Some see it as blue, pink, white, or green. Many claim it will become a cornerstone of our energy supply in the coming years. It will heat homes and industries, power trucks and ships, and enable the storage of intermittent renewable energies. To some, it represents the energy of the future, with its diverse and unlimited uses allowing our economies to break free from fossil fuels. This marvel of potential is hydrogen, the smallest molecule in all of chemistry. Small, but apparently very powerful, as many are betting the energy future of our country and all of Europe on its fragile atoms.
In just a few years, a new economy has been built around hydrogen. Numerous national strategies, sometimes supplemented by regional plans, have been developed to support this sector. Yet, before it was considered a viable energy option by the public and policymakers, hydrogen was known only for its reactive properties. For chemists, hydrogen is primarily a reactant, a reducing agent involved in the industrial production of ammonia, methanol, and the synthesis of other specialty products. Hydrogen is also known for removing sulfur from petroleum products, thus ridding fuels of undesirable compounds. It is estimated that nearly all available hydrogen on the market, about 95 million tons, is destined for these industrial applications, with almost half used in petroleum refining alone.
Versatile, the hydrogen molecule can also combine with the oxygen in the air to form water. In the presence of a flame, however, this combination can trigger an explosion. Scientists, always seeking to control chaos, have managed to regulate this reaction under strictly controlled conditions. They exploit the intense heat produced for applications such as aerospace propulsion. They have also developed fuel cells where the combination of hydrogen and oxygen generates an electric current, paving the way for powering light electric vehicles. But to imagine that hydrogen would become the abundant source of heat and electricity for future generations required a considerable intellectual leap that no one expected to make.
There is no doubt that hydrogen has promising energy capabilities, but it also presents numerous challenges. This partly explains why the adoption of hydrogen in energy applications remains marginal, representing less than 0.1% of the current global demand for hydrogen. Being a low-density gas, hydrogen is difficult to store and transport over long distances without resorting to very energy-intensive compression or liquefaction processes. Moreover, hydrogen is not naturally present in significant quantities on Earth, except in a few rare geological deposits. This means hydrogen must be synthesized before use. Due to these logistical challenges, hydrogen production is often located near consumption sites. Sometimes, consumers even produce their own hydrogen. Regardless of where it is produced, this production is far from virtuous. It relies almost exclusively on fossil inputs and requires large amounts of non-renewable energy. The molecule is obtained either by steam reforming natural gas, gasifying coal, or steam cracking petroleum hydrocarbons. Whichever method is used, substantial greenhouse gas emissions, mainly carbon dioxide and methane, are generated without mitigation. In 2022, these emissions exceeded 1.1 billion tons, giving the hydrogen production chain one of the largest carbon footprints in the entire manufacturing industry.
A Rhetorical Fancy?
A paradoxical question arises spontaneously: how did we transition from a synthetic chemical reactant with an alarming carbon footprint to an inexhaustible clean energy source in a world seeking solutions to climate change? Or, to put it more directly, how did hydrogen acquire such an almost mystical aura over time that it is now considered the green energy worthy of massive investment?
To understand the current enthusiasm for hydrogen, it is essential to analyze the origins of this public fascination, which is more rooted in the works of writers and economists than in scientific discourse. Jules Verne, for instance, envisioned hydrogen as the future energy for humanity, set to replace coal. More recently, essayist Jeremy Rifkin prophesied that this molecule would become a clean and inexhaustible energy resource for industrialized nations facing future oil shortages. Rifkin believed that hydrogen, accessible through a global distribution network, would pave the way for an economic revolution. Three main arguments underpin this true adulation of hydrogen. Firstly, the belief that it could be produced in a less polluting manner by exploiting water electrolysis, a process that decomposes water into oxygen and hydrogen using an electric current. Since water is abundant on our planet, this method could render hydrogen truly « green » and inexhaustible. Secondly, the use of hydrogen, which contains no carbon, would not emit carbon compoundsâsuch as carbon dioxideâproducing only water as a « waste » that would re-enter the natural cycle. Lastly, hydrogen could be produced locally, both industrially and domestically, enabling each territory or individual to become energy self-sufficient and thus reducing dependency on third parties. Thus, hydrogen offers a fabulous promise! The molecule symbolizes a clean and inexhaustible substance, providing a vision of a democratic, universal, and egalitarian energy system. Hydrogen would also guarantee an energy regime free from the risk of restrictions due to geopolitical conflicts, the depletion of fossil resources, or the potential rise in traditional fuel prices.
How can one not be charmed by the idea that technology might solve the energy and ecological crisis? How can one not be awed by this molecule, seen as the answer to our psychological comfort needs in a society attempting to reconcile planetary limits with demographic growth? To its supporters, hydrogen seems to meet all expectations: it is abundant, accessible, and promises independence, progress, and democratization. According to a powerful interest group, hydrogen should even play a major ecological role by contributing more than 20% of the emissions reductions needed for the world to reach its net-zero target. This assertion, lacking substantial critical counter-analysis, is frequently echoed by politicians and the media, further amplifying hydrogenâs importance in the environmental transition. However, hydrogenâs detractors hold a very different view: they argue that the moleculeâs performance is overrated and, worse still, consider hydrogen as the Trojan horse of the fossil fuel industry.
Propelled by a dynamic of converging symbolism and collective optimism, the hydrogen sector has benefited from vast funding. In Europe, the Commission even announced in March 2023 the creation of the European Hydrogen Bank, whose role will be to facilitate investments in the hydrogen value chain. It is estimated that by 2050, cumulative funds dedicated to hydrogen technology development within the European Union will reach between 180 and 470 billion euros. A colossal sum for a sector that, admittedly, faces significant technical uncertainties.
The Utopia of Omnivalence
First and foremost, itâs important to note that hydrogen is not an energy source. Nor is it the new oil as its most fervent advocates claim. Scientists view hydrogen as an energy carrier, similar to electricity or heat. In other words, hydrogen should be seen as a material method for temporarily storing and transporting primary energy that is naturally available. To understand this, imagine large electrolyzers powered by electricity from photovoltaic panels or wind turbines producing « green » hydrogen. The molecule thus produced would capture the energy of the sun or wind, which it could then release on demand. Hydrogen would become a tool for storing electricity, thus addressing the fluctuations of renewable energies, whose intermittency remains the main constraint.
What a pragmatic and appealing vision! Hydrogen could become a transportable substance, capable of delivering electricity via fuel cells wherever and whenever needed. « Green » electricity from hydrogen could then power engines in light vehicles or trucks, buses, and trains, becoming a key asset in decarbonizing the transportation sector. Beyond mobility, hydrogen could also fuel fuel cells to provide electricity in stationary applications, such as buildings or generators for isolated sites or areas frequently disrupted by network outages. But thatâs not all! Hydrogen could also release its intrinsic heat through combustion in engines, thermal power plants, or furnaces, becoming a valuable energy source for heavy industries or securing the supply of electricity production networks. Thus, hydrogen would be a versatile solution for heat and electricity. It could be used to heat, cool, illuminate, move, and propel, meeting all the expectations of our modern world, whether associated with mobility, buildings, or industries.
This array of applications is, of course, still under study. Some have validated potential, while it is already established that others are mere fictions contrary to factual scientific conclusions. According to the most optimistic estimates, all these new applications, whether validated or chimeric, could require at least 450 million tonnes of hydrogen by 2050âor moreâmore than five times the current global supply. Mobility would be the most demanding sector, consuming around 150 million tonnes, while heating and electricity supply would consume nearly 100 million tonnes. This doesnât even account for traditional hydrogen uses in the chemical industry and oil refining, which will continue to grow, absorbing more than 121 million tonnes of hydrogen, a more than 25% increase from current demand. A quick calculation shows that we will not only need to significantly ramp up hydrogen production in the coming years, but also make this production environmentally acceptable.
Producing green hydrogen by water electrolysis is certainly the ideal option, but only if the electricity used comes from renewable sources. Otherwise, the carbon impact of this production can be as high as that of hydrogen production by coal gasificationâabout 23 tons of CO2 emitted per ton of hydrogen generatedâwhen electrolyzers are powered by electricity from the average global energy mix. Production would become truly virtuous, with near-zero emissions, if we exclusively used solar, wind, or even nuclear energy. Today, this « green » hydrogen represents only 0.1% of the global supply, although the number of production projects has seen notable growth in recent years, particularly in Europe, Australia, and especially China. The low availability of green hydrogen is explained by technical constraints, such as a lack of efficiency leading to low yields, which affects prices. In 2023, according to the International Energy Agency, the price of green hydrogen ranged between $3.4 and $12 per kg, while conventional hydrogen from fossil resources sold for between $1 and $3 per kg. Naturally, research is focused on improving electrolysis performance, designing new electrolyzers, new separation membranes, as well as new electrodes or catalysts. However, these advances are met with another strategy, largely supported by current producers: capturing carbon dioxide from existing production units. Practically speaking, the production of this so-called « blue » hydrogen currentlyâand with the current state of technologyâsees its collateral carbon emissions drop from 12 tons of CO2 during fossil gas steam reforming to less than 3 tons of CO2 per ton of hydrogen with a partial carbon capture system. Given the efficiency of fossil-based productions, the current market costs of this « blue » hydrogen are quite competitive, ranging in 2023 between $1.5 and $3.6 per kg.
Produce Elsewhere, Consume Here
Letâs summarize the situation. Major industrialized nations hope to massively integrate hydrogen into their energy plans in the near future. Green hydrogen, considered the Holy Grail, is not yet available in sufficient quantities and faces numerous technical and economic constraints. So, what to do? Knowing that many industrialized countries do not yet have enough renewable electricity to meet their own consumption, one option proposed by policymakers and interest groups is to offshore hydrogen production to countries, often in the South, where sunlight and/or winds are sufficient for more efficient production. Morocco, Algeria, Egypt, and Namibia are among these nations chosen to meet the needs of the North, creating a climate criticized as energy colonialism. Produced in large photovoltaic solar plants, sometimes combined with immense wind farms, hydrogenâand the intrinsic local energy it carriesâwould then be transported to consumer countries. What a reversal from the initial promises of hydrogen! While it was touted as enabling each nation to achieve energy sovereignty, it turns out that this sovereignty would be gained by appropriating the energy available elsewhere, in countries where access to energy, and water, is already very limited. Meeting our voracious energy needs without changing our way of life will thus be done by redistributing already complex geopolitical cards.
We thus find ourselves in an imbroglio. Not only will it be necessary to sort out hydrogen uses, but we will also need to improve and increase its production. Moreover, significant logistical problems will need to be resolved. Since hydrogen production will be distant from consumption sites, and knowing that hydrogen is not the best candidate for long-distance transport, one advanced strategy is to convert hydrogen into a more easily transportable molecule. Among the options considered, the transformation of hydrogen into methane by combining it with carbon dioxide is supported by gas groups. They could then use existing pipelines or liquefied natural gas transport infrastructures to convey methane to Europe, where it would be used as a source of electricity or heat. Large maritime groups, on the other hand, believe that ammonia would be the key to efficiently transporting hydrogen. Ammonia could serve as a carbon-free fuel for ships or be used in thermal power plants as a supplement to coal. Oil and aviation groups argue that hydrocarbons, especially e-kerosene, derived from the catalytic combination of carbon dioxide and hydrogen, will offer the greatest efficiency and financial guarantee. Others propose building appropriate pipelines to create a true hydrogen valley in Europe, a backbone linking major industrial sites through a network of high-tech pipes.
What a brouhaha! Between those betting on green hydrogen, those developing carbon capture methods, those who think natural hydrogen deposits should be exploited, those who dream of mobility use, those who bet on heating, those who support industry, those investing in port and maritime infrastructures, those turning to Africa, those who believe hydrogen should be compressed, and those who think it should be transformed back into hydrocarbons, no scientific subject has ever known so many divergences and non-consensus. Worse still, by focusing too much on hydrogen through the exaggerated prism of its uses, demand has been cultivated without ensuring supply. This implies that if electrolysis does not penetrate the market better, the only option to meet demand will be to continue using fossil materials for hydrogen production. In any case, forecasts guarantee that coal, fossil gas, and petroleum inputs will remain heavily exploited in production chains, with volumes far exceeding those used today. Hydrogen is therefore absolutely not the solution to rid ourselves of fossil materials. On the contrary, hydrogen production will depend even more heavily on them.
Between Sobriety and Folly
Convincing people that hydrogen is the sole solution to all our energy and climate problems in the medium and long term is therefore deceptive. It sends a misleading message to users, whether individuals or professionals, who are prone to using energy excessively without regard for sobriety and energy efficiency. It also gives the false impression that hydrogen is free from environmental issues, omitting to mention that this molecule has a fairly high potential for global warming and that leaks could seriously disrupt our climate. Moreover, it risks further binding us to fossil fuels if our hydrogen consumption targets are neither regulated nor prioritized. This is particularly unfortunate because the hydrogen sector, if it does not divert essential investments from the deployment of renewable energies and the implementation of energy optimization plans, has real potential in certain sectors of our daily lives, as fully validated by the IPCC.
Yes, hydrogen is a molecule full of paradoxes. When used wisely and produced responsibly, hydrogen can stimulate certain industrial dynamics and contribute to strategies for mitigating the effects of global warming. Used excessively and without critical analysis, hydrogen will bring with it the disturbing specter of fossil energy industries and initiate in the collective subconscious the myth of infinite energy. Thus, experts agree that hydrogen should not be used as a fuel or electricity source in buses and trains. It should not be exploited in domestic or industrial heating, even when mixed with methane. Nor should it be used in thermal power plants, in its current state or as methane, to produce electricity. Hydrogen is in no way a substitute for fossil gas. Similarly, developing a hydrogen strategy for regional truck transport does not meet any beneficial environmental or technical criteria. However, hydrogen has a promising future in applications where its reactivity is its main advantage. Hydrogen is, above all, a molecule and if it is perceived as such, its economic, environmental, and technical co-benefits will be the strongest. Scientific experts assert that hydrogen, provided its production becomes more sustainable and ethical, will remain indispensable for the production of methanol, ammonia, and the nitrogen fertilizers derived from them. Hydrogen will also be essential for hydrogenation reactionsâhow could it be otherwise!âin the chemical, pharmaceutical, and food industries. It will remain the reagent of choice in oil refining, both in hydrocracking operations and in fuel desulfurization. Specialists estimate that hydrogen will also have a respectable place with the creation of new provisional markets or the transient penetration of existing economic sectors, in maritime transport, either in the form of methanol or ammonia, or in aviation, in the form of alternative hydrocarbons to traditional jet fuels. Hydrogen will also help balance the power grid over prolonged periods. Finally, the molecule will offer great opportunities in steel production where its reducing character will allow the substitution of coke in the reduction of iron ores, providing an option for defossilization and carbon emission reduction in the steel production chain.
One thing is already certain: contrary to Jeremy Rifkin’s predictions, our civilization will not be rebuilt on the energy foundations offered by hydrogen. Hydrogen is a molecule and must continue to be treated as such. There will be no grand global hydrogen distribution network, which would be subject to the same constraints as the current capitalistic energy network. Offshoring hydrogen production, knowing that the electric grid is not developing rapidly enough to meet the growing needs of populations without electricity, raises ethical issues that must be addressed as a priority. Using hydrogen when direct electrification or storage in stationary batteries are more effective options in certain sectors also raises questions about the choices supported by policymakers. Today, in our excessive quest for energy, it becomes crucial to inject a dose of reason into the development of the hydrogen sector. Without this, we risk darkening our already uncertain climate future even further.
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