised to assume an elevated role in the nation’s motor-fuel pool, especially as it relates to the fueling of large vehicles.

In order to achieve success, though, the world’s producers and suppliers of LH2 must be fully aware of the “bad” characteristics that are fundamental to its handling and dispensing in order to realize the “good” that can come from its use. RegO and OPW Clean Energy Solutions have taken a positive step forward in that quest. www.opwglobal.com

The HydrOMac® LH₂ nozzle is lighter than competing models, making it easier to handle during refueling. Credit: Gawda Media