Throughout the expanding realm of existence we know as the universe, hydrogen occupies around 73% of all visible mass. At this unparalleled abundance, this element is an obvious choice to generate energy. However, there are some hurdles with hydrogen gas vehicles.
An American National Standard and National Standard of Canada, CSA/ANSI HGV 2-2021: Compressed Hydrogen Gas Vehicle Fuel Containers, addresses one such issue: storing compressed hydrogen gas on the vehicle that they propel.
The Advantages of Hydrogen Vehicles
With a propulsion similar to that of electric vehicles, energy stored as hydrogen in fuel cell electric vehicles (FCEVs) is converted to electricity by the fuel cell. However, unlike electric vehicles, which recharge by plugging in, fuel cell electric vehicles can fuel in less than 4 minutes. Much like conventional vehicles, they have a driving range of over 300 miles.
Hydrogen (H2) is considered an alternative fuel under the Energy Policy Act of 1992. Such unconventional vehicles appeal to consumers due to their benefits in combating pollution and anthropogenic climate change. Gasoline and diesel vehicles emit carbon dioxide (and other hydrocarbons), nitrogen oxide, and particulate matter. In fact, a typical passenger vehicle emits about 4.6 metric tons of carbon dioxide each year. One driver, operating one vehicle, is harmless to the entire planet’s atmosphere. However, when simultaneously polluting this shared commons—transportation accounts for 28% of all US greenhouse gas (GHG) emissions—vehicles play a major role among the various industrial sources driving climate change.
Hydrogen-powered vehicles, alternatively, emit no harmful substances, only water and warm air. While these vehicles emit no carbon dioxide, water vapor is a greenhouse gas—the most abundant GHG in the atmosphere, in fact. However, the H2O concentrations in the earth’s air derive from climate feedbacks and are not the direct result of industrial emissions. Furthermore, while the operation of hydrogen gas vehicles emits no hydrocarbons, the act of separating hydrogen from its natural compounds can lead to harmful emissions.
This is another hurdle to overcome with FCEVs. Natural hydrogen does appear in drillable wells, but it is often manufactured. Pure hydrogen needs to be separated from the abundant molecular compounds in which naturally appears (in water, hydrocarbons, and other organic matter). Steam reforming or electrolysis typically accomplish this goal.
Despite these challenges, the hydrogen market is projected to reach $207 billion by 2026. With this potential, it’s no surprise that hydrogen is often speculated as a potential disruptor to the energy industry.
About CSA/ANSI HGV 2-2021
Because hydrogen has a low volumetric energy density, it’s stored onboard a vehicle as a compressed gas to achieve the driving range of conventional vehicles. With this, various concerns are present relating to the material and integrity of the containers. CSA/ANSI HGV 2-2021 addresses this extensively by covering service conditions, material qualification tests, manufacturing processes, inspection requirements, batch testing, impact testing, stress analysis, container wall thickness, and other considerations.
Overall, CSA/ANSI HGV 2-2021 contains requirements for the material, design, manufacture, marking, and testing of serially produced, refillable Type HGV2 containers intended only for the storage of compressed hydrogen gas for on-road vehicle operation.
According to the standard, these containers:
- are to be permanently attached to the vehicle
- have a capacity of up to 1000 L (35.4 ft3) water capacity
- have a nominal working pressure that does not exceed 70 MPa
Changes to CSA/ANSI HGV 2-2021
Prepared by the HGV 2 Subcommittee on Fuel Containers for Compressed Hydrogen Vehicles, CSA/ANSI HGV 2-2021 revises the previous edition of the standard from 2014. In total, it underwent several changes, including the:
- distinction between category A and B containers (category B containers are intended to be further qualified in accordance with the UN GTR No. 13 for hydrogen and fuel cell vehicles with a gross vehicle mass of 4536 kg or less, or with SAE J2579)
- inclusion of conformable container requirements
- addition of mechanical tests
CSA/ANSI HGV 2-2021: Compressed Hydrogen Gas Vehicle Fuel Containers is available on the ANSI Webstore.