Hydrogen 3.0

Hydrogen 3.0

“Are we on the cusp of a hydrogen revolution or merely witnessing the build-up of another bubble?” In his new book Hydrogen 3.0 – Reality Check, author Frank Genin seeks to separate fact from fiction. In doing so, the American invites his readers on a journey to uncover the truth behind the hydrogen hype.

Spanning 280 pages and with numerous black-and-white illustrations (also available in color in the digital version), the book provides an all-encompassing view of the global hydrogen economy – in Genin’s words a “nuanced, well-researched perspective” – in which he shines a light on a multitude of topics including various application areas and markets – from China to Germany.


Genin asks whether hydrogen is really the fuel of the future – the green panacea, the magic bullet that we have all been waiting for – or whether, in our desperation, we have perhaps overstated its potential. Written in an impartial and factual style, the book is aimed at investors and environmentalists alike as well as anyone who wants to find out more about hydrogen.

Genin, Frank; Hydrogen 3.0, ISBN 978-2-958-293093, 2024

Mechatronic H2 pressure regulator

Mechatronic H2 pressure regulator

Up until now, Italian company Landi Renzo has been mainly known for its conversion sets for gas engines. Now the automotive supplier, which employs more than 1,200 staff globally, is venturing into the hydrogen sector and developing an advanced electronic pressure regulator for medium- and heavy-duty vehicles with H2 combustion engines.

The Cavriago-based company has joined forces with German group Bosch to help it broaden its range beyond components for natural gas, biomethane or LPG. Its aim is to produce and market hydrogen-based fuel systems with next-generation mechatronic pressure regulators before the end of 2024. In doing so, Landi Renzo hopes to become an enabler of carbon-neutral commercial vehicle operation and thus play a part in accelerating the decarbonization of the mobility and transport sector.


Damiano Micelli, head of technology, commented: “This mechatronic hydrogen pressure regulator is an important milestone in technological advancement which we are able to offer to the rapidly evolving mobility and transportation market. […] This is a highly innovative solution that will be available shortly for medium- and heavy-duty applications.”

Pressure regulators are a key element in conversion kits since they help to balance out large pressure differences and, if needed, change the state of a particular fuel. According to Landi Renzo, “a simple and robust mechanical regulator” was previously sufficient to fulfill this function. However, mechatronic pressure regulators such as the EM-H can also control and calibrate the hydrogen delivery pressure in line with vehicle requirements. In a two-stage process, the inlet pressure is initially reduced mechanically from high to medium. The pressure is then lowered entirely electronically to the desired value.

Landi Renzo has over 70 years of experience in the automotive and energy sectors and its facilities include an H2 center of excellence in Bologna which has a well-equipped, modular Class 8 clean room.

Establishment of a metrological infrastructure

Establishment of a metrological infrastructure

Flow measurement of high-pressure gas and liquid hydrogen

In the field of flow measurement, the use of hydrogen, especially regeneratively produced hydrogen, as a process gas and energy carrier has become a focal point in many applications. Due to the need to use storage capacity efficiently, hydrogen must be stored under high pressure or in liquid state. Metrologically verified quantity measurement is needed for the low to high pressure range of gaseous and liquefied hydrogen applications. In addition, appropriate traceability chains to the SI system need to be established for the wide range of operating conditions in order to make valid statements about the measurement accuracy and stability of the flow meters used. The EMPIR project 20IND11 MetHyInfra addresses these challenges by providing reliable data, metrological infrastructure, validated procedures and normative support.


Critical Flow Venturi Nozzles (CFVN) are widely used today and represent a standardised and accepted method of flow measurement. The main details of the shape and theoretical model are defined in the ISO 9300 standard. CFVNs are used in legal metrology and are recognised as a reliable standard with high long-term stability. The low cost and low maintenance CFVNs provide stable, reproducible measurements with a well-defined geometry and are only dependent on the gases used. The ISO 9300 standard describes two nozzle shapes, cylindrical and toroidal. In reality, however, the nozzle contours manufactured to this standard deviate from these ideal shapes. In most cases, the actual shape is between the two ideal shapes.

The achievable measurement uncertainty is also limited by the quality of the models of the thermophysical properties of the gases to be measured. The current reference Equation of State (EoS) for normal hydrogen (n-H2) was developed by Leachman et al [1]. Due to the limited thermodynamic measurement data available for n-H2 with comparatively high measurement uncertainties, the uncertainties for the various properties are generally an order of magnitude higher than for other gases.

Therefore, in this project, new Speed of Sound (SoS) measurements were performed at temperatures from 273 to 323 K and pressures up to 100 MPa. The data obtained were used to develop a new EoS for n-H2 optimised for gas-phase calculations [2]. The measurements made it possible to significantly reduce the uncertainties of the SoS calculated from the EoS in the investigated temperature and pressure range.

Extensive Computational Fluid Dynamics (CFD) simulations were carried out in the project to gain further insight into the flow physics in the nozzle. For this purpose, a numerical model for high-pressure hydrogen flows in the CFVN was developed in OpenFOAM, taking into account various relevant gas effects such as compressibility effects, boundary layer effects and transition effects. The results obtained are in much better agreement with the experimental data than previously available implementations.

In order to be able to evaluate and compare the flow behaviour of non-ideal nozzle contours, CFD simulations were also carried out for the ideal nozzles investigated experimentally in this project, as well as for parameterised nozzles. The flow coefficient of these non-ideal nozzles can be predicted very well using the proposed nozzle shape characterisation. The implementations developed in the project are freely available [3].

Figure 2: Mobile HRS flow standard

As there is currently no test facility with traceable standards available, that can be used to calibrate CFVNs directly with high pressure hydrogen, an alternative method had to be developed. The chosen approach is to calibrate a Coriolis flow meter (CFM) under high pressure conditions (range 10 MPa to 90 MPa) with a traceable gravimetric primary standard, so that it can later be used as a reference for the nozzle calibration.

The H2 test filling station (Hydrogen Refuelling Station, HRS) at the Centre for Fuel Cell Technology (ZBT) in Duisburg was selected for the calibration of the reference meter. For the measurements, a Rheonik RHM04 CFM was installed as a reference flow meter in the “warm zone” of the HRS, i.e. upstream of the heat exchanger and the pressure control valve. In this area, the temperature is always close to the ambient temperature and the pressure is constantly high, typically around 90 MPa. A mobile HRS primary flow standard was used for the calibration, which was connected directly to the HRS and thus took the role of a vehicle.

In the final step, the results of the CFVN measurement campaign will be compared with those of the CFD simulations. The newly developed EoS will be used in both the measurement campaign and the CFD simulations in order to compare both results in the best possible way.

Measurement method for liquid hydrogen

In addition to gaseous hydrogen, the project focuses on liquefied hydrogen (LH2). There are currently no primary or transfer standards for the measurement of LH2. The uncertainty associated with using a flow meter to measure the quantity of LH2 is unknown and unquantified as there is no direct traceability to calibrations using LH2 as the calibration liquid. The lack of calibration facilities means that meters used with LH2 must be calibrated with alternative liquids such as water, liquid nitrogen (LN2) or liquefied natural gas (LNG).

The project has therefore developed three approaches based on completely independent traceability chains for LH2 flow measurement. The first two approaches are applicable to flow rates during loading and unloading of LH2 tankers (flow rates up to 3,000 kg/h for a DN25 cross-section at pressures up to about 1 MPa), the third for smaller flow rates (4 kg/h for a DN3 cross-section at pressures up to about 0.2 MPa).

The first approach is based on the evaluation of the transferability of water and LNG calibrations to LH2 conditions. The study will identify and analyse potential uncertainty contributions for cryogenic CFMs. The experimental and theoretical analysis will serve as a basis for guidelines for the design and selection of CFMs suitable for SI traceable LH2 flow measurements. CFMs are a well-accepted technology for direct measurement of mass flow and density of liquids and are typically used in cryogenic custody transfer for transport fuel applications.

The literature review identified several temperature correction models applicable to LH2 flow measurement, i.e. how the LH2 flow measurement should be corrected due to temperature effects affecting the CFM measurement. Numerical finite element methods (FEM) for U-shaped, arc-shaped and straight pipe designs have been used to predict the temperature sensitivity of CFMs for LH2 flow measurement [4]. Finally, FEM can also be used to estimate the achievable measurement uncertainty using the current state of the art for LH2 flow measurement.

The second approach is based on cryogenic Laser Doppler Velocimetry (LDV) and is referred to as “Référence en Débitmétrie Cryogénique Laser” (RDCL). Traceability is ensured by velocity measurements and it can be used either as a primary standard or as a secondary standard for flow measurements of LH2. Its in-situ calibration uncertainty in cryogenic flows (i.e. LN2, LNG) has been estimated to be 0.6% (k = 2) [5]. Since the RDCL can be installed in any LNG plant, it has the advantage that a representative calibration can be performed directly in the plant under process conditions.

Figure 3: LDV standard for traceable cryogenic flow measurement

The third approach is known as the vaporisation method. Traceability to SI units is ensured in the gas phase by calibrated Laminar Flow Elements (LFE) after the liquefied gas has been evaporated. The LFEs are traceable to the Physikalisch-Technische Bundesanstalt (PTB). As with the first approach, the transferability of alternative liquid calibrations using water, LN2 and liquefied helium (LHe) must be evaluated, as the calibration rig is not suitable for direct use of LH2 for safety reasons. The lower flow range and the fact that non-explosive gases are used are operational advantages of the evaporation method. Another benefit is the use of LHe (boiling point about 4 K) so that the uncertainty of the alternative liquid calibration is based on interpolation rather than extrapolation.

An important aspect to consider in the vaporisation method is the conversion of para hydrogen (para-H2) to normal hydrogen (n-H2), which has been studied in detail by Günz [6]. At low temperatures, para-H2 is present almost exclusively; at room temperature, the ratio changes to 25% para-H2 and 75% ortho-hydrogen (n-H2). Para-H2 and ortho-hydrogen differ significantly in certain physical properties such as thermal conductivity, heat capacity or SoS. These can strongly influence the gas flow measurement, depending on the measuring principle of the flow meter. LFEs used to measure gas flow at ambient conditions are not affected by this as density and viscosity show negligible differences, particularly in the temperature range of interest here.

In summary, the results of the project will increase the confidence of end users and consumers. The methods presented will ensure reliable measurement data, which is important for increasing the share of hydrogen in total energy consumption.

This project (20IND11 MetHyInfra) has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.


[1] Leachman, J. W.; Jacobsen, R. T.; etc., Fundamental Equations of State for Parahydrogen, Normal Hydrogen, and Orthohydrogen, J. Phys. Chem. Ref. Data 38(3): 721-748 (2009)

[2] Nguyen, T.-T.-G.; Wedler, C., etc., Experimental Speed-of-Sound Data and a Fundamental Equation of State for Normal Hydrogen Optimized for Flow Measurements. International Journal of Hydrogen Energy, 2024.

[3] Weiss, S. (2023). Derivation and validation of a reference data-based real gas model for hydrogen (V1.0) [Data set].

[4] Schakel, M. D.; Gugole, F.; etc., Establish traceability for liquefied hydrogen flow measurements, FLOMEKO, Chongqing, 2022

[5] Maury, R., Strzelecki, A., etc., Cryogenic flow rate measurement with a laser Doppler velocimetry standard, Measurement Science and Technology, vol. 29, no. 3, p. 034009, 2018

[6] Günz, C., Good practice guide to ensure complete conversion from para to normal hydrogen of vaporized liquified hydrogen,

Authors: Oliver Büker, RISE Research Institutes of Sweden, Borås, Sweden, Benjamin Böckler, PTB Physikalisch-Technische Bundesanstalt, Braunschweig, Germany

Fuel cell systems for grid hardening

Fuel cell systems for grid hardening

Interview with Christian Leu and Benedikt Eska from Axiosus

An important but often neglected area of application for H2 technology is the uninterrupted supply of power. To prevent flickering lights and even more so blackouts, so-termed UPS (uninterruptible power supply) systems are indispensable. In the best-case scenario, when the network is stable, they will not be used, but their presence is nevertheless of central importance. H2-international spoke about this to Benedikt Eska and Christian Leu, the managing directors of Axiosus Energy GmbH, as well as about the company itself and the technology platform Clean Power Net (CPN).


Fig.: Christian Leu

H2-international: Let’s start with your FC and hydrogen CV. You have both been in the H2 business for some time already. Since when and where or as what?

Leu: It all started when I started working as a development engineer for fuel cell technology at the Berlin start-up Heliocentris in 1998. Most recently, I was responsible for the stationary fuel cell power supply product line there and during this time involved in the first commercial roll-outs for FC grid replacement systems at the radio communications service BOS in Germany.

Eska: My first serious contact with the subject of fuel cells was over 25 years ago already. In 2001, I then started at Proton Motor and was one of the people responsible for the IPO in London in 2006. In 2009, I founded my consulting company with focus on fuel cells and hydrogen.

Mr. Leu, after this long time at Heliocentris, you were initially active alone in Berlin. Why then did you join forces with Mr. Eska?

Leu: Following the insolvency of Heliocentris in 2017, I took over a position at the firm ITK Engineering, a company within the Bosch Group, for the development of expertise and business in the field of hydrogen and fuel cell technology. Over time, I developed the desire not only to support developers, but above all to help users successfully bring finished developments into commercial use in the long term. As this was not compatible with the business model of ITK, I was looking for opportunities for my own business. In Benedikt, I found an ideal partner – like-minded and complementary in experiences and strengths.

Mr. Eska, after these years of working independently – what prompted you to found your own company with Mr. Leu??

Eska: There were more and more requests in my consulting company asking if I could also help with implementation. For this reason, I had been thinking about changing my legal form for some time and putting my business on a broader footing. Then, something of a coincidence conspired, as I phoned Christian at the right moment. After having already worked together on other occasions, we had an intensive exchange and saw common ground. Admittedly, before COVID and the learning curve with online meetings, we probably wouldn’t have founded the company together in this form a few years ago.

When exactly did you start working together?

Eska: We founded the company together in 2022, but we actually already knew each other from the VDMA (German association for mechanical engineers) working group on fuel cells, or really – for those who know it – from the predecessor AK Berta. That must have been around 2003 or 2004.

Before we come to your services: What does Axiosus stand for?

Leu: We often get this question, of course. Axiosus is a made-up word and already has our field of activity in its name. Axiosus is composed of the Greek axiópistos for “reliable” and the English “sustainability.” Axiosus Energy therefore stands for reliable, sustainable energy supply solutions.

I see. What exactly do you offer then?

Eska: We see ourselves strongly at the interface between system providers and users. The suppliers want to focus on their standard products, and the users are looking for an optimal solution for themselves. We bring both sides together. This starts with the technical conception and site planning through to implementation on site with the various builders. For this, we rely on our partners, for example from the electrical and civil engineering industry. From the user’s point of view, we can also act as a general contractor for suitable projects. We act manufacturer-neutral and open to all technologies.

In summary, there are two pillars: consulting and project development. Our hardware projects are currently mainly in the area of emergency power supply for critical infrastructure. We also provide consulting services in the fields of electrolysis, hydrogen supply and strategic-technological corporate development.

Can you please give us an insight into how big the market for this is – here in Germany alone?

Leu: Without taking into account other applications from other areas of critical infrastructure, 3,800 base stations are in operation in the BOS radio network alone, with power requirements of less than 5 kW. In the service range, we tend to assume more than 10,000 applications with high availability requirements.

You look after, for example, the BOS digital radio in Brandenburg. Can you briefly discuss what you’re doing there with respect to this project?

Eska: In Brandenburg, we are are working as subcontractors of the fuel cell manufacturer Advent Technologies from Denmark. We coordinate all necessary planning and installation work for emergency power systems. We are also the first point of contact for technical questions for the operator. In the next phase, we will also take care of the maintenance and service work.

There’s this great term “grid hardening.” What does that mean?

Leu: The aim of grid hardening is to secure the entire BOS radio network for 72 hours. For this purpose, the existing battery UPS systems are usually supplemented by stationary emergency power systems. Many of the German states rely on fuel cell solutions for this.

Axiosus was at a CPN workshop in 2022, but isn’t, according to the website, a partner of Clean Power Net (CPN). This alliance has been very quiet in recent years. This was once one of the lighthouse projects (Leuchturmprojekt) of the German administrative agency for hydrogen and fuel cell technology (NOW). Is anything still happening there?

Eska: We see CPN as a valuable alliance of manufacturers and suppliers. As we are not members ourselves, we cannot comment on current CPN activities. As guests at the 2022 workshop, we were able to report on our operating experience in Brandenburg.

What is your latest project?

Leu: In our latest project, we are currently helping a big company with the design and procurement of hydrogen storage systems along with the associated logistics concept. We are also continuing to build up our company. First of all, we need to recruit more staff this year in order to meet demand. If all inquiries materialize, we will be able to provide larger power supply services and other orders as a general contractor.

Last question: Are you actually also internationally active?

Eska: Even though we have not been operating for long under Axiosus Energy, we already have customers from both EU and non-EU countries. Our collaboration with the Danish Advent Technologies A/S we’ve already mentioned.

Thank you very much for your answers to the questions.

Interviewer: Sven Geitmann

New CFO for H-Tec Systems

New CFO for H-Tec Systems

Electrolyzer manufacturer H-Tec Systems underwent restructuring at the turn of the year and brought in Markus Weber to join the team as chief financial officer. Up until now, the position had been held by Frank Zimmermann who decided to leave the company of his own accord. CEO Robin von Plettenberg explained: “Given his wealth of experience in large multinationals, Markus Weber is the ideal replacement for the post of chief financial officer (CFO). His wide-ranging experience in transformative and dynamic working environments will be beneficial for the international growth of H-Tec Systems.”

Weber, who has a degree in business administration, was previously employed by listed company Jenoptik where he was responsible for the financial department in his role as executive vice president of controlling and accounting. Before that, he held various leadership positions at Würzburg-based printing press manufacturer Koenig & Bauer, at elumatec and in the Voith Group. According to Weber, H-Tec Systems, which is a subsidiary of MAN Energy Solutions, is a “rapidly growing company in the vitally important field of renewables, both in terms of Germany as well as the international market.”


As of March 2024, four new vice presidents have also been appointed at H-Tec Systems: Jochen Straub, Nima Pegemanyfar, Bernd Behnke and Claudio Bravo Granadino.

One-man show continues to grow

One-man show continues to grow

Hydrogeit Verlag celebrates its 20th anniversary

The Hydrogeit Verlag publishing house has been reporting on hydrogen and fuel cell technology for more than 20 years. In these two decades, what was once a one-man operation has now become a key player in the H2 community, providing information and comment through its books and particularly through its specialist journal H2-international and its German counterpart HZwei.

It all began with a book with a very rudimentary design that was published single-handedly in 2002. The title: “Wasserstoff und Brennstoffzellen – Die Technik von morgen” (Hydrogen and Fuel Cells – The Technology of Tomorrow). Due to a lack of enthusiasm from existing publishers at that time, not to mention the outrageously low remuneration that would have been offered to the author, the first edition was released as a “book on demand,” a printing and copying process suitable for small print runs which emerged in the early aughts.


Despite its simplistic layout, the publication still managed to find an interested readership – not least because of the lack of other books on hydrogen – as did the booklet on “Wasserstoff- und Brennstoffzellen-Projekte” (Hydrogen and Fuel Cell Projects) published shortly afterward. The book attracted the attention of graphic designer Andreas Wolter, who liked the content but thought the layout was “unworthy” and offered to raise the quality bar for the second edition. And so it was that the reworked edition appeared two years later with a slick new design, published by the newly founded Hydrogeit Verlag.

Thus Andreas Wolter was the first to join our ever-growing team. A team that makes Hydrogeit Verlag what it is today: the first, and still only, specialist publisher for hydrogen and fuel cells.

Heartfelt thanks!

We’d also like to extend a very special thank-you to everyone who has played a part in creating the books, magazines, websites and newsletters: Henrike Hiersig and Robert Müller, who never fail to be utterly reliable and conscientious in their layout work; Dione Gutzmer, who has proofread so meticulously from the start; Wolf and Kathrin Lewitz, who for many years have showed their creativity in handling all things online; Nicole Helmich and Ina Woryna from fulfillment company VAH Jager, who initially took over the shipping and now also handle the billing; Michael Suckow from printec who, along with his team, brings our creations to life in print, as well as Karlee Archer and Nicola Bottrell Hayward for rendering the German articles into English.

And – crucially – the ever-growing editorial team with Eva Augsten, Sven Jösting, Monika Rößiger, Niels Hendrik Petersen and Aleksandra Fedorska in addition to many others who – time permitting – can always be relied upon to contribute valuable content.

Needless to say, there have also been many others involved in the wide array of publishing projects, be it the hydrogen CD, the teaching material on batteries and fuel cells, the study pack on renewable raw materials or diverse books that have been and will continue to be issued.

Thanks also go to the numerous project partners that over this long period have had a considerable influence on the development of the publishing house and thus likewise on the development of the renewables sector. And, of course, we thank our loyal readers.

It is all thanks to you that Hydrogeit Verlag continues to grow and that – at least to a certain degree – the H2 and FC industry is where it is today. It’s certainly no exaggeration to say that this small publishing house has succeeded in reaching many readers, among them a number of decision-makers, something which has likely helped hydrogen and fuel cells move beyond its niche and into the mainstream.

And with this in mind, we are excited to see what may lie ahead.

Author: Sven Geitmann