FAQs - Hydrogen
Is hydrogen flammable or explosive?
Yes, hydrogen is highly flammable and can be explosive in air. But it's not inherently more dangerous than petrol or natural gas. With proper engineering controls and safety design, hydrogen can be handled safely in vehicles, refueling stations, and industrial processes. It disperses quickly, making outdoor use generally safer than in enclosed spaces.
Hydrogen is often called the fuel of the future — and for good reason. It leaves no carbon footprint when used as fuel and can be produced in many sustainable ways, including from water (green), natural gas (blue or grey), nuclear (pink), solar (yellow), and biomass (orange), to name a few.
While technical and economic hurdles remain, hydrogen is expected to play a major role in our future energy systems. Here's a breakdown of common questions and answers to clear up misconceptions:
IS HYDROGEN FUEL MORE DANGEROUS THAN PETROL/GASOLINE/NAPHTHA?
No. Hydrogen fuel systems in vehicles and at refueling stations are designed with strict safety standards and multiple layers of protection to keep the driver and public safe. They are no more dangerous than current fuels used in internal combustion engines when managed correctly.
IS HYDROGEN TOXIC OR POISONOUS?
No. Hydrogen is not toxic. It’s the simplest element in the universe, made of just one proton and one electron. Because of this, it doesn’t have the complex chemistry needed to be poisonous.
Is hydrogen combustible?
The classification of ‘flammability’ and ‘combustibility’ relate to the flash point temperature of the material. Flammable materials have a low flash point (<100F) and thus are easy to ignite. Combustible materials have a higher flash point (>100F) and thus are harder to ignite.
Therefore as hydrogen is easier to ignite, it is classified as a flammable material rather than as a combustible material.
IS HYDROGEN A SAFETY HAZARD?
Yes – but so are all flammable gases. Hydrogen has a wide flammability range and ignites easily, but with proper engineering controls for generation, storage, and transport, it can be managed safely — similar to natural gas or other fuels.
See blog: https://www.alpha-systems.com.au/blog/hydrogen-safety-same-risks-different-rulesnbsp
IS HYDROGEN GAS EXPLOSIVE?
Yes, it can be. A hydrogen-air mixture is highly explosive. However, hydrogen is extremely light (low specific gravity) and disperses quickly in open air, making it less likely to form dangerous clouds outdoors. Enclosed spaces do present greater risks, and that's where specialist hydrogen safety engineers are essential.
HOW DO GREEN METHANOL AND AMMONIA RELATE TO HYDROGEN?
Hydrogen is difficult to store and transport. Converting it into methanol or ammonia makes handling much easier and safer. These fuels can be used directly or reconverted into hydrogen when needed.
CAN HYDROGEN SAFETY BE ASSESSED THE SAME WAY AS METHANE/LNG?
In a nutshell - no. Hydrogen does not behave the same as methane / LNG both inside the process and upon release. Hydrogen’s chemical and reactive properties introduce a unique set of challenges in keeping it safe. Having said that, hydrogen as a fuel is not new and there has, and continues to be, a lot of published research in hydrogen safety. Additionally, there are formally trained specialist hydrogen safety engineers to ensure that the generation, storage, transportation, and use of hydrogen is safe.
What are the key differences between hydrogen and methane/LNG?
Specific Gravity: Hydrogen is much lighter (0.07) compared to methane (0.5), causing it to rise quickly.
Flammability Range: Hydrogen has a broader range, increasing ignition likelihood.
Thermal Expansion: Hydrogen expands more upon vaporization (1:847) than LNG (1:600), impacting storage design.
Material Interaction: Hydrogen can permeate materials more easily allowing it to escape and cause embrittlement in metals.
Flame Characteristics: Hydrogen burns with an almost invisible flame, emitting less radiant heat.
IF HYDROGEN IS THE FUEL OF THE FUTURE, WHY ARE COMPANIES ABANDONING HYDROGEN PROJECTS?
Not because of safety. Many projects are paused or shelved due to:
High current technology development, production and infrastructure costs
Current low and uncertain demand
Uncertainty in regulatory support and requirements
As these factors evolve, many in the industry expect hydrogen to make a strong comeback.
What are the key differences between hydrogen and methane/LNG?
Specific Gravity: Hydrogen is much lighter (0.07) compared to methane (0.5), causing it to rise quickly.
Flammability Range: Hydrogen has a broader range, increasing ignition likelihood.
Thermal Expansion: Hydrogen expands more upon vaporization (1:847) than LNG (1:600), impacting storage design.
Material Interaction: Hydrogen can permeate materials more easily allowing it to escape and cause embrittlement in metals.
Flame Characteristics: Hydrogen burns with an almost invisible flame, emitting less radiant heat.
How does hydrogen permeability and embrittlement affect infrastructure?
Hydrogen embrittlement weakens certain metals, leading to potential leaks or failures. Design strategies must account for this by selecting appropriate materials and implementing regular inspections. The high permeability of hydrogen enables for accumulation of flammable clouds in enclosed spaces.
Hydrogen's low molecular density and high diffusivity make it prone to leakage. Its expansive nature upon vaporisation and potential for embrittlement require specialised storage solutions and materials.
Why is hydrogen storage more challenging than other fuels?
Hydrogen's low molecular density and high diffusivity make it prone to leakage. Its expansive nature upon vaporisation and potential for embrittlement require specialised storage solutions and materials.
What considerations are there for hydrogen in power generation?
While hydrogen can reduce carbon footprints in power generation, it introduces challenges like different combustion properties, flame detection difficulties, and material compatibility issues. Retrofitting existing systems requires comprehensive engineering safety assessments.
How does hydrogen modelling differ from other fuels?
Standard models, like the Chamberlain equation used for methane, often overestimate hydrogen flame lengths. Hydrogen's unique properties necessitate specialised modelling approaches to accurately predict behaviour.
Green methanol is produced by combining green hydrogen with captured carbon dioxide. It offers a more stable and less flammable alternative for hydrogen storage and transport, addressing some of hydrogen's logistical challenges.