Green hydrogen is to help many sectors achieve climate neutrality in the future. Yet there are still gaps for the implementation of it in transport as well as storage. The H2 lead project TransHyDE, funded by the German ministry for education and research (BMBF), is looking at various chemical transport options for green hydrogen: gaseous hydrogen (GH2), liquid hydrogen (LH2), ammonia (NH3) and liquid organic hydrogen carriers (LOHCs).
On December 30, 2022 in Berlin, the first scientific conference of the H2-Leitprojekt (H2 lead project) TransHyDE took place, at which techno-economic and regulatory obstacles on the path to an efficient storage and transport infrastructure stood at the focus. There, project members presented important approaches to solutions and findings from their research work, and discussed these with stakeholders from politics, business and academia.
Holistic system analysis for the infrastructure
In the keynote of the scientific conference, Prof. Dr. Mario Ragwitz (Fraunhofer IEG) illustrated the pronounced relevance of sector coupling in a climate-neutral future energy system. Particularly the complexity of modeling multi-energy systems as well as the high spatial resolution required for the associated infrastructures clarify the task of TransHyDE. Only the holistic unification of system-analytical models with specific expertise will be able to answer the open questions of the energy transition.
Source: Benjamin Lux, Joshua Fragoso, Frank Sensfuß – TransHyDE scientific conference 2022
Dr. Joshua Fragoso Garcia (Fraunhofer ISI) in his contribution dealt with the question of how the European demand for hydrogen can be met cost-effectively. For this, he investigated two model-based scenarios, which differ mainly in their hydrogen demand (basic scenario: H2 only as a raw material for the chemical and steel industry; expanded scenario: broader application of hydrogen additionally in the field of process heat, trucks on long hauls and decentralized heat supply).
The modeling results show that there is sufficient renewable potential in Europe to cost-efficiently cover most of the hydrogen demand (see Fig. 1). H2 imports from outside of Europe are, due to the costs, only to a small extent part of the solution (~10% of modelled 1,383 TWh for basic scenario or 12.7% of modelled 2,495 TWh for extended scenario in year 2045). For intra-European equalization of hydrogen supply and demand, the scenario results show an advantage for regional hydrogen production (see Fig. 2) coupled with expansion of H2 pipelines connecting Northern and Southern Europe with Central Europe.
Safe hydrogen transport: Reality instead of vision
The requirement from systems analysis to transport larger quantities of gaseous hydrogen via pipelines raises immediate safety concerns, which Dr. Frank Schweizer (Fraunhofer IWM) as well as Prof. Dr. Jürgen Wöllenstein (Fraunhofer IPM) addressed in their presentations. The speakers emphasized that steel samples already can be tested for their hydrogen compatibility in hydrogen environments through relevant procedures and calculations related to static loads, fatigue and crack propagation. Furthermore, accurate and cost-effective detection of hydrogen leakage, for example via the characteristic thermal conductivity or the sonic velocity of hydrogen, is possible.
In addition to the safety-critical H2 leakage measurement, guaranteeing the continuous quality of the transported hydrogen is equally necessary. Dr. Achim Zajc (Meter‑Q Solutions), with the proprietary nanogas process chromatograph MGC, presented in his speech a way to measure hydrogen gas and its impurities with high accuracy. The MGC makes use of the excellent thermal conductivity of hydrogen. Through the direct coupling of MGC to pipelines, not only can the requirements for gas group A of the German gas quality standards be met (DVGW G260 9/2020), but the measurement times (< 45 s) and the resulting emissions are significantly reduced, as unnecessary bypasses, long transport routes and hydrogen emissions can be avoided.
Ammonia: Much more than just a chemical H2 storage medium
Ammonia is already a central basic material for various industries today and is being discussed as a molecule for efficient intercontinental energy transport as well as numerous direct applications. Despite the already multifarious possibilities for use, the conversion of ammonia to hydrogen gas (reforming) could be necessary to cover the H2 demand in various scenarios. The potential of ammonia reforming for the energy industry was the focus of Dr. Michael Poschmann (Max Planck Institute CEC) during his presentation of research work on the improvement of the catalysts used. Using reforming test rigs specially developed for this purpose (pressure range up to 40 bar), essential characteristics of the reaction (such as degree of conversion, reaction kinetics, etc.) were analyzed for various catalyst materials and structures, and compared with known catalysts from similar catalytic processes.
One of the versatile direct applications of ammonia was carried out in the following way by Prof. Dr. Hinrich Mohr (GasKraft Engineering) using an ammonia-fueled internal combustion engine as example, which with a power of 350 kW can find use in inland waterway transport. Preliminary single-cylinder combustion tests of a 50/50 gas mixture of NH3/H2 at partial load operation with a mean effective pressure of 11 bar achieved an efficiency of already 39 percent.
Klaas Büsen (Hochschule Wismar) expanded the presented topics in the context of an ammonia value chain to further aspects. In his presentation, he introduced flexible refueling and bunkering concepts (both onshore and offshore) as well as technologies to ensure safety of use. With consideration of technological, economic and ecological aspects, a scenario-based demand plan for the transport logistics of ammonia is being made, with focus on the year 2035.
Australian Ambassador to Germany Philip Green raised the issue of transport logistics to a global level and outlined the possibilities for a future ammonia transport chain from Australia to Germany. Through projects such as Asian Renewable Energy Hub (26 GW wind and PV generation capacity), with which Australia is making enormous investments to exhaust of its renewable energy potentials, large quantities of green hydrogen (bound in ammonia) will eventually be able to be annually exported. With the low cost to produce electricity in Australia as well as minor additional costs for ammonia synthesis, ship transport, and reforming, competitive prices should be possible.
Liquid hydrogen – Tested transport option with potential
An alternative transport and storage option to ammonia is liquid hydrogen. Dr. Michael J. Wolf and Sebastian Palacios V. (both at the Karlsruhe Institute of Technology) presented in their speeches the unique properties of LH2 and its possibilities but also specific challenges, which are explained in more detail in a recently published white paper on the website for the lead project. Significant potential for efficiency gains can be tapped for example through combination with high-temperature superconductors for coupled transport of electricity and hydrogen (hybrid pipeline) or through the electrical components by increasing the power density. Prof. Alexander Alekseev (Linde) illustrated by means of a dynamic simulation model of an LH2 transport chain in the equilibrium and nonequilibrium state that faster and more efficient filling as well as emptying of LH2 tanks by large-scale centrifugal LH2 pumps could be beneficial.
Heat utilization in LOHC processes
For the transport and storage logistics of liquid organic hydrogen carriers are likewise solid possibilities for optimization. For example, efficiency can be increased by using the waste heat from hydrogenation or dehydrogenation as industrial process heat on site, as said by Monja Grote (Hamburger Hafen and Logistik AG) and Siying Huang (Hydrogenious LOHC Technologies). In addition, large parts of the existing infrastructure for liquid fuels can still have economic use, since Hydrogenious has made the thermal oil benzyltoluene usable as an LOHC, which is similar in ease of handling to diesel. The leveraging of this potential allows the business case for building supply chains with LOHCs, to be further developed and eventually transferred to the real economy, according to the speakers.
No hydrogen economy without standards
For their practical introduction, however, all the presented technologies require uniform guidelines such as norms, standards and certifications. Thomas Systermans (DVGW) provided the results up to now of an inventory analysis of technical regulations, which included the hydrogen transport options in TransHyDE. The statistical evaluations regarding their relevance for H2 showed that 57 percent of the 693 documents are applicable to hydrogen. Another two percent have only limited H2 applicability, while 41 percent are not suitable for hydrogen. The consolidated data will lead to a next step of an analysis of the norms that need revision in order to determine gaps, which will then be filled by recommendations in a last step.
The enormous importance of a consistent legal framework for the development of a transport and storage infrastructure was pointed out in the proceeding presentation by Friederike Allolio and Leony Ohle (both at IKEM). In their study, gaps in the existing regulatory framework along the entire H2 value chain, with emphasis on the transport infrastructure, were identified. Particularly the long and complex approval processes create concrete obstacles for expansion of an infrastructure.
Research minister sees H2 as “missing puzzle piece”
German minister of education Bettina Stark-Watzinger, through a live feed, added the political perspective. She highlighted the need for the energy transition in order to meet the many challenges in our current unsettling and crisis-ridden times. Climate neutrality can only be achieved through the rapid expansion of renewable energies along with the use of hydrogen as a versatile energy carrier. Stark-Watzinger stressed that the combination of research and practical demonstrations forms the basis for acceleration of the development and expansion of hydrogen technologies. TransHyDE, as one of the H2 lead projects, is demonstrating how to remove the obstacles on the way to a hydrogen infrastructure and showing suitable approaches to solutions. With the help of the results of the project, the basis for the establishment of a hydrogen economy will be created.
Techno-economic and regulatory gaps
Concluding the conference, under the moderation of Lea-Valeska Giebel (DENA), a panel discussion with participants from research, industry and community development took place. The overarching question focused on the techno-economic and regulatory gaps in building a hydrogen economy.
Besides TransHyDE coordinator Prof. Dr. Robert Schlögl (director of the Fritz Haber Institute of the Max Planck Society) and Prof. Dr. Mario Ragwitz, Piotr Kuś (general director at ENTSOG) and Ralph Bahke (managing director at ONTRAS) from the industrial sector, as well as World Wildlife Fund climate and energy policy advisor Ulrike Hinz (WWF Deutschland), took part in the discussion. There, Piotr Kuś made clear the complexity of the task of integrating future hydrogen infrastructures into existing energy landscapes. In his view, this would ideally be done in a bottom-up manner.
For Ulrike Hinz, the essential challenge consists of holistically viewing the aspects of climate and environmental impact, security of supply and affordability. In her opinion, an essential task is the expansion of renewable energies, as a prerequisite for the establishment of a green hydrogen economy. There was fundamental agreement among the panelists on the criticalness of developing a regulatory framework. To Ralph Bahke, suitable models for financing a future hydrogen economy are especially important for this framework.
Robert Schlögl and Mario Ragwitz supplemented that the development of a hydrogen economy in Germany requires technological openness and European cooperation. For the planning and development of the infrastructure, all options will receive attention and a corresponding system-analytical optimization will be performed.
Authors: Fenja Bleich, fenja.bleich@cec.mpg.de
Hauke Hinners, hauke.hinners@cec.mpg.de
Both at the Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany
Source: Benjamin Lux, Joshua Fragoso, Frank Sensfuß – TransHyDE scientific conference 2022
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