Glossary

Chemical compound that binds hydrogen to a carrier element, enabling it to be transported by ship without requiring a great deal of energy. At the destination, the hydrogen is separated from the nitrogen again by ammonia cracking and can be transported away or used.

The amortization account is used in the hydrogen core network to pre-finance high initial investments for pipeline infrastructure. The costs are spread over a longer period and refinanced through subsequent grid fees. This reduces the economic risk for grid operators. It accelerates grid expansion and enables early connections for industry and producers.

Process for the capture and permanent storage of CO₂ emissions from industrial processes or energy generation. The aim is to quickly convert existing processes to be climate-neutral, for example by storing CO2 produced during steam reforming.

A state funding instrument that compensates climate-friendly companies for the difference between the price of CO₂ avoidance and the EU emissions trading scheme. This makes the use of green hydrogen in industry more economically attractive.

Underground cavities, usually in salt rock, for large-volume storage of natural gas and hydrogen. They offer large capacities, are tried and tested in operation and can thus balance out seasonal fluctuations between generation and consumption and increase security of supply.

EU legislation regulates which hydrogen is classified as green. This involves not only the origin of the electricity—whether it comes from wind turbines or other sources—but also factors such as the timing between the generation of renewable electricity and its consumption in an electrolyser. Only hydrogen that meets these criteria and is classified as green can be counted towards CO2 reduction.

An electrolyser is a device in which a chemical reaction is induced using electrical current. In our context, this refers to water electrolysis, where water is split into hydrogen and oxygen. If the electricity used comes from renewable energy sources, the resulting hydrogen is referred to as green hydrogen. There are different types of water electrolysis. In the GET H2 Nukleus project, the construction of a PEM electrolyzer is planned. PEM stands for Proton Exchange Membrane. In a PEM electrolysis process, no additional chemicals are added.

In a fuel cell, the chemical binding energy of hydrogen and oxygen is released by combining the two elements. It is therefore the reverse process of electrolysis. The result is an electrical voltage that can then be used. This process is not ‘combustion’ in the traditional sense, but is rather referred to as ‘cold combustion’ because it does not produce flames, only electrical energy.

Whoever wants to produce hydrogen using renewable electricity is obligated to prove that the energy used is indeed renewable. This is done through so-called guarantees of origin, which are linked to specific criteria.

A technical concept that describes whether systems – in particular power plants or industrial processes – can be operated with pure hydrogen in the future. H₂-ready means that only minor conversions are required to switch operation from natural gas to hydrogen.

The hydrogen core grid is the planned basic framework for the nationwide transportation of hydrogen. It connects production sites with industrial consumers and consists largely of converted natural gas pipelines. The aim is an efficient, nationwide market ramp-up of the hydrogen economy. It creates planning security and reduces infrastructure costs through shared network use.

A European funding framework for large, strategic projects with cross-border significance. In the hydrogen sector, IPCEI helps to finance the development of a European hydrogen economy.

The German government’s Power Station Strategy regulates the construction of new, flexible power stations that are intended to secure the electricity supply in the event of fluctuating renewable input. They are initially to be operated with natural gas and converted to climate-neutral hydrogen in the medium term (“H₂-ready”). The strategy is part of the national hydrogen and energy transition plan.

Liquid Organic Hydrogen Carrier (LOHC) are liquid organic substances with the ability to store hydrogen. In such a carrier, hydrogen can be stored — with the thermal oil benzyltoluene for example, that’s up to 54 kilograms of hydrogen per cubic meter of LOHC. The LOHC can be transported safely and without special cooling by tanker truck, train, or tanker ship. At the destination, the hydrogen is released from the LOHC in a dehydrogenation unit and then used. The thermal oil used as LOHC can be loaded and unloaded with hydrogen hundreds of times after the hydrogen is released and is recyclable.

Thermal process for extracting hydrogen from methane – this produces solid carbon instead of CO₂.

Stategy paper by the German government for the development and scaling of a hydrogen economy in Germany. The aim is to develop a market for green hydrogen, including infrastructure, production, import and use. The strategy is regularly adapted and updated in line with developments, most recently in 2023 with a stronger focus on industrial applications, international partnerships and the regulatory framework.

Verfahren zur Umwandlung von elektrischer Energie in Gasförmige Energieträger, meist Wasserstoff oder synthetisches Methan. Dies geschieht etwa in Form der Wasserstofferzeugung per Elektrolyse. PtG ist damit Teil der Sektorenkopplung.

Linking the energy sectors of electricity, heat, transport and industry through the joint and comprehensive use of energy in various forms. The aim is to increase the efficiency of the energy used.

The hydrogen currently utilised in Germany is obtained via steam reformers. This process involves splitting natural gas into its components by feeding in hot steam. This produces hydrogen and nitrogen, but also climate-damaging carbon dioxide. The hydrogen produced in this way is known as “grey hydrogen”.

Also known as synfuels, synthetic fuels are typically artificially produced fuels where the traditional crude oil base is replaced with other, more environmentally friendly alternatives. The latest and most climate-friendly form of these fuels are called e-fuels. In the production of e-fuels, renewable electricity, hydrogen, and CO₂ captured from the air are used to create climate-neutral fuel.