https://newatlas.com/aircraft/universal-hydrogen-airliners-pods/

Universal Hydrogen to convert 15-plus airliners to run on H2 pods

By Loz Blain
July 19, 2021

Universal Hydrogen is building interchangeable hydrogen pods for fuel-cell
airliners, and has signed deals with three airlines to convert 21 aircraft
to hydrogen-electric
Universal Hydrogen is building interchangeable hydrogen pods for fuel-cell
airliners, and has signed deals with three airlines to convert 21 aircraft
to hydrogen-electricUniversal Hydrogen
VIEW 2 IMAGES

Universal Hydrogen has signed letters of intent with three airlines to
convert more than 15 regional airliners to run on green hydrogen. The
company is developing conversion kits that accept interchangeable hydrogen
modules that work like recyclable coffee pods.

The aircraft in question will be De Havilland Canada DHC8-Q300, or Dash-8.
Universal Hydrogen has been working on a Dash-8 kit for some time now
https://newatlas.com/aircraft/universal-hydrogen-magnix-largest-hydrogen-plane/?itm_source=newatlas&itm_medium=article-body
, replacing the standard plane's Pratt & Whitney turboprops and jet fuel
tanks with a pair of two-megawatt Magnix electric motors, a hefty fuel cell
and a modular hydrogen fuel system whose tanks pop in and out like great big
seven-foot (2 m) long Nespresso pods. That's a comparison the company seems
keep to push, as evidenced by this recent Reuters interview.
https://www.reuters.com/business/aerospace-defense/exclusive-universal-hydrogen-zero-carbon-plane-deals-with-icelandair-others-2021-07-13/

The hydrogen conversion takes up some space – the Dash-8's cabin shrinks
from 56 seats to 40 – but these planes will offer a groundbreaking
emissions-free travel service up to range figures around 460 miles (740 km).
That covers about 75 percent of current routes flown by Dash-8s, says
Universal, and they could extend that to 95 percent when they get liquid
hydrogen figured out.

The company has signed letters of intent with Spain's Air Nostrum for 11
aircraft
https://www.businesswire.com/news/home/20210714005532/en/Universal-Hydrogen-and-Air-Nostrum-Sign-LOI-for-Hydrogen-Powered-Turboprops
, Ravn Alaska for 5 aircraft
https://www.businesswire.com/news/home/20210714005543/en/Universal-Hydrogen-and-Ravn-Alaska-Sign-LOI-for-Hydrogen-Powered-Dash-8s-as-Airline-Expands-Efforts-Towards-Carbon-Free-Aircraft-Network
, and Icelandair Group
https://www.businesswire.com/news/home/20210714005516/en/Universal-Hydrogen-and-Icelandair-Group-Sign-LOI-for-Hydrogen-Powered-Dash-8-Fleet-to-Eliminate-Carbon-Emissions
for an unspecified "fleet" of planes. All these deals would also establish
Universal as the hydrogen pod service provider.

A De Havilland Canada DCH-8 (Dash-8) Q300 like the aircraft above will be
retrofitted with a hydrogen fuel cell powertrain to become the world's
largest hydrogen aircraft
A De Havilland Canada DCH-8 (Dash-8) Q300 like the aircraft above will be
retrofitted with a hydrogen fuel cell powertrain to become the world's
largest hydrogen aircraftBiggerben @ Wikimedia Commons
No terms for the deals have been announced, and while this does seem like
good news for clean aviation, evtol.com has found some reasons to pump the
brakes on the hype train here. LOIs are preliminary, non-binding and often
highly provisional.

And one of the companies involved, Ravn Alaska, is only a year out of
bankruptcy, and its new owners have also signed a LOI for 50 electric STOL
aircraft from Airflow, and told employees in a leaked briefing that it was
also planning to run a low-cost carrier using Boeing 757s. Ambition clearly
isn't a problem here, but delivering on all these plans will require
enormous funds.

Still, if these plans come to fruition, and Universal does manage to "bring
hydrogen-powered Dash-8s to our skies in the next several years," as
Icelandair President and CEO Nils Bogason hopes, it would certainly seem
like an inflection point in this very exciting new technology, and there
will certainly be passengers ready to choose a greener option.

Source: Universal Hydroge: https://www.hydrogen.aero/
===================================================

https://www.energy.gov/eere/fuelcells/hydrogen-storage

Hydrogen Storage
Hydrogen and Fuel Cell Technologies Office
Office of Energy Efficiency & Renewable Energy Hydrogen Storage
The Hydrogen and Fuel Cell Technologies Office (HFTO) is developing onboard
automotive hydrogen storage systems that allow for a driving range of more
than 300 miles while meeting cost, safety, and performance requirements.

Why Study Hydrogen Storage
Hydrogen storage is a key enabling technology for the advancement of
hydrogen and fuel cell technologies in applications including stationary
power, portable power, and transportation. Hydrogen has the highest energy
per mass of any fuel; however, its low ambient temperature density results
in a low energy per unit volume, therefore requiring the development of
advanced storage methods that have potential for higher energy density.

How Hydrogen Storage Works

Hydrogen can be stored physically as either a gas or a liquid. Storage of
hydrogen as a gas typically requires high-pressure tanks (350–700 bar
[5,000–10,000 psi] tank pressure). Storage of hydrogen as a liquid requires
cryogenic temperatures because the boiling point of hydrogen at one
atmosphere pressure is -252.8°C. Hydrogen can also be stored on the surfaces
of solids (by adsorption) or within solids (by absorption).

Research and Development Goals
HFTO conducts research and development activities to advance hydrogen
storage systems technology and develop novel hydrogen storage materials. The
goal is to provide adequate hydrogen storage to meet the U.S. Department of
Energy (DOE) hydrogen storage targets for onboard light-duty vehicle,
material-handling equipment, and portable power applications. By 2020, HFTO
aims to develop and verify onboard automotive hydrogen storage systems
achieving targets that will allow hydrogen-fueled vehicle platforms to meet
customer performance expectations for range, passenger and cargo space,
refueling time, and overall vehicle performance. Specific system targets
include the following:

1.5 kWh/kg system (4.5 wt.% hydrogen)
1.0 kWh/L system (0.030 kg hydrogen/L)
$10/kWh ($333/kg stored hydrogen capacity).
The collaborative Hydrogen Storage Engineering Center of Excellence conducts
analysis activities to determine the current status of materials-based
storage system technologies.

The Hydrogen Materials—Advanced Research Consortium (HyMARC) conducts
foundational research to understand the interaction of hydrogen with
materials in relation to the formation and release of hydrogen from hydrogen
storage materials.

Related links provide details about DOE-funded hydrogen storage activities.

Challenges

The 2010 U.S. light-duty vehicle sales distribution by driving range.

Comparison of specific energy (energy per mass or gravimetric density) and
energy density (energy per volume or volumetric density) for several fuels
based on lower heating values.

High density hydrogen storage is a challenge for stationary and portable
applications and remains a significant challenge for transportation
applications. Presently available storage options typically require
large-volume systems that store hydrogen in gaseous form. This is less of an
issue for stationary applications, where the footprint of compressed gas
tanks may be less critical.

However, fuel-cell-powered vehicles require enough hydrogen to provide a
driving range of more than 300 miles with the ability to quickly and easily
refuel the vehicle. While some light-duty hydrogen fuel cell electric
vehicles (FCEVs) that are capable of this range have emerged onto the
market, these vehicles will rely on compressed gas onboard storage using
large-volume, high-pressure composite vessels. The required large storage
volumes may have less impact for larger vehicles, but providing sufficient
hydrogen storage across all light-duty platforms remains a challenge. The
importance of the 300-mile-range goal can be appreciated by looking at the
sales distribution by range chart on this page, which shows that most
vehicles sold today are capable of exceeding this minimum.

On a mass basis, hydrogen has nearly three times the energy content of
gasoline—120 MJ/kg for hydrogen versus 44 MJ/kg for gasoline. On a volume
basis, however, the situation is reversed; liquid hydrogen has a density of
8 MJ/L whereas gasoline has a density of 32 MJ/L, as shown in the figure
comparing energy densities of fuels based on lower heating values. Onboard
hydrogen storage capacities of 5–13 kg hydrogen will be required to meet the
driving range for the full range of light-duty vehicle platforms.

To overcome these challenges HFTO is pursuing two strategic pathways,
targeting both near-term and long-term solutions. The near-term pathway
focuses on compressed gas storage, using advanced pressure vessels made of
fiber reinforced composites that are capable of reaching 700 bar pressure,
with a major emphasis on system cost reduction. The long-term pathway
focuses on both (1) cold or cryo-compressed hydrogen storage, where
increased hydrogen density and insulated pressure vessels may allow for DOE
targets to be met and (2) materials-based hydrogen storage technologies,
including sorbents, chemical hydrogen storage materials, and metal hydrides,
with properties having potential to meet DOE hydrogen storage targets.