We are asked many questions about hydrogen as a fuel. We hope to answer them for you on this page. Before you start you need to know, that when referring to hydrogen fuel in combustion for cooking, heating and hot water, or for use in hydrogen fuel cells, that hydrogen is hydrogen gas (H2). When comparing gases such as hydrogen to other gases, the measurement, normal metres cubed (Nm3) is used.
Liquid hydrogen (LH2) does not naturally occur on Earth. Hydrogen is liquefied for medical, scientific, aerospace, and industrial purposes, along with ease of shipping. When comparing liquid hydrogen to other liquid fuels, all liquid fuels are compared to one another in kilograms (kg).
The potential energy and the characteristic properties of liquid hydrogen (LH2) and hydrogen gas (H2) are worlds apart. Therefore, the safety considerations for both will be different.
What is a hydrogen battery?
This is one of the best questions regarding storing hydrogen. There are two ways to look at hydrogen batteries; there are hydrogen batteries that extract, store and convert hydrogen to electricity, and there are hydrogen batteries that only store hydrogen.
Hydrogen batteries that extract, store, and convert
These batteries consist of an electrolyser that use electricity to split water into H2 and O2. The H2 is stored in a canister or in high-strength hydrogen storage cylinders, onsite. When electricity is required to operate appliances, the H2 is recombined with O2 in a hydrogen fuel cell. If the electricity is derived from a renewable source such as solar, wind or hydro, these hydrogen batteries are known as renewable energy storage systems or green energy batteries.
The hydrogen fuel cells used in these batteries use a Polymer Electrolyte Membrane, also known as a Proton Exchange Membrane (PEM) fuel cell. In this fuel cell, the protons from the stored hydrogen pass through a membrane to the oxygen on the other side. The electrons from the hydrogen pass around to the other side of the membrane through a conductive circuit, creating an electrical current, water and heat. The electric current can be used to power appliances in your home.
To see how a hydrogen battery works or learn more about hydrogen battery packs, checkout the LAVO Hydrogen Technology Battery System on our resources page.
Storage-only hydrogen batteries
Hydrogen is an energy carrier and can easily be converted into electric power and heat. Therefore, a hydrogen battery is any system that can store hydrogen for short or long periods of time. Local gas networks, interstate transmission pipelines, gas storage cylinders and metal hydride canisters are all basic types of hydrogen batteries. The hydrogen stored in these containers can be either green, blue, grey, or brown.
Electricity transmission and distribution wires cannot store electricity, and the electrons they carry must be used instantly or curtailed (dumped to earth). The hydrogen held in storage containers can be held almost indefinitely, until needed. A gas distribution network can typically store enough hydrogen gas to supply its customers for days.
If you would like to know more about the effects of hydrogen on gas pipes and appliances you can read more here – Will hydrogen destroy gas pipes and appliances in my house or business?
Can I make hydrogen at home?
Put simply, the answer is, “Yes, and it can be used in numerous ways.”
Initially, hydrogen use in our homes will commence with onsite production of pure hydrogen gas via water electrolysis, where electricity is used to split pure water into H2 and O2. This hydrogen is stored in canisters or cylinders, for later use in hydrogen fuel cells to power lights and appliances. Think of it like a home hydrogen battery connected to PV or other renewable generation systems, for your home. As gas appliances evolve, this hydrogen gas will likely be used for cooking and possibly heating and hot water.
Gas network operators will also introduce blends of hydrogen gas into the natural gas networks, starting quite low, working towards 100%. Because this hydrogen gas is not pure, it can only be used for combusting in hot water systems, heaters, and cookers. If the networks’ operators can get close to blends of 98% hydrogen, it can be used in PEM hydrogen fuel cells to produce electricity, too.
Other technologies to create electricity and heat from blended hydrogen gas and natural gas exist, but are not common.
To see how a hydrogen battery works, and how it can provide reliable green energy in your home or learn more about hydrogen battery packs. Checkout the LAVO Home Hydrogen Battery System on our resources page.
Can I use hydrogen in my business?
The Answer is, “Yes”.
Initially, hydrogen use for business will commence with onsite production of pure hydrogen gas via water electrolysis. This will be stored in canisters or cylinders, for later use in hydrogen fuel cells to power lights, heating and cooling systems and computers. Think of it like a hydrogen battery connected to PV or other renewable generation systems, for your business. As gas appliances evolve, this hydrogen gas will likely be used for cooking and possibly heating and hot water.
Hydrogen battery storage can provide a secure and stable source of backup power for critical infrastructure such as communications, medical and emergency services. Hydrogen batteries can also be used as a cheaper alternative to diesel generators when providing a stable power supply for remote communities and resorts.
Gas network operators will also introduce blends of hydrogen gas into the natural gas networks, starting quite low, working towards 100%. Because this hydrogen gas is not pure, it can only be used for combusting in hot water systems, heaters, and cookers. If the networks’ operators can get close to blends of 98% hydrogen, it can be used in PEM hydrogen fuel cells to produce electricity, too.
Other fuel cell technologies to create electricity and heat from blended hydrogen gas and natural gas exist but are not very common.
To see how a hydrogen battery works and how it could benefit your business with green reliable energy or learn more about hydrogen battery packs. Checkout the LAVO Commercial Hydrogen Battery System on our resources page.
Hydrogen safety
Is hydrogen gas safe to use in my home or business when compared to other commonly used fuel gases?
Hydrogen safety is one of the most common concerns about transition to a hydrogen future.
The simple answer is, ”Yes – hydrogen gas is safe if handled and stored correctly, and used in a hydrogen fuel cell.”
While we use and combust 100% hydrogen in industry, we are not yet at the stage where 100% hydrogen gas can be safely combusted in appliances like hot water systems, heaters, or cookers for our homes and businesses.
In the meantime, natural gas network operators will be introducing hydrogen gas into the gas networks in blends of up to 14%. This has already been established as a safe ratio of hydrogen gas to natural gas. Australians will also be creating our own green hydrogen via water electrolysis, storing it and reusing it in hydrogen fuel cells to make electricity in our own homes. These are called hydrogen batteries. This technology is well developed, and hydrogen production, storage and fuel cell technologies are extremely safe.
Are hydrogen batteries safe to use in my home or business when compared to lithium-ion batteries?
The answer is, “Yes – however, both Li-ion and hydrogen batteries do not come without their own risks.”
Hydrogen batteries store pure hydrogen in cylinders or in canisters filled with a metal hydride. Like all gas storage systems, the safest place for a hydrogen battery is outdoors. Hydrogen has unique combustion characteristics that give it the NFPA 704’s highest rating of 4 on the flammability scale. However, hydrogen has other characteristics that make it safer than many other liquid or gas fuels.
Lithium-ion batteries catch fire, and in some cases, they do not need to suffer external damage to do so. These fires are hard to extinguish and burn extremely hot. When damaged lithium-ion batteries have three main safety concerns. These are thermal runaway, stranded energy, and battery reignition. The energy remaining in a damaged high-voltage lithium-ion battery is known as stranded energy, and according to the NTSB, poses a risk of electric shock and creates the potential for thermal runaway that can result in battery reignition and fire.
Did hydrogen help start the fire in the Hindenburg?
The answer is, “Probably, but the outcomes could have been a lot worse.”
It is likely that a small spark (possibly static electricity) ignited the hydrogen gas contained in the Hindenburg. This hydrogen accident sadly caused the death of 13 passengers, 22 crew members and one man on the ground. 62 of the 97 people onboard the Hindenburg survived. Apart from the one man on the ground who was killed, there were dozens of people awaiting the blimp’s arrival who were not harmed.
The majority survived the Hindenburg disaster because the unburnt hydrogen gas in the blimp rose rapidly, ignited, was consumed by flames, and did not produce a lot of radiant heat. The fuel in fire that burnt after the Hindenburg hit the ground was diesel, furniture, fabric, glue, and paint.
If the Hindenburg had been filled with natural gas or LPG, it is likely that there would have been no survivors onboard or on the ground. In an LPG explosion, the unburnt gas would have dropped towards the ground, spreading out until reaching the right air-to-gas ratio for combustion, and the resulting flames would have released 7 times the amount of energy released by the burning of hydrogen gas that day.
This does not mean we should fear the use of hydrogen gas. Hydrogen gas is odourless, colourless and the flame is nearly invisible to the naked eye in daylight. Hydrogen requires a small amount of energy to ignite, hydrogen fires give off low radiant heat, and hydrogen gas will ignite in concentrations between 4% and 75% in air.
Are there dangers associated with hydrogen fuel?
The answer is, “Yes, because of hydrogen’s unique characteristics.”
Hydrogen takes less energy to ignite, it burns ten times faster than natural gas, and it has the widest air-to-gas ratio for combustion to occur. Hydrogen is colourless and odorless. Therefore, 100% hydrogen gas leaks are more difficult to detect without specific gas leak detection equipment. A hydrogen flame is barely visible to naked eye in daylight, and it does not produce a lot of radiant heat.
However, there are numerous and varying dangers associated with all fuels, liquids, and gases, just as there are many dangers associated with electricity, if not handled properly.
The safe use of any fuel, liquid or gas should focus on preventing situations where the three combustion factors – ignition source (spark or heat), oxidant (air), and fuel—are not controlled. A thorough understanding of a fuel’s properties, with appropriate engineering controls and established guidelines, ensures the safe handling and use of that fuel.
Is hydrogen gas safe to use?
The answer is, “Definitely yes.”
Hydrogen gas’ properties make it safer to handle and use than many other fuel gases and liquid fuels commonly used today. For example, hydrogen is non-toxic. Hydrogen gas is 14 times lighter than air, and hydrogen gas molecules bond rapidly with other elements. Therefore, it dissipates rapidly when it is released, allowing for relatively quick dispersal if a leak occurs. LPG is 1.5 times heavier than air, will likely accumulate, and does not dissipate rapidly. Natural gas is 1.5 times lighter than air and does not dissipate or disperse as fast as hydrogen gas.
Hydrogen has a high autoignition/spontaneous ignition temperature (SIT) of 557°C. The SIT of propane is 490°C and the SIT of petrol is 232°C. Hydrogen has a high flame speed of 300 cm/s. Methane has a flame speed of 30cm/s. Therefore, a hydrogen fire will burn out much quicker than a methane fire.
Hydrogen gas properties require additional engineering controls to ensure its safe use. Specifically, hydrogen gas has a wide range of flammable concentrations in air and lower ignition energy than gasoline or natural gas, which means a spark can ignite it more easily. Consequently, adequate ventilation and leak detection are important.
In many cases, the consequences of uncontrolled ignition of hydrogen gas are less costly than when compared to LPG or natural gas. LPG contains 7 times, and natural gas 3 times, the heat value of hydrogen gas. The consequences of igniting liquid hydrogen is a different matter. 1kg of liquid hydrogen contains 3.5 times the potential energy of 1kg of gasoline.
All fuels – liquid or gas by nature, have some degree of danger associated with them. The safe use of any fuel should focus on preventing situations where the three combustion factors – ignition source (spark or heat), oxidant (air), and fuel – are not controlled. A thorough understanding of a fuel’s properties, with appropriate engineering controls and established guidelines ensures the safe handling and use of that fuel.
Hydrogen gas is odourless, colourless and the flame is nearly invisible in daylight to the naked eye, and only requires a small amount of energy to ignite. Hydrogen fires give off low radiant heat and hydrogen gas will ignite in concentrations between 4% and 75% in air. Hydrogen also has a high flame speed – meaning it will burn out quicker. Therefore, we should treat hydrogen gas like all other fuel gases: with caution.
Will hydrogen destroy gas pipes and appliances in my house or business?
The answer is, “Not likely, in most homes and businesses”.
Gas pressure, temperature, purity, yield strength, composition, and presence of existing flaws, will influence hydrogen’s compatibility with certain materials.
The gas pipes on the downstream side of consumer gas meter/piping, and inside most Australian homes and commercial premises are quite new and made of copper or a polyethylene composite. These are quite compatible with hydrogen. In some of Australia’s older cities, the gas pipes may be steel and may not be suitable to carry high hydrogen blends.
Since the 1870’s, a significant amount of research has been conducted on hydrogen embrittlement. There are numerous scientific and engineering articles written about hydrogen embrittlement and its prevention in pipelines and other materials.
Testing by Evoenergy in Canberra, in the Australian Capital Territory (ACT), has found that pure hydrogen is not compatible with some seals and diaphragms found in gas meters, gas regulators, and some gas appliances. However, because hydrogen will initially be introduced into consumer piping systems as a blend of up to 14%, this will not cause damage to existing seals, diaphragms, or appliance components.
Around the world, gas network operators are studying the effects of hydrogen on piping systems and appliances. Their work will ensure that the transition to hydrogen is safe for everyone, and they are sharing their knowledge with other gas network operators and appliance manufacturers.
Gas consumer piping systems typically operate at extremely low pressures, between 1.5kPa and 7kPa. The gas distribution network and the inlet service between the distribution network, and the consumer gas meter in the Australian Capital Territory, is operated by Evoenergy. They operate at a pressure of 210kPa. They are a combination of polyethylene and nylon. The main transmission pipeline supplying gas to the ACT’s gas distribution network is called the Eastern Gas Pipeline.
It operates at pressures up to 17,000kPa. It is a combination of materials, including steel.
For the most part, where fuel gases for domestic and commercial premises are concerned, operators of older metallic gas networks, large gas transmission pipelines, and owners of steel consumer piping systems, are the only ones who need to be very concerned about the effects of hydrogen leaks and embrittlement on pipelines.
Will it cost more to transition existing gas appliances to hydrogen gas appliances?
The answer is, “No, but it is extremely likely that you will need to change your gas appliances sometime between 2030 and 2040.”
Natural gas is made mostly of methane (CH4 ). Methane is a molecule of four hydrogen atoms and one carbon atom. Initially, gas network operators will introduce hydrogen gas to the natural gas networks as a blend of up to 14% hydrogen gas. Your existing appliances should not be affected by this blend.
Eventually the gas network operators will move to blends closer to 50%, and later, 100%. It is likely that by the time a 50% blend occurs, gas appliance manufacturers will be producing gas appliances that can take blends of 50% to 100% hydrogen gas. Some minor changes in gas pressure and jet sizes may need to be made to gas appliances when making the final transition to 100% hydrogen gas.
CO2 reductions from transition to hydrogen
How will a transition to 100% hydrogen effect CO2 emissions from the gas networks?
The answer is, “Initially, not by much.”
Decarbonising the gas networks will not happen overnight. Hydrogen gas has one third of the heat energy value of natural gas. 3 normal metres cubed (Nm3) of hydrogen will be required to do the same work as 1Nm3 of natural gas. Therefore, to provide the same amount of energy to customers, a blend of 10% hydrogen will only result in a 3.3% reduction in CO2 emissions. It is only when the gas networks carry 100% hydrogen, will they be emissions free.
| Volume of Green H2 injected into the natural gas networks | 0% | 0% | + 10% | + 14% | + 50% | + 100% |
| Total CO2 emissions reduction in the natural gas networks | 0% | 0% | - 3.3% | - 4.66% | - 16.6 | - 100% |
| Year emissions reductions achieved | 2021 | 2025 | 2030 | 2035 | 2040 | 2045 |
The above table is indicative only. Evoenergy is doing a lot of work with hydrogen in Canberra. Given the current pace of hydrogen technology developments, it is possible that CO2 emissions could be totally eliminated from the gas networks sooner than 2040.