LH2 Era™ blog

Wednesday, April 23, 2025

Moran Innovation Liquid Hydrogen (LH2) Newsletter [Issue 2025.1]

See document summary and SAE aerospace decarbonization webinar here [1]

Welcome to the Moran Innovation Liquid Hydrogen (LH2) newsletter! The goal is to help anyone involved or interested in liquid hydrogen systems to stay informed of the latest news, developments, best practices, training, events, and other relevant LH2 content.

This newsletter will also be posted to the LinkedIn Global Liquid Hydrogen (LH2) Systems group and emailed to interested individuals. If you would like to receive the email version, please send an email to info@moraninnovation.com with "LH2 newsletter" in the subject line from the account you wish to receive it.

Note that links to sources are sprinkled throughout the newsletter and appear as blue underlined text when you hover your mouse over them (or tap them on phones or tablets). Light yellow highlights indicate recommended sites to visit for more in-depth content.

LH2 Systems Training

Online on-demand course can be completed in a day
Concise treatment of liquid hydrogen (LH2) systems for quickly getting up to speed for those new to the topic
Advanced tools, knowledge, and hard to find data for more experienced participants
Applicable and adaptable to any mobile or stationary LH2 system with examples from infrastructure and aerospace
Video clips from live course lectures edited to provide the most relevant information to learn at your own pace
Downloadable PDF of over 350 slides with supplemental data and hyperlinks to more details
Instructor has 40 years of engineering experience with LH2 technologies and systems development for NASA, military, industrial, and commercial customers

Visit the LH2 Era™ Library for this and other on-demand online training materials

Upcoming Events

Apr 25, 2025, "Large Scale Projects: The Road to Full-Scale Hydrogen Deployment" H2 View webinar.
May 7, 2025: "Liquid Hydrogen Systems and the Role of Vacuum Jackets" Leybold webinar, 1-2 pm ET.
May 15, 2025: "Hydrogen for Energy Storage", Interagency Advanced Power Group (IAPG) Mechanical Working Group (MWG) meeting, Power Conversion Panel presentation.
January 16 - December 18, 2025: Liquid Hydrogen Systems course. 24-hour free online viewing of one of the course lectures on the third Thursday of each month starting at 10 am ET.

Visit the Moran Innovation's Training page for more resources and learning opportunities

Moran Innovation News and Updates

Artemis Human Landing Systems: Completed subcontract providing cryogenic fluid management subject matter expertise to the NASA and Blue Origin teams developing the Blue Moon LH2/LOx lunar lander. (posted Mar 31, 2025)
Ohio Fuel Cell and Hydrogen Consortium (OFCHC): "Hydrogen 101" virtual presentation for OFCHC members and other registrants. (posted Mar 25, 2025)
Center for Transportation and the Environment (CTE): Completed the final Q&A session with the CTE engineering team after they used the online, on-demand liquid hydrogen systems course. (posted Mar 3, 2025)
Engineering in Construction & Manufacturing Conference and Trade Show (EC&M): "Hydrogen-Based Energy Systems" panel and presentation on "Hydrogen Microgrids for Resiliency and Fuel Offtake". (posted Feb 27, 2025)
Mission Hydrogen: Presented on liquid hydrogen fluid management and had a lively Q&A for more than 90 minutes on this very popular global webinar series (1341 live participants). (posted Feb 26, 2025)
EU HASTA Project: Gave an invited presentation on liquid hydrogen sloshing to the European Union Hydrogen Aircraft Sloshing Tank Advancement (HASTA) Project. (posted January 23, 2025)

Visit Moran Innovation's Home page for more information on LH2 systems, technologies, services, training, consulting, customers, partners, blog index, IP, projects, and more.

References

[1] Decarbonizing Mobility with Liquid Hydrogen, SAE Research Report, 2024.

[2] John Timmer, Ars Technica, Jan 27, 2025.

[3] Liquid Hydrogen Systems Course, 2025.

Author Bio

Matt Moran is the Managing Member at Moran Innovation LLC, and previous Managing Partner at Isotherm Energy. He's been developing power and propulsion systems for more than 40 years; and first-of-a-kind gas, slush, and liquid hydrogen systems since the mid-1980s. Matt was also the Sector Manager for Energy & Materials in his last position at NASA where he worked for 31 years. He's been a cofounder in seven technology-based startups; and provided R&D and engineering support to many organizations. Matt has three patents and more than 50 publications including his online Cryogenic Fluid Management guide and Decarbonizing Mobility with Liquid Hydrogen SAE report. He has created and taught liquid hydrogen courses, webinars, and workshops to global audiences.

Tuesday, April 15, 2025

Tankage Options for Liquid Hydrogen

Single wall metal tanks with foam insulation have been routinely used in launch vehicles where onboard storage times for LH2 is short prior to feeding it to the rocket engines. The primary advantage of this approach is the high mass fraction potential, which is critical for launch vehicles. However, the very poor thermal performance of a single wall tank with foam makes it unsuitable for most mobile applications unless a similar concept of operation is envisioned (i.e., short storage time followed by high consumption rate).

Stationary LH2 storage vessels have an inner wall that contains the fluid, an outer wall exposed to ambient conditions, and an evacuated volume between the walls (akin to a Thermos bottle) [1]. A high level of vacuum must be created and maintained between the walls to ensure adequate thermal performance. Insulation is generally used in the evacuated space to further reduce heat transfer to the inner tank wall. Commonly used insulation types—ordered in increasing thermal performance in a high-vacuum environment—include aerogels, perlite, glass bubbles, and multilayer insulation.

This double wall dewar construction, also referred to as “vacuum-jacketed,” is needed for most mobile applications to achieve an acceptable boil-off rate and to meet other system requirements. Vacuum-jacketed piping, valves, and connections are also used to minimize heat load during transfer and other LH2 operations.

Typical inner wall materials compatible with LH2 service include 300-series stainless steel and aluminum alloys. Composite formulations are currently under development as a lighter-weight option to achieve higher mass fraction LH2 storage. Airbus and the Royal Netherlands Aerospace Centre are developing composite LH2 dewars for aircraft. Gloyer-Taylor Laboratories is also developing single- and double-walled composite storage vessels for a variety of applications. Conformable tanks for improved form factor integration, as well as additive manufacturing techniques, are being developed by various organizations [2].

Fundamentals of Liquid Hydrogen

The Phases of Hydrogen Based on Vapor Pressure and Temperature [1]

The concept of operations for a mobile application dictates the design of ground support and onboard LH2 systems. Typical key operations include conditioning, fueling, standby storage, pressure control, variable feed rates, refueling, defueling, purging, inerting, and various maintenance activities.

Cryogenic fluid management of the hydrogen temperature, pressure, and phase conditions are critical during all of these operations. Thermal environments imposed on a mobile LH2 system vary depending on the operations underway, system design, and local natural conditions.

Solar flux and surrounding air or water temperatures and velocities drive heat loads from the environment. Additional heat loads to onboard LH2 systems come from warmer structures and penetrations via thermal conduction, and surrounding temperature boundaries via noncontact thermal radiation.

Transient heat loads are also imposed by any internal heat exchangers and thermal soak back from operating fuel cells, engines, or other sources [2].

Survey Results of Liquid Hydrogen Users (n = 75)

View detailed results here

In early 2025, I conducted a survey of global liquid hydrogen users that resulted in 75 responses. A summary of the results can be viewed by clicking on the above caption. Many thanks to the fantastic team at Mission Hydrogen for getting the word out about this survey!

The first two questions looked at regional demographics. The majority of respondents were from Europe, followed by Asia and North America. The remaining respondents were split among South America, Africa, and Oceania. The location of their customers followed the same trend, although with slightly different percentage values.

Energy led the primary industry pick for the respondents at 40% followed by research plus R&D at almost 19%. Aviation, automotive, and processing made up the next tier of respondents. The remaining industries represented were maritime, military, rail, trucking, multiple sectors, third party testing, hazardous area classification, consulting, and water.

The vast majority of respondents (61%) identified water electrolysis as their primary hydrogen production method. The other identified methods were SMR with CCUS, hydrocarbon feedstock w/o CCUS, other hydrocarbon feedstock with CCUS, and geological extraction. The percentage of respondents who indicated undecided or other methods was 20%.

Things get very interesting as the survey starts zeroing in on liquid hydrogen (LH2). Nearly 39% have not identified a supply source of LH2 for their needs, a clear gap or opportunity depending on your perspective. An onsite liquefaction system was identified by 24% of respondents. The remainder were equally split between a primary supplier in large quantities and intermediate supplier in moderate or small quantities.

LH2 storage vessel size covered the gambit among the respondents with the most common size between 1-10 cubic meters, and the next most common size of 10-100 cubic meters. On the large end, nearly 19% indicated greater than 1000 cubic meters, and 20% selected 100-1000 cubic meters. That's a lot of large LH2 storage vessels.

Most of the respondents plan a LH2 storage time of several days to several weeks. The next largest groups indicated storage needs of several months or more than six months. Less than 7% needed less than a day of storage.

More than 45% of respondents thought operational LH2 systems would be available in their industry in 1 to 5 years. And 8% indicated LH2 has already become operational in their industry. Nearly a third of the respondents chose 6-10 years, with the remaining selecting more than 10 years.

Cost of hydrogen and economic viability were the highest ranking reasons respondents identified as preventing widespread adoption of LH2 in their industry. These were followed by insufficient investment and public policy. Technical feasibility, workforce skills, and standards and safety rounded out the rest.

Answers to the final five questions provide a wealth of qualitive data that is difficult to categorize, but well worth studying for insights:

How can adoption of liquid hydrogen be accelerated in your industry?
Which liquid hydrogen applications do you see becoming common in 5 yrs? 10 yrs? Longer?
Where is liquid hydrogen currently getting the most traction (i.e., region or country)? Why?
What role should hydrogen play in the transition to a more sustainable future?
Is there any other feedback that you want to provide?

Thank you to all the respondents for sharing your perspectives!

Thursday, February 13, 2025

Safety with Liquid Hydrogen

Relative to conventional fuels, hydrogen has a wider flammability range in air (4–75%), higher permeability through some materials, and a lower ignition energy (0.02 mJ). These characteristics make it vital to provide adequate ventilation, prevent leaks, and eliminate ignition sources in any hydrogen system design and operation. System monitoring and detection is important to ensure that all safety precautions are active and operating as intended.

The very rapid 20 m/s rise rate of gaseous hydrogen in air under ambient conditions greatly aids with ventilation and dilution. Hydrogen also has an auto-ignition temperature of 585°C, which is higher than most fuels. Hydrogen is colorless, odorless, and not toxic to breathe. However, low oxygen detection is needed anywhere hydrogen may accumulate near personnel since asphyxiation is possible if insufficient oxygen is available.

When combusted, hydrogen produces no smoke or soot, which eliminates associated inhalation risks common with fossil and other hydrocarbon fuels. The resulting flame also produces much less radiant energy compared to hydrocarbon fires, thereby reducing the zone of potential heat damage or burns. A hydrogen flame is nearly invisible under daylight conditions, requiring infrared sensors or cameras for detection. At night, the flame is pale blue in appearance. For all hydrogen systems, emergency and fire response planning and coordination is a critical consideration.

The use of LH2 introduces additional safety concerns beyond gaseous hydrogen due to the temperature extremes and phase change characteristics inherent in cryogenic fluid systems. Personnel training, appropriate protective clothing, human interface designs, and safe operations are key to mitigating frostbite and other physiological risks. Appropriate equipment design that eliminates the possibility of human contact with cryogenic surfaces is preferable whenever possible. Exclusion zones, caution and warning systems, safety sensors, and approved operational procedures further mitigate risks to personnel.

The large temperature ranges in cryogenic systems require careful materials selection and design to accommodate differences in thermal expansion and contraction. Phase change from liquid to vapor (and sometime the reverse) occurs throughout a LH2 system, resulting in potential rapid pressure changes in isolated volumes. This must be addressed with appropriate design, operations, and pressure relief devices. If maximum vent relief flow rates are high enough, flaring may be required.

Mitigation of ice buildup is necessary where it may cause key components to not operate properly or create other hazards. Likewise, prevention of oxygen condensing out of the air is addressed with proper insulation on any surfaces that may reach low enough cryogenic temperatures. Any LH2 spills will begin to immediately vaporize and rise as the vapor warms. However, the initially cold hydrogen vapor will be denser than air and can result in temporary regions of high concentration near the ground.

Material selection for hydrogen service must address the design and operational requirements for strength, ductility, fatigue, permeability, and other material properties. Approved cleaning processes must be followed to ensure that unacceptable contaminants are not introduced to the system from materials. Purity levels of the hydrogen are generally dictated by the fuel cell specifications or other feed requirements. Purging and inerting of the assembled system is required for various operations to prevent the introduction of air or other contaminant fluids.

Retrograde US Energy Policy

"The biggest story in the data is the dramatic growth of [US] solar energy, with a 30 percent increase in generation in a single year, which will allow solar and wind combined to overtake coal in 2024." [1]

This pie chart and quote may be one of the last bits of promising US energy news we'll get for the next few years. Many colleagues have asked my opinion about the prospects for hydrogen in the US under the new administration. Here's a breakdown of what we already know, and my guess about what's to come.

Federal Energy Policy

The new federal energy policy can be summarized as a huge step backwards that prioritizes oil and gas while demonizing intermittent renewables [2]. This ignores the fact that solar and wind are the lowest cost power generation sources to bring online and operate, which is the primary reason they have grown so rapidly in recent years.

Mitigation of greenhouse gases and pollution are existentially crucial additional benefits of renewables, making them the logical focus for growth from both an economics and environmental perspective. But propaganda trumps cost of electricity, public health, casualty losses, and the future quality of life for coming generations in the current administration.

The new secretary of energy has parroted this policy, with additional emphasis on liquefied natural gas (LNG) exports from the US. LNG is 85-95% methane, which is a 25 times more potent greenhouse gas than carbon dioxide over 100 years (85 times more over 20 years). Gas leaks and intentional venting are prevalent sources of methane emissions from production, transport, and end use of LNG.

What About Hydrogen?

There is no mention of hydrogen whatsoever in any US energy policy documents released by the new administration. So what does that mean for federal policy regarding hydrogen? Let's connect some dots by enumerating a few key benefits of hydrogen in the energy sector:

Hydrogen produces no greenhouse gases and no pollution of any kind when used to produce electricity with fuel cells. If burned in a turbine or other combustion engine, it produces some NOx (as all combustion processes do) that can be minimized with various design and operational parameters.
Hydrogen can store energy at nearly unlimited scale from intermittent renewables when excess generation capacity is available, and be used to generate electricity when demand exceeds generation capacity.
Hydrogen's unparalleled specific energy relative to any other conventional fuel enables high performance sustainable solutions across multiple mobile and transportation sectors (e.g., aviation, rail, maritime, trucking, etc.)
Hydrogen provides unique energy resiliency and eliminates fuel logistics dependencies for remote or isolated regions.

Note that none of the above benefits are aligned with the new federal energy policies. Nor were they eight years ago when we saw this energy policy disaster unfold the first time around. Looking back at that timeframe may help make a clear-eyed assessment of what's to come.

The Path Ahead

Within this new reality, what is the future for hydrogen in the US? Regrettably, here are my predictions:

Federal funding for hydrogen programs, including the hydrogen hubs, will be largely gutted. One potential exception is military applications where hydrogen addresses strategic defense and national security challenges that no other approach can match.
States and local policies and funding will help in a few US regions. California will remain the hydrogen hotbed it has been for many years. Hawaii, New York, Pennsylvania, and parts of New England also have or may provide supportive policies for hydrogen. Texas will be a wildcard since there is much in place for hydrogen production, but may have fractured policies depending on the area (e.g., Gulf coast vs rural areas). However, many other states and locales already have policies that are hostile toward renewables and hydrogen, and will be emboldened to double down on derailing permitting and similar tactics with the new federal policies.
Private sector funding for hydrogen systems and products has been extensive in some industry sectors and regions. Many of these hydrogen applications have demonstrated performance and economic viability at various commercial readiness levels. It's unlikely that private investors will walk away from sunk cost investments if there is an opportunity to get a reasonable return. The challenge is which global markets are the best targets if most of the US is off the table, which leads to my final prediction.
Global regions will likely stay the course, or even accelerate hydrogen plans, as the US backs away. China will build on its lead as the largest producer and user of hydrogen and associated systems. The European Union, United Kingdom, India, South Korea, Japan, and Australia may find increased interest in new hydrogen projects in their regions with the drying up of US funds and incentives. The same for other countries and regions with established and emerging hydrogen programs such as Canada, South America, Middle East, Africa, and other countries in the Asia and Indo-Pacific regions.

[1] John Timmer, Ars Technica, Jan 27, 2025.

[2] Executive Order, Jan 20, 2025.

[3] Secretarial Order, Feb 5, 2025.

Matt Moran is the Managing Member at Moran Innovation LLC, and previous Managing Partner at Isotherm Energy. He's been developing power and propulsion systems for more than 40 years; and break-through liquid, slush, and gaseous hydrogen systems since the mid-1980s. Matt was also the Sector Manager for Energy & Materials in his last position at NASA where he worked for 31 years. He's been a co-founder in seven technology startups; and provided R&D and engineering support to many organizations. Matt has three patents and more than 50 publications including the Cryogenic Fluid Management series. He also teaches courses, workshops, and webinars on liquid hydrogen systems.

Tuesday, January 28, 2025

Cryogenic Hydrogen Thermal Design Options

A key storage consideration for liquid hydrogen is the vaporization rate caused by environmental heat loads, often referred to as boil-off. The above graphic shows some of the established methods for mitigating or eliminating boil-off categorized by the input power required [1].

Passive techniques require no input power and include design and material selection for insulation, structural supports, piping, and other tank interfaces that minimize heat transfer to the inner tank wall. Hybrid methods require some input power for valve actuation, mixers, pumps, or other components to reduce the boil-off rate.

Finally, active techniques require power input for cryo-refrigeration or densification processes. Depending on the concept of operation for the system, application of the appropriate combination of these methods can minimize or eliminate boil-off losses [2].