Germany

Hydrogen (H2) is expected to be a key building block in future greenhouse gas neutral energy systems. This study investigates the role of liquid hydrogen (LH2) in a national greenhouse gas-neutral energy supply system for Germany in 2045. The integrated energy system model suite ETHOS is extended by LH2 demand profiles in the sectors aviation mobility and chemical industry and means of LH2 transportation via inland vessel rail and truck. This case s Read More

The European aviation sector must substantially reduce climate impacts to reach net-zero goals. This reduction however must not be limited to flight CO2 emissions since such a narrow focus leaves up to 80% of climate impacts unaccounted for. Based on rigorous life-cycle assessment and a time-dependent quantification of non-CO2 climate impacts here we show that from a technological standpoint using electricity-based synthetic jet fuels and compe Read More

Carbon neutrality (or climate neutrality) has been a global consensus and international experience exchange is essential. Given the differences in the degree of social development resource endowment and technological level each country should build a carbon-neutral plan based on its national conditions. Compared with other major developed countries (e.g. Germany the United States and Japan) China's carbon neutrality has much bigger challenge Read More

Green hydrogen via renewable powered electrolysis has a high relevance in decarbonization and supply security. Achieving economically competitive hydrogen production costs is a major challenge in times of an energy price crisis. Our objective is to show the economically optimal installed capacity of electrolysers in relation to wind and solar power so swift and credible statements can be made regarding the system design. The ratio between re Read More

Dynamically-operated water electrolyzers enable the production of green hydrogen for cross-sector applications while simultaneously stabilizing power grids. In this study the start-up phase of polymer electrolyte membrane (PEM) water electrolyzers is investigated in the context of intermittent renewable energy sources. During the start-up of the electrolysis system the temperature increases which directly influences hydrogen production efficiency. Experi Read More

Hydrogen safety issues attract focuses increasingly as more and more hydrogen powered vehicles are going to be operated in traffic infrastructures of different kinds like tunnels. Due to the confinement feature of traffic tunnels hydrogen deflagration may pose a risk when a hydrogen leak event occurs in a tunnel e.g. failure of the hydrogen storage system caused by a car accident in a tunnel. A water injection system can be designed in tunnels as a Read More

The European Commission aims to establish green hydrogen produced through electrolysis using renewable electricity and in a transition phase hydrogen produced in a low-carbon process or blue hydrogen. In an extensive cost analysis for Germany up to 2050 based on scenario data and a component-based learning rate approach we find that blue hydrogen is likely to establish itself as the most cost-effective option and not only as a medium-term low- Read More

Over the past two years requirements to meet climate targets have been intensified. In addition to the tightening of the climate targets and the demand for net-zero achievement by as early as 2045 there have been discussions on implementing and realizing these goals. Hydrogen has emerged as a promising climate-neutral energy carrier. Thus over the last 1.5 years more than 25 countries have published hydrogen roadmaps. Furthermore various stud Read More

The increasing penetration of renewable energies will make new storage technologies indispensable in the future. Power-to-Gas (PtG) is one long-term storage technology that exploits the existing gas infrastructure. However this technology faces technical economic environmental challenges and questions. This contribution presents the final results of a large research project which attempted to address and provide answers to some of these question Read More

In light of offshore wind expansions in the North and Baltic Seas in Europe further ideas on using offshore space for renewable-based energy generation have evolved. One of the concepts is that of energy islands which entails the placement of energy conversion and storage equipment near offshore wind farms. Offshore placement of electrolysers will cause interdependence between the availability of electricity for hydrogen production and for power trans Read More

The worsening climate crisis has increased the urgency of transitioning energy systems from fossil fuels to renewable sources. However many industrialized countries are struggling to meet their growing demand for renewable energy (RE) through domestic production alone and therefore seek to import additional RE using carriers such as hydrogen ammonia or metals. The pressing question for RE importers is therefore how to select trading partners i.e. RE Read More

Green hydrogen is central to the global energy transition. This paper introduces a renewable hydrogen production system model that optimizes hydrogen production on a worldwide 50 km × 50 km grid considering country-specific investment risks. Besides the renewable energy’s impact on the hydrogen production system (HPS) design we analyze the effect of country-specific interest rates on the levelized cost of hydrogen (LCOH) production. Over Read More

One of the significant safety concerns in large-scale storage and transportation of liquefied (cryogenic) hydrogen (LH2) is the formation of flammable hydrogen/air mixtures after leakages during storage or transportation. Especially in maritime transportation hydrogen accumulations could occur within large and congested geometries. The installation of passive auto-catalytic recombiners (PARs) is a suitable mitigation measure for local areas where ve Read More

Hydrogen has become a key enabler for decarbonization as countries pledge to reach net zero carbon emissions by 2050. With hydrogen infrastructure expanding rapidly beyond its established applications there is a requirement for robust safety practices solutions and regulations. Since the 1980s considerable efforts have been undertaken by the nuclear community to address hydrogen safety issues because in severe accidents of water-coo Read More

The results shown in this paper extend our research group’s previous work which presents the theoretically achievable hydrogen engine-out NOeo x (H2-NOeo x ) Pareto front of a hydrogen hybrid electric vehicle (H2-HEV). While the Pareto front is calculated offline which requires significant computing power and time this work presents an online-capable algorithm to tackle the energy management of a H2-HEV with explicit consideration of the H2-NOe Read More

Geological structures in deep aquifers and salt caverns can play an important role in large-scale hydrogen storage. However more work needs to be done to address the hydrogen storage demand for zero-emission energy systems. Thus the aim of the article is to present the demand for hydrogen storage expressed in the number of salt caverns in bedded rock salt deposits and salt domes or the number of structures in deep aquifers. The analysis co Read More

The glass industry is part of the energy-intensive industry with most of the energy needed to melt the raw materials. To produce glass temperatures between 1000 and 1600 °C are necessary. Presently mostly fossil natural gas is the dominant energy source. As direct electrification is not always possible in this paper a Life Cycle Assessment (LCA) for specialty glass production is conducted where the conventional fossil-based reference process is compar Read More

Synthetic current density profiles with wind and photovoltaic power characteristics were calculated by autoregressive-moving-average (ARMA) models for the experimental evaluation of dynamic operating concepts for alkaline water electrolyzers powered by renewable energy. The selected operating concepts included switching between mixed and split electrolyte cycles and adapting the liquid electrolyte volume flow rate depending on the current densit Read More

The transition to renewable energy sources to mitigate climate change will require large-scale energy storage to dampen the fluctuating availability of renewable sources and to ensure a stable energy supply. Energy storage in the geological subsurface can provide capacity and support the cycle times required. This study investigates hydrogen storage methane storage and compressed air energy storage in subsurface porous formations and qua Read More

While the share of renewable energy sources increased within the last years with an ongoing upward trend the energy sector is facing the problem of storing large amounts of electrical energy properly. To compensate daily and seasonal fluctuations a sufficient storage system has to be developed. The storage of hydrogen in the subsurface referred to as Underground Hydrogen Storage (UHS) shows potential to be a solution for this problem. Hydrogen prod Read More

We investigate the challenges and options for repurposing existing natural gas pipelines for hydrogen transportation. Challenges of re-purposing are mainly related to safety and due to the risk of hydrogen embrittlement of pipeline steels and the smaller molecular size of the gas. From an economic perspective the lower volumetric energy density of hydrogen compared to natural gas is a challenge. We investigate three pipeline repurposing options in dept Read More

The need to reduce the carbon footprint of conventional energy sources has made green hydrogen a promising solution for the energy transition. The most environmentally friendly way to produce hydrogen is through water-based production using renewable energy. However the availability of fresh water is limited so switching to wastewater instead of fresh water is the key solution to this problem. In response to this issue the present review reports th Read More

Environmental emissions global warming and energy-related concerns have accelerated the advancements in conventional vehicles that primarily use internal combustion engines. Among the existing technologies hydrogen fuel cell electric vehicles and fuel cell hybrid electric vehicles may have minimal contributions to greenhouse gas emissions and thus are the prime choices for environmental concerns. However energy management in fuel cell Read More

Due to its ability to reduce emissions in the hard-to-abate sectors hydrogen is expected to play a significant role in future energy systems. This study modifies a sector-coupled dynamic modeling framework for electricity and hydrogen by including policy constraints carbon prices and possible hydrogen pathways and applies it to Texas in 2050. The impact of financial policies including the US clean hydrogen production tax credit on required infrastructure and co Read More

The import of hydrogen and derivatives forms part of many national strategies and is fundamental to achieving climate protection targets. This paper provides an overview and technical comparison of import pathways for hydrogen and derivatives in terms of efficiency technological maturity and development and construction times with a focus on the period up to 2030. The import of hydrogen via pipeline has the highest system efficiency Read More

Hydrogen storage is crucial to developing secure renewable energy systems to meet the European Union’s 2050 carbon neutrality objectives. However a knowledge gap exists concerning the site-specific performance and economic viability of utilizing underground gas storage (UGS) sites for hydrogen storage in Europe. We compile information on European UGS sites to assess potential hydrogen storage capacity and evaluate the associated current and Read More

The decarbonization of the energy sector has been a subject of research and of political discussions for several decades gaining significant attention in the last years. It is commonly acknowledged that the most obvious way to achieve decarbonization is the use of renewable energy sources. Within the context of the energy sector decarbonization many mainly industrialized countries recently started developing national plans to establish a hydrogen-based e Read More

The derivation of an efficient operational strategy for storing intermittent renewable energies using a hybrid battery-hydrogen energy storage system is a difficult task. One approach for deriving an efficient operational strategy is using mathematical optimization in the context of model predictive control. However mathematical optimization derives an operational strategy based on a non-exact mathematical system representation for a specified pr Read More

The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry politics and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologie Read More

With the aim of reducing carbon emissions and seeking independence from Russian gas in the wake of the conflict in Ukraine the use of hydrogen in the European Union is expected to rise in the future. In this regard hydrogen transport via pipeline will become increasingly crucial either through the utilization of existing natural gas infrastructure or the construction of new dedicated hydrogen pipelines. This study investigates the effects of hydrogen blen Read More

This research delineates a pivotal advancement in the domain of sustainable energy systems with a focused emphasis on the integration of renewable energy sources—predominantly wind and solar power—into the hydrogen production paradigm. At the core of this scientific endeavor is the formulation and implementation of a deep-learning-based framework for short-term localized weather forecasting specifically designed to enhance the efficiency Read More

The large deployment of hydrogen technologies for new applications such as heat power mobility and other emerging industrial utilizations is essential to meet targets for CO2 reduction. This will lead to an increase in the number of hydrogen installations nearby local populations that will handle hydrogen technologies. Local regulations differ and provide different safety and/or separation distances in different geographies. The purpose of this work is Read More

In the quest for a sustainable future energy-intensive industries (EIIs) stand at the forefront of Europe’s decarbonisation mission. Despite their significant emissions footprint the path to comprehensive decarbonisation remains elusive at EU and national levels. This study scrutinises key sectors such as non-ferrous metals steel cement lime chemicals fertilisers ceramics and glass. It maps out their current environmental impact and potential for mitiga Read More

This study introduces a hybrid energy storage system that combines advanced flywheel technology with hydrogen fuel cells and electrolyzers to address the variability inherent in renewable energy sources like solar and wind. Flywheels provide quick energy dispatch to meet peak demand while hydrogen fuel cells offer sustained power over extended periods. The research explores the strategic integration of these technologies within a hybrid photovoltaic (P Read More

To meet the new regulation for the deployment of alternative fuels infrastructure which sets targets for electric recharging and hydrogen refuelling infrastructure by 2025 or 2030 a large infrastructure comprising trucksuitable hydrogen refuelling stations will soon be required. However further standardisation is required to support the uptake of hydrogen for heavy-duty transport for Europe’s green energy future. Hydrogen-powered vehi Read More

Direct solar hydrogen generation via a combination of photovoltaics (PV) andwater electrolysis can potentially ensure a sustainable energy supply whileminimizing greenhouse emissions. The PECSYS project aims at demonstrating asolar-driven electrochemical hydrogen generation system with an area >10 m 2with high efficiency and at reasonable cost. Thermally integrated PV electrolyzers(ECs) using thin-film silicon undoped and silver-doped Cu Read More

To achieve sustainable development the transition from a fossil-based economy to a circular economy is essential. The use of renewable energy sources to make the overall carbon foot print more favorable is an important pre-requisite. In this context it is crucial to valorize all renewable resources through an optimized local integration. One opportunity arises through the synergy between bioresources and green hydrogen. Through techno-economic ass Read More

Climate change is a major concern for the sustainable development of global energy systems. Hydrogen produced through water electrolysis offers a crucial solution by storing and generating renewable energy with minimal environmental impact thereby reducing carbon emissions in the energy sector. Our research evaluates current hydrogen production technologies such as alkaline water electrolysis (AWE) proton exchange membrane water electro Read More

Green hydrogen is expected to be traded globally in future greenhouse gas neutral energy systems. However there is still a lack of temporally- and spatially-explicit cost-potentials for green hydrogen considering the full process chain which are necessary for creating effective global strategies. Therefore this study provides such detailed cost-potentialcurves for 28 selected countries worldwide until 2050 using an optimizing energy systems approach based on Read More

The global population is predicted to increase from ~7.3 billion to over 9 billion people by 2050.Together with rising economic growth this is forecast to result in a 50% increase in fueldemand which will have to be met while reducing carbon dioxide (CO 2 ) emissions by 50–80%to maintain social political energy and climate security. This tension between rising fuel demandand the requirement for rapid global decarbonization highlights the need to fast-track th Read More

Hydrogen is set to become an important energy carrier in Germany in the next decades in the country’s quest to reach the target of climate neutrality by 2045. To meet Germany’s potential green hydrogen demand of up to 587 to 1143 TWh by 2045 electrolyser capacities between 7 and 71 GW by 2030 and between 137 to 275 GW by 2050 are required. Presently the capacities for electrolysis are small (around 153 MW) and even with an increase in el Read More

This study uses a multi-method design to investigate the media’s role in shaping Germans’ attitudes toward green hydrogen. It combines an automatized content analysis of 7649 German newspaper articles published between July 2021 and June 2024 and a three-wave panel survey of the German population conducted between June 2023 and June 2024 with an initial sample of 2701 participants. The findings show that the intensity of media reporting o Read More

Hydrogen is becoming increasingly important to achieve the valid defossilization goals. However due to its physical properties especially the storage of hydrogen is challenging. One option in this regard are metal hy drides which are able to store hydrogen in chemically material-bound form. Against this background the goal of this paper is an analysis of possible technical application areas of such metal hydrides – both regarding transport and stati Read More

Integrated steelworks off-gases are generally exploited to produce heat and electricity. However further valorization can be achieved by using them as feedstock for the synthesis of valuable products such as methane and methanol with the addition of renewable hydrogen. This was the aim of the recently concluded project entitled “Intelligent and integrated upgrade of carbon sources in steel industries through hydrogen intensified synthesis process Read More

This work presents a study of the effects that integration of electrolysis facilities for Power-to-X processes have on the power grid. The novel simulation setup combines a high-resolution grid optimization model and a detailed scheduling model for alkaline water electrolysis. The utilization and congestion of power lines in northern Germany is investigated by setting different installed capacities and production strategies of the electrolysis facility. For electrolysi Read More

The geographical understanding of directionality in the literature on mission-oriented innovation systems is still underdeveloped. Therefore this article reflects on whether the allocation of funding for R&D activities to different places can direct innovation systems in space. A placebased approach to the allocation of funding and its effects on innovation systems is developed to analyze how the German national government allocates funding to the national innov Read More

A series of unconfined hydrogen detonation bench-mark experiments are analyzed with respect to CFD code validation and safety measures development. 1-Dimensional in-house code COM1D was applied for validation against experimental data for unconfined detonation of a hemispherical envelope of about 3- and 5-m radius with hydrogen-air mixtures from 20 to 30% hydrogen in air. The code demonstrates a very good agreement with experimental dat Read More

Climate change and the pressure to decarbonize as well as energy security concerns have drawn the attention of policymakers and the industry to hydrogen energy. To advance the hydrogen economy at a global scale research and innovation progress is of significant importance among others. However previous studies have provided only limited quantitative evidence of the effects of research and innovation on the formation of a global hydrogen market. I Read More

Alkaline water electrolysis is a key technology for large-scale hydrogen production. In this process safety and efficiency are among the most essential requirements. Hence optimization strategies must consider both aspects. While experimental optimization studies are the most accurate solution model-based approaches are more cost and time-efficient. However validated process models are needed which consider all important influences and ef Read More