What is hydrogen? How can it be produced? And how can you guarantee the availability of hydrogen, even on your most remote production sites? Below, you can find the answers to some of the most frequently asked questions in our field of expertise.

Frequently asked questions

What’s the difference between a water electrolyzer and a Fuel Cell?

A water electrolyzer is a device designed to separate water (H2O) into its fundamental elements hydrogen (H2) and oxygen (O2), through the application of electrical energy. The gases remain segregated after the separation process.

A Fuel Cell operates in the opposite manner: it combines hydrogen and oxygen to produce water through an electrochemical process. This process also releases electrical energy that can be stored or used, such as for powering Fuel Cell Electric Vehicles (FCEVs).

Can hydrogen fuel electric vehicles, and what’s the difference with battery electric vehicles?

Hydrogen can serve as a fuel for electric vehicles. These include Fuel Cell Electric Vehicles (FCEVs) and Battery Electric Vehicles (BEVs), both of which rely on electricity as their energy source. In FCEVs, electricity is generated while driving by combining hydrogen with oxygen from the air. In BEVs, batteries are charged, and electricity is drawn from the battery during driving. Apart from FCEVs, hydrogen can also be utilized in hydrogen combustion engines.

Currently, BEVs are most suitable for short-distance city traffic. FCEVs and vehicles with Hydrogen Internal Combustion engines are better suited for long distances and heavy transport. By incorporating a mix of BEVs, FCEVs, and vehicles with Hydrogen Internal Combustion engines, we can effectively optimize the utilization of available energy within the energy mix.

Can green hydrogen be used on a large scale?

Our HyGGeTM water electrolyzers can produce hydrogen on a large scale. While CapEx is important, the expense of the renewable energy used in hydrogen production will predominantly determine the OpEx of green hydrogen production. This cost consideration will heavily influence the decision to implement large-scale green hydrogen usage.

Can hydrogen be easily transported?

Hydrogen can be transported as a gas via tube trailers or through dedicated pipelines. Hydrogen is also transportable in liquid form, although the cryogenic handling required to keep the liquid at temperatures below -253°C can be expensive. Another option is to combine hydrogen with nitrogen to produce ammonia. This ammonia can be conveniently transported in liquid form, either in tanks or through pipelines. Subsequently, it can be cracked back into hydrogen and nitrogen, or used as ammonia without additional processing.

Can hydrogen be used to produce electricity?

Yes! Hydrogen can be used to produce electricity. For instance, hydrogen can be combined with oxygen to form electrical energy that can be stored in Fuel Cells. One can also use a combustion engine and a generator to create electricity from hydrogen. The efficiency of this process is somewhat limited, though. Yet, capturing the heat generated during this process can enhance the overall efficiency.

Is Hydrogen safe to use?

Hydrogen has been extensively used, produced, stored, and handled in numerous industrial applications since the beginning of the 20th century. When one adheres to the established safety standards, hydrogen is perfectly safe to use.

However, it’s important to note that hydrogen remains a highly flammable gas, lighter than air. In the event of a leak, hydrogen will rapidly rise and disperse into the atmosphere. If high concentrations of hydrogen are ignited (and only minimal amounts of energy are required to ignite hydrogen), it can lead to explosions that can be dangerous if not handled with care.

How much CO2 pollution is generated during hydrogen production?

The extent of CO2 pollution (as well as the environmental impact) generated during hydrogen production depends on two factors: the chemical composition of the compound containing the H2 molecule, and the energy utilized to break the bonds within this compound.

The following list refers to the various ‘colors’ of hydrogen, arranged from the least environmentally impactful to the most:

  • White Hydrogen: H2 sourced from Earth’s internals. This pure, natural H2 requires no breaking of molecular bonds, resulting in no production of CO2 or other polluting molecules. However, harvesting White Hydrogen proves to be very challenging. Consequently, hydrogen production becomes necessary. Hydrogen can be produced in several ways, yielding different types of hydrogen, as detailed below.
  • Green Hydrogen: H2 obtained from water electrolysis using renewable energy sources such as wind or solar power. This process does not emit CO2. However, it is reasonable to assume a CO2 emission of 0 to 2 kg for every kilogram of hydrogen produced, depending on the source of electricity used.
  • Pink Hydrogen: Electrolytic hydrogen produced with nuclear power. Typically, this process produces 1 kg of CO2 for every kilogram of hydrogen produced.
  • Turquoise Hydrogen: Hydrogen produced by thermal methane splitting (methane pyrolysis). This process doesn’t inherently generate CO2, but solid elemental carbon (carbon black) instead. However, maintaining the required production temperature of 1000°C proves challenging. Sustaining such high temperatures demands additional energy, resulting in CO2 emissions.
  • Blue Hydrogen: Hydrogen derived from fossil fuels, with the CO2 captured and either stored or utilized in a separate process and not released into the atmosphere.
  • Brown Hydrogen: Hydrogen produced as a by-product of industrial processes. The level of CO2 pollution depends on the waste products from the source processes.
  • Grey Hydrogen: Hydrogen extracted from Natural Gas (CH4) using Steam-Methane Reforming (SMR). The majority of H2 gas is produced through this method, resulting in 8 to 10 kg of CO2 emissions for every kilogram of hydrogen produced.
  • Yellow Hydrogen: Electrolytic H2 from Grid energy. The amount of CO2 pollution depends on the energy mix used to create the electricity on the Grid.
  • Black Hydrogen: Hydrogen produced through Coal Gasification. This method leads to a significant emission of 14 to 15 kg of CO2 for every kilogram of hydrogen produced, making it the most environmentally impactful form of hydrogen production.
How is Hydrogen produced?

Natural hydrogen (also known as ‘white’ hydrogen) can be found worldwide, yet it is not easily extracted. Fortunately, hydrogen is also widely available in compound forms. For instance, water (H2O), fossil fuels, and natural oils all contain hydrogen. This hydrogen can be extracted by breaking the molecular bonds and isolating the H2 molecules as a result. Unfortunately, this process often leads to the formation of polluting molecules such as NOx, CO, and CO2.

At present, most hydrogen is obtained by ‘cracking’ methane (CH4) through Steam Methane Reforming. While this process isolates the H2 molecule, it also causes the carbon to combine with oxygen, resulting in approximately 8 to 10 kg of CO2 for every kilogram of hydrogen produced. This has a significant environmental impact.

Fortunately, hydrogen production through water electrolysis (as achieved with our HyGGeTM water electrolyzers) does not have such a negative effect on the environment. In fact, if our HyGGeTM units are powered by renewable energy sources like solar or wind energy, the electrolysis process generates ‘green’ hydrogen – the most environmentally friendly form of H2, second only to natural or white hydrogen.

How can we get energy from Hydrogen?

Hydrogen is an energy carrier: it can store energy within the H2 molecule, and this energy can be released when the H2 molecule combines with other elements. For instance, the fusion of hydrogen with oxygen in a combustion engine releases energy in the form of an explosion, propelling the engine. The electrochemical combination of hydrogen with oxygen produces electrical energy.

Does hydrogen come in different colors?

Hydrogen is colorless, but color coding is used to indicate the environmental impact of different hydrogen production methods. The following terminology refers to hydrogen production, arranged from the least environmentally impactful to the most:

  • White Hydrogen: H2 from Earth’s internals. This is very challenging to harvest.
  • Green Hydrogen: H2 from water electrolysis using renewable energy (wind, solar…) without any CO2 emissions.
  • Pink Hydrogen: Electrolytic hydrogen produced with nuclear power.
  • Turquoise Hydrogen: Hydrogen produced by thermal methane splitting (methane pyrolysis) with solid carbon as a by-product. It is very challenging to keep the production process at 1000°C.
  • Blue Hydrogen: Hydrogen produced from fossil fuels, where the CO2 is captured and stored, or used in a different process (i.e., not released in the atmosphere).
  • Brown Hydrogen: Hydrogen produced as a by-product of industrial processes.
  • Grey Hydrogen: Hydrogen extracted from Natural Gas (CH4) using Steam-Methane Reforming (SMR). Most H2 gas is produced this way, with lots of CO2 as a by-product.
  • Yellow Hydrogen: Electrolytic H2 from Grid energy, regardless of the energy mix.
  • Black Hydrogen: Hydrogen from Coal Gasification. This produces lots of CO2.
What is green hydrogen?

Hydrogen gas is colorless. Nonetheless, the term ‘green hydrogen’ is used to refer to hydrogen that was produced with an electrolyzer and a renewable energy source without any other emissions (e.g. wind or solar energy).

What is hydrogen?

Hydrogen is the lightest and most abundant chemical substance in the universe. It always combines with other elements. In its simplest state, it manifests as a diatomic molecule, hydrogen gas (H2). Hydrogen gas is colorless, odorless, tasteless, non-toxic, and incredibly combustible. That’s why we have so many safety measures in place to guarantee safe hydrogen production with our HyGGeTM 100A water electrolyzers.

Which is better? Pressurized or non-pressurized water electrolyzers?

Depending on your use of hydrogen, having it available at a specific pressure can be interesting. For processes operating at 3 bar, a 5 bar system might suffice if the electrolyzer meets demand consistently. Atmospheric electrolyzers always require an additional compression system, incurring an OpEx in addition to a CapEx. If you need hydrogen at higher pressure, e.g., in mobility applications, you will have to compress the gas.

A compressor is a ‘multiplier’ of the pressure. Typically, a compressor compresses up to 6 times the input pressure in a single stage. For instance, 10 bar input can yield 360 bar output of a 2-stage compressor. Starting at 30 bar input, you can reach 1000bar at the output after 2 stages (mobility), or 180bar after only 1 stage, which could be enough to fill bottles/racks.

Which electrolyzer technologies are most used?

Commonly used and commercially available electrolyzer technologies include:

  • Alkaline Atmospheric
  • Alkaline Pressurized
  • PEM Pressurized
  • PEM Atmospheric
  • SOEC
  • AEM

For more information on the technologies used in our HyGGeTM 100A water electrolyzer, please contact Exion Hydrogen: sales@exionhydrogen.com

Does the Exion’s HyGGe™ 100A water electrolyzer store hydrogen?

The HyGGeTM 100A water electrolyzer does not store hydrogen inside the unit. In fact:

  • Exion’s HyGGeTM100 has only a minimal volume of hydrogen gas in the unit.
  • Strict safety measures prevent incidents with hydrogen in the unit.
  • All produced hydrogen is promptly transferred to the user line.
  • Hydrogen production halts automatically when demand is low.
  • Hydrogen production resumes automatically with increased demand.
  • Gas storage, if needed, can occur in separate on-site storage recipients.
  • Specific safety measures apply depending on the volume, pressure, and location where you store your produced hydrogen.

For more information, please contact Exion Hydrogen: sales@exionhydrogen.com

What makes Exion’s HyGGe™ 100A water electrolyzer unique and valuable?

The HyGGeTM 100A water electrolyzer is unique because:

  • It adheres to European Directives and the highest international safety standards.
  • It runs on two newly designed cell stacks that are very robust, reliable, and efficient.
  • The innovative design of our components mitigates the risk of deformations.
  • We only use premium materials such as solid nickel stack elements, enhanced with catalytic coatings for improved efficiency and productivity.
  • Since we use premium materials, our unit requires little or no maintenance.
  • Our units can be combined. You will never have to overshoot or undershoot with water electrolyzers that are too large or too small for your requirements.

For more information, please contact Exion Hydrogen: sales@exionhydrogen.com

What makes Exion Hydrogen a unique valued hydrogen partner?

Exion Hydrogen is an experienced, reliable, and accountable partner for your business:

  • Together, we have over 100 years of hydrogen production industry experience.
  • We developed a new cell stack from scratch to make it more robust and efficient.
  • We have an extremely experienced Research and Development (R&D) team.
  • We have state-of-the-art production facilities and engineers.
  • At Exion Hydrogen, you will always get sound advice from experienced engineers.
  • We only use top-quality materials to make our electrolyzers more durable.
  • Market expertise, offering direct delivery or through value-added third parties.
  • We serve both end consumers and hydrogen (merchant gas) suppliers.

For more information, please contact Exion Hydrogen: sales@exionhydrogen.com

How do you calculate the business case for on-site hydrogen production?

Several factors determine the viability of on-site hydrogen production for your business:

  • Electricity costs

In on-site water electrolysis for hydrogen production, your energy consumption will be your primary operational expenditure, significantly affecting the total cost of ownership.

  • Required volume

Do you need large quantities of hydrogen, or do you seek to use abundant renewable energy (green electricity) for hydrogen production and subsequent storage as an energy source? This affects the required number of water electrolyzers to operate simultaneously.

  • On-site storage availability

Do you have sufficient pipeline networks, silos, or other storage solutions to store all the hydrogen you will generate?

  • Downtime cost

How much will it cost when your business halts due to hydrogen shortages? In other words, how valuable is it to achieve independence from external hydrogen suppliers, enabling your business to operate 24/7 through self-produced hydrogen?

  • Comparison with other hydrogen sources
    How does the above align with costs tied to alternative hydrogen sources, accounting for factors like geographic proximity to supply centers and supplier accessibility to your production sites?

For detailed calculations, please contact Exion Hydrogen: sales@exionhydrogen.com

What’s better? Delivered hydrogen or on-site hydrogen production?

This depends on several factors:

  • Delivered hydrogen cylinders are bulky, heavy, and not easy to handle.
  • Delivered hydrogen supply can be inconsistent, causing production interruptions.
  • Bottled gases are also subject to price fluctuations. This can affect your OpEx.
  • Connections to gas pipelines can be expensive, but your cost per kg will be lower.
  • Remote locations may incur high costs for bottled gas delivery.
  • On-site hydrogen production stands as a secure and cost-efficient alternative to conventional supply methods.

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International standards

✔️ ISO 22734-1: 2008 Hydrogen generators using water electrolysis process -Part 1: Industrial and commercial applications

✔️ IEC 60204-1:2005 Safety of machinery –electrical equipment of machines –part 1 general requirements

✔️ IEC 61439-1:2011 Low voltage switchgear and control gear assemblies –part 1: general rules

✔️ IEC 61439-2:2011 Low voltage switchgear and control gear assemblies –part 2: power switch gear and control gear assemblies

✔️ IEC 60634-5-52:2009 Selection and erection of electrical equipment –wiring systems

✔️ IEC 61000-6-2:2005 EMC Part 6.2 generic standards –immunity for industrial environments

✔️ IEC 61000-6-4:2006 EMC part 6.4 generic standards -emission standard for industrial environments

✔️ EN 50160: 2019 Voltage characteristics of electricity supplied by public electricity networks

✔️ ISO 12944-5:2018 Paints and varnishes. Corrosion protection of steel structures by protective paint systems Protective paint systems

✔️ ASME Boiler and Pressure Vessel Code section VIII Div 1-ASME B31.3 Process piping-Standard for maintenance ails & escape roads

European Directives

✔️ Machine Directive2006/42/EC

✔️ Low Voltage Directive 2014/35/EU3

✔️ ATEX 137 1999/92/EC4

✔️ Electromagnetic compatibility 2014/30/EU5

✔️ Pressure equipment Directive 2014/68/EU (PED)