xtracting clean energy from water has been a dream for more than a century. Many of us remember the book Jules Verne wrote in 1874, 'The Mysterious Island,' and its vision to extract hydrogen from water, an infinite source of energy for future generations. So for 147 years, the use of civil hydrogen has been up for debate and we are unable to hazard a guess at the number of articles, conferences and announcements supporting the inception of hydrogen as an undoubtable source of energy.

For us as power electronics engineers, very much as it was in Jules Verne's vision, hydrogen energy is achieved by electrolyzing hydrogen and oxygen, and then deploying a fuel cell to generate electricity. In reality, production of hydrogen by electrolyzation is currently less than 4% worldwide, with more than 94% of this hydrogen produced from fossil resources, mainly coal and gas, and with production from biomass and other representing just 2%.

70% of the overall hydrogen produced in the world is extracted from the natural gas methane. Its extraction uses a so called 'steam reforming' process in which high-temperature steam (700°C – 1,000°C) is used to produce hydrogen. The steam reforming process, if the carbon dioxide is not captured, is responsible for high levels of greenhouse gas emissions. The amount of CO2 released ino the atmosphere by worldwide hydrogen production is estimated to be around 830 million tons.

Although this is where we are today, with the conundrum 'green hydrogen - myth or a reality' fueling the debate. But things are changing and we are getting closer and closer to Jules Verne's vision!

The shades of hydrogen!

To simplify the understanding of the different production methods and their environmental impact, industry has codified hydrogen by color. In practice, four main categories are commonly used; brown, grey, blue, and green. From time to time sub-categories appear e.g., the hydrogen that is produced by electrolyzers powered by nuclear plants is sometimes referred to as 'pink', but that is more anecdotal than a de facto delineation.

Brown hydrogen:
The color brown has been assigned to hydrogen extracted from coal by gasification. In this process the carbon based material is converted into a mix of carbon monoxide, hydrogen, and carbon dioxide. Gasification is achieved at very high temperatures (>700°C) without combustion with a controlled amount of oxygen and/or steam. The carbon monoxide then reacts with water to form carbon dioxide and more hydrogen via a water-gas shift reaction. The resulting gas from this process is called syngas. The hydrogen produced by this method is known as brown (lignite) or black (bituminous) depending on the type of coal used. However, this process is highly polluting since both the CO2 and carbon monoxide cannot be reused and are released into the atmosphere.

Grey hydrogen:
Nowadays, grey hydrogen represents the highest portion of production. More than 70% of hydrogen currently produced worldwide is classified as grey hydrogen. The most common production process uses steam methane reforming (SMR). In this process high pressure steam reacts with methane resulting in hydrogen and the greenhouse gas CO2. About 9.3kg of CO2 per kg of hydrogen is generated in this process. Although this is lower than brown hydrogen it is still a substantial amount when released into the atmosphere.

Blue hydrogen:
When CO2 produced from the previous methods is captured and stored underground using industrial carbon capture and storage (CSS) the manufacturing process is less harmful for the environment, but this process is more expensive and less efficient than conventional methods. Blue hydrogen is considered an important step in the energy transition towards green hydrogen and the vast majority of new production units are strictly controlled in terms of their environmental impact. However, despite high levels of improvement compared to brown and grey, 10% to 20% of the CO2 cannot be captured and is released.

Green hydrogen
Globally, the amount of hydrogen production from water electrolysis is very small, less than 4%, but it is the most well-known technique, one that some of us will remember from our school chemistry lessons. Using electricity, hydrogen is produced by splitting water molecules into hydrogen and oxygen. In the case of green hydrogen, the electricity is produced by renewable energy sources (less than 1%). In this process the electrolyzers are the 'masterpiece' and have been used for decades with an average efficiency of 73% (compared to 65% for the steam reforming process). As for the power supply, improving its efficiency is obviously vitally important to reduce energy consumption and cost. Intensive research aims to achieve a 95% conversion efficiency, which in fact we are not far away from achieving.

Hydrogen in Europe - state of the business

Many are aware of climate challenges and the Paris agreement adopted by 196 Parties at COP 21 in Paris on December 12, 2015. The ratified agreement was entered into force on 4 November 2016. The Paris Agreement embraces a vision of fully utilizing the development of technology and transfer for both improving resilience to climate change and reducing greenhouse gas emissions.

Illustration 01 – The European Green Deal overview (Source PRBX/ European Commission)

To achieve this goal many activities have been initiated and one of those is to develop and deploy a European strategy for hydrogen. This strategy was published in July 2020, setting out a vision of how the EU can turn clean hydrogen into a viable solution to decarbonize different sectors over time, installing at least 6GW of renewable hydrogen electrolyzers in the EU by 2024 and 40GW of renewable hydrogen electrolyzers by 2030.

To support that strategy, it is important to have global coordination between public authorities, industry, civil society and the research community. A number of alliances have been formed, facilitating synergies and the execution of strategies.

The EU Clean Hydrogen Alliance
As part of the New Industrial Strategy for Europe, in July 2020 the European Clean Hydrogen Alliance (ECH2A) was launched in the context of the hydrogen strategy for a climate-neutral Europe.

The European Clean Hydrogen Alliance is aimed at developing and deploying hydrogen as a viable and competitive energy source in Europe. The Alliance supports the implementation of the hydrogen strategy for a climate neutral Europe, by working towards developing a full and accessible EU wide hydrogen value chain. This will be achieved through, among others things, an investment agenda and a pipeline of projects, as well as by mobilizing resources and actions to install renewable hydrogen electrolyzers to achieve the aforementioned 6GW and 40GW objectives.

In April 2021, the EU Commission sent an invitation to all 1000+ members of the European Clean Hydrogen Alliance inviting them to submit projects for renewable and low-carbon hydrogen technologies and solutions. In June 2021 the second European Hydrogen Forum took place and reported an impressive number of 1,052 submitted projects, from which 997 met the eligibility criteria. This number reflects the very high interest and engagement of European industry to accelerate the development of hydrogen on the continent.

The EU Fuel Cells and Hydrogen Joint Undertaking
Because the importance of developing efficient electrolyzers is a high priority, as long ago as 2003 the European Commission facilitated the creation of the European Hydrogen and Fuel Cell Technology platform with the goal to link public and private research and to create initiatives to accelerate the development of efficient fuel-cell and hydrogen technologies.

From this initiative, in May 2008 the Council of the European Union set up the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) with the objective: To contribute to the implementation of the Seventh Framework Program and in particular the Specific Program 'Cooperation' themes for 'Energy', 'Nanosciences, Nanotechnologies, Materials and New Production Technologies', 'Environment (including Climate Change)', and 'Transport (including Aeronautics)'.

Illustration 02 – AIRBUS Zero emission airplane powered by Hydrogen (Source PRBX/AIRBUS)

Amongst the notable projects and initiatives underway is one very interesting study, commissioned by Clean Sky 2 and Fuel Cells & Hydrogen 2 Joint Undertakings on hydrogen's potential for use in aviation. Using hydrogen in aeronautics will require a huge amount of technical innovation and a new infrastructure, but it is seen as a major step forwards in the reduction of CO2 emissions from the aviation sector. The airplane manufacturer AIRBUS took part in the study and it's worth mentioning the company's ambition to develop the world's first zero-emission commercial aircraft by 2035 (illustration 02).

From small to big, hydrogen is making its way!

Step by step, slowly but surely, green hydrogen is becoming a reality and the number of installed electrolyzers is rapidly increasing. Clearly it would be difficult to list all the projects, but it's interesting to mention a few of them to illustrate the evolving reality.

Illustration 03 – Sweden / Mariestad ElectriVillage solar to hydrogen autonomous station (Source PRBX / Mariestad Municipality)

Sweden – Mariestad ElectriVillage
Located in the southern part of Sweden on the shore of the lake Vänern, the municipality of Mariestad developed a concept to create a sustainable energy ecosystem based on renewable energy and hydrogen. The original project included a large array of solar panels to power electrolyzers generating hydrogen for an autonomous refuelling station for cars and utility vehicles. Exploring the large range of possibilities offered by this technology, the station could also use the stored hydrogen to supply a fuel cell to generate electricity. The oxygen resulting from the split process in the electrolyzers is captured and stored for medical, industrial or farming applications. This autonomous station is a good example of what could be deployed at a larger scale and even to generate hydrogen for other vehicles such as local trains (illustration 03)

Germany – Wesseling EU Largest PEM electrolyzers
As part of the REFHYNE European consortium and with EU funding through the Fuel Cells and Hydrogen Joint Undertaking (FCH JU), the largest European polymer electrolyte membrane (PEM) water electrolyzers began operating at Shell's Energy and Chemicals Park in Rhineland near Cologne. The Rheinland electrolyzers will use renewable electricity to produce up to 1,300 tons of green hydrogen a year, and plans are underway to expand capacity of the electrolyzers from 10 megawatts to 100 megawatts (illustration 04).

These two examples reflect the scale of hydrogen initiatives in Europe and especially considering the large number of projects, place Europe as a leading player in energy transition and industry decarbonization.

In conclusion
After decades of interest in hydrogen, we have finally entered a new era. Europe began its 'H' engagement more than 20 years ago and the 'Green Deal' boosted research, cooperation and deployment. There is no doubt that Europe has taken major steps to reach the 2050 goal and other countries are also speeding-up their hydrogen strategies. In the US, under President Joe Biden's direction, major activities are taking place. As announced on July 7, 2021 by the U.S. Department of Energy (DOE), an allocation of $52.5 million will fund 31 projects to advance next-generation clean hydrogen technologies and support DOE's recently announced Hydrogen Energy Earthshot initiative to reduce the cost and accelerate breakthroughs in the clean hydrogen sector. These are clear signs that hydrogen is an important part of the US energy transition strategy.

Hydrogen is no longer a myth and Jules Verne's vision: "Water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable" will become a reality.

Provided by Patrick Le Fèvre Chief Marketing and Communications Officer, Powerbox

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