Netherlands
Modelling of Hydrogen Dispersion with Effects
Sep 2023
Publication
The paper shows the latest developments of Gexcon’s consequence modelling software EFFECTS with validation based on hydrogen experimental data for different storage conditions and scenarios including liquid hydrogen two-phase jet releases. The effect of atmospheric turbulence on the dispersion and potential worst-case scenarios of hydrogen which are very different from heavy gas releases are discussed. Beside validation for gaseous hydrogen releases a validation study for pressurised liquid hydrogen jet releases including a sensitivity analysis is performed and the results are compared with experimental data.
A Novel Sustainable Approach for Site Selection of Underground Hydrogen Storage in Poland Using Deep Learning
Jul 2024
Publication
This research investigates the potential of using bedded salt formations for underground hydrogen storage. We present a novel artificial intelligence framework that employs spatial data analysis and multi-criteria decision-making to pinpoint the most appropriate sites for hydrogen storage in salt caverns. This methodology incorporates a comprehensive platform enhanced by a deep learning algorithm specifically a convolutional neural network (CNN) to generate suitability maps for rock salt deposits for hydrogen storage. The efficacy of the CNN algorithm was assessed using metrics such as Mean Absolute Error (MAE) Mean Squared Error (MSE) Root Mean Square Error (RMSE) and the Correlation Coefficient (R2 ) with comparisons made to a real-world dataset. The CNN model showed outstanding performance with an R2 of 0.96 MSE of 1.97 MAE of 1.003 and RMSE of 1.4. This novel approach leverages advanced deep learning techniques to offer a unique framework for assessing the viability of underground hydrogen storage. It presents a significant advancement in the field offering valuable insights for a wide range of stakeholders and facilitating the identification of ideal sites for hydrogen storage facilities thereby supporting informed decisionmaking and sustainable energy infrastructure development.
Charting the Course: Navigating Decarbonisation Pathways in Greece, Germany, The Netherlands, and Spain’s Industrial Sectors
Jul 2024
Publication
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 mitigation through innovative strategies. The analysis spans across Spain Greece Germany and the Netherlands highlighting sector-specific ecosystems and the technological breakthroughs shaping them. It addresses the urgency for the industry-wide adoption of electrification the utilisation of green hydrogen biomass bio-based or synthetic fuels and the deployment of carbon capture utilisation and storage to ensure a smooth transition. Investment decisions in EIIs will depend on predictable economic and regulatory landscapes. This analysis discusses the risks associated with continued investment in high-emission technologies which may lead to premature decommissioning and significant economic repercussions. It presents a dichotomy: invest in climate-neutral technologies now or face the closure and offshoring of operations later with consequences for employment. This open discussion concludes that while the technology for near-complete climate neutrality in EIIs exists and is rapidly advancing the higher costs compared to conventional methods pose a significant barrier. Without the ability to pass these costs to consumers the adoption of such technologies is stifled. Therefore it calls for decisive political commitment to support the industry’s transition ensuring a greener more resilient future for Europe’s industrial backbone.
Hydrogen Sampling Systems Adapted to Heavy-duty Refuelling Stations' Current and Future Specifications - A Review
Sep 2024
Publication
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 vehicles require pure hydrogen as some contaminants can reduce the performance of the fuel cell even at very low levels. Even if previous projects have paved the way for the development of the European quality infrastructure for hydrogen conformity assessment sampling systems and methods have yet to be developed for heavy-duty hydrogen refuelling stations (HD-HRS). This study reviews different aspects of the sampling of hydrogen at heavy-duty hydrogen refuelling stations for purity assessment with a focus on the current and future specifications and operations at HD-HRS. This study describes the state-of-the art of sampling systems currently under development for use at HD-HRS and highlights a number of aspects which must be taken into consideration to ensure safe and accurate sampling: risk assessment for the whole sampling exercise selection of cylinders methods to prepare cylinders before the sampling filling pressure and venting of the sampling systems.
Determining Onshore or Offshore Hydrogen Storage for Large Offshore Wind Parks: The North Sea Wind Power Hub Case
Aug 2024
Publication
The large-scale integration of renewable energy sources leads to daily and seasonal mismatches between supply and demand and the curtailment of wind power. Hydrogen produced from surplus wind power offers an attractive solution to these challenges. In this paper we consider a large offshore wind park and analyze the need for hydrogen storage at the onshore and offshore sides of a large transportation pipeline that connects the wind park to the mainland. The results show that the pipeline with line pack storage though important for day-to-day fluctuations will not offer sufficient storage capacity to bridge seasonal differences. Furthermore the results show that if the pipeline is sufficiently sized additional storage is only needed on one side of the pipeline which would limit the needed investments. Results show that the policy which determines what part of the wind power is fed into the electricity grid and what part is converted into hydrogen has a significant influence on these seasonal storage needs. Therefore investment decisions for hydrogen systems should be made by considering both the onshore and offshore storage requirements in combination with electricity transport to the mainland.
Simulation of DDT in Obstructed Channels: Wavy Channels vs. Fence-type Obstacles
Sep 2023
Publication
The capabilities of an OpenFOAM solver to reproduce the transition of stoichiometric H2-air mixtures to detonation in obstructed 2-D channels were tested. The process is challenging numerically as it involves the ignition of a flame kernel its subsequent propagation and acceleration interaction with obstacles formation of shock waves ahead and detonation onset (DO). Two different obstacle configurations were considered in 10-mm high × 1-m long channels: (i) wavy walls (WW) that mimic the behavior of fencetype obstacles but prevent abrupt area changes. In this case flame acceleration (FA) is strongly affected by shock-flame interactions and DO often results from the compression of the gas present between the accelerating flame front and a converging section of the channel. (ii) Fence-type (FT) obstacles. In this case FA is driven by the increase in flame surface area as a result of the interaction of the flame front with the unburned gas flow field ahead particularly downstream of obstacles; shock-flame interactions play a role at the later stages of FA and DO takes place upon reflection of precursor shocks from obstacles. The effect of initial pressure p0 = 25 50 and 100 kPa at constant blockage ratio (BR = 0.6) was investigated and compared for both configurations. Results show that for the same initial pressure (p0 = 50 kPa) the obstacle configurations could lead to different final propagation regimes: a quasi-detonation for WW and a choked-flame for FT due to the increased losses for the latter. At p0 = 25 kPa however while both configurations result in choked flames WW seem to exhibit larger velocity deficits than FT due to longer flame-precursor shock distances during quasi-steady propagation and to the increased presence of unburnt mixture downstream of the tip of the flame that homogeneously explodes providing additional support to the propagation of the flame.
Energy Use and Greenhouse Gas Emissions of Traction Alternatives for Regional Railways
Feb 2024
Publication
This paper presents a method for estimating Well-to-Wheel (WTW) energy use and greenhouse gas (GHG) emissions attributed to the advanced railway propulsion systems implemented in conjunction with different energy carriers and their production pathways. The analysis encompasses diesel-electric multiple unit vehicles converted to their hybrid-electric plug-in hybrid-electric fuel cell hybrid-electric or battery-electric counterparts combined with biodiesel or hydrotreated vegetable oil (HVO) as the first and second generation biofuels liquefied natural gas (LNG) hydrogen and/or electricity. The method is demonstrated using non-electrified regional railway network with heterogeneous vehicle fleet in the Netherlands as a case. Battery-electric system utilizing green electricity is identified as the only configuration leading to emission-free transport while offering the highest energy use reduction by 65–71% compared to the current diesel-powered hybrid-electric system. When using grey electricity based on the EU2030 production mix these savings are reduced to about 27–39% in WTW energy use and around 68–73% in WTW GHG emissions. Significant reductions in overall energy use and emissions are obtained for the plug-in hybrid-electric concept when combining diesel LNG or waste cooking oil-based HVO with electricity. The remaining configurations that reduce energy use and GHG emissions are hybrid-electric systems running on LNG or HVO from waste cooking oil. The latter led to approximately 88% lower WTW emissions than the baseline for each vehicle type. When produced from natural gas or EU2030-mix-based electrolysis hydrogen negatively affected both aspects irrespective of the prime mover technology. However when produced via green electricity it offers a GHG reduction of approximately 90% for hybrid-electric and fuel cell hybrid-electric configurations with a further reduction of up to 92–93% if combined with green electricity in plug-in hybrid-electric systems. The results indicate that HVO from waste cooking oil could be an effective and instantly implementable transition solution towards carbon–neutral regional trains allowing for a smooth transition and development of supporting infrastructure required for more energy-efficient and environment-friendly technologies.
Hydrogen Storage Solutions for Residential Heating: A Thermodynamic and Economic Analysis with Scale-up Potential
Jul 2024
Publication
The study presents a thermodynamic and economic assessment of different hydrogen storage solutions for heating purposes powered by PV panels of a 10-apartment residential building in Milan and it focuses on compressed hydrogen liquid hydrogen and metal hydride. The technical assessment involves using Python to code thermodynamic models to address technical and thermodynamic performances. The economic analysis evaluates the CAPEX the ROI and the cost per unit of stored hydrogen and energy. The study aims to provide an accurate assessment of the thermodynamic and economic indicators of three of the storage methods introduced in the literature review pointing out the one with the best techno-economic performance for further development and research. The performed analysis shows that compressed hydrogen represents the best alternative but its cost is still too high for small residential applications. Applying the technology to a big system case would enable the solution making it economically feasible.
Benchmark of J55 and X56 Steels on Cracking and Corrosion Effects Under Hydrogen Salt Cavern Boundary Conditions
Feb 2024
Publication
Salt caverns have great potential to store relevant amounts of hydrogen as part of the energy transition. However the durability and suitability of commonly used steels for piping in hydrogen salt caverns is still under research. In this work aging effects focusing on corrosion and cracking patterns of casing steel API 5CT J55 and “H2ready” pipeline steel API 5L X56 were investigated with scanning electron microscopy and energy dispersive X-ray spectroscopy after accelerated stress tests with pressure/temperature cycling under hydrogen salt cavern-like conditions. Compared to dry conditions significant more corrosion by presence of salt ions was detected. However compared to X56 only for J55 an intensification of corrosion and cracking at the surface due to hydrogen atmosphere was revealed. Pronounced surface cracks were observed for J55 over the entire samples. Overall the results strongly suggest that X56 is more resistant than J55 under the conditions of a hydrogen salt cavern.
Analysing the Prospects of Grid-connected Green Hydrogen Production in Predominantly Fossil-based Countries - A Case Study of South Africa
Aug 2024
Publication
Importing substantial amount of green hydrogen from countries like South Africa which have abundant solar and wind potentials to replace fossil fuels has attracted interest in developed regions. This study analyses South African strategies for improving and decarbonizing the power sector while also producing hydrogen for export. These strategies include the Integrated Resource Plan the Transmission Development Plan Just Energy Transition and Hydrogen Society Roadmap for grid connected hydrogen production in 2030. Results based on an hourly resolution optimisation in Plexos indicate that annual grid-connected hydrogen production of 500 kt can lead to a 20–25% increase in the cost of electricity in scenarios with lower renewable energy penetration due to South African emission constraints by 2030. While the price of electricity is still in acceptable range and the price of hydrogen can be competitive on the international market (2–3 USD/kgH2 for production) the emission factor of this hydrogen is higher than the one of grey hydrogen ranging from 13 to 24 kgCO2/kgh2. When attempting to reach emission factors based on EU directives the three policy roadmaps become unfeasible and free capacity expansion results in significant sixteen-fold increase of wind and seven-fold increase in solar installations compared to 2023 levels by 2030 in South Africa.
Can an Energy Only Market Enable Resource Adequacy in a Decarbonized Power System? A Co-simulation with Two Agent-based-models
Feb 2024
Publication
Future power systems in which generation will come almost entirely from variable Renewable Energy Sources (vRES) will be characterized by weather-driven supply and flexible demand. In a simulation of the future Dutch power system we analyze whether there are sufficient incentives for market-driven investors to provide a sufficient level of security of supply considering the profit-seeking and myopic behavior of investors. We cosimulate two agent-based models (ABM) one for generation expansion and one for the operational time scale. The results suggest that in a system with a high share of vRES and flexibility prices will be set predominantly by the demand’s willingness to pay particularly by the opportunity cost of flexible hydrogen electrolyzers. The demand for electric heating could double the price of electricity in winter compared to summer and in years with low vRES could cause shortages. Simulations with stochastic weather profiles increase the year-to-year variability of cost recovery by more than threefold and the year-to-year price variability by more than tenfold compared to a scenario with no weather uncertainty. Dispatchable technologies have the most volatile annual returns due to high scarcity rents during years of low vRES production and diminished returns during years with high vRES production. We conclude that in a highly renewable EOM investors would not have sufficient incentives to ensure the reliability of the system. If they invested in such a way to ensure that demand could be met in a year with the lowest vRES yield they would not recover their fixed costs in the majority of years.
Towards Low-carbon Power Networks: Optimal Location and Sizing of Renewable Energy Sources and Hydrogen Storage
Apr 2024
Publication
This paper proposes a systematic optimization framework to jointly determine the optimal location and sizing decisions of renewables and hydrogen storage in a power network to achieve the transition to low-carbon networks efficiently. We obtain these strategic decisions based on the multi-period alternating current optimal power flow (AC MOPF) problem that jointly analyzes power network renewable and hydrogen storage interactions at the operational level by considering the uncertainty of renewable output seasonality of electricity demand and electricity prices. We develop a tailored solution approach based on second-order cone programming within a Benders decomposition framework to provide globally optimal solutions. In a test case we show that the joint integration of renewable sources and hydrogen storage and consideration of the AC MOPF model significantly reduces the operational cost of the power network. In turn our findings can provide quantitative insights to decision-makers on how to integrate renewable sources and hydrogen storage under different settings of the hydrogen selling price renewable curtailment cost emission tax price and conversion efficiency.
Profitability of Hydrogen Production: Assessment of Investments in Electrolyser Under Various Market Circumstances
Aug 2024
Publication
Although hydrogen is increasingly seen as a crucial energy carrier in future zero-carbon energy system a profitable exploitation of electrolysers requires still high amounts of subsidies. To analyze the profitability of electrolysers attention has to be paid not only to the costs but also to the interaction between electricity and hydrogen markets. Using a model of internationally integrated electricity and hydrogen markets this paper analyses the profitability of electrolysers plants in various future market circumstances. We find that in particular the future supply of renewable electricity the demand for electricity as well as the prices of natural gas and carbon strongly affect the profitability of electrolysis. In order to make massive investments in electrolysers profitable with significantly lower subsidy requirements the amount of renewable electricity generation needs to grow strongly and the carbon prices should be higher while the demand for electricity should not increase accordingly. This research underscores the critical role of market conditions in shaping the viability of hydrogen electrolysis providing valuable insights for policymakers and stakeholders in the transition to a zero-carbon energy system.
Will Hydrogen and Synthetic Fuels Energize our Future? Their Role in Europe's Climate-neutral Energy System and Power System Dynamics
Aug 2024
Publication
This study evaluates the technoeconomic impacts of direct and indirect electrification on the EU's net-zero emissions target by 2050. By linking the JRC-EU-TIMES long-term energy system model with PLEXOS hourly resolution power system model this research offers a detailed analysis of the interactions between electricity hydrogen and synthetic fuel demand production technologies and their effects on the power sector. It highlights the importance of high temporal resolution power system analysis to capture the synergistic effects of these components often overlooked in isolated studies. Results indicate that direct electrification increases significantly and unimpacted by biomass CCS and nuclear energy assumptions. However indirect electrification in the form of hydrogen varies significantly between 1400 and 2200 TWhH2 by 2050. Synthetic fuels are essential for sector coupling making up 6–12% of total energy consumption by 2050 with the power sector supplying most hydrogen and CO2 for their production. Varying levels of indirect electrification impact electrolysers renewable energy and firm capacities. Higher indirect electrification increases electrolyser capacity factors by 8% leading to more renewable energy curtailment but improves system reliability by reducing 11 TWh unserved energy and increasing flexibility options. These insights inform EU energy policies stressing the need for a balanced approach to electrification biomass use and CCS to achieve a sustainable and reliable net-zero energy system by 2050. We also explore limitations and sensitivities.
A Thermodynamically Consistent Methodology to Develop Predictive Simplified Kinetics for Detonation Simulations
Sep 2023
Publication
The number of species and elementary reactions needed for describing the oxidation of fuels increases with the size of the molecule and in turn the complexity of detailed mechanisms. Although the kinetics for conventional fuels (H2 CH4 C3H8...) are somewhat well-established chemical integration in detonation applications remains a major challenge. Significant efforts have been made to develop reduction techniques that aim to keep the predictive capabilities of detailed mechanisms intact while minimizing the number of species and reactions required. However as their starting point of development is based on homogeneous reactors or ZND profiles reduced mechanisms comprising a few species and reactions are not predictive. The methodology presented here relies on defining virtual chemical species such that the thermodynamic equilibrium of the ZND structure is properly recovered thereby circumventing the need to account for minor intermediate species. A classical asymptotic expression relating the ignition delay time with the reaction rate constant is then used to fit the Arrhenius coefficients targeting computations carried out with detailed kinetics. The methodology was extended to develop a three-step mechanism in which the Arrhenius coefficients were optimized to accurately reproduce the one-dimensional laminar ZND structure and the D−κ curves for slightly-curved quasi-steady detonation waves. Two-dimensional simulations performed with the three-step mechanism successfully reproduce the spectrum of length scales present in soot foils computed with detailed kinetics (i.e. cell regularity and size). Results attest for the robustness of the proposed methodology/approximation and its flexibility to be adapted to different configurations.
Voltage Losses in Zero-gap Alkaline Water Electrolysis
Apr 2021
Publication
Reducing the gap between the electrodes and diaphragm to zero is an often adopted strategy to reduce the ohmic drop in alkaline water electrolyzers for hydrogen production. We provide a thorough account of the current–voltage relationship in such a zero-gap configuration over a wide range of electrolyte concentrations and current densities. Included are voltage components that are not often experimentally quantified like those due to bubbles hydroxide depletion and dissolved hydrogen and oxygen. As is commonly found for zero-gap configurations the ohmic resistance was substantially larger than that of the separator. We find that this is because the relatively flat electrode area facing the diaphragm was not active likely due to separator pore blockage by gas the electrode itself and or solid deposits. Over an e-folding time-scale of ten seconds an additional ohmic drop was found to arise likely due to gas bubbles in the electrode holes. For electrolyte concentrations below 0.5 M an overpotential was observed associated with local depletion of hydroxide at the anode. Finally a high supersaturation of hydrogen and oxygen was found to significantly increase the equilibrium potential at elevated current densities. Most of these voltage losses are shown to be easily avoidable by introducing a small 0.2 mm gap greatly improving the performance compared to zero-gap.
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