Sunday, March 19, 2023

Pre-Test Results for April 2023 LH2 Era™ Webinar Session 1: Introduction to Hydrogen


LinkedIn Poll Results and Correct Answers

Below are the pre-test questions for April's session along with the LinkedIn poll results and correct answers. Follow me on LinkedIn if you'd like to test your hydrogen knowledge and see how others vote in real time.

Questions 1 and 2:


Gaseous hydrogen was the first fuel used for the pioneering work in jet engine research in the 1930's. The first successful liquid hydrogen fueled jet aircraft flights were done in the 1950's. A liquid hydrogen fueled jet engine with an afterburner was also successfully developed and ground tested in the 1950's. More details can be found here:

In the 1960's, liquid hydrogen made it's operational rocket debut in the Centaur upper stage and subsequently became the workhorse propellant for many launch vehicles (including the space shuttle). Modern operational launch systems using liquid hydrogen besides Centaur and other upper stages include: NASA's new Space Launch System, the Ariane 5 (and soon 6), the JAXA H3, and several variants and stages of the Long March rocket family.

As a result, the space industry has evolved the requisite technology and operations required for large scale liquid hydrogen systems over the past six decades. Meanwhile, aviation is returning to its (sometimes forgotten) roots to decarbonize air travel and improve performance using hydrogen.

Questions 3:


Liquid hydrogen (LH2) at 1 bar saturated conditions has a density of 71 kg/m^3. Compressed hydrogen gas (GH2) at 700 bar and ambient temperature (27 C) has density of 39 kg/m^3. So LH2 has nearly double the density of compressed GH2 at these conditions. More information can be found here:

Extra credit for the beer at any bar votes...

Question 4:


Only a couple of years ago the correct answer would have been the large spherical liquid hydrogen dewar tank used for the NASA shuttle launches for decades which is ~3200 cubic meters. And hopefully in the not distant future the answer will be the newly designed (but not yet operational) large shipping dewar tanks of ~20000 cubic meters.

But as of now, the correct answer is the recently commissioned dewar tank at NASA KSC supporting the Artemis program (~4700 cubic meters). This link has some information on it and the role I played in it's design:

And thank you for the dad joke votes...

Question 5:


Any answer is arguably correct on this question (see: Generating hydrogen by water electrolysis produces oxygen as a "byproduct" which can be released to ambient air, used locally, or stored for later use or sale.

When hydrogen is used in a fuel cell or combusted, significant quantities of water are produced. With proper material selection and handling, the water can be used for drinking, agriculture, and many other purposes.

Waterworld was a post-apocalyptic 1995 movie premised on the melting of the polar regions due to global warming. This future (hopefully) fictional world is completely covered by oceans, and Kevin Costner's character has gills. Basically, Mad Max with boats instead of all-terrain vehicles....

Question 6:


Any answer is correct on this question, but "all of the above" is the most correct (see: The wisdom of the crowd prevails this time.

Most people already know that electrolysis of water produces hydrogen. In addition to fresh water, it is feasible to use seawater, waste water, and even urine (animal or human) with the appropriate processing and design. Waste biomass from agriculture, livestock, and other sources can also be processed to extract hydrogen.

Likewise with methane (the primary constituent in natural gas), coal, and other hydrocarbons, although carbon capture is a key consideration. Cows and other ruminant animals are prodigious producers of methane (from both ends). As a soymilk drinking vegan most of the time, I say free all the cows but harvest their emissions! A win-win for both species.

Question 7:


The correct answer to this question hinges on the interpretation of "at scale". It was intended to mean commercially available at a physical equipment scale that is competitive with legacy options, and has already been deployed in operational systems. Based on that meaning of at scale, both fuel cells and hydrogen turbines for power generation are correct.

A system architecture take on it can be found here:

For those who interpreted at scale to mean fully adopted as the dominant solution, that hasn't occurred yet in most industry sectors. Accelerating that transition is paramount to addressing the existential threat of continued fossil fuel usage.

(According to the "Back to the Future" movies, Dr. Emmett Brown's flux capacitor runs on various fuels including garbage. Perhaps hydrogen will be in the mix too. Guess we will have to wait until the future arrives to find out...)

Question 8:


My answer to this question is none. Below is the reason why, and more can be found here: It would be interesting to hear others' thoughts in the comments about which specific technology gaps they believe exist.

NASA, where I spent most of my career, defines a technology gap as the difference between a capability needed to *enable* a future mission and the current state-of-the-art. In contrast, an *enhancing* technology improves some aspect of a mission but is not required for it to be fulfilled. 

Based on that mental model, there are no existing technology gaps for the use of liquid hydrogen as a replacement for fossil fuels. That said, there are certainly a plethora of enhancing technologies that could improve the performance and economics (e.g., new materials, better cryocoolers, improved insulation, etc.).

However, all the technology necessary to implement liquid hydrogen systems to replace fossil fuels already exists. Capital investments, domain knowledge, and good engineering are what's needed. Favorable public policy and regulations also helps to accelerate the transition.

Homework and Upcoming Session

If you didn't get a chance to do the reading assignment, it can be accessed here: The Infinity Fuel for a Sustainable Future. And the viewing assignment is available here: Online Resources for the LH2 Era™ Webinar Series

To participate in next month's pre-test poll, follow my posts on LinkedIn. And to get details and register for the next LH2 Era™ webinar visit HERE.

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 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 cofounder in seven technology based start-ups; and provided R&D and engineering support to hundreds of organizations. Matt has three patents and more than 50 publications including the Cryogenic Fluid Management report series. He also leads the LH2 Era™ Webinar SeriesMore about Matt can be found on his LinkedIn page.