Editorial - VGB PowerTech Journal 3/2021
Hydrogen as an energy carrier plays an important role in achieving climate neutrality and in the success of the energy transition.
Hydrogen, the energy industry and energy technology can look back on a long history and thus also have extensive experience in handling and using it. Hydrogen has been studied and used in science and technology for more than 200 years. In 1806, the French inventor Francois Isaac de Rivaz constructed the De Rivaz engine, the first internal combustion engine powered by a hydrogen/oxygen mixture. Today, hydrogen is an integral, important part of the refinery sector; since 1975, the demand for hydrogen in this area of energy and also raw material supply has tripled, whereby the demand is still largely covered by the use of fossil primary energy sources, i.e. about 6 percent of global natural gas production and 2 percent of coal production are used to produce hydrogen.
However, hydrogen can also be produced in a climate-neutral way. In this case, climate-neutral energy sources would have to be used for extraction or production, or the emissions would have to be used as materials or stored. Renewable energy sources are currently the main focus of interest as energy sources, especially since their volatility can be balanced to a certain extent via the chain of hydrogen production, hydrogen storage and transport to consumption – the hydrogen chain thus acts as a buffer, so to speak, an important advantage of hydrogen use in the electricity–gas combination.
Another advantage of hydrogen is that it can be used individually in virtually all sectors of consumption and can be coupled with other sectors. Hydrogen can also either replace energy carriers with emissions or other, even new technologies can be applied. A practical example is the transport sector: hydrogen can be used emission-free in conventional combustion engines, but can also provide propulsion via fuel cell electricity.
This change in energy production and supply is therefore an impetus for a growing number of countries worldwide to also deal with the topic of hydrogen and to set up respective hydrogen strategies. Depending on the availability of primary energy resources, these are closely linked to the opportunities of a hydrogen economy, either, for example, with imports and climate and energy policy goals or as an export product and the associated opportunities for business and labour.
Therefore, in addition to climate and energy policy aspects, sustainable jobs as well as new value creation potentials in a growing global market are on the agenda.
On the technology side, a broad field of research and development is opening up with the known and proven processes. Power-to-gas and power-to-X technologies use electricity – from low-emission sources – and electrolysis processes. Four main technical processes are mentioned today: Alkaline electrolysis (AEL), proton exchange membrane electrolysis (PEM), anion exchange membrane electrolysis (AEM) and high temperature electrolysis (HTEL). Alkaline electrolysis has been known, proven and widely used for more than one hundred years. The PEM process is much younger and can be used commercially today. For AEM and HTEL, experience is available beyond the laboratory scale and pilot phase or introduction into commercial use is pending. All these processes “deliver” “green hydrogen”, i.e. emission-neutral in its overall balance, with an emission-free supply of electricity. The well-known production of hydrogen from hydrocarbons can be combined with carbon capture and storage, i.e. geological storage of the resulting carbon. This produces “blue” hydrogen with comparatively lower emissions. One advantage lies in the use of known and mature technical processes. The thermal cracking of methane leads to “turquoise” hydrogen, since elemental carbon is produced as a by-product. This does not raise the challenges of geological storage of carbon dioxide. To be sure, this list is incomplete. It is essentially intended to show that there is considerable technical potential in the central question of a hydrogen economy: how to produce it.
With its know-how, our industry therefore has an important and responsible role to play in the development and broad introduction of the hydrogen economy. At the beginning of the hydrogen production chain lie essential building blocks for success in technical implementation and wide market introduction.