Hydrogen - the flexible energy carrier of the future

Clean, safe and available in almost unlimited quantities: Hydrogen. The most common element in the universe is also the lightest in the periodic table - and a versatile energy carrier.

But what is hydrogen? How is it produced? And how can the element even play a key role in the energy transition? Here are the most important questions and answers about hydrogen.

The natural chemical element hydrogen (H₂) is a molecule with two hydrogen atoms, the nucleus consisting of one proton and one electron.

Hydrogen occurs in nature exclusively in bound form, for example as water (H₂O). It is an energy carrier for storing, transporting and providing energy.

Hydrogen ...

is gaseous at room temperature
is odorless, colorless and combustible
is 14 times lighter than air
is neither toxic nor caustic or radioactive

does not ignite spontaneously and burns with colorless flame without residues

Power generation, heat supply, industry (refineries, fertilizer production ... ) and mobility sector - these are the biggest applications for hydrogen.

From powering cars, trains or ships to heating homes: Hydrogen is considered an important energy carrier of tomorrow. Industry is also increasingly relying on it, for example for the production of fuels, gases or as a raw material for industrial processes.

How is hydrogen produced?

Hydrogen occurs exclusively in compounds. To release it from these compounds, it must be split off with the help of energy. The raw materials in this process are:

Water (H2O)
Natural gas, which consists mainly of methane (CH4)
Hydrocarbons (e.g. crude oil)
Biomass
other compounds containing hydrogen

The energy source is chemical energy or externally supplied electrical, thermal or solar energy.

What is "gray", "blue / turquoise" and "green" hydrogen?

When it comes to the production of hydrogen, a distinction is often made between three color categories, namely "gray", "blue / turquoise" and "green" hydrogen. The colors indicate the type of production, energy carriers and energy sources used. Climate neutrality also plays a role.

Gray hydrogen: This is obtained by splitting fossil fuels and electricity from fossil energies. In Germany, primarily from natural gas. Due to the high emission of CO₂, gray hydrogen is considered harmful to the climate.
Blue / turquoise hydrogen: The source is also fossil fuels. However, during cracking, no or very little CO2 is released into the atmosphere. The resulting CO₂ is either stored, reused or not produced at all by using pyrolysis processes. Thus, blue hydrogen does not emit any CO₂at all, hence the name "turquoise" hydrogen. However, the long-term consequences of storage are still unclear.
Green hydrogen: Electrolysis of water and electricity from renewable energy sources produces green hydrogen. A second method of production is thermochemical or biological conversion processes from biomass. Both processes are climate neutral.

Good to know: The color palette can be expanded as desired. For example, there is also "red" hydrogen. Like green hydrogen, this is produced from the electrolysis of water, but using nuclear energy.

What are the technologies for the production of hydrogen?

Hydrogen electrolysis

Water (H₂O) is at the center of hydrogen electrolysis. Through the application of electric current, it splits into its components hydrogen and oxygen. The electrical energy used is converted into chemical energy and stored in the hydrogen. Wind power, hydropower or solar energy - the electricity needed for this comes from these renewable energy sources. Green hydrogen is produced.

The methane pyrolysis

Methane pyrolysis is used to produce turquoise hydrogen. In this process, natural gas, for example methane, splits under the input of heat. Hydrogen (H₂) and carbon (C) are produced. To keep the process CO₂-neutral, the thermal energy is obtained from renewable energy. The resulting carbon is ultimately used in the construction and materials industries, among others.

Methane Steam reforming

In steam reforming, a carbon-containing fuel - today mainly natural gas - reacts with the addition of steam. Hydrogen is produced. The problem is that for every ton of hydrogen produced, ten to 19 tons of climate-damaging carbon dioxide are released. The process is mostly used in oil refineries. Steam reforming can also be used with biomass, i.e. to produce biohydrogen by biomass gasification.

What is the significance of hydrogen in the context of the energy transition?

If hydrogen is produced by using electrolysis and electricity from renewable energy sources, the element is essential for the energy transition and for achieving climate goals:

"Hydrogen produced in a climate-friendly way makes it possible to significantly reduce CO2 emissions, especially in industry and transport, where energy efficiency and the direct use of electricity from renewable sources are not sufficient." (German Federal Ministry of Economics and Infrastructure)

The advantages are obvious:

Hydrogen is renewable and easily available
It is widely available and can be used in a variety of ways
Energy can be easily stored and transported with hydrogen

Whether in industry, mobility, the energy industry or in the heating sector - there is a need to make greater use of hydrogen in numerous areas.

One example is the decarbonization of processes that are difficult to electrify: While coal or natural gas are currently mostly used for steel production or ammonia production, such industrial processes could be converted to hydrogen in the future.

What challenges lie in the "fuel of the future"?

There are still a number of hurdles to overcome for the widespread use of hydrogen. It is true that industries such as the chemical industry already use electrolysis to break water down into its components and use the hydrogen to produce ammonia and methanol, for example (the starting basis for fertilizers, for example).

But the biggest drawback is usually cost. Green hydrogen is significantly more expensive compared to the alternatives. Another problem: Hydrogen admixtures in natural gas can cause problems in certain industrial plants.

Read also: What are the challenges for valve manufacturers and plant designers in particular? And what requirements are placed on valve solutions?

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Do you have further questions about hydrogen in industry?

Do not hesitate to contact us.

Dominic Hock

Managing Director

I’m happy to support you with projects and enquiries in the field of valve technology as well as measurement and control technology. My areas of expertise are automation technology and networks.

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