Hydrogen facts: No, it’s not abundant on Earth. Nor green nor an energy source, but energy storage.

Synopsis: A hydrogen economy is just a fossil fuelled dream.

Unfortunately, the dream is mostly based on illusions and a whole lot of confirmation bias, and the dream fades quickly when examined. We are faced with passionate people who believe the distortions arising from their confirmation biased view of reality and those with a US$7 billion a day incentive to keep the dream alive even if they don’t believe it. A problem is, the people funding the spin, have big budgets, so it can require work to unpick what is spin and what is real.

The dream vs reality:

• Dream: Pure hydrogen is the most abundant substance in the universe!
  • Reality: Yes, true as the universe is almost all stars and nebula, but on rocky planets like Earth, there is far less hydrogen, and almost all of that is already “locked up”.
• Dream: We can use hydrogen for energy in a similar way to how we used fossil fuels.
  • Reality: All the hydrogen is either locked up in water, or locked up if fossil fuels.
    • Extracting hydrogen from water requires putting in 3x more energy than you get back (green hydrogen)
    • Extracting hydrogen from fossil fuels results in emissions that no carbon capture and storage can fully mitigate (blue hydrogen).
• Dream: Hydrogen is a solution to reducing carbon emissions.
  • Reality: Hydrogen makes it 3x harder to reduce emissions.

In summary, most hydrogen so far is produced from fossil fuels by an emission intensive process, but although more expensive so far, it is also possible to produce “green” hydrogen without creating emissions. It is important to distinguish ‘grey’ and ‘blue’ which are hydrogen extracted from fossil fuels, from ‘green hydrogen’ which is extracted from water using renewable energy.

Hydrogen is not a source of energy but can work as energy storage and other energy sources can be converted into hydrogen fuel, for any situations where hydrogen fuel is more desirable than the original form of energy.

‘Green’ hydrogen, obtained by using renewable electrical energy, is a viable and emissions free replacement for fossil fuels in many situations where no other substitute is viable. The limitation of hydrogen is that where battery storage is viable that is a far more efficient and cost-effective solution, which means as battery solutions become viable in more applications, the energy applications for hydrogen become fewer.

The strengths of hydrogen are:

• Suitability as a reduction agent for smelting ores.
• Combustibility for applications unsuitable for electrical heat-pumps.
• Highest energy density per unit weight of any fuel can in some cases offset the very low energy density per unit volume and problematic storage.

At this time an actual ‘hydrogen economy’ seems unlikely. Hydrogen fuelled space missions prove there is at least one case where the weight savings overcome the disadvantages and efficiency problems, but hydrogen fuelled cars have been surpassed for range and recharging by EVs, hydrogen trucks seem to have limited applications, hydrogen planes are not yet proven and transport problems risk hydrogen projects becoming failures.

Facts vs Myths.

Abundance Myth.

A clear indication that an article on hydrogen is hype is that it begins with the rather irrelevant and misleading fact that hydrogen is the most abundant substance in the universe.

Despite hydrogen being the most abundant, and lightest, element in the Universe, there is no huge supply here on Earth. The Universe is around 70% natural hydrogen, while the Earth is less than 0.001% natural hydrogen, and although hydrogen locked up in water other compounds are included hydrogen then adds up to 0.14% of the Earth, it should be clear that hydrogen in the H₂0 of the water compound is not readily available to be used as fuel. To quote Monty Python: “there is bugger all down here on Earth“.

Most of the universe is also colder than 200 degrees below zero, so clearly conditions for “most of the universe” are not how things are here on Earth. Yes, hydrogen is the most abundant element in the universe, at around 70% of all regular matter (regular as in ignoring dark matter) and hydrogen and helium together account for 98% but unless we accept find a new way to mine from space, it would require far, far, more energy to get hydrogen from space than any hydrogen retrieved could provide.

Earth is less than 0.001% natural hydrogen, and all hydrogen including that is water etc adds up to only around 0.14% Hydrogen. Oxygen (47%), Silicon (28%), Aluminium (8%) and Iron (5%) are the most common elements here on Earth. Hydrogen is not as abundant here on Earth as some sources suggest.

Why is hydrogen abundant in the universe but not abundant on Earth?

Hydrogen is element number 1, and the lightest element in the universe. During formation, the Earth was not sufficiently massive to retain free hydrogen (or even helium, the next lightest) because these gases are so lightweight, so instead of being 98% hydrogen and helium like the universe overall, the earth started out with zero free hydrogen and helium, as both floated off into space. The only hydrogen retained when the Earth formed, was hydrogen chemically attached to other, heavier elements, as chemical compounds like water.  As the 2nd most abundant element in the universe helium does not form compounds, the Earth did not retain significant amounts of helium in any form, and what helium exists on Earth now is a by-product almost 5 billion years of radioactive decay of radioactive decay of larger elements. While helium is the second most abundant substance in the universe, we are in danger of running out here on Earth.

Although hydrogen atoms will normally combine with other atoms to form compounds on Earth, in space there is so much more hydrogen than any other element hydrogen can combine with, that most of the atoms in the universe are as unattached hydrogen atoms or molecules. On Earth, all the hydrogen is normally bound in compounds like water, or at risk of floating of into space. Unlike helium, we are not yet running out of hydrogen on Earth, but the “most abundant” does not apply for Earth.

Hydrogen isn’t an energy source: It is only problematic energy storage.

Using hydrogen for energy storage is just inefficient storage.

On Earth, producing hydrogen requires an energy source with more hydrogen than can be obtained from using the hydrogen produced.

You can produce “grey hydrogen” from natural gas, but the hydrogen has only around 1/2 the energy of the original natural gas and yet is responsible for the same total emissions.

“Green hydrogen” starts with 3x the energy available from the hydrogen produced.

This same, “less energy that you start with” equation applies to every form of hydrogen.

The logic for converting energy into hydrogen is only valid when there are advantages to having the energy in the form of hydrogen over and above more efficient storage.

The biggest advantage of energy in the form of hydrogen is that it is very light, and this has been proven as advantage in space exploration, but so far, that is the only practical example at scale for energy storage.

Before batteries evolved to be smaller and lower cost, it did appear automobiles may be an application justifying the inefficiencies, but that day seems to have passed as batteries have improved.

Hydrogen actually makes reducing emissions 3x harder.

The problem with hydrogen being such inefficient storage is that you need 3x more clean energy when using hydrogen for storage. Hydrogen means 3x times more wind and solar is needed before the grid becomes “green”.

Sustainable?

Hydrogen is ‘sustainability neutral’ in that Hydrogen being involved says nothing about whether a particular use is sustainable or not. Hydrogen project can be highly sustainable, but so far most are not at all sustainable. This is because most hydrogen in use so far, is extracted from fossil fuels in process just polluting as just using fossils for energy. Sustainability of the project is dependent of the source of the hydrogen, as discussed below.

Even use of ‘green’ hydrogen is not without sustainability risks. Remember how the Earth has insufficient mass to have retained free hydrogen when the Earth formed? Well, the Earth still loses hydrogen every year through Atmospheric Escape, and separating hydrogen accelerates that process, so any leaks of hydrogen can be the ultimate in unsustainability, as the material it is gone forever, as opposed to in landfill requiring costly extraction. When burning fossil fuels, at least all the atoms remain here on Earth. For abundance of elements here on Earth, it is oxygen (47%), silicon (28%), aluminium (8%) and iron (5%) as the most commonly available elements, with hydrogen down at 0.14%. Water is hydrogen and oxygen, so simply put, the less hydrogen, the less water. And we will miss the water if we lose too much hydrogen.

Hydrogen colours and why it isn’t an energy source.

The Earth can’t retain natural hydrogen, which means creates an energy cost.

Unlike in space, such as in the Sun (91% hydrogen), or Jupiter(90%) and other massive planets (Neptune at 80%), where hydrogen atoms outnumber all other atoms, the Earth is too small to retain hydrogen molecules and what hydrogen there is on Earth (0.14% of Earths crust) exists almost entirely bonded into compounds with other atoms, and energy is required to extract that hydrogen. The are three groups of relatively abundant compounds containing hydrogen.

• water (H₂0), consisting of hydrogen and oxygen
• carbohydrates, consisting of hydrogen, carbon and oxygen
• hydrocarbons, consisting of hydrogen and carbon

Extracting hydrogen consumes energy, because each of these processes requires more energy input to produce the hydrogen, than the energy which can be output by using the hydrogen fuel produced.

Further, extracting hydrogen from anything other than water, results in also extracting carbon, in practice, in the form of CO₂.

Natural “White”/”Gold” hydrogen: Very rare and generally inaccessible on Earth.

Yes, there are pages and like this one from “the voice of downstream petroleum” suggesting there is great potential for white hydrogen, even this rather anti-renewables-resource that mistakenly claims “hydrogen is the most abundant element on Earth” when in reality it is less abundant than titanium, yet even they concede the may form videos mistakenly claiming that hydrogen is the most abundant element on Earth, confusing the abundance of hydrogen in the

‘Grey’ Hydrogen: Extracted From Natural Gas, with the CO₂ emitted at the plant.

Around 95% of all hydrogen in use commercially today (2021) is ‘grey’ hydrogen which is produced from natural gas. When you burn natural gas (CH₄), you get CO₂ + water. Imagine if you could burn the carbon first, producing the all the CO₂ at the factory, and then ship the just the hydrogen, so burning the rest will only produce the water. That is basically the process with ‘grey’ hydrogen. The same amount of CO₂, but all produced in advance at the plant that extracts the hydrogen from the natural gas. It would be simply moving the pollution, but unfortunately, because the energy from the carbon of the methane, producing the CO₂, has already been used at the factory, the hydrogen contains a portion of energy of the original natural gas. This means for the same energy to be available in the form of energy, you need to start with more natural gas, and will consume more natural gas than direct using the natural gas as fuel. So in fact, this process increases the total CO₂ produced.

So why bother extracting hydrogen from natural gas when it would be, less expensive, more efficient, and less polluting overall to just use the natural gas as fuel? Answer, because sometimes the hydrogen provides benefits that justify the extra cost and extra total pollution:

• Hydrogen can be used to produce electricity with no combustion, providing clean power at the point of usage even if the overall process produces more CO2.
• Hydrogen is far lighter than natural gas, and in critical applications where weight is critical such as rocket engines, headed for space, the cost and inefficiencies are justified.

This means hydrogen powered vehicles, or whatever uses the hydrogen, can produce almost no pollution and mostly just water, because almost all the pollution was already produced at the factory. The overall process will result in more greenhouse gas per km travelled by the vehicle than staying with fossil fuels and keeping gasoline powered cars, but most of the pollution occurs away from the vehicle. This is the case with hydrogen vehicles today (2021) , because most hydrogen (95%) available now is ‘grey’ hydrogen produced from fossil fuels.

There are four main sources for the commercial production of hydrogen: natural gas, oil, coal, and electrolysis; which account for 48%, 30%, 18% and 4% of the world’s hydrogen production respectively.^[5] Fossil fuels are the dominant source of industrial hydrogen.^[6] Carbon dioxide can be separated from natural gas with a 70–85% efficiency for hydrogen production and from other hydrocarbons to varying degrees of efficiency.^[7] Specifically, bulk hydrogen is usually produced by the steam reforming of methane or natural gas.^[8]

Steam reforming is a hydrogen production process from natural gas. This method is currently the cheapest source of industrial hydrogen. The process consists of heating the gas to between 700–1100 °C in the presence of steam and a nickel catalyst. The resulting endothermic reaction breaks up the methane molecules and forms carbon monoxide CO and hydrogen H₂. The carbon monoxide gas can then be passed with steam over iron oxide or other oxides and undergo a water gas shift reaction to obtain further quantities of H₂. The downside to this process is that its major by products are CO, CO₂ and other greenhouse gases.^[5] Depending on the quality of the feedstock (natural gas, rich gases, naphtha, etc.), one ton of hydrogen produced will also produce 9 to 12 tons of CO₂, a greenhouse gas that may be captured.^[9]

Wikipedia

Natural gas, consists of both carbon and hydrogen, as does gasoline (petrol). Burning natural gas, as does burning gasoline, produces CO₂ and H₂0, both dirty (CO₂) and clean (HO₂)exhaust, as well as combusted impurities and a small amount of nitrous oxides. The CO₂ and impurities are the major problem, and ‘mining’ hydrogen from natural gas, is effectively burning only the carbon and impurities at processing plant, leaving the hydrogen as the far clearer part of the fuel. The ‘dirty’ exhaust is produced in the same in the same quantities, but is almost all produced at the factory where potential for carbon sequestration is increased, leaving ‘clean’ hydrogen as fuel for consumers. Overall, since more natural gas is required, the pollution is greater than simply moving cars to run on natural gas.

When those promoting coal and gas also promote hydrogen, be wary, as it can be simply a way to promote future production of coal and gas, and ‘greenwash’ the pollution which no longer takes place at the vehicle. Potentially zero tailpipe emissions, but overall, increased emissions.

The clear point is, that while hydrogen can be greenhouse gas free fuel supply, the production of the hydrogen is not necessarily green.

Note, there are some, including the government of Australia which is regarded by some (as of 2020) as the last Western holdout on the climate crisis, that have a goal to become a major international suppliers of ‘clean’ hydrogen fuel, without necessarily any commitment as what level of pollution will result from the production of the hydrogen.

‘Blue’ Hydrogen: Grey Hydrogen With the CO2 ‘Greenwashed’.

What Is Blue Hydrogen?

What if the CO₂ produced making ‘grey’ hydrogen, could be captured and stored? A dream for the natural gas industry, and very much the plan for several government and fossil fuel industry products worldwide.

Welcome to ‘blue hydrogen‘: hydrogen extracted as ‘grey hydrogen but working to use carbon capture and storage to offset the greenhouse penalty.

‘Blue’ Hydrogen has been described as greenwashing by some, a great hope by others. The central idea is that the natural gas industry will have a significantly brighter future if Hydrogen produced from natural gas can be seen to be environmentally friendly, as opposed to being a huge emitter of CO₂, CO and other harmful by products as is currently the case.

The whole ‘blue hydrogen’ proposal is at best very questionable, but it has been helpful in promising a future for natural gas as sources of hydrogen with reduced emissions, although in practice, so far, direct use of the natural gas provides less emissions for a given amount of energy than blue hydrogen. Still, blue hydrogen enables coal and gas companies to promote they have a future.

The Carbon Capture and Storage Blue Hydrogen Problem.

Despite what you might read, carbon capture and storage can work for some applications. However, ‘blue hydrogen’ is not one of them.

A Myth Created To Delay Replacement of Fossil Fuels?

The label ‘blue’ is chosen to reflect that the process in not green, but perhaps the colour is just as attractive. Producing Hydrogen from natural gas is a well proven process, which, by removing the carbon from methane using oxygen, converts natural gas into Hydrogen and CO₂. Since the CO₂ is produced at the point of production, it is argued that sequestration of the CO₂ will be easier that with natural gas. However, successful sequestration is still a concept, rather than a practice, and has not been demonstrated to be successful at this time.

Blue hydrogen is often touted as a low-carbon fuel for generating electricity and storing energy, powering cars, trucks and trains and heating buildings. But according to a new report by Cornell and Stanford University researchers in the US, it may be no better for the climate – and potentially a fair bit worse – than continuing to use fossil natural gas, which currently keeps 85% of UK homes warm. In the US, about half of all homes use natural gas for space and water heating.

Is Blue Hydrogen Really Better for the Environment than Natural Gas?

So far, since the conversion process itself requires energy and increases energy requirements, Hydrogen from natural gas results in more CO₂ for a given amount of energy than if directly using natural gas.

The reality is that ‘blue hydrogen’ is not likely to be ever realised, and instead proposed in order to suggest electric vehicles and other solutions are only interim, and that we should should use fossil fuels while we wait.

Clean ‘Green’ Hydrogen: Renewable, Sustainably Extracted From Water.

Hydrogen can also be produced using green ‘energy’ sources. Even if there was abundant ‘free’ hydrogen on earth, accessing free hydrogen, and combining it with oxygen to form ‘water + energy’ would not be renewable, even if it was sustainable. The only way to have renewable hydrogen, is to extract hydrogen from water, completing the cycle. Fortunately for a sustainable planet, that is the definition of green hydrogen.

What makes hydrogen a big deal is the diversity of its potential uses. Green hydrogen — produced by splitting water into hydrogen and oxygen in an electrolyser, using renewable-powered electricity — can exponentially expand the use of solar and wind power. Right now, renewables can be used to pump the grid, but that’s almost it. You can’t put solar or wind power into your car or a plane. However, green hydrogen created by solar and wind power has the potential to do that.

Green hydrogen isn’t a stand-alone solution. It could answer up to 24% of our energy needs by 2050⁵, and would be used along with electrification to head towards net zero carbon emissions by 2050. But what it does do is provide a green alternative for ‘hard-to-abate’ industries that can’t adapt to electrification.

Bank of America Investment Notes on ‘green hydrogen’

The above extract from the Bank of America web site (not from a ‘green’ advocate), explains ‘green hydrogen’ in a nutshell. A solution, storing energy from wind or solar or other sources, applicable for ‘hard-to-abate’ industries that can’t adapt to electrification.

Any search on ‘green hydrogen’ should give many useful results. Another useful recent page, this time from CNBC:

Hydrogen is a clean-burning molecule, meaning that it can help to decarbonize a range of sectors that have proved hard to clean up in the past

But today, 99% of hydrogen is still made using fossil fuels, usually through a pollution-heavy process

Green hydrogen, which is produced using electricity from renewable resources, could be the key to curb our carbon footprint

CNBC: Green Hydrogen is gaining traction.

More colours: Brown, black, turquoise, yellow, purple and pink.

Brown and black hydrogen

Brown hydrogen (made from brown coal) and black hydrogen (made from black coal) are produced via gasification. It’s an established process used in many industries that converts carbon-rich materials into hydrogen and carbon dioxide. As a result, gasification releases those by-products into the atmosphere.

However, if technology ends up storing those emissions, that hydrogen can sometimes be called blue.

Turquoise hydrogen

Turquoise hydrogen describes hydrogen produced when natural gas is broken down into hydrogen and solid carbon via pyrolysis. This method uses heat to break down a material’s chemical make up. It’s seen as ‘low carbon’ as the hydrogen production process doesn’t emit any GHGs. But there can be emissions associated with the mining and transport of natural gas that is used as the starting product.

Yellow, purple and pink hydrogen

But wait, there’s more! We occasionally see yellow hydrogen describing hydrogen made from direct water splitting, or purple (or pink) for hydrogen derived using nuclear power. There are also murmurings of white hydrogen, which may be extractable from underground.

The colours, however, can be distracting from the main game. Hydrogen will only achieve its goal of being a clean source of energy if it does not generate emissions during production.

the colours of hydrogen explained

Other Renewable Hydrogen?

Renewable sources have also been proposed for extracting Hydrogen from Hydrocarbons or Carbohydrates. While there would still be CO₂ as a by-product of extracting the Hydrogen, the same amount of CO₂ should also be consumed in producing the renewable source. For example, if extracted from vegetable oil, growing the vegetables should absorb at least as much CO₂ as gained from extracting the Hydrogen. The negative is that in some cases, such as a proposal to use manure as a source, do mean liberating already captured CO₂, that would otherwise remain captured. Overall, while there is research on other green sources of hydrogen, they are all indirect use of solar energy and probably inefficient compared with solar panels. For example, growing a crop, which is a form of capture of solar energy by plants, to then process organic material to extract the energy in the form of hydrogen, requires far more land and more water, than using solar cells as an source of energy to extract the hydrogen from water.

Hydrogen as fuel: Nuclear, Chemical or Electrical?

So once the hydrogen has been obtained, (hopefully ‘green hydrogen’ obtained by electrolysis using green electricity), how should it then be used to produce energy? Hydrogen can be used in Nuclear Fusion, Hydrogen Fuel cells to produce electricity, or it can be burnt to produce heat.

Nuclear.

Hydrogen can be used in nuclear fusion reactions, the same process that powers the Sun, and powers the H-Bomb. Despite the enormous energy potential of nuclear fusion, using hydrogen for fuel is not synonymous with fusion power. In fact fusion from Hydrogen requires so much head an pressures, the H-Bombs use an atom bomb to generate the energy to trigger the nuclear fusion. So far, fusion reactors as a power source require more energy to trigger the fusion than is generated by the reactor. There is promising research, but reactors are beyond current technology, and if/when they become practical, they require very little hydrogen, and produce ample energy to extract what they do need from water.

Chemical Energy: Combustion, or Burning Hydrogen.

Combustion: Burning Hydrogen To For Heat.

The chemical reaction of burning hydrogen also produces significant energy, as demonstrated when the Hindenburg caught fire. The best use of combustion, is when heat is the goal. A gas stove, or a gas room heater, or gas hot water heater, all can use hydrogen as the gas. Burning pure hydrogen, as opposed to other gases, eliminates CO₂ as by-product of the combustion. Natural gas, CH₄, produces CO₂ + water (H₂O) when burnt, while instead, burning hydrogen produces only water. There is one trap, and that is the plumbing that has no leaks with natural gas, may leak the far small hydrogen molecules, so existing plumbing will not always be safe. Leaks aside, hydrogen could replace natural gas for heating and cooking. Not necessarily the best replacement, but it is possible.

Internal Combustion Engines: A poor alternative to fuel cells & electric motors.

Hydrogen burns or ‘combusts’ in a manner suitable for the familiar Internal Combustion Engine, and there has been over a century of experience with these engines that burn fuel and convert the heat into motion. Not only is this familiar, but unlike with other fuels, which have both carbon and hydrogen and produce CO₂ as well as H₂O when burnt, hydrogen produces only H₂O. This is a big step forward. A familiar process, with no nasty CO₂! Except, that ‘familiar’, despite all that experience is only at best close to 40% efficient, and typically closer to 20%. In the end no matter how much you refine the process, combustion primarily produces heat, and will always be losses converting heat into motion.

Fossil fuels, have a greater energy density by volume than hydrogen, which means there can be so much energy in a given space that we can live with the inherent inefficiency of using combustion to produce motion. It can be surprising to realise just how much energy is in a typically car fuel tank.

Not only are fossil fuels good in terms of energy density by volume, we have not found a better alternative to combustion to tap the stored energy. With fossil fuels, the volume is not such a problem, and we have no alternative anyway.

The lower energy density by volume means hydrogen tanks need to be larger for a given range than with fossil fuels. If you are going to burn the hydrogen in an internal combustion engine, than fuel tanks over six time (6x) larger will be required to achieve similar range to that of fossil fuel vehicle. Cars that burn hydrogen have been built, but the inefficiency of internal combustion when combined with lower energy density of hydrogen, made these cars impractical, with the range on a tank approximately 200km when powered by hydrogen.

The inefficiency result from energy lost as heat, which in internal combustion engine is quite intense. The intense heat can also lead to burning the nitrogen from the hydrogen/air mix, producing harmful, nitrous oxides, introducing pollution to what would otherwise be a clean fuel. Plus, if you use ‘green hydrogen’, instead of just digging up the fuel, making the fuel consumes energy that is expensive to waste.

We tolerate the inefficiency with fossil fuels because we have no better alternative for converting the stored energy of the fuel into motion, the size of the tanks was acceptable, and we had no alternative way to access the energy, but with Hydrogen, we do have a more efficient alternative. Which means smaller tanks, less heat, and far lower consumption of the energy used to make hydrogen.

Electrical Energy from Hydrogen: The Hydrogen Fuel Cell.

The electrical hydrogen fuel cell in combination with an electric motor is far more efficient than even the best internal combustion engine and produces far less heat that an internal combustion engine. Electrical fuel cells also combine hydrogen from on board tanks and oxygen from the air to produce energy, but as a more controlled reaction, the fuel cell is more efficient because there is very little heat. Less heat means less wasted energy.

The efficiency of hydrogen fuel cells combined with electric motors are the reason that hydrogen car projects based on burning hydrogen ceased. As of 2023 there are still hydrogen-based cars, but all current production hydrogen car models use electrical fuel cells, as the greater efficiency of fuel cells delivers far more range for a given amount of hydrogen. The problem is the low volumetric density of hydrogen means large fuel tanks, so maximum range on a given tank capacity is essential. Producing electricity in place of heat, the energy can far more efficiently propel a vehicle. Without wasted heat, or risks of pollution from burning nitrogen or other elements, the best electrical fuel cell vehicles in production can now deliver over 400km of range, or even with larger tanks now 750km of range on a tank of hydrogen, although the Hyundai Nexo also claims to have the longest range of 380 miles or just over 600km. Not quite the range of the best battery cars from Tesla or the longest-range Lucid Air at 516 miles or 830km, but still highly competitive, and amazingly the hydrogen at 350 times the pressure of BBQ gas cylinders can still be lighter in weight than most current conventional lithium batteries providing similar range.

If the application is not actually heating, electrical energy from hydrogen wins over combustion!

Hydrogen for Stored Energy.

How do you store Hydrogen?

Hydrogen can be physically stored as either a gas or a liquid. Storage as a gas typically requires high-pressure tanks (5000–10,000 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.

energy.gov

You can store hydrogen as a liquid, as a compressed gas, or using a hydrogen absorbing material.

The liquid storage problem.

Note that unlike LPG, which can become a liquid at ‘normal’ temperatures simply by compressing the gas, compressing hydrogen at regular temperatures will not result in a liquid, no matter how much compression is applied. Unless the temperature is kept below the critical temperature of -240°C, pressurized hydrogen will not liquify. This means keeping hydrogen in liquid form for an extended time requires energy to run refrigeration. As with any supercooled liquid, (e.g. liquid Nitrogen), slow boiling of some the liquid, and the resulting expansion of gas can provide some refrigeration, so using the hydrogen can itself aid in keeping the storage cold. This means that for a plane or a car or boat, or when used as rocket fuel, using liquid fuel is most practical if the vehicle will start using fuel immediately upon refuelling, as using some fuel helps keep the rest cold. This is the same process that can be observed with liquid Nitrogen, which although requiring to be kept at a similar temperature, can be kept cold when in an insulated container, by allowing some liquid Nitrogen to ‘boil’, thus removing sufficient heat.

The pressure problem.

Tyres are normally around 30-40 psi which is around 220 to 280 kpa. BBQ gas cylinders are kept a little above the 220 kPa required to keep butane/propane in the liquid state, which equates to 2.2 bar. Now consider hydrogen as 700 bar which is 10,153 psi or 70,000 kpa (kilopascals). This is 350 times as much pressure! Keeping an explosive gas at that pressure requires not only very strong tanks but also creates the risk of explosion in the event of any damage to those tanks even if the gas inside was not explosive.

The efficiency problem and emissions: 3x less efficient.

While there “green hydrogen” and other “colours” of hydrogen that result in zero emissions during production, there is still the efficiency problem, which creates its own problems stemming from the need for more energy than if a more efficient storage can be found.

For example, “Green” hydrogen made from renewable electricity increases the need renewable electricity by a factor of 3x over other forms of storage, which means more wind and/or solar must be built or the green electricity will be diverted from other uses. Either way, the inefficiency has an environmental impact.

The inefficiency comes from the fact that there are losses at each of the following steps:

• Electrolysis is required to convert electricity to hydrogen which is at best 70% efficient according to Saul Griffith.
• Compression of hydrogen for storage.
• Transport of hydrogen.
• Losses within fuel cells in conversion of hydrogen back to electricity.

Each of these steps contributes to the picture, and one of the hardest to address is the compression of hydrogen as increasing the pressure of a gas results in also increasing the temperature as noted in Gay-Lussac’s law. Clearly raising the pressure to 700 bar, which is over 10,000 psi, has to result in extreme heat which must be dissipated and thus normally lost as waste heat prior to transport.

Storage Comparison with Natural Gas, LPG, Gasoline and Diesel Fuel.

The main alternative to hydrogen as chemicals for storing energy are Hydrocarbons such as Natural Gas, LPG. Hydrocarbon are the core ingredients of Gasoline and Diesel Fuel. These hydrocarbons combine hydrogen and carbon into chains of Carbon, with hydrogen attached to the carbon chain.

The more carbon atoms, the longer the chain, and the higher the melting and boiling temperatures. Natural gas, which is Methane and has one Carbon (CH₄). LPG which is mix of Propane (C₃H₈), and Butane (C₄H₁₀) have, respectively, 3 and 4 carbons atoms. Gasoline has a mixture of hydrocarbons with between 5 and 12 carbons, diesel fuel has hydrocarbons with between 10 and 15 carbon atoms, and candle wax made from paraffin has 25 carbon atoms. The melting and boiling temperatures increase as the chain get longer, and the characteristics progress as follows:

Name	Carbon atoms	Characteristics
Hydrogen	0	Always a gas unless kept below -240 °C
Natural Gas/ Methane	1	Always a gas unless kept below -150 °C
LPG/ Propane, Butane mix	3-4	Normally a gas, but liquid below -42°C or at pressure above 220kpa
Gasoline/Petrol	5-12	Normally liquid, but a percentage as vapour
Diesel Fuel/Distillate	10-15	Liquid, less vapour, but can become waxy when cold
Candle/paraffin	25	Solid at room temperature

For internal combustion engines, a fluid is required, and liquids have better energy density than gases.

Comparison of gasses, and potential for long term storage as liquid without refrigeration.

Gas	Boiling Temp	Liquid at Pressure?(kilopascals)	Combustion Temp
LPG/Propane or Butane	-42°C/-44°F,	Yes: 220kpa at room temp	1970 °C 3578 °F
Natural Gas/ Methane	−161.5 °C/−258.7 °F	only possible below -150 °C	1950 °C 3542 °F
Hydrogen	−252.879 °C, ​−423.182 °F	only possible below −240.21∘C	2111 °C 3831 °F

Energy Reservoirs.

A major use of ‘green hydrogen‘ is to add storage to electrical grids powered by renewables, acting as a giant battery. Renewable energy must be combined with storage to replace fossil fuels for electrical supply. Large scale hydrogen tanks for stored energy can be located anywhere, sometimes giving such tanks an advantage over stored hydro which is dependant on terrain, and often best located in mountainous terrain that hosts delicate ecosystems. Hydrogen tanks could be one way of restoring open cut coal mines, which are typically close to power plants and significant infrastructure for connection to the electrical grid.

For bulk storage, either compressed gas or storage using a hydrogen absorbing material are possible.

Pipes.

But how do you get hydrogen to the consumers for heating, or to fuel tanks for any cars, planes, and ships? One possible solution is to convert current gas pipe infrastructure from the normal methane to hydrogen. There are three challenges to be overcome:

• Pipes and valves that do not leak methane (CH4) may leak the smaller hydrogen, molecules so testing and an upgrade may be required.
• Current gas burners are optimised for LPG (propane) or natural gas (methane), but not hydrogen. Changes would be required.
• Burners for methane have to be adapted for propane, so it is likely burners will also need to be adapted for hydrogen.

Michael Liebreich, the influential energy analyst and founder of BloombergNEF, told Recharge in June: “You’re not going to have hydrogen in your home for safety reasons. It’s just not going to be a thing.”

‘Hydrogen in the home would be four times more dangerous than natural gas‘: government report: Recharge.

While there are proposals to convert gas infrastructure to hydrogen, these only seem to be viable from the perspective of fossil fuel sellers.

Fuel Tanks.

For fuel tanks, research continues into hydrogen absorbing materials, but so far, the choices are:

• Liquid Hydrogen, where consumption can begin immediately and continue, or with refrigeration.
  • suitable for: race cars, planes, ship engines, special purpose automobiles.
• Compressed gas, that can be stored indefinitely without refrigeration.
  • all above uses, plus consumer automobiles, ‘gas bottles’, and home storage.

Hydrogen: Energy for when batteries are unworkable.

When Hydrogen Beats Batteries.

So, what is the main use of hydrogen?

• It is not a source of energy and so does not replace fossil fuels, wind solar, hydro or nuclear.
• It is less efficient the regular batteries due to the losses that are inherent in the required compression.

Why not just use a battery, since batteries are more efficient?

Because it turns out there are applications where batteries simply do not hold enough energy. While the compression of hydrogen costs money and reduces efficiency, with a sufficient budget, at lot of energy can be compressed into a small and light package. If there is room for batteries, and they are not too heavy, batteries will always be a better solution, but for some applications there is no room or the batteries will be too heavy, which means the less ideal hydrogen energy storage is the only option.

Hydrogen: The stepping stone that became redundant.

Prior to around 2010, battery technology limited electric cars to a range of around 100km even if they were driven at limited speed. By 2014, still most battery electric cars had a range of only 200km and companies such as Toyota felt that battery electric cars could never be ‘real cars’. At the time the only way to get any range was to significantly limit speed and acceleration, or use huge expensive batteries, and even then range was insufficient for “road trips“.

Toyota North America CEO Jim Lentz told Automotive News the Japanese car maker has conceded that battery-powered electric vehicles are only viable in specific and limited applications, following two decades of attempting to make a long-range pure-electric vehicle a reality.

“In short-range vehicles that take you that extra mile, from the office to the train, or home to the train, as well as being used on large campuses,” Lentz said, “but for long-range travel primary vehicles, we feel there are better alternatives, such as hybrids and plug-in hybrids, and tomorrow with fuel cells.”

Lentz’s comments follow Toyota’s decision to end its partnership with Tesla that saw the electric vehicle specialist supply Toyota with components for the recently discontinued RAV4 EV (pictured top).

“It was time to either continue or stop,” Lentz said. “My personal feeling was that I would rather invest my dollars in fuel cell development than in another 2500 EVs.”

Toyota will launch its first hydrogen fuel cell passenger car next year. The all-new, zero-emission sedan will take inspiration from the FCV-R concept of 2011 (pictured above), which claimed a driving range of approximately 700km.

Most of today’s electric cars have a range of less than 200km, while one of the most advanced models in the world, the Tesla Model S, can travel no further than 426km on a full charge of its battery.

2014: Toyota abandons long-range EV plans to focus on hydrogen fuel cells – report

The problem for hydrogen is that in 2022 hydrogen compliance vehicles have delivered a range of up to 750 km, full production versions of that Tesla Model S from 2014 have almost caught up at 650 km and have been demonstrated with over 1,200 km range that is beyond the dreams of hydrogen vehicles.

It feels like the time for hydrogen in some applications has already passed, and it looks like it will pass in others as well.

Updates

• 2023 December 4th : New edition of this page, with additions including white and pink hydrogen and more on the pressure required for storage.

Added links:

Fully Charged, The Future is not Hydrogen, and no coincidence that a lot of the backers of hydrogen are oil and gas companies, but hydrogen can work for storage.