Hydrogen—the simplest and most abundant element in the universe—has a rich history that dates back to its discovery by British scientist Henry Cavendish in the 18th century. Since then, this molecule has undergone a remarkable evolution, transforming from a scientific curiosity into a key component of many modern applications, now developed within thriving H₂ ecosystems.

The Age of Enlightenment: The Discovery of Hydrogen

In 1766, British physicist and chemist Henry Cavendish made a major scientific breakthrough by discovering a unique gaseous substance during his experiments on acidity. Three years later, he published his findings, revealing the distinctive nature of this light gas, which he referred to at the time as “inflammable air.”

In 1783, French chemist Antoine Lavoisier recognised that Cavendish’s “inflammable air” was, in fact, a distinct chemical element that, when burned in the presence of oxygen, played a role in the formation of water. He therefore proposed the name “hydrogen” for this element, derived from the Greek words hydro (meaning “water”) and genes (meaning “creator” or “former”).

H₂: The Chemical Formula for Hydrogen

Why Is Hydrogen Referred to as H₂?

The molecular form of hydrogen is dihydrogen. As the name suggests, this molecule consists of two hydrogen atoms, which is why its chemical formula is written as H₂.

The Era of Chemical Renaissance: H₂ Gas Becomes an Energy Carrier

In 1839, Sir William Grove—a British lawyer and amateur chemist—developed the Grove cell, also known as the gas voltaic battery, by combining platinum electrodes with hydrogen and oxygen. This invention directly converted chemical energy into electricity without combustion, offering a clean and efficient alternative to traditional electricity generation methods.

In the following years, he published a series of papers and, during a lecture in 1842, he discussed the concept of energy conservation—making one of the earliest references to it, five years before Hermann von Helmholtz.

His gas cell would remain dormant for decades, but it would later emerge as a crucial precursor to the invention of the modern fuel cell.

Thus, the era of chemical renaissance was not only a witness to fundamental scientific discoveries, but also a catalyst for a new age in the field of energy—marked by the innovative use of hydrogen as an energy carrier.

Industrial Revolution: Expanding Uses of Hydrogen

In the 20th century, hydrogen became a vital resource in industry, with a wide range of applications that helped shape global manufacturing processes and production systems. One of its most significant uses is in ammonia production. This chemical reaction, known as the Haber–Bosch process, combines hydrogen with atmospheric nitrogen to produce ammonia—a key raw material in the manufacturing of fertilisers.

The oil industry has also incorporated hydrogen gas into its processes. In petroleum refining, for example, hydrogen is used to remove impurities and enhance the quality of petroleum products. One key application is the hydrodesulfurization process, which uses hydrogen to reduce the sulphur content in fuels—contributing to cleaner combustion and improved environmental performance.

Hydrogen: An Essential Gas to Meet the Needs of Modern Society

Hydrogen is also used in metallurgy to reduce metal ores such as iron, thereby contributing to steel production. This specific application, known as direct reduction, enables the extraction of metals from their oxides and plays a key role in the manufacturing of materials essential to numerous industries.

In the electronics sector, hydrogen plays a role in the production of semiconductors and advanced electronic components. Its use in these applications supports the ongoing advancement of information and communication technologies.

Hydrogen’s central role in fertiliser production, oil refining, and other industrial processes makes it an indispensable resource for meeting the growing needs of modern society.

Post-Industrial Era: H₂ in the Ecological Transition

While still widely used to decarbonise industry, hydrogen has emerged—at the turn of the 21st century—as a promising solution to environmental and energy-related challenges, making it a key player in the ecological transition. One of its main advantages lies in the decoupling of production and consumption: hydrogen can be produced during off-peak hours, stored safely, and used whenever needed.

This is why H₂ is now being used as a means of energy storage: it serves as an energy carrier to store renewable electricity generated from intermittent sources such as wind and solar. In doing so, it helps smooth out fluctuations in energy production, contributing to a more stable and reliable power supply to the grid.

Hydrogen (H₂): A Decarbonisation Solution for the Transport Sector

Hydrogen is also part of the solutions for decarbonising transport, offering zero CO₂-emission mobility and thereby helping to reduce the sector’s carbon footprint while also improving air quality.

For example, hydrogen can be used to power fuel cells that generate electricity for electric vehicles. In addition, hydrogen’s storage capacity is leveraged in these vehicles: the energy not immediately used by the electric motor is stored in a battery, which can then support the fuel cell when needed.

Hydrogen vehicles require dedicated infrastructure for refuelling: hydrogen stations. These rapidly developing stations are equipped with dispensers capable of injecting hydrogen gas under pressure directly into the vehicle’s tank.

Hydrogen is therefore emerging as a versatile player in the energy transition, offering innovative solutions to address the climate and energy challenges of the 21st century.

Did You Know?

Although hydrogen is a colourless and odourless gas, it’s still given a whole spectrum of colours!

Indeed, the colours of hydrogen are designations that refer to how it is produced and, in some cases, the type of electricity used in the process. “Green” hydrogen, for example, is produced using renewable or low-carbon energy sources—such as wind, solar, or water electrolysis.

Hydrogen: A Key Energy Carrier in the Ecological Transition

From its discovery by Cavendish to its modern-day applications, the story of hydrogen is a saga of scientific breakthroughs and technological innovation. As we continue to explore new ways to harness this versatile molecule, it is clear that hydrogen will remain a key player in the pursuit of a sustainable energy future.

Hydrogen is a chemical element abundantly present in the universe, but it is rarely found in its pure form on Earth. Unlike fossil fuels such as coal or oil, hydrogen must be produced from other primary energy sources. This makes it an energy carrier—much like electricity—with significant potential, as it can serve as a clean and sustainable alternative to fossil fuels across a wide range of sectors, including industry, power generation, and transport.

Using hydrogen as an energy source can help reduce greenhouse gas emissions and improve air quality. Moreover, hydrogen is easy to store and transport, making it a flexible and versatile energy solution. In short, hydrogen stands out as a promising energy carrier for the transition toward a cleaner and more sustainable economy.

The Various Methods of Hydrogen Production: From Fossil Resources to Water Electrolysis

Hydrogen production is emerging as a key industry in meeting society’s growing demand for clean and renewable energy.

An Introduction to Hydrogen: Properties and Potential

Hydrogen is a chemical element made up of one proton and one electron. The hydrogen molecule (H₂), also known as dihydrogen, consists of two hydrogen atoms. In common usage, the term “hydrogen” typically refers to dihydrogen (H₂).

What is hydrogen energy used for in France?

In France, hydrogen is primarily used in the chemical industry and oil refining. It also serves as a key feedstock for the production of ammonia (used in fertilizers) and methanol.

In the context of the energy transition, hydrogen energy holds the potential to be leveraged for many additional applications in the future.

• As a clean fuel: when combined with a fuel cell, hydrogen undergoes a reaction that generates electricity. It acts as a clean energy carrier, making it possible to power an electric motor—this is the operating principle behind hydrogen-powered vehicles.
• To store electricity, helping to optimise power generation capacity and address the intermittency of renewable energy sources.
• In the industrial sector, to replace fossil fuel use and supply industries with low-carbon energy.

How Is Hydrogen Produced? The Production Process

There are several methods for producing hydrogen. Today, the most widely used process is steam methane reforming (SMR). This technique relies on fossil fuels such as natural gas or biogas, using steam to break the carbon-hydrogen bonds in methane. Through two successive chemical reactions, the atoms are separated and recombined into dihydrogen (H₂) and carbon dioxide (CO₂). The resulting gas mixture is then purified to obtain “grey” hydrogen with a purity of approximately 99.9%. While steam reforming offers a competitive cost advantage, it has a significant carbon footprint—generating more than 10 kg of CO₂ for every kilogram of grey hydrogen produced.

Coal gasification was also widely used in the 19th century to produce town gas and liquid fuels for military purposes. When coal is subjected to extremely high temperatures, it vaporises, and the carbon it contains reacts with steam to produce synthesis gas, or “syngas”. Hydrogen can then be extracted from the syngas after impurities and CO₂ are removed. This method, which also generates high levels of CO₂ emissions, is still used today in countries with a strong coal-based industrial heritage—such as China, the United States, and Germany—to produce what is known as “grey” hydrogen on an industrial scale.

However, these hydrogen production methods are increasingly being called into question due to their significant environmental impact. As hydrogen mobility continues to gain momentum, several alternative pathways are currently under development—most notably hydrogen production through electrolysis.

Hydrogen Produced by Electrolysis: A Promising Alternative to Fossil Fuels

How Is Green Hydrogen Produced?

Green hydrogen is considered one of the key components of the energy transition toward cleaner and more sustainable energy sources. In this context, water electrolysis is a promising method for producing hydrogen using renewable energy sources such as solar or wind power. This technology triggers a reaction that splits water molecules into dihydrogen and dioxygen by applying an electric current. In practical terms, two molecules of water (H₂O) yield two molecules of hydrogen gas (H₂) and one molecule of oxygen (O₂).

2H₂O → 2H₂ + O₂

Did You Know? Electrolysers Are Key to Producing Renewable Hydrogen

When the electrolyser is powered by renewable electricity, the hydrogen produced is considered “green,” as it generates no greenhouse gas emissions from production through to end use.

Water electrolysis is therefore a key technology for green hydrogen production, helping to reduce its carbon footprint and providing a sustainable transport solution for a cleaner future.

The Electrolyser: A Key Technology at the Heart of the Compact S Hydrogen Station’s Low-Carbon Hydrogen Production System by Atawey

Capable of integrating an electrolyser, Atawey’s Compact S hydrogen station can produce up to 2 kg of hydrogen per day—equivalent to approximately 200 km of driving range for a light-duty vehicle. By adopting this approach, the compact station becomes an all-in-one solution: it combines production, storage, compression, distribution, and the Human-Machine Interface (HMI) in a single integrated unit.

The station is connected to the mains water supply and uses alkaline electrolysis technology to split water molecules. Once the water molecule is separated, the low-carbon hydrogen is stored, while the oxygen is released into the atmosphere. When the station reaches its maximum storage capacity, hydrogen production is automatically halted.

Did You Know?

The Compact S station is the ideal solution for stakeholders located in island or remote areas!

The electrolysers integrated into the Compact S stations were designed by Atawey and are manufactured in France, in Saint-Étienne.

A Compact S Station Commissioned in Guadeloupe

Delivered to Guadeloupe at the end of 2022, the Compact S station will serve as a seed station for the company SARA.

Capable of producing 2 kg of hydrogen per day and dispensing up to 6 kg in a single day, this station will supply two 700-bar vehicles.

This station is the first of its kind in Guadeloupe and was installed in March in the Jarry area. It is powered by renewable energy, supplied through photovoltaic panels.

Challenges to Overcome for Accelerating the Energy Transition: Replacing Steam Methane Reforming

Steam methane reforming, currently the most widely used method for producing low-carbon hydrogen, is set to be gradually phased out as part of the ecological transition due to its high CO₂ emissions. Water electrolysis is regarded as the most advanced alternative technology, although hydrogen production costs remain high—approximately three times more than steam reforming—and are heavily dependent on electricity prices.

The Compact S stations developed by Atawey use an integrated electrolyser to produce hydrogen. For the other stations in the range—namely the Compact M and the Evolutive hydrogen stations—an electrolyser can be installed alongside the station to enable on-site hydrogen production.

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