Publications

The International Energy Agency (IEA) established the "H2 Implementing Agreement (HIA)" to promote H2 transition in various economic sectors. Today less than one percent of the world's H2 production is “Green”. Lack of regulations high production costs and inadequate infrastructure are significant impediments. The U.S. Department of Energy set a "111-target" which translates into $1/kg-H2 in the next decade. Many countries in the Middle East and North Africa (MENA) region have announced ambitious plans to produce green H2. Through techno-economic metrics and the impact of economies of scale this study investigates H2@Scale production. H2 Production Analysis and the System Advisor Model developed by the U.S. Department of Energy were used for analysis. The results demonstrate a significant decrease in the levelized cost of H2 (LCOH) when the production volume is scaled up. It was determined that the key cost drivers are capital cost energy installed balance of the plant and mechanical and electrical subsystems. The studied location is found promising for scaled production and developing its commodity status. The findings could serve as a benchmark for key stakeholders investors policymakers and the developer of relevant strategies in the infrastructure and H2 value chain.

Hydrogen is commonly used as feedstock in industrial processes and is regarded as a potential future energy carrier. However its reactivity and low density make it difficult to handle and store safely. Indoor hydrogen dispersion can cause a fire or explosion hazard if encountering an ignition source. Safety practices often use time expensive modelling techniques to estimate risk associated with hydrogen. A neural network based surrogate model could efficiently replace Computational Fluid Dynamics (CFD) modelling in safety studies. To lower the dimensionality of this surrogate model a dimensional analysis based on Buckingham’s Pi-theorem is proposed. The dimensional analysis examines stratified filling and highlights the functional parameters involved in the process. Stratified filling occurs for buoyancy dominated releases and is characterized by layers of decreasing concentration starting at the ceiling of the enclosure and developing towards the bottom. The study involves four dimensional cases that were simulated using Computational Fluid Dynamics (CFD) to demonstrate the usefulness of the proposed dimensionless time and dimensionless volume. The setup considered in this paper consists of a parallelepiped enclosure with standard atmospheric conditions a single release source and one pressure outlet to ensure constant pressure during the release. The results of the CFD simulations show a distinct pattern in the relation of hydrogen molar fraction and dimensionless time. The pattern depends on the dimensionless height of the measurement location. A five-parameter logistic (5PL) function is proposed to fit the data from the CFD models. Overall the paper provides insights into the functional parameters involved in the evolution of hydrogen mass fractions during stratified filling. It provides a nondimensional surrogate model to compute the evolution of the local concentrations of hydrogen during the development of stratification layers.

Converting renewable electricity via water electrolysis into green hydrogen and hydrogen-based products will shape a global trade in power-to-x (PtX) products. The European Union's renewable hydrogen import target of 10 million tonnes by 2030 reflects the urgent need for PtX imports by sea to early high-demand countries like Germany. This study evaluates the cost efficiency and greenhouse gas (GHG) emissions of four hydrogen carrier ship import options considering a reconversion to H2 at the import terminal for a final delivery to offtakers via a H2 pipeline network in 2030. This includes ammonia a liquid organic hydrogen carrier (LOHC) system based on benzyltoluene (BT) and a novel CO2/e-methane and CO2/e-methanol cycle where CO2 is captured at the reconversion plant and then shipped back to the PtX production site in a nearly closed carbon loop. The GHG emission accounting includes well-to-wake emissions of the marine fuels and direct emissions of the carbon capture plant. Two GW-scale case studies reveal the impact of a short and long-distance route from Tunisia and Australia to Germany whereas the specific PtX carriers are either fuelled by its PtX cargo as a renewable marine fuel or by conventional heavy fuel oil (HFO). Ammonia outperforms the other PtX routes as the total hydrogen supply cost range between 5.07 and 7.69 for Australia (low: NH3 HFO high: LOHC HFO) and 4.78–6.21 € per kg H2 for Tunisia (low: NH3 HFO high: CH4 HFO) respectively. The ammonia routes achieve thereby GHG intensities of 31 % and 86 % below the EU threshold of 3.4 kg CO2(e) per kg H2 for renewable hydrogen. LOHC though unless switching to low-emission fuels and the CO2/e-methanol cycle exceed the GHG threshold at shipping distances of 12300 and 16600 km. The hydrogen supply efficiencies vary between 57.9 and 78.8 %LHV (low: CH4 PtX-fuelled high: NH3 HFO) with a PtX marine fuel consumption of up to 15 % LHV for the Australian methanol route whereas high uncertainties remain for the ammonia and methanol reconversion plant efficiencies. The CO2 cyle enables a cost-efficient CO2 supply easing the near-term shortage of climate-neutral CO2 sources at the cost of high GHG emissions for long-distance routes.

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 blending in existing pipelines on the European energy system by the year 2050 by introducing hydrogen blending sensitivities to the Global Energy System Model (GENeSYS-MOD). Results indicate that hydrogen demand in Europe is inelastic and limited by its high costs and specific use cases with hydrogen production increasing by 0.17% for 100%-blending allowed compared to no blending allowed. The availability of hydrogen blending has been found to impact regional hydrogen production and trade with countries that can utilize existing natural gas pipelines such as Norway experiencing an increase in hydrogen and synthetic gas exports from 44.0 TWh up to 105.9 TWh in 2050 as the proportion of blending increases. Although the influence of blending on the overall production and consumption of hydrogen in Europe is minimal the impacts on the location of production and dependence on imports must be thoroughly evaluated in future planning efforts.

Developing an effective energy transition roadmap is crucial in the face of global commitments to achieve net zero emissions. While renewable power generation systems are expanding challenges such as curtailments and grid constraints can lead to energy loss. To address this surplus electricity can be converted into green hydrogen serving as a key component in the energy transition. This research explores the use of renewable solar energy for powering a proton exchange membrane electrolyser to produce green hydrogen while a downdraft gasifier fed by municipal solid waste generates hydrogen-enriched syngas. The blended fuel is then used to feed a Solid Oxide Fuel Cell (SOFC) system. The study investigates the impact of hydrogen content on the performance of the fuel cell-based power plant from thermodynamics and exergoeconomic perspectives. Multiobjective optimisation using a genetic algorithm identifies optimal operating conditions for the system. Results show that blending hydrogen with syngas increases combined heat and power efficiency by up to 3% but also raises remarkably the unit product cost and reduces carbon dioxide emissions. Therefore the optimal values for hydrogen content current density temperatures and other parameters are determined. These findings contribute to the design and operation of an efficient and sustainable energy generation system.

This work studies the efficiency and long-term viability of powered hydrogen production. For this purpose a detailed exploration of hydrogen production techniques has been undertaken involving data collection information authentication data organization and analysis. The efficiency trends environmental impact and hydrogen production costs in a landscape marked by limited data availability were investigated. The main contribution of this work is to reduce the existing data gap in the field of hydrogen production by compiling and summarizing dispersed data. The findings are expected to facilitate the decision-making process by considering regional variations energy source availability and the potential for technological advancements that may further enhance the economic viability of electrolysis. The results show that hydrogen production methods can be identified that do not cause significant harm to the environment. Photolysis stands out as the least serious offender producing 0 kg of CO2 per kg of H2 while thermolysis emerges as the major contributor to emissions with 20 kg of CO2 per kg of H2 produced.

Potential carbon neutrality of the global trucking shipping and aviation sectors by 2050 could be achieved by substituting fossil fuels with renewable hydrogen and synthetic fuels. To investigate the economic impact of fuel substitution over time a holistic cost model is developed and applied to three case studies in Norway an early adopter of carbon-neutral freight transport. The model covers the value chains from local electricity and fuel production (hydrogen ammonia Fischer–Tropsch e-fuel) to fuel consumption for long-haul trucking short-sea shipping and mid-haul aviation. The estimates are internally consistent and allow cross-mode and cross-fuel comparisons that set this work apart from previous studies more narrowly focused on a given transport mode or fuel. The model contains 150 techno-economic parameters to identify which components along the value chains drive levelized costs. This paper finds a cost reduction potential for renewable fuels of 41% to 68% until 2050 but carbon-neutral transport will suffer asymmetric cost disadvantages. Fuel substitution is most expensive in short-sea shipping followed by mid-haul aviation and long-haul trucking. Cost developments of electricity direct air capture of carbon vehicle expenses and fuel-related payload losses are significant drivers.

Green hydrogen a critical element in the shift towards sustainable energy is traditionally produced by electrolysis powered by solar photovoltaic (PV) systems. This research explores the potential of underexploited photovoltaic thermal (PV-T) systems for efficient green hydrogen generation. This paper compares this advanced technology performance and economic viability against conventional PV setups. This paper uses TRNSYS simulation software to analyze two distinct solar-based hydrogen production configurations – PV and PV-T – across diverse climatic conditions in Doha Tunis and Stuttgart. The paper’s findings indicate that PV-T significantly outperforms PV in hydrogen generation across diverse climates (Doha Tunis Stuttgart). For instance in Doha PV-T systems increase hydrogen output by 78% in Tunis by 59% and in Stuttgart by 25%. An economic assessment reveals PV panels as the most cost-effective option with hydrogen production costs ranging from $4.92/kg to $9.66/kg across the studied locations. For PV-T collectors the hydrogen cost range from $6.66/kg to $16.80/kg across the studied locations. Nevertheless this research highlights the potential of PV-T technology to enhance the efficiency and economic viability of green hydrogen production. These findings offer valuable insights for policymakers investors and researchers pursuing more efficient solutions for sustainable energy.

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 effects of complete alkaline water electrolysis systems. This study presents a dynamic process model for a pressurized alkaline water electrolyzer consisting of four submodels to describe the system behavior regarding gas contamination electrolyte concentration cell potential and temperature. Experimental data from a lab-scale alkaline water electrolysis system was used to validate the model which could then be used to analyze and optimize pressurized alkaline water electrolysis. While steady-state and dynamic solutions were analyzed for typical operating conditions to determine the influence of the process variables a dynamic optimization study was carried out to optimize an electrolyte flow mode switching pattern. Moreover the simulation results could help to understand the impact of each process variable and to develop intelligent concepts for process optimization

Purpose: The purpose of the hydrogen supply and demand data stream is to provide an overview of the hydrogen market in Europe and to track industry’s progress in deploying clean hydrogen technologies. Scope: Data about hydrogen production capacity and consumption in EU countries together with Switzerland Norway Iceland and the United Kingdom. Hydrogen production capacity is presented by country and by production technology whereas the hydrogen consumption data is presented by country and by end-use sector. The analysis undertaken for this report was completed using data reflecting end of 2020. Key Findings: The current hydrogen market (on both the demand and supply side) is dominated by refining and ammonia industries with four countries (DE NL PL ES) responsible for more than half of hydrogen consumption. Hydrogen is overwhelmingly produced by reforming of fossil fuels (mostly natural gas). Clean hydrogen production capacities are currently insignificant with hydrogen produced from natural gas coupled with carbon capture at 0.42% and hydrogen produced from water electrolysis at 0.14% of total production capacity.