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As part of the Hydrogen Generation and Demand (WEB) market survey, numerous distribution system operators also submitted demand reports. This clearly shows that entire regions must be developed with an efficient hydrogen infrastructure at an early stage and on a large scale in order to be able to ensure the supply of a large number of customers via the distribution networks.

The reports submitted by distribution system operators in the NEP Gas 2022-2032 result in a withdrawal volume of 54 TWh for the year 2032. The further increase in volumes in the following years underscores the significant demand for hydrogen in the distribution network and the efforts of distribution network operators to contribute to climate protection in the long term.

Similar to the L-/H-gas conversion, the conversion of network areas from natural gas to hydrogen involves interdependence between the parties involved.

Efficient conversion of an area along a transmission system operator’s line in terms of network expansion can only be ensured if all connected customers (distribution system operators or industrial customers connected to the transmission system) can convert to hydrogen in the same period of time. This is the only way to avoid economically inefficient, parallel hydrogen or methane pipelines, which may only be needed temporarily until all consumers along a pipeline have been completely converted.

In the regular process, the resolution of the above dependency takes place through the formation of cross-network operator, area-related working groups (also within the framework of the respective GTP creation) as well as through the conclusion of multilateral changeover schedules in which all mutual dependencies between the participants are assessed. This procedure has already proven useful for the L/H gas conversion and has thus been tested in practice.

The basis for planning the conversion of pipelines to hydrogen by the transmission system operators is initially the specific demand reports from various demand carriers (distribution system operators or industrial customers directly connected to the transmission system). These demand reports were secured via Memorandum of Understanding (MoU) in the NEP Gas 2022-2032 before they were included in the modeling of the transmission system operators in the NEP Gas process. For the demand reports of the distribution system operators, the transmission system operators first carry out a so-called hydrogen test in the current NEP gas cycle. In the future, the hydrogen testing process will be replaced as soon as demand notifications with a higher level of commitment are received or corresponding MoUs are concluded between transmission system operators and demand carriers. The conversion to hydrogen is made finally binding by the conclusion of a conversion schedule between the transmission system operator and the consumer.

The conversion roadmap defines the points at which a supply of hydrogen can be guaranteed by a defined deadline. The technical lead time for conversion to hydrogen is significantly longer than for conversion from L-gas to H-gas. In this respect, it can be assumed that conversion schedules between the transmission system operator and the demand side would also have to be concluded with a significantly longer lead time than is usual in comparison with the L/H gas conversion (there, at the latest 2 years and 8 months according to the Gas Cooperation Agreement). In this respect, the entire process, starting with the first demand reports and building on this, the agreement of MoUs must also be started much earlier.

The federal government is working to ensure that, as far as possible, every new heating system will be powered by at least 65% renewable energy (on balance sheet or physical) from 2024 [BMWK 2022]. This includes all renewable energies, i.e. also green and climate-neutral gaseous energy sources such as biomethane or green hydrogen. However, for all decarbonization options to be fully exploited, a technology-open approach is needed that takes into account all climate-neutral gases such as blue hydrogen.

Market space conversion to hydrogen is not feasible until as many gas appliances as possible have been installed that can run on natural gas and biomethane as well as hydrogen. From 2025 at the latest, the manufacturers organized in the Federal Association of the German Heating Industry (BDH) will be launching series devices on the market that can initially be set to methane or methane-hydrogen mixtures and converted to a hydrogen device by an installer with little effort by means of a conversion kit. By installing these hydrogen-capable appliances, the customer creates the conditions for a climate-neutral heat supply, enabling him to meet the 65% renewable energy target initially via the balance sheet purchase and later via the physical purchase of hydrogen.

Each distribution network in Germany has its own regional characteristics. For climate neutrality to be achieved locally, these specifics must always be taken into account. Therefore, after the analysis and planning process in an initial phase, the expansion phase will begin to upgrade the distribution networks or convert them to other green and climate-neutral gases in order to reach the target state by 2045 at the latest. In addition to the technical feasibility and availability of green and climate-neutral gases, it is of central importance that distribution system operators promptly enter into continuous dialog with users, producers, politicians and other stakeholders such as installers, heating manufacturers, etc., and conduct this dialog steadily and permanently.

Therefore, the Gas Grid Area Transformation Plan (GTP) envisions working with local business and other local stakeholders to develop decarbonization solutions that are effective and targeted for broad adoption. These region-specific solutions and conversion paths must be enabled and flanked by appropriate, nationwide laws and regulations.

An overview of the hydrogen network planning concept in the context of a holistic energy system view is shown in the figure. The concept presented for future hydrogen network planning will be integrated into the proven gas network development planning process. At the same time, by taking a holistic view of the energy system, new elements are also proposed to enable gas grid planning for hydrogen and methane to make a stronger contribution to achieving the targets of the Federal Climate Protection Act in the future.

Based on the modeling results of the hydrogen variant 2032 in the NEP Gas 2022-2032, the transmission system operators perform a hydrogen test for the year 2032 for the reported demands of the distribution system operators.

The objective of the hydrogen test is to identify network interconnection points (NCPs) or exit zones of the distribution system operators that can be reached with a hydrogen infrastructure without further network expansion measures on the part of the transmission system operators based on the results of the hydrogen variant for the year 2032. Furthermore, it will be examined whether a simultaneous supply with methane could be considered for the identified NCPs in principle, so that blending is possible at the distribution grid level. If there is a possibility to convert first areas or individual NKPs of the distribution system operators to 100% hydrogen, first potential “hydrogen conversion areas” could be identified, analogous to the planning process of the L-H gas market area conversion.

Accordingly, the transmission system operators determine the first potentials for a possible initial use of hydrogen in the distribution system on the basis of the reports received from the distribution system operators and the modeling results of the hydrogen variant 2032. The transmission system operators are already in close contact with the distribution system operators in order to develop initial joint concepts. The planned procedure for hydrogen testing is shown in the figure.

The hydrogen network 2032 presented in the interim status for the NEP Gas 2022-2032 shows the result of the modeling of a Germany-wide hydrogen network for the year 2032 based on the MoU requirements, the results of the network development plan Gas 2020-2030 and the pipeline reports of the transmission system operators and other potential hydrogen network operators as well as on existing parallel pipeline systems in the transmission system. This results in a hydrogen network with a pipeline length of 7,600-8,500 km by 2032.

The hydrogen network 2027 presented in the interim status for the NEP Gas 2022-2032 shows the result of the modeling of a Germany-wide hydrogen network for the year 2027 based on the MoU requirements, the results of the network development plan Gas 2020-2030 and the pipeline reports of the transmission system operators and other potential hydrogen network operators as well as on existing parallel pipeline systems in the transmission system. This will result in a hydrogen network with a pipeline length of 2,900-3,000 km by 2027.

Whether small or on an industrial scale, research in nature or ready for practical application, narrowly focused or spanning value-adding stages: the listed selection of over 30 projects at the distribution grid level gives an impression of the current, diverse decarbonization activities of distribution grid operators spread across Germany. These underscore the relevance of the distribution network to the development of the hydrogen economy. The figure depicts current hydrogen projects related to the distribution grid.