Publications

The purpose of this study is to analyze and compare the techno-economic performance of grid-connected Hybrid Energy Systems (HES) consisting of Photovoltaic (PV) and Reformer Fuel-Cell (RF-FC) using different types of solar PV tracking techniques to supply electricity to a small location in the City of Chlef Algeria. The PV tracking systems considered in this study include fixed facing south at four different angles (32◦ 34◦ 36◦ 38◦) horizontal-axis with continuous adjustment vertical-axis with continuous adjustment and a two-axis tracking system. The software tool HOMER Pro (Hybrid Optimization of Multiple Energy Resources) is used to simulate and analyze the technical feasibility and life-cycle cost of these different configurations. The meteorological data consisting of global solar radiation and air temperature used in this study was collected from the geographical area of the City of Chlef during the year 2020. This study has shown that the optimal design of a grid-connected hybrid PV/RF-FC energy system with Vertical Single Axis Tracker (VSAT) leads to the best economic perfor mance with low values of Net Present Cost (NPC) Cost of Energy (COE) with a Positive Return on Investment (ROI) and the shortest Simple Payback (SP) period. In addition from the simulation results obtained it can be concluded that the Horizontal and Vertical Single-Axis Trackers (HSAT and VSAT) as well as the Dual-Axis Tracker (DAT) are not always cost effective compared to the Fixed Tilt System (FTS). Therefore it is neces sary to carefully analyze the use of each tracker to assess whether the energy gain achieved outweighs the overall shortcomings of the tracker.

This paper investigates the circularity of green hydrogen and resource recovery from brine using an integrated approach based on alkaline water electrolysis (AWE). Traditional AWE employs highly alkaline electrolytes which can lead to electrode corrosion undesirable side reactions and gas cross-over issues. Conversely indirect brine electrolysis requires pre-treatment steps which negatively impact both techno-economics and environmental sustainability. In response this study proposes an innovative brine electrolysis process utilizing solid electrolytes (SELs). The process includes an on-site brine treatment facility leveraging a self-driven phase transition technique and incorporates a hydrophobic membrane as part of a membrane distillation (MD) system to facilitate the gas pathway. Polyvinyl alcohol (PVA) and tetraethylammonium hydroxide (TEAOH)-based electrolytes combined with potassium hydroxide (KOH) at various concentrations function as a self-wetted electrolyte (SWE). This design partially disperses water vapor while effectively preventing the intrusion of contaminated ions into the SWE and electrode-catalyst interfaces. PVA-TEAOH-KOH-30 wt% SWE demonstrated the highest ion conductivity (112.4 mScm−1) and excellent performance with a current density of 375 mAcm−2. Long-term electrolysis confirmed with a nine-fold brine in volume concentration factor (VCF) demonstrated stable performance without MD membrane wetting. The Cl−/ClO− and Br− concentrations in the SWE were reduced by five orders of magnitude compared to the original brine. This electrolyzer supports the circular use of resources with hydrogen as an energy carrier and concentrated brine and oxygen as valuable by-products aligning with the sustainable development goals (SDGs) and net-zero emissions by 2050.

The growing penetration of renewable energy sources requires resilient microgrids capable of providing stable and continuous operation. Hybrid energy storage systems (HESS) which integrate hydrogen-based storage systems (HBSS) battery storage systems (BSS) and supercapacitor banks (SCB) are essential to ensuring the flexibility and robustness of these microgrids. Accurate modelling of these microgrids is crucial for analysis controller design and performance optimization but the complexity of HESS poses a significant challenge: simplified linear models fail to capture the inherent nonlinear dynamics while nonlinear approaches often require excessive computational effort for real-time control applications. To address this challenge this study presents a novel state space model with linear variable parameters (LPV) which effectively balances accuracy in capturing the nonlinear dynamics of the microgrid and computational efficiency. The research focuses on a high-voltage DC bus microgrid architecture in which the BSS and SCB are connected directly in parallel to provide passive DC bus stabilization a configuration that improves system resilience but has received limited attention in the existing literature. The proposed LPV framework employs recursive linearisation around variable operating points generating a time-varying linear representation that accurately captures the nonlinear behaviour of the system. By relying exclusively on directly measurable state variables the model eliminates the need for observers facilitating its practical implementation. The developed model has been compared with a reference model validated in the literature and the results have been excellent with average errors MAE RAE and RMSE values remaining below 1.2% for all critical variables including state-of-charge DC bus voltage and hydrogen level. At the same time the model maintains remarkable computational efficiency completing a 24-h simulation in just 1.49 s more than twice as fast as its benchmark counterpart. This optimal combination of precision and efficiency makes the developed LPV model particularly suitable for advanced model-based control strategies including real-time energy management systems (EMS) that use model predictive control (MPC). The developed model represents a significant advance in microgrid modelling as it provides a general control-oriented approach that enables the design and operation of more resilient efficient and scalable renewable energy microgrids.

The reliance on fossil fuels for electricity production in insular regions creates critical environmental economic and logistical challenges particularly for ecologically fragile islands. Transitioning to renewable energy is essential to mitigate these impacts enhance energy security and preserve unique ecosystems. This systematic review addresses key research questions: what practical strategies have proven effective in reducing fossil fuel dependency in island contexts and what barriers hinder their widespread adoption? By applying the PRISMA methodology this study examines a decade (2014–2024) of research on renewable energy systems highlighting successful initiatives such as the integration of solar and wind systems in Hawaii energy storage advancements in La Graciosa hybrid renewable grids in the Galápagos Islands and others. Specific barriers include high upfront costs regulatory challenges and technical limitations such as grid instability due to renewable energy intermittency. This review contributes by synthesizing lessons from diverse case studies and identifying innovative approaches like hydrogen storage predictive control systems and community-driven renewable projects. The findings offer actionable insights for policymakers and researchers to accelerate the transition towards sustainable energy systems in island environments.

This study explores the potential of solar tracking technologies to enhance South Africa’s energy transition focusing on their role in supporting green hydrogen production for domestic use and export. Using the Global Energy System Model (GENeSYS-MOD) it evaluates four solar tracking technologies — horizontal axis tilted horizontal axis vertical axis and dual-axis — across six scenarios: tracking and non-tracking versions of a Business-as-Usual (BAU) scenario a 2 ◦C scenario and a high hydrogen demand and export (HighH2) scenario. The results identify horizontal axis tracking as the most cost-effective option followed by tilted horizontal axis tracking which is particularly prominent in the HighH2 scenario. Tracking systems enhance hydrogen production by extending power output and increasing electrolyzer full-load hours. In the HighH2 scenario they reduce hydrogen production costs in 2050 from 1.47 e/kg to 1.34 e/kg and system cost by 0.66% positioning South Africa competitively in the global hydrogen market. By integrating tracking technologies South Africa can align hydrogen production ambitions with renewable energy growth while mitigating grid and financial challenges. The research underscores the need for targeted energy investments and policies to maximize renewable energy and hydrogen potential ensuring a just energy transition that supports export opportunities domestic energy security and equitable socio-economic growth.

Hydrogen production is increasingly vital for global decarbonization but remains a waterand energy-intensive process especially in arid regions. Despite growing attention to its climate benefits limited research has addressed the environmental impacts of water sourcing. This study employs a life cycle assessment (LCA) approach to evaluate three water supply strategies for hydrogen production: (1) seawater desalination without brine treatment (BT) (2) desalination with partial BT and (3) freshwater purification. Scenarios are modeled for the United Arab Emirates (UAE) Australia and Spain representing diverse electricity mixes and water stress conditions. Both electrolysis and steam methane reforming (SMR) are evaluated as hydrogen production methods. Results show that desalination scenarios contribute substantially to human health and ecosystem impacts due to high energy use and brine discharge. Although partial BT aims to reduce direct marine discharge impacts its substantial energy demand can offset these benefits by increasing other environmental burdens such as marine eutrophication especially in regions reliant on carbon-intensive electricity grids. Freshwater scenarios offer lower environmental impact overall but raise water availability concerns. Across all regions feedwater for SMR shows nearly 50% lower impacts than for electrolysis. This study focuses solely on the environmental impacts associated with water sourcing and treatment for hydrogen production excluding the downstream impacts of the hydrogen generation process itself. This study highlights the trade-offs between water sourcing brine treatment and freshwater purification for hydrogen production offering insights for optimizing sustainable hydrogen systems in water-stressed regions.

The European Union promotes decarbonization in energy-intensive industries like glass manufacturing. Collaboration between industry and researchers focuses on reducing CO2 emissions through hydrogen (H2) integration as a natural gas substitute. However to the best of the authors’ knowledge no updated real-world case studies are available in the literature that consider the on-site implementation of an electrolyzer for autonomous hydrogen production capable of meeting the needs of a glass manufacturing plant within current technological constraints. This study examines a representative hollow glass plant and develops various decarbonization scenarios through detailed process simulations in Aspen Plus. The models provide consistent mass and energy balances enabling the quantification of energy demand and key cost drivers associated with H2 integration. These results form the basis for a scenario-specific techno-economic assessment including both on-grid and off-grid configurations. Subsequently the analysis estimates the levelized costs of hydrogen (LCOH) for each scenario and compares them to current and projected benchmarks. The study also highlights ongoing research projects and technological advancements in the transition from natural gas to H2 in the glass sector. Finally potential barriers to large-scale implementation are discussed along with policy and infrastructure recommendations to foster industrial adoption. These findings suggest that hybrid configurations represent the most promising path toward industrial H2 adoption in glass manufacturing.

With the accelerating global transition to clean energy underground hydrogen storage (UHS) has gained significant attention as a flexible and renewable energy storage technology. Ontario Canada as a pioneer in energy transition offers substantial underground storage potential with its geological conditions of salt limestone and sandstone providing diverse options for hydrogen storage. However the hydrogen transport characteristics of different rock media significantly affect the feasibility and safety of energy storage projects warranting in-depth research. This study simulates the hydrogen flow and transport characteristics in typical energy storage digital rock core models (salt rock limestone and sandstone) from Ontario using the improved quartet structure generation set (I-QSGS) and the lattice Boltzmann method (LBM). The study systematically investigates the distribution of flow velocity fields directional characteristics and permeability differences covering the impact of hydraulic changes on storage capacity and the mesoscopic flow behavior of hydrogen in porous media. The results show that salt rock due to its dense structure has the lowest permeability and airtightness with extremely low hydrogen transport velocity that is minimally affected by pressure differences. The microfracture structure of limestone provides uneven transport pathways exhibiting moderate permeability and fracture-dominated transport characteristics. Sandstone with its higher porosity and good connectivity has a significantly higher transport rate compared to the other two media showing local high-velocity preferential flow paths. Directional analysis reveals that salt rock and sandstone exhibit significant anisotropy while limestone’s transport characteristics are more uniform. Based on these findings salt rock with its superior sealing ability demonstrates the best hydrogen storage performance while limestone and sandstone also exhibit potential for storage under specific conditions though further optimization and validation are required. This study provides a theoretical basis for site selection and operational parameter optimization for underground hydrogen storage in Ontario and offers valuable insights for energy storage projects in similar geological settings globally.

The combustion of pure H2 in engines is still troublesome needing further research and development. Using H2 and diesel in a dual-fuel compression ignition engine appears as a more feasible approach. Here we report an experimental assessment of performance and emissions for a single-cylinder four-stroke air-cooled compression ignition engine operating with neat diesel and H2-diesel dual-fuel. Previous studies typically show the performance and emissions for a specific operation condition (i.e. a fixed engine speed and torque) or a limited operating range. Our experiments covered engine speeds of 3000 and 3600 rpm and torque levels of 3 and 7 Nm. An in-house designed and built alkaline cell generated the H2 used for the partial substitution of diesel. Compared with neat diesel the results indicate that adding H2 decreased the air-fuel equivalence ratio and the Brake Specific Diesel Fuel Consumption Efficiency by around 14–29 % and 4–31 %. In contrast adding H2 increased the Brake Fuel Conversion Efficiency by around 3–36 %. In addition the Brake Thermal Efficiency increased in the presence of H2 in the range of 3–37 % for the lower engine speed and 27–43 % for the higher engine speed compared with neat diesel. The dual-fuel mode resulted in lower CO and CO2 emissions for the same power output. The emissions of hydrocarbons decreased with H2 addition except for the lower engine speed and the higher torque. However the dual-fuel operation resulted in higher NOx emissions than neat diesel with 2–6 % and 19–48 % increments for the lower and higher engine speeds. H2 emerges as a versatile energy carrier with the potential to tackle current energy and emissions challenges; however the dual-fuel strategy requires careful management of NOx emissions.

Underground hydrogen storage is critical for supporting the transition to renewable energy systems addressing the intermittent nature of solar and wind power. Despite its promise as a carbon-neutral energy carrier there remains limited understanding of the geomechanical behavior of subsurface reservoirs under hydrogen storage conditions. This knowledge gap is particularly significant for fast-cycling operations which have yet to be implemented on a large scale. This review evaluates current knowledge on the geomechanics of underground hydrogen storage focusing on risks and challenges in geological formations such as salt caverns depleted hydrocarbon reservoirs saline aquifers and lined rock caverns. Laboratory experiments field studies and numerical simulations are synthesized to examine cyclic pressurization induced seismicity thermal stresses and hydrogen-rock interactions. Notable challenges include degradation of rock properties fault reactivation micro-seismic activity in porous reservoirs and mineral dissolution/precipitation caused by hydrogen exposure. While salt caverns are effective for low-frequency hydrogen storage their behavior under fast-cyclic loading requires further investigation. Similarly the mechanical evolution of porous and fractured reservoirs remains poorly understood. Key findings highlight the need for comprehensive geomechanical studies to mitigate risks and enhance hydrogen storage feasibility. Research priorities include quantifying cyclic loading effects on rock integrity understanding hydrogen-rock chemical interactions and refining operational strategies. Addressing these uncertainties is essential for enabling large-scale hydrogen integration into global energy systems and advancing sustainable energy solutions. This work systematically focuses on the geomechanical implications of hydrogen injection into subsurface formations offering a critical evaluation of current studies and proposing a unified research agenda.

The maritime sector’s transition to sustainable energy is critical for achieving global carbon neutrality with container terminals representing a key focus due to their high energy consumption and emissions. This study explores the potential of hydrogen energy as a decarbonization solution for port operations using the Chuanshan Port Area of Ningbo Zhoushan Port (CPANZP) as a case study. Through a comprehensive analysis of hydrogen production storage refueling and consumption technologies we demonstrate the feasibility and benefits of integrating hydrogen systems into port infrastructure. Our findings highlight the successful deployment of a hybrid “wind-solar-hydrogen-storage” energy system at CPANZP which achieves 49.67% renewable energy contribution and an annual reduction of 22000 tons in carbon emissions. Key advancements include alkaline water electrolysis with 64.48% efficiency multi-tier hydrogen storage systems and fuel cell applications for vehicles and power generation. Despite these achievements challenges such as high production costs infrastructure scalability and data integration gaps persist. The study underscores the importance of policy support technological innovation and international collaboration to overcome these barriers and accelerate the adoption of hydrogen energy in ports worldwide. This research provides actionable insights for port operators and policymakers aiming to balance operational efficiency with sustainability goals.

This study evaluates and compares physical chemical and dual activation methods for preparing activated carbons from spent coffee grounds to optimize their porosity for hydrogen storage. Activation processes including both one-step and two-step chemical and physical methods were investigated incorporating a novel dual activation process that combines chemical and physical activation. The findings indicate that the two-step chemical activation yields superior results producing activated carbons with a high specific surface area of 1680 m2 /g and a micropore volume of 0.616 cm3 /g. These characteristics lead to impressive hydrogen uptake capacities of 2.65 wt% and 3.66 wt% at 77 K under pressures of 1 and 70 bar respectively. The study highlights the potential of spent coffee grounds as a cost-effective precursor for producing high-performance activated carbons.

This study evaluates the effects of adding a hydrogen gaseous mixture (HGM) to primary fuel in a single cylinder research engine (SCRE). Storage and transportation of high-purity hydrogen limit the application of this gas. With the development of fuel reforming methods using hydrogenenriched mixtures in spark-ignited internal combustion engines is a convenient option to fossil fuels. Ethanol and gasoline were used as primary fuel by direct injection (DI) and gaseous mixture was added by fumigation system (FS). The experimental analysis was developed in Spark Ignition (SI) four-stroke engine 4 valves and 0.45 L of cubic capacity. For each operation condition and primary fuel spark timing and amount of HGM were adjusted in order to keep air-fuel ratio stochiometric (λ = 100). However the spark timing and the percentage of gas varied aiming to evaluate the behavior of the air-fuel mixture. It was evaluated the specific fuel consumption and the evolution of the combustion process. The results showed that the addition of reformed gas promotes acceleration of the combustion process ethanol and gasoline. Results were expressive when using ethanol. A reduction in fuel-specific consumption - for this fuel - with combustion centralized which did not occur when gasoline was employed.

To enable a sustainable and socially accepted hydrogen and methanol economy it is crucial to prioritize green and water-conscious production. In this review we reveal that there is a significant research gap regarding comprehensive assessments of such production methods. We present an innovative process chain consisting of adsorption-based direct air capture solid oxide electrolysis and methanol synthesis to address this issue. To allow future comprehensive techno-economic assessments we perform a systematic literature review and harmonization of the techno-economic parameters of the process chain’s technologies. Based on the conducted literature review we find that the long-term median specific energy demand of adsorption-based direct air capture is expected to decrease to 204 kWhel/tCO2 and 1257 kWhth/tCO2 while the capture cost is expected to decrease to 162 €2024/tCO2 with a relative high uncertainty. The evaluated sources expect a future increase in system efficiency of solid oxide electrolysis to 80% while the purchase equipment costs are expected to decrease significantly. Finally we demonstrate the feasibility of the process chain from a technoeconomic perspective and show a potential reduction in external heat demand of the DAC unit of up to 34% when integrated in the process chain.

This paper deals with proton exchange membrane (PEM) electrolyzers directly coupled with a photovoltaic source. It proposes a method to increase the energy delivered to the electrolyzer by reconfiguring the electrical connection of the arrays according to solar radiation. Unlike the design criterion proposed by the literature the suggested approach considers a source obtained by connecting arrays in parallel depending on solar radiation based on a fixed photovoltaic configuration. This method allows for the optimization of the operating point at medium or low solar radiation where the fixed configuration gives poor results. The analysis is performed on a low-power plant (400 W). It is based on a commercial photovoltaic cell whose equivalent model is retrieved from data provided by the manufacturer. An equivalent model of the PEM electrolyzer is also derived. Two comparisons are proposed: the former considers a photovoltaic source designed according to the traditional approach i.e. a fixed configuration; in the latter a DC/DC converter as interface is adopted. The role of the converter is discussed to highlight the pros and cons. The optimal set point of the converter is calculated using an analytical equation that takes into account the electrolyzer model. In the proposed study an increase of 17% 62% and 93% of the delivered energy has been obtained in three characteristic days summer spring/autumn and winter respectively compared to the fixed PV configuration. These results are also better than those achieved using the converter. Results show that the proposed direct coupling technique applied to PEM electrolyzers in low-power plants is a good trade-off between a fixed photovoltaic source configuration and the use of a DC/DC converter.

The H2STORE collaborative project investigates potential geohydraulic petrophysical mineralogical microbiological and geochemical interactions induced by the injection of hydrogen into depleted gas reservoirs and CO2- and town gas storage sites. In this context the University of Jena performs mineralogical and geochemical investigations on reservoir and cap rocks to evaluate the relevance of preferential sedimentological features which will control fluid (hydrogen) pathways thus provoking fluid-rock interactions and related variations in porosity and permeability. Thereby reservoir sand- and sealing mudstones of different composition sampled from distinct depths (different: pressure/temperature conditions) of five German locations are analysed. In combination with laboratory experiments the results will enable the characterization of specific mineral reactions at different physico-chemical conditions and geological settings.

Chemical looping hydrogen generation (CLHG) from biomass is a promising technology for producing carbonnegative hydrogen. However achieving autothermal operation without sacrificing hydrogen yield presents a significant thermodynamic challenge. This study proposes and evaluates a novel thermal management strategy that enables a self-sustaining process by balancing the system’s heat load with its internal exothermic reactions. A comprehensive analysis was conducted using process simulation to assess the system’s thermodynamic performance identify key sources of inefficiency through exergy analysis and determine its economic viability via a detailed techno-economic assessment. The results show that a 200 MWth CLHG plant can produce 2.06 t-H2/h with a hydrogen production efficiency and exergy efficiency of 34.46 % and 44.4 % respectively. The exergy analysis identified the fuel reactor as the largest source of thermodynamic inefficiency accounting for 66.4 % of the total exergy destruction. The techno-economic analysis yielded a base-case minimum selling price (MSP) of hydrogen of 2.63 USD/kg a rate competitive with other carbon-capture-enabled hydrogen production methods. Sensitivity analysis confirmed that the MSP is most influenced by biomass price and discount rate. Crucially the system’s carbon-negative nature allows it to leverage carbon pricing schemes which can significantly improve its economic performance. Under the EU’s current carbon price the MSP falls to 0.98 USD/kg-H2 and it can become negative in regions with higher carbon taxes suggesting profitability from carbon credits alone. This study demonstrates that the proposed CLHG system is a technically robust and economically compelling pathway for clean hydrogen production particularly in regulatory environments that incentivize carbon capture.

Hydrogen-enriched compressed natural gas (HCNG) holds significant promise for renewable energy absorption and hydrogen utilization while also increasing the complexity of Integrated Energy System (IES) structures which presents challenges for optimal HCNG-IES operation. Energy inertia provides IES with potential operational flexibility. However existing HCNG-IES optimization technologies inadequately account for hydrogen and thermal inertia leaving significant opportunities to enhance system performance. In this study we begin with a comprehensive analysis and modeling of the hydrogen-thermal multi-energy inertia (HTMEI) processes which encompass the hydrogen inertia of HCNG loads and hydrogen storage tanks as well as the thermal inertia of thermal storage tanks and buildings. Following this we develop an optimization model for the operation of HCNG-IES that incorporates HTMEI to optimize the system's overall performance in terms of economic environmental and energy efficiency criteria. The resulting optimal scheduling scheme integrates the outputs of energy devices and multi-energy inertia processes. Case studies validate the efficacy of the proposed operational optimization method. The results indicate that in comparison with an operational optimization method that does not consider energy inertia the proposed approach reduces operational costs by 34.79% carbon emissions by 32.93% electricity purchased from the grid by 95.37% and natural gas consumption by 11.8%. Furthermore the analysis has verified the mutual enhancement between hydrogen inertia and thermal inertia along with their positive individual impacts on operational performance of the HCNGIES.

Ammonia (NH3) has emerged as a promising hydrogen carrier due to its high hydrogen content favourable storage and transport properties and carbon-free utilisation. Its ability to be stored as a liquid under relatively mild conditions and its compatibility with existing industrial infrastructure make it an efficient and scalable solution for hydrogen distribution. This study conducts a detailed investigation into the kinetics of ammonia decomposition over rutheniumbased catalysts which are known for their high catalytic activity for ammonia cracking. Experimental data across a wide range of operating conditions are used to validate the proposed models with a promising catalyst (0.5 wt.% Ru/Al2O3). The study employs kinetic models based on different theoretical frameworks such as the Langmuir isotherm the Temkin-Pyzhev approach and the microkinetic model focusing on evaluating various rate-determining steps. A comparison of these models shows that those that consider nitrogen desorption a ratedetermining step provide the best predictions of NH3 conversion effectively capturing the dependencies on temperature and feed molar fractions of reactants and products. This multifaceted approach integrates experimental data with proposed kinetic models contributing to a better understanding of NH3 decomposition through parameter optimisation. The findings provide valuable insights for modelling catalytic reactors optimising conditions and enhancing catalyst performance for efficient hydrogen production from ammonia.

Energy management in hybrid fuel cell ship systems faces the dual challenges of optimizing hydrogen consumption and ensuring power quality. This study proposes an Improved Weighted Antlion Optimization (IW-ALO) algorithm for multi-objective problems. The method incorporates a dynamic weight adjustment mechanism and an elite-guided strategy which significantly enhance global search capability and convergence performance. By integrating IW-ALO with the Equivalent Consumption Minimization Strategy (ECMS) an improved weighted ECMS (IW-ECMS) is developed enabling real-time optimization of the equivalence factor and ensuring efficient energy sharing between the fuel cell and the lithium-ion battery. To validate the proposed strategy a system simulation model is established in Matlab/Simulink 2017b. Compared with the rule-based state machine control and optimization-based ECMS methods over a representative 300 s ferry operating cycle the IW-ECMS achieves a hydrogen consumption reduction of 43.4% and 42.6% respectively corresponding to a minimum total usage of 166.6 g under the specified load profile while maintaining real-time system responsiveness. These reductions reflect the scenario tested characterized by frequent load variations. Nonetheless the results highlight the potential of IW-ECMS to enhance the economic performance of ship power systems and offer a novel approach for multi-objective cooperative optimization in complex energy systems.

Green H2 production using electrolyzer technology is an emerging method in the current mandate using renewable-based power sources integrated with electrolyzer technology. Prior research has been extensively studied to understand the effects of intermittent power sources on the hydrogen production output. However in this context the characteristics of the working electrolyzer behave differently under system-level operation. In this paper we investigated a 25 kW alkaline electrolyzer for its stack performance in terms of stack efficiency the stack current vs. stack voltage and the relationship between the H2 flow rate and stack current. It was found that the current of 52 A produces the best system efficiency of 64% under full load operation for 1 h. The H2 flow rate behaves in an exponential asymptotic pattern and it is also found that the ramp-up time for hydrogen generation by the electrolyzer is significantly low thus marking it as an efficient option for producing green hydrogen with the input of a hybrid grid and renewable PV-based power sources. Hydrogen production techno-economic analysis has been conducted and the LCOH is found to be on the higher side for the current electrolyzer under investigation.

Alkaline water electrolysis (AWE) is the most mature electrochemical technology for hydrogen production from renewable electricity. Thus its mathematical modeling is an important tool to provide new perspectives for the design and optimization of energy storage and decarbonization systems. However current models rely on numerous empirical parameters and neglect variations of temperature and concentration alongside the electrolysis cell which can impact the application and reliability of the simulation results. Thus this study proposes a simple four-parameter semi-empirical model for AWE system analysis which relies on minimal fitting data while providing reliable extrapolation results. In addition the effect of model dimensionality (i.e. 0D 1/2D and 1D) are carefully assessed in the optimization of an AWE system. The results indicate that the proposed model can accurately reproduce literature data from four previous works (R 2 ≥ 0.98) as well as new experimental data. In the system optimization the trade-offs existing in the lye cooling sizing highlight that maintaining a low temperature difference in AWE stacks (76-80°C) leads to higher efficiencies and lower hydrogen costs.

This article examines the growing potential of low-emission hydrogen as an innovative solution supporting the decarbonization of the agricultural sector. It discusses its potential applications on farms including as an energy source for powering agricultural machinery producing fertilizers and storing energy from renewable sources. Within the European context it considers actions arising from the European Green Deal and the “Fit for 55” strategy which promote the development of hydrogen infrastructure and support research into low-emission technologies. The article also discusses global initiatives and trends in the development of the hydrogen economy pointing to international cooperation investment and the need for technology standardization. It highlights the challenges related to cost infrastructure and scalability as well as the opportunities hydrogen offers for a sustainable and energy-efficient agriculture of the future.

As the global demand for energy increases and the transition to renewable and clean sources accelerates microgrid (MG) has emerged as a promising solution. Hydrogen fuel cell vehicles (HFCVs) offer significant advantages over gasoline vehicles in terms of reducing carbon dioxide emissions. However the development of HFCVs is hindered by the substantial up-front costs of hydrogen refueling stations (HRSs) coupled with the high cost of hydrogen transportation and the limitations of the hydrogen supply chain. This research proposes a multimicrogrid (MMG) system that integrates hydrogen energy and utilizes it as the HRS for fuel vehicle refueling. An adaptive hydrogen energy management method is employed for fuel cell vehicles to optimize the coupling between the transportation network and the power system. An integrated transportation state assessment model is developed and a smart MMG system is deployed to receive information from the transportation network. Building on this foundation an adaptive hydrogen scheduling model is developed. HFCVs are influenced by the hydrogen price adjustments leading them to travel to different MGs for refueling which in turn regulates the unit output of the MMG system. The MMG system is then integrated with the IEEE 33 bus distribution system to analyze the daily load balance. This integrated approach results in reduced traffic congestion lower MG costs and optimized power distribution network load balance.

The power-to-methanol (PtMeOH) will play a crucial role as a form of renewable chemical energy storage. In this paper PtMeOH techno-economics are assessed using the promising configuration from the previous work (Mbatha et al. [1]). This study evaluated the effect of parameters such as the CO2 emission tax electricity price and CAPEX reduction on the product methanol economic parity with respect to a reference case. Superior to previous economic studies a scenario where an existing methanol synthesis infrastructure is 100 % retrofitted with the promising electrolyser is assessed in terms of its economics and the associated economic parity. The volatile South African electricity market is considered as a case study. The sensitivity of the PtMeOH and green H2 profitability are checked. Grid-connected and standalone renewable energy PtMeOH scenarios are assessed. Foremost generalisable effect trends of these parameters on the net present value (NPV) and the levelized cost of methanol(LCOMeOH) and H2 (LCOH2) are discussed. The results show that economic parity of H2 (LCOH2 = current selling price = 4.06 €/kg) can be reached with an electricity price of 30 €/MWh and 70 % of the CAPEX. While the LCOMeOH will still be above 2 €/kg at 80 % of the CAPEX and electricity price of 20 €/MWh. This indicates that even if the CAPEX reduces to 20 % of its original in this study and the electricity price reduces to about 20 €/MWh the LCOMEOH will still not reach economic parity (LCOMeOH > current selling price = 0.44 €/kg). The results show that to make the retrofitted plant with a minimum of 20 years of life span profitable a feasible reduction in the electricity price to below 10 €/MWh along with favourable incentives such as CO2 credit and reduction in CAPEX particularly that of the electrolyser and treatment of the PtMeOH as a multiproduct plant will be required.

The high potential of hydrogen as a key factor on the pathway towards a climate neutral economy leads to rising demand in technical applications where gaseous hydrogen is used. For several metals hydrogen-metal interactions could cause a degradation of the material properties. This is especially valid for low carbon and highstrength structural steels as they are commonly used in natural gas pipelines and analyzed in this work. This work provides an insight to the impact of hydrogen on the mechanical properties of an API 5L X65 pipeline steel tested in 60 bar gaseous hydrogen atmosphere. The analyses were performed using the hollow specimen technique with slow strain rate testing (SSRT). The nature of the crack was visualized thereafter utilizing μCT imaging of the sample pressurized with gaseous hydrogen in comparison to one tested in an inert atmosphere. The combination of the results from non-conventional mechanical testing procedures and nondestructive imaging techniques has shown unambiguously how the exposure to hydrogen under realistic service pressure influences the mechanical properties of the material and the appearance of failure.

Hydrogen energy is critical in replacing fossil fuels and achieving net zero carbon emissions by 2050. Three measures can be implemented to promote hydrogen energy: reduce the cost of low-carbon hydrogen through technological improvements increase the production capacity of low-carbon hydrogen by stimulating investment and enhance hydrogen use as an energy carrier and in industrial processes by demand-side policies. This article examines how effective these measures are if successfully implemented in boosting the hydrogen market and reducing global economy-wide carbon emissions using a global computable general equilibrium model. The results show that all the measures increase the production and use of low-carbon hydrogen whether implemented alone or jointly. Notably the emissions reduced by joint implementation of all the measures in 2050 become 2.5 times the sum of emissions reduced by individual implementation indicating a considerable multiplier effect. This suggests supply and demand side policies be implemented jointly to maximize their impact on reducing emissions.

Large-scale H2 storage in depleted hydrocarbon reservoirs offers a practical way to use existing energy infra structure to address renewable energy intermittency. Cushion gases often constitute a large initial investment especially when expensive H2 is used. Cheaper alternatives such as CO2 or in-situ CH4 can reduce costs and in the case of CO2 integrate within carbon capture and storage systems. This study explored cushion and working gas dynamics through numerically modelling a range of storage scenarios in laterally extensive reservoirs – such as those in the Southern North Sea. In all simulations the cushion and working gases were separated laterally to limit contact surface area and therefore mixing. This work provides valuable insights into (i) capacity estima tions of CO2 storage and H2 withdrawal (ii) macro-scale fluid dynamics and (iii) the effects of gas mixing trends on H2 purity. The results underscore key trade-offs between CO2 storage volumes and H2 withdrawal and purity

The methanol industry responsible for around 10% of GHG emissions in the chemical sector faces growing challenges due to its environmental impacts. This article aims to reduce the lifecycle environmental impacts of the CO2-to-methanol process by exploring advanced electrification methods for hydrogen production and CO2 conversion. The process analysis and comprehensive life cycle assessment (LCA) are conducted on four different methanol production pathways: conventional natural gas CO2 hydrogenation trireforming of methane (TRM) and the novel electrified combined reforming (ECRM) by including two hydrogen production routes: PEM electrolysis and the innovative plasma-assisted methane pyrolysis. The LCA was performed using the ReCiPe method covering midpoint and endpoint categories across four Canadian provinces—British Columbia Alberta Ontario and Quebec. The efficient plasma technology improves environmental performance for all pathways. The plasma-assisted CO2 hydrogenation pathway in British Columbia and Quebec shows the lowest GHG emissions achieving -2.01 and -1.72 kg CO2/kg MeOH respectively. In Alberta the conventional pathway has the lowest impact followed by plasmaassisted TRM. The CO2 hydrogenation with the PEM pathway shows the highest GHG emissions at 8.00 kg CO2/kg MeOH highlighting the challenges of using hydrogen from PEM electrolysis in regions with carbon-intensive electricity grids. However the inclusion of carbon black as a byproduct further reduces the environmental impact making these plasma-assisted pathways more viable. This LCA study underscores the influence of regional factors and technology choices on the sustainability of methanol production with an example of a 107% reduction in GHG emissions when plasma-assisted ECRM is shifting from Alberta to Quebec.

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.

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.

In order to study the flow blending and transporting process of hydrogen that injects into the natural gas pipelines a three-dimensional T-pipe blending model is established and the flow characteristics are investigated systematically by the large eddy simulation (LES). Firstly the mathematical formulation of hydrogen-methane blending process is provided and the LES method is introduced and validated by a benchmark gas blending model having experimental data. Subsequently the T-pipe blending model is presented and the effects of key parameters such as the velocity of main pipe hydrogen blending ratio diameter of hydrogen injection pipeline diameter of main pipe and operating pressure on the hydrogen-methane blending process are studied systematically. The results show that under certain conditions the gas mixture will be stratified downstream of the blending point with hydrogen at the top of the pipeline and methane at the bottom of the pipeline. For the no-stratified scenarios the distance required for uniformly mixing downstream the injection point increases when the hydrogen mixing ratio decreases the diameter of the hydrogen injection pipe and the main pipe increase. Finally based on the numerical results the underlying physics of the stratification phenomenon during the blending process are explored and an indicator for stratification is proposed using the ratio between the Reynolds numbers of the natural gas and hydrogen.

Hydrogen crossover limits the load range of alkaline water electrolyzers hindering their integration with renewable energy. This study examines the impact of the electrode-diaphragm gap on crossover focusing on diffusive transport. Both finite-gap and zero-gap designs employing the state-of-the-art Zirfon UTP Perl 500 and UTP 220 diaphragms were investigated at room temperature and with a 12 wt% KOH electrolyte. Experimental results reveal a relatively high crossover for a zero-gap configuration which corresponds to supersaturation levels at the diaphragm-electrolyte interface of 8–80 with significant fluctuations over time and between experiments due to an imperfect zero-gap design. In contrast a finite-gap (500 μm) has a significantly smaller crossover corresponding to supersaturation levels of 2–4. Introducing a cathode gap strongly decreases crossover unlike an anode gap. Our results suggest that adding a small cathode-gap can significantly decrease gas impurity potentially increase the operating range of alkaline electrolyzers while maintaining good efficiency.

A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems namely PV/T- and CPV/T-coupling PEMEC respectively are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00 with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.

Hydrogen storage plays a crucial role in achieving net-zero emissions by enabling large-scale energy storage balancing renewable energy fluctuations and ensuring a stable supply for various applications. This study provides a comprehensive analysis of hydrogen storage technologies with a particular focus on underground storage in geological formations such as salt caverns depleted gas reservoirs and aquifers. These formations offer high-capacity storage solutions with salt caverns capable of holding up to 6 TWh of hydrogen and depleted gas reservoirs exceeding 1 TWh per site. Case studies from leading projects demonstrate the feasibility of underground hydrogen storage (UHS) in reducing energy intermittency and enhancing supply security. Challenges such as hydrogen leakage groundwater contamination induced seismicity and economic constraints remain critical concerns. Our findings highlight the technical economic and regulatory considerations for integrating UHS into the oil and gas industry emphasizing its role in sustainable energy transition and decarbonization strategies.

The present study explores the potential of integrating the NET Zero Cycle (NZC) with hydrogen production by alkaline electrolyzers. To achieve this an Aspen Plus model was developed for the NZC and its accuracy was first confirmed by comparing it with literature data. The creation of a model for an alkaline electrolyzer was achieved using Aspen Custom Modeler and later imported into Aspen Plus. A comprehensive simulation was conducted in Aspen Plus to examine the synergies between the NZC and the alkaline electrolyzer. In this integration the oxygen demand of the NZC is met by a combination of an air separation unit (ASU) and the electrolyzer. The electrolyzer not only partially fulfills the oxygen requirements but also acts as an external heat supplier for the regenerator. Additionally the NZC supplies deionized water to the electrolyzer. A thermodynamic analysis in dicates that the integration of the NZC and alkaline electrolyzers results in a higher efficiency of 56.5 % compared to the stand-alone NZC an improvement of 2.3 %. Assuming that the NZC and alkaline electrolyzer operate at the same power production and input levels the alkaline electrolyzer can generate substantial oxygen to reduce the energy consumption of the ASU significantly. This aspect represents one of the primary reasons for the enhanced efficiency observed in this study. However the ASU still needs to be operated to provide the full oxygen demands of the process. To identify the key parameters influencing the integration of the NZC and alkaline electrolyzers a sensitivity analysis was performed. To enhance the system efficiency a comprehensive investigation was conducted to analyze the influence of key parameters such as combustor outlet temperature (COT) turbine outlet pressure (TOP) and combustor outlet pressure (COP) on the thermodynamic first law efficiency of the cycle. An increase in electrolyzer input power and a reduction in electrolyzer inlet feed were associated with a higher cycle effi ciency. The results also highlight that the TOP COT and the electrolyzer input power have a more significant impact on the cycle thermodynamic first law efficiency within the range of 5.7 4.0 and 2.6 % respectively while COP only causes a 0.4 % change in cycle efficiency. The integrated system demonstrates an impressive system first law thermodynamic efficiency of 62.5 % and exergy efficiency of 60.6 %.

Developing countries including Ghana face challenges ensuring access to clean and reliable cooking fuels and technologies. Traditional biomass sources mainly used in most developing countries for cooking contribute to deforestation and indoor air pollution necessitating a shift towards environmentally friendly alternatives. The study’s primary objective is to evaluate the economic viability of using solar PV-based green hydrogen as a sustainable fuel for cooking in Ghana. The study adopted well-established equations to investigate the economic performance of the proposed system. The findings revealed that the levelized cost of hydrogen using the discounted cash flow approach is about 89% 155% and 190% more than electricity liquefied petroleum gas (LPG) and charcoal. This implies that using the hydrogen produced for cooking fuel is not cost-competitive compared to LPG charcoal and electricity. However with sufficient capital subsidies to lower the upfront costs the analysis suggests solar PV-based hydrogen could become an attractive alternative cooking fuel. In addition switching from firewood to solar PVbased hydrogen for cooking yields the highest carbon dioxide (CO2) emissions savings across the cities analysed. Likewise replacing charcoal with hydrogen also offers substantial CO2 emissions savings though lower than switching from firewood. Correspondingly switching from LPG to hydrogen produces lower CO2 emissions savings than firewood and charcoal. The study findings could contribute to the growing body of knowledge on sustainable energy solutions offering practical insights for policymakers researchers and industry stakeholders seeking to promote clean cooking adoption in developing economies.

In the present study pilot simulations of the phenomena of blast wave and fireball generated by the rupture of a high-pressure (35 MPa) hydrogen tank (volume 72 L) due to fire were carried out. The computational fluid dynamics (CFD) model includes the realizable k-ε model for turbulence and the eddy dissipation model coupled with the one-step chemical reaction mechanism for combustion. The simulation results were compared with experimental data on a stand-alone hydrogen tank rupture in a bonfire test. The simulations provided insights into the interaction between the blast wave propagation and combustion process. The simulated blast wave decay is approximately identical to the experimental data concerning pressure at various distances. Fireball is first ignited at the ground level which is considered to be due to stagnation flow conditions. Subsequently the flame propagates toward the interface between hydrogen and air.

Studies estimating the production cost of hydrogen-based fuels known as e-fuels often use renewable power profile time series obtained from open-source simulation tools that rely on meteorological reanalysis and satellite data such as Renewables.ninja or PVGIS. These simulated time series contain errors compared to real on-site measured data which are reflected in e-fuels cost estimates plant design and operational performance increasing the risk of inaccurate plant design and business models. Focusing on solar-powered e-fuels this study aims to quantify these errors using high-quality on-site power production data. A state-of-the-art optimization techno-economic model was used to estimate e-fuel production costs by utilizing either simulated or high-quality measured PV power profiles across four sites with different climates. The results indicate that in cloudy climates relying on simulated data instead of measured data can lead to an underestimation of the fuel production costs by 36 % for a hydrogen user requiring a constant supply considering an original error of 1.2 % in the annual average capacity factor. The cost underestimation can reach 25 % for a hydrogen user operating between 40 % and 100 % load and 17.5 % for a fully flexible user. For comparison cost differences around 20 % could also result from increasing the electrolyser or PV plant costs by around 55 % which highlights the importance of using high-quality renewable power profiles. To support this an open-source collaborative repository was developed to facilitate the sharing of measured renewable power profiles and provide tools for both time series analysis and green hydrogen techno-economic assessments.

A sudden release of compressed gases and the formation of a jet flow can occur in nature and various engineering applications. In particular high-pressure hydrogen jets can spontaneously ignite when released into an environment that contains oxygen. For some scenarios these high-pressure hydrogen jets can be released into a mixture containing hydrogen and oxygen. This scenario can possibly lead to a wide range of combustion regimes such as jet flames slow or fast deflagrations or even hazardous detonations. Each combustion regime is characterized by typical pressures and temperatures however fast transition between regimes is also possible.<br/>A common project between Tel Aviv University (TAU) Nuclear Research Center Negev (NRCN) and Commissariat à l’Energie Atomique et aux énergies alternatives (CEA) has been recently launched in order to understand these phenomena from experimental modelling and numerical points of view. The main goal is to investigate the dynamics and combustion regimes that arise once a pressurized hydrogen jet is released into a reactive environment that contains inhomogeneous concentrations of hydrogen steam and air.<br/>In this paper we present the first numerical results describing high-pressure hydrogen release obtained using a massively parallel compressible structured-grid flow solver. The experimental arrangements devoted to this phenomenon will also be described.

The development of hydrogen production technologies as well as new uses represents an opportunity both to accelerate the ecological transition and to create an industrial sector. However the risks associated with the use of hydrogen must not be overlooked. The mitigation of a hydrogen explosion in an enclosure is partly based on prevention strategies such as detection and ventilation but also on protection strategies such as explosion venting. However in several situations such as in highly constrained urban environments the discharge of the explosion through blast walls could generate significant overpressure effects outside the containment which are unacceptable. Thus having alternative mitigation solutions can make the effects of the explosion acceptable by reducing the flame speed and the overpressure loading or suppressing the secondary explosion. The objective of this paper is to present the experimental study of the mitigation of hydrogen-air deflagration in a 4 m3 vented enclosure by injection of aqueous foam. After a description of the experimental set-up the main experimental results are presented showing the influence of aqueous foam on flame propagation (Fig. 1). Different foam expansion ratios were investigated. An interpretation of the mitigating effect of foam on the explosion effects is proposed based on the work of Kichatov [5] and Zamashchikov [2].

Driven by global targets to reduce greenhouse gas emissions energy systems are expected to undergo fundamental changes. In light of carbon neutrality policies China is expected to significantly increase the proportion of hydrogen and electricity in its energy system in the future. Nevertheless the future trajectory remains shrouded in uncertainty. To explore the potential ramifications of varying growth scenarios pertaining to hydrogen and electricity on the energy landscape this study employs a meticulously designed bottom-up model. Through comprehensive scenario calculations the research aims to unravel the implications of such expansions and provide a nuanced analysis of their effects on the energy system. Results show that with an increase in electrification rates cumulative carbon dioxide emissions over a certain planning horizon could be reduced at the price of increased unit reduction costs. By increasing the share of end-use electricity and hydrogen from 71% to 80% in 2060 the unit carbon reduction cost will rise by 17%. Increasing shares of hydrogen could shorten the carbon emission peak time by approximately five years but it also brings an increase in peak shaving demand.

This report shows how the infrastructure that exists today can evolve from one based on the supply of fossil fuels to one providing the backbone of a clean hydrogen system. The ambitious government hydrogen targets across the UK will only be met with clarity focus and partnership. The gas networks are ready to play their part in the UK’s energy future. They have a plan know what is needed to deliver it and are taking the necessary steps to do just that.

Hydrogen energy is crucial for achieving net zero targets making the resilience of hydrogen supply chains (HSCs) increasingly important. Understanding current research on HSC resilience is key to enhancing it. Few studies summarise HSC resilience evaluation methods and link them to the general supply chain resilience and complex adaptive system (CAS) evaluation approaches. This study addresses this gap by systematically reviewing the literature on HSC resilience evaluations defining HSC resilience and conducting content analysis. It proposes a conceptual framework integrating technical operational and organisational perspectives. Each perspective is further subdivided based on the course of events resulting in a system-based HSC resilience evaluation frame work with three layers of analysis. By linking HSC indicators with CAS theory and supply chain performance metrics the study offers novel insights into HSC resilience evaluations identifies research gaps provides prac tical guidance for practitioners and outlines future research directions for advancing HSC resilience understanding.

Green hydrogen has recently gained importance as a key element in the transition to a low-carbon energy future sparking a boom in possible production regions. This article aims at situating incipient hydrogen production in the Argentine province of Río Negro within a global production network (GPN). The early configuration of the hydrogen-GPN includes several stakeholders and is contested in many ways. To explore the possible materialization of the hydrogen economy in Argentina this article links GPN literature to the concept of sociotechnical imaginaries. In so doing this study finds three energy imaginaries linked to hydrogen development: First advocates of green hydrogen (GH2) project a sociotechnical imaginary in which GH2 is expected to promote scientific and technological progress. Second proponents of blue hydrogen point to Vaca Muerta and the role of natural gas for energy autonomy. Third opponents of the GH2 project question the underlying growth and export model emphasizing conservation and domestic energy sovereignty. The competition between different capital fractions i.e. green and fossil currently poses the risk of pro-fossil path decisions and lock-in effects. Current power constellations have led to the replacement of green with low-emission resulting in the promotion of multi-colored hydrogen. This is particularly evident in the draft for the new national hydrogen law and the actors involved in defining the national hydrogen strategy. The conceptual combination of actors and their interests their current power relations and the sociotechnical imaginaries they deploy illustrates how Argentina's energy future is already being shaped today.

The updraft rotating bed gasifier (URBG) offers a sustainable solution for waste-to-energy conversion utilizing low-grade lignite and municipal solid waste (MSW) from metropolitan dumping sites. This study investigates the co-gasification of lignite with various MSW components demonstrating a significant enhancement in gasification efficiency due to the synergistic effects arising from their higher hydrogen-to-carbon (H/C) ratios. We find feedstock blending is key to maximizing gasification efficiency from 11% to 52% while reducing SO emissions from 739 mg/kg to 155 mg/kg. Increasing the combustion zone temperature to 1100 K resulted in a peak hydrogen yield which was 19% higher than at 800 K. However steam management is complicated as increasing it improves hydrogen fraction in produced gas but gasification efficiency is compromised. These findingsshowcase the URBG’s potential to address both energy production and waste management challenges guiding fossil-reliant regions toward a more sustainable energy future.

To improve the recovery of waste heat and avoid the problem of abandoning wind and solar energy a multi-energy complementary distributed energy system (MECDES) is proposed integrating waste heat and surplus electricity for hydrogen storage. The system comprises a combined cooling heating and power (CCHP) system with a gas engine (GE) solar and wind power generation and miniaturized natural gas hydrogen production equipment (MNGHPE). In this novel system the GE’s waste heat is recycled as water vapor for hydrogen production in the waste heat boiler while surplus electricity from renewable sources powers the MNGHPE. A mathematical model was developed to simulate hydrogen production in three building types: offices hotels and hospitals. Simulation results demonstrate the system’s ability to store waste heat and surplus electricity as hydrogen thereby providing economic benefit energy savings and carbon reduction. Compared with traditional energy supply methods the integrated system achieves maximum energy savings and carbon emission reduction in office buildings with an annual primary energy reduction rate of 49.42–85.10% and an annual carbon emission reduction rate of 34.88–47.00%. The hydrogen production’s profit rate is approximately 70%. If the produced hydrogen is supplied to building through a hydrogen fuel cell the primary energy reduction rate is further decreased by 2.86–3.04% and the carbon emission reduction rate is further decreased by 12.67–14.26%. This research solves the problem of waste heat and surplus energy in MECDESs by the method of hydrogen storage and system integration. The economic benefits energy savings and carbon reduction effects of different building types and different energy allocation scenarios were compared as well as the profitability of hydrogen production and the factors affecting it. This has a positive technical guidance role for the practical application of MECDESs.

The transition from traditional petrol-based combustion engines to hydrogen-powered systems represents a promising advancement in sustainable and clean energy solutions. This review paper explores the intricacies of converting a conventional internal combustion engine to operate on hydrogen gas. Key topics include the performance limitations of hydrogen engines the role of water injection in combustion modulation and the investigation of direct injection and port injection systems. This review also examines challenges associated with lean and rich mixtures risks of backfire and pre-ignition and the conversion’s overall impact on engine performance and longevity. Additionally this paper discusses hydrogen lubrication to prevent mechanical wear and addresses emission-related considerations.

Future liquid hydrogen-powered aircraft requires the design and optimization of a large number of systems and subsystems with cryogenic tanks being one of the largest and most critical. Considering previous space applications these tanks are usually stiffened by internal members such as stringers frames and stiffeners resulting in a complex geometry that leads to an eventual reduction in weight. Cryogenic tanks experience a variety of mechanical and thermal loading conditions and are usually constructed out of several different materials. The complexity of the geometry and the loads highlights the necessity for a computational tool in order to conduct analysis. In this direction the present work describes the development of a multi-physics finite element digital simulation conducting heat transfer and structural analysis in a fully parametric manner in order to be able to support the investigation of different design concepts materials geometries etc. The capabilities of the developed model are demonstrated by the design process of an independent-type aluminum 2219 cryogenic tank for commuter aircraft applications. The designed tank indicates a potential maximum take-off weight reduction of about 8% for the commuter category and demonstrates that aluminum alloys are serious candidate materials for future aircraft.

Hydrogen valleys are encompassed within a defined geographical region with various technologies across the entire hydrogen value chain. The scope of this study is to analyze and assess the different hydrogen technologies for their application within the hydrogen valley context. Emphasizing on the coupling of renewable energy sources with electrolyzers to produce green hydrogen this study is focused on the most prominent electrolysis technologies including alkaline proton exchange membrane and solid oxide electrolysis. Moreover challenges related to hydrogen storage are explored alongside discussions on physical and chemical storage methods such as gaseous or liquid storage methanol ammonia and liquid organic hydrogen carriers. This article also addresses the distribution of hydrogen within valley operations especially regarding the current status on pipeline and truck transportation methods. Furthermore the diverse applications of hydrogen in the mobility industrial and energy sectors are presented showcasing its potential to integrate renewable energy into hard-to-abate sectors.