Italy

In this paper we propose an alternative strategy to produce green hydrogen in a more sustainable way than standard water electrolysis where a substantial amount of the electrical energy is wasted in the oxygen evolution quite often simply released in the atmosphere. The HER (hydrogen evolution reaction) is effectively coupled with the oxidation of guaiacol at the anode leading to the simultaneous production of H2 and valuable guaiacol oligomers. Significative points i) a substantial decrease of the potential difference for the HER 0.85 V with guaiacol ii) HER is accompanied by the production of industrially appealing and sustainable guaiacol based oligomers iii) guaiacol oxidation runs efficiently on carbon-based surfaces like graphite and glassy carbon which are cheap and not-strategic materials. Then the electrochemical oxidation mechanism of guaiacol is studied in detail with in-situ EPR measurements and post-electrolysis product characterization: LC-DAD LC-MS and NMR. Experimental results and theoretical calculations suggest that guaiacol polymerization follows a Kane-Maguire mechanism.

A comprehensive literature review highlights how the nature of active metals support materials promoters and synthesis methods influences catalytic performance with particular attention to ruthenium-based catalysts as the current benchmark. Kinetic models are presented to describe the reaction pathway and predict catalyst behavior. Various reactor configurations including fixed-bed membrane catalytic membrane perovskitebased and microreactors are evaluated in terms of their suitability for ammonia decomposition. While ruthenium remains the benchmark catalyst alternative transition metals such as iron nickel and cobalt have also been investigated although they typically require higher operating temperatures (≥500 °C) to achieve comparable conversion levels. At the industrial scale catalyst development must balance performance with cost. Inexpensive and scalable materials (e.g. MgO Al2O3 CaO K Na) and simple preparation techniques (e.g. wet impregnation incipient wetness) may offer lower performance than more advanced systems but are often favored for practical implementation. From a reactor engineering standpoint membrane reactors emerge as the most promising technology for combining catalytic reaction and product separation in a single unit operation. This review provides a critical overview of current advances in ammonia decomposition for hydrogen production offering insights into both catalytic materials and reactor design strategies for sustainable energy applications.

As the need to reduce Greenhouse Gas (GHG) emissions and dependence on fossil fuels grows new vehicle concepts are emerging as sustainable solutions for urban mobility. Beyond evaluating tailpipe emissions indirect emissions associated with energy and hydrogen production as vehicle manufacturing must be accounted offering a holistic Lifecycle Assessment (LCA) perspective. This study compares Battery Electric Vehicles (BEVs) Fuel Cell Vehicles (FCVs) Hydrogen Internal Combustion Engine Vehicles (H2ICEVs) and hybrid H2ICEVs analyzing energy efficiency and GHG emissions in urban environment across the European Union. Future scenarios (2030 2050) are examined as well with evolving energy mixes and manufacturing impacts. Findings show BEVs as the most efficient configuration with the lowest GHG emissions in 2024 while FCVs become the best option in future scenarios due to greener hydrogen production and improved manufacturing. This study emphasizes the need for tailored strategies to achieve sustainable urban mobility providing insights for policymakers and stakeholders.

A tool for parametric finite element modeling and analysis of LH2 tanks for aviation is developed. Passively insulated cryogenic composite sandwich pressure vessels are investigated as they conjugate simplicity effectiveness and lightweight design for aeronautical applications. Several parametric analyses are performed with the aim of gaining both general and case-specific understanding of how particular design choices may impact the tank mechanical and thermal performance. Differently from most of previous studies multiple design choices including tank walls thicknesses constraints for airframe integration strategies as well as the presence position and integration of refuelling cutouts and anti-sloshing bulkheads are considered. The thermo-mechanical analyses are performed considering first a simple reference configuration with the aim of evaluating possible directions for performance enhancement. Results indicate how different design features affect the gravimetric and thermal efficiency of the tank without compromising structural integrity if the walls thicknesses are suitably sized. The effects of different constraints and geometric discontinuities which reflect specific fuselage integration choices must be carefully assessed as they reduce safety margins. Ultimately a vessel model including features necessary for safe operation is presented as it serves as a baseline for further optimization.

Hydrogen is commonly perceived as the key player in the transition towards a low-carbon future. Nevertheless H2 low energy density hinders its easy storage and transportation. To address this issue different alternatives (liquefied hydrogen ammonia and liquid organic hydrogen carriers) are explored as hydrogen vectors. The techno-economic assessment of H2 transport through these carriers is strongly dependent on the basis of design adopted such that it is difficult to draw general conclusions. In this respect this work is aimed at performing a sensitivity analysis on the hypotheses introduced in the layout of H2 value chains. Different scenarios are discussed depending on harbour-to-harbour distances cost of utilities and raw materials and H2 application to the industrial or mobility sector. The most cost-effective carrier is selected for each case-study: NH3 is the most advantageous for industrial sector while LH2 holds promises for mobility. Critical issues are pointed out for future large-scale applications.

Solid oxide electrolysis cells (SOEC) system has potential to offer an efficient green hydrogen production technology. However the significant cost of this technology is related to the high operating temperatures materials and thermal management including the waste heat. Recovering the waste heat can be conducted through techniques to reduce the overall energy consumption. This approach aims to improve accuracy and efficiency by recovering and reusing the heat that would otherwise be lost. In this paper thermal energy models are proposed based on waste heat recovery methodologies to utilize the heat from outlet fluids within the SOEC system. The mathematical methods for calculating thermal energy and energy transfer in SOEC systems have involved the principles of heat transfer. To address this different simplified thermal models are developed in Simulink Matlab R2025b. The obtained results for estimating proper thermal energy for heating incoming fluids and recycled heat are discussed and compared to determine the efficient and potential thermal model for improvement the waste heat recovery.

As highlighted by the recent roadmaps from the European Union and the United States water electrolysis is the most valuable high-intensity technology for producing green hydrogen. Currently two commercial low-temperature water electrolyzer technologies exist: alkaline water electrolyzer (A-WE) and proton-exchange membrane water electrolyzer (PEM-WE). However both have major drawbacks. A-WE shows low productivity and efficiency while PEM-WE uses a significant amount of critical raw materials. Lately the use of anion-exchange membrane water electrolyzers (AEM-WE) has been proposed to overcome the limitations of the current commercial systems. AEM-WE could become the cornerstone to achieve an intense safe and resilient green hydrogen production to fulfill the hydrogen targets to achieve the 2050 decarbonization goals. Here the status of AEM-WE development is discussed with a focus on the most critical aspects for research and highlighting the potential routes for overcoming the remaining issues. The Review closes with the future perspective on the AEM-WE research indicating the targets to be achieved.

The development of hydrogen refueling infrastructure plays a strategic role in enabling the decarbonization of the transport sector especially along major freight and passenger corridors such as the Trans-European Transport Network (TEN-T). Despite the growing interest in hydrogen mobility existing methodologies for the optimal location of hydrogen refueling stations (HRS) remain fragmented and often overlook operational dynamics. Following a review of the existing literature on HRS location models and approaches this study highlights key methodological gaps that hinder effective infrastructure planning. In response a two-stage framework is proposed combining a flow-based location model with a stochastic queueing approach to determine both the optimal placement of HRS and the number of dispensers required at each site. The method is applied to a real segment of the TEN-T network in Northern Italy. The results demonstrate the flexibility of the model in accommodating different hydrogen vehicle penetration scenarios and its utility as a decision-support tool for public authorities and infrastructure planners.

Direct electrification and hydrogen utilization represent two key pathways for decarbonizing the glass industry with their effectiveness subject to adequate furnace design and renewable energy availability. This study presents a techno-economic assessment for optimal solar energy integration in a representative 300 t/d oxyfuel container glass furnace with a specific energy consumption of 4.35 GJ/t. A mixed-integer linear programming formulation is developed to evaluate specific melting costs carbon emissions and renewable energy self-consumption and self-production rates across three scenarios: direct solar coupling battery storage and a hydrogen-based infrastructure. Battery storage achieves the greatest reductions in specific melting costs and emissions whereas hydrogen integration minimizes electricity export to the grid. By incorporating capital investment considerations the study quantifies the cost premiums and capacity requirements under varying decarbonization targets. A combination of 30 MW of solar plant and 9 MW of electric boosting enables the realization of around 30% carbon reduction while increasing total costs by 25%. Deeper decarbonization targets require more advanced systems with batteries emerging as a cost-effective solution. These findings offer critical insights into the economic and environmental trade-offs as well as the technical constraints associated with renewable energy adoption in the glass industry providing a foundation for strategic energy and decarbonization planning.

In this work we present the simulation of a plant for the exploitation of renewable hydrogen (e.g. from biomass gasification) with production of renewable ammonia as hydrogen vector and energy storage medium. The simulation and sizing of all unit operations were performed with Aspen Plus® as software. Vegetable waste biomass is used as raw material for hydrogen production more specifically pine sawdust.<br/>The hydrogen production process is based on a gasification reactor operating at high temperature (700–800 °C) in the presence of a gasifying agent such as air or steam. At the outlet a solid residue (ash) and a certain amount of gas which mainly contains H2 CH4 CO and some impurities (e.g. sulphur or chlorine compounds) are obtained. Subsequently this gas stream is purified and treated in a series of reactors in order to maximize the hydrogen yield. In fact after the removal of the sulphur compounds through an absorption column with MEA (to avoid poisoning of the catalytic processes) 3 reactors are arranged in series: Methane Steam Reforming (MSR) High temperature Water-Gas Shift (HT-WGS) Low temperature Water-Gas Shift (LT-WGS).<br/>In the first MSR reactor methane reacts at 1000 °C in presence of steam and a nickel-based catalyst in order to obtain mainly H2 CO and CO2. Subsequently two steps of WGS are present to convert most of the CO into H2 and CO2. Also these reactions are carried out in the presence of a catalyst and with an excess of water.<br/>All the oxygenated compounds must be carefully eliminated: the remaining traces of CO are methanated while CO2 is removed by a basic scrubbing with MEA (35 wt%) inside an absorption column. The Haber-Bosch synthesis of ammonia was carried out at 200 bar and in a temperature range between 300 and 400 °C using two catalysts: Fe (wustite) and Ru/C.<br/>As overall balance from an hourly flow rate of 1000 kg of dry biomass and 600 kg of nitrogen 550 kg of NH3 at 98.8 wt% were obtained demonstrating the proof of concept of this newly designed process for the production of hydrogen from renewable waste biomass and its transformation into a liquid hydrogen vector to be easily transported and stored.

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 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.

For centuries fossil fuels have been the primary energy source but their unchecked use has led to significant environmental and economic challenges that now shape the global energy landscape. The combustion of these fuels releases greenhouse gases which are critical contributors to the acceleration of climate change resulting in severe consequences for both the environment and human health. Therefore this article examines the potential of hydrogen as a sustainable alternative energy source capable of mitigating these climate impacts. It explores the properties of hydrogen with particular emphasis on its application in industrial burners and furnaces underscoring its clean combustion and high energy density in comparison to fossil fuels and also examines hydrogen production through thermochemical and electrochemical methods covering green gray blue and turquoise pathways. It discusses storage and transportation challenges highlighting methods like compression liquefaction chemical carriers (e.g. ammonia) and transport via pipelines and vehicles. Hydrogen combustion mechanisms and optimized burner and furnace designs are explored along with the environmental benefits of lower emissions contrasted with economic concerns like production and infrastructure costs. Additionally industrial and energy applications safety concerns and the challenges of large-scale adoption are addressed presenting hydrogen as a promising yet complex alternative to fossil fuels.

In the current context of increasing demand for clean transportation hydrogen usage in internal combustion engines (ICEs) represents a viable solution to abate all engine-out criteria pollutants and almost zeroing CO2 tailpipe emissions. Indeed the wider flammability limits thanks to the higher flame propagation speed and the lower minimum ignition energy compared with conventional fuels extend the stable combustion regime to leaner mixtures thus allowing high thermal efficiency keeping under control the NOX emissions. To fully exploit the potential of hydrogen as a fuel and to avoid undesired abnormal combustion processes a deep characterization of the combustion process is needed. With this aim a 6-cylinder 12.9-L heavy-duty engine was converted from a port-fuel injected compressed natural gas to a direct injected hydrogen spark ignition one. A wide experimental campaign was carried out consisting of several sweeps of relative air-fuel ratios spark advances and injection timings at different engine speeds and loads aiming to define a preliminary engine map. The effect of each calibration parameter at different engine load and speed has been analyzed through the combination of relevant combustion parameters as well as NOX emissions. The results have demonstrated the critical influence of the mixture inhomogeneity when the injection is retarded through the top dead center firing as indicated by the increase in NOX emissions and combustion variability. The analysis of the combustion timing has indicated the dependence of the optimal MFB50 on the relative air-fuel ratio. Lastly the analysis of 200 consecutive cycles for each operating condition has allowed the evaluation of the influence of the main calibration parameters on the cyclic variability thus providing further insights about the lean limit of hydrogen in ICE.

The impact of the HyResponder project on the training of responders in 10 European countries is described. An overview is presented of training activities undertaken within the project in Austria Belgium Czech Republic France Germany Italy Norway Spain Switzerland and the United Kingdom. National leads with training expertise are given and the longer-term plans in each region are mentioned. Responders from each region took part in a specially tailored “train the trainer” programme and then delivered training within their regions. A flexible approach to training within the HyResponder network has enabled fit for purpose region appropriate activities to be delivered impacting over 1250 individuals during the project and many more beyond. Teaching and learning materials in hydrogen safety for responders have been made available in 8 languages: English Czech Dutch French German Italian Norwegian Spanish. They are being used to inform training within each of the partner countries. Dedicated national working groups focused on hydrogen safety training for responders have been established in Belgium the Czech Republic Italy and Switzerland.

This study presents sector-coupled PyPSA-Earth: a novel global open-source energy system optimization model that incorporates major demand sectors and energy carriers in high spatial and temporal resolution to enable energy transition studies worldwide. The model includes a workflow that automatically downloads and processes the necessary demand supply and transmission data to co-optimize investment and operation of energy systems of countries or regions of Earth. The workflow provides the user with tools to forecast future demand scenarios and allows for custom user-defined data in several aspects. Sector-coupled PyPSA-Earth introduces novelty by offering users a comprehensive methodology to generate readily available sector-coupled data and model of any region worldwide starting from raw and open data sources. The model provides flexibility in terms of spatial and temporal detail allowing the user to tailor it to their specific needs. The capabilities of the model are demonstrated through two showcases for Egypt and Brazil. The Egypt case quantifies the relevant role of PV exceeding 35 GW and electrolysis in Suez and Damietta regions for meeting 16% of the EU hydrogen demand. Complementarily the Brazil case confirms the model’s ability in handling hydrogen planning infrastructure including repurposing of existing gas networks which results in 146 M€ lower costs than building new pipelines. The results prove the suitability of sector-coupled PyPSA-Earth to meet the needs of policymakers developers and scholars in advancing the energy transition. The authors invite the interested individuals and institutions to collaborate in the future developments of the model within PyPSA meets Earth initiative.

The coupling of offshore wind energy with hydrogen production involves complex energy flow dynamics and management challenges. This study explores the production of hydrogen through a PEM electrolyzer powered by offshore wind farms and Lithium-ion batteries. A digital twin is developed in Python with the aim of supporting the sizing and carrying out a techno-economic analysis. A controller is designed to manage energy flows on an hourly basis. Three scenarios are analyzed by fixing the electrolyzer capacity to meet a steel plant’s hydrogen demand while exploring different wind farm configurations where the electrolyzer capacity represents 40% 60% and 80% of the wind farm. The layout is optimized to account for the turbine wake. Results reveal that when the electrolyzer capacity is 80% of the wind farm a better energy balance is achieved with 87.5% of the wind production consumed by the electrolyzer. In all scenarios the energy stored is less than 5% highlighting its limitation as a storage solution in this application. LCOE and LCOH differ minimally between scenarios. Saved emissions from wind power reach 268 ktonCO2 /year while those from hydrogen production amount to 520 ktonCO2 /year underlying the importance of hydrogen in hard-to-abate sectors.

Hydrogen leakage in Proton Exchange Membrane (PEM) fuel cells poses critical safety efficiency and operational reliability risks. This study introduces an innovative infrared (IR) thermography-based methodology for detecting and quantifying hydrogen leaks towards the outside of PEM fuel cells. The proposed method leverages the catalytic properties of a membrane electrode assembly (MEA) as an active thermal tracer facilitating real-time visualisation and assessment of hydrogen leaks. Experimental tests were conducted on a single-cell PEM fuel cell equipped with intact and defective gaskets to evaluate the method’s effectiveness. Results indicate that the active tracer generates distinct thermal signatures proportional to the leakage rate overcoming the limitations of hydrogen’s low IR emissivity. Comparative analysis with passive tracers and baseline configurations highlights the active tracer-based approach’s superior positional accuracy and sensitivity. Additionally the method aligns detected thermal anomalies with defect locations validated through pressure distribution maps. This novel non-invasive technique offers precise reliable and scalable solutions for hydrogen leak detection making it suitable for dynamic operational environments and industrial applications. The findings significantly advance hydrogen’s safety diagnostics supporting the broader adoption of hydrogen-based energy systems.

The ecological transition in the transport sector is a major challenge to tackle environmental pollution and European legislation will mandate zero-emission new cars from 2035. To reduce the impact of petrol and diesel vehicles much emphasis is being placed on the potential use of synthetic fuels including electrofuels (e-fuels). This research aims to examine a levelised cost (LCO) analysis of e-fuel production where the energy source is renewable. The energy used in the process is expected to come from a photovoltaic plant and the other steps required to produce e-fuel: direct air capture electrolysis and Fischer-Tropsch process. The results showed that the LCOe-fuel in the baseline scenario is around 3.1 €/l and this value is mainly influenced by the energy production component followed by the hydrogen one. Sensitivity scenario and risk analyses are also conducted to evaluate alternative scenarios and it emerges that in 84% of the cases LCOe-fuel ranges between 2.8 €/l and 3.4 €/l. The findings show that the current cost is not competitive with fossil fuels yet the development of e-fuels supports environmental protection. The concept of pragmatic sustainability incentive policies technology development industrial symbiosis economies of scale and learning economies can reduce this cost by supporting the decarbonisation of the transport sector.

This paper deals with the optimal scheduling of the resources of a renewable energy community whose coordination is aimed at providing flexibility services to the electrical distribution network. The available resources are renewable generation units battery energy storage systems dispatchable loads and power-to-hydrogen systems. The main purposes behind the proposed strategy are enhancement of self-consumption and hydrogen production from local resources and the maximization of the economic benefits derived from both the selling of hydrogen and the subsidies given to the community for the shared energy. The proposed approach is formulated as an economic problem accounting for the perspectives of both community members and the distribution system operator. In more detail a mixed-integer constrained non-linear optimization problem is formulated. Technical constraints related to the resources and the power flows in the electrical grid are considered. Numerical applications allow for verifying the effectiveness of the procedure. The results show that it is possible to increase self-consumption and the production of green hydrogen while providing flexibility services through the exploitation of community resources in terms of active and reactive power support. More specifically the application of the proposed strategy to different case studies showed that daily revenues of up to EUR 1000 for each MW of renewable energy generation installed can be obtained. This value includes the benefit obtained thanks to the provision of flexibility services which contribute about 58% of the total.

This article analyzes a power-to-hydrogen system designed to provide high-temperature heat to hard-to-abate industries. We leverage on a geospatial analysis for wind and solar availability and different industrial demand profiles with the aim to identify the ideal sizing of plant components and the resulting Levelized Cost of Hydrogen (LCOH). We assess the carbon intensity of the produced hydrogen especially when grid electricity is utilized. A methodology is developed to size and optimize the PV and wind energy capacity the electrolyzer unit and hybrid storage by combining compressed hydrogen storage with lithium-ion batteries. The hydrogen demand profile is generated synthetically thus allowing different industrial consumption profiles to be investigated. The LCOH in a baseline scenario ranges from 3.5 to 8.9 €/kg with the lowest values in wind-rich climates. Solar PV only plays a role in locations with high PV full-load hours. It was found that optimal hydrogen storage can cover the users’ demand for 2–3 days. Most of the considered scenarios comply with the emission intensity thresholds set by the EU. A sensitivity analysis reveals that a lower variability of the demand profile is associated with cost savings. An ideally constant demand profile results in a cost reduction of approximately 11 %.

This article discusses possible strategies for decarbonizing the energy systems of an existing port. The approach consists in creating a complete superstructure that includes the use of renewable and fossil energy sources the import or local production of hydrogen vehicles and other equipment powered by Diesel electricity or hydrogen and the associated refuelling and storage units. Two substructures are then identified one including all these options the other considering also the addition of the energy demand of an adjacent steel industry. The goal is to select from each of these two substructures the most cost-effective configurations for 2030 and 2050 that meet the emission targets for those years under different cost scenarios for the energy sources and conversion/storage units obtained from the most reliable forecasts found in the literature. To this end the minimum total cost of all the energy conversion and storage units plus the associated infrastructures is sought by setting up a Mixed Integer Linear Programming optimization problem where integer variables handle the inclusion of the different generation and storage units and their activation in the operational phases. The comprehensive picture of possible solutions set allows identifying which options can most realistically be realized in the years to come in relation to the different assumed cost scenarios. Optimization results related to the scenario projected to 2030 indicate the key role played by Diesel hybrid and electric systems while considering the most stringent or much more stringent scenarios for emissions in 2050 almost all vehicles energy demand and industry hydrogen demand is met by hydrogen imported as ammonia by ship.

Given the global effort to embrace research actions and technology enhancement for the energy transition innovative sustainable systems are needed both for energy production and for those sectors that are responsible for high pollution and CO2 emissions. In this context electrolytic cells and fuel cells in their variety and flexibility are energy systems characterized by high efficiency and important performance guaranteeing a sustainable solution for future energy systems and for the circular economy. The scope of this paper is therefore to present the state of the art of such systems. An overview of the electrolyzers for hydrogen production is presented by detailing the level of applications for their different technologies from low-temperature units to high-temperature units the fuel flexibility the electrolysis and co-electrolysis mode and the potential coupling with renewable sources. Fuel cell-based systems are also presented and their application in the mobility sector is investigated by considering road transport with light-duty and heavy-duty applications and marine transport. A comparison with conventional technologies will be also presented providing some hints on the potential applications of electrolytic cells and fuel cell systems given their important contribution to the sustainable and circular economy.

Green hydrogen is among the most promising energy vectors that may enable the decarbonization of our society. The present study addresses the decarbonization of hard-to-abate sectors via the deployment of sustainable alternatives to current technologies and processes where the complete replacement of fossil fuels is deemed not nearly immediate. In particular the investigated case study tackles the emission reduction potential of steelmaking in the Italian industrial framework via the implementation of dedicated green hydrogen production systems to feed Hydrogen Direct Reduction process the main alternative to the traditional polluting routes towards emissions abatement. Green hydrogen is produced via the coupling of an onshore wind farm with lithium-ion batteries alkaline type electrolyzers and the interaction with the electricity grid. Building on a power generation dataset from a real utility-scale wind farm techno-economic analyses are carried out for a large number of system configurations varying components size and layout to assess its performance on the basis of two main key parameters the levelized cost of hydrogen (LCOH) and the Green Index (GI) the latter presented for the first time in this study. The optimal system design and operation logics are investigated accounting for the necessity of providing a constant mass flow rate of H2 and thus considering the interaction with the electricity network instead of relying solely on RES surplus. In-house-developed models that account for performances degradation over time of different technologies are adapted and used for the case study. The effect of different storage technologies is evaluated via a sensitivity analysis on different components and electricity pricing strategy to understand how to favour green hydrogen penetration in the heavy industry. Furthermore for a better comprehension and contextualization of the proposed solutions their emission-reduction potential is quantified and presented in comparison with the current scenario of EU-27 countries. In the optimal case the emission intensity related to the steel making process can be lowered to 235 kg of CO2 per ton of output steel 88 % less than the traditional route. A higher cost of the process must be accounted resulting in an LCOH of such solutions around 6.5 €/kg.

Remote locations and off-grid regions still rely mainly on diesel generators despite the high operating costs and greenhouse gas emissions. The exploitation of local renewable energy sources (RES) in combination with energy storage technologies can be a promising solution for the sustainable electrification of these areas. The aim of this work is to investigate the potential for decarbonizing remote islands in Norway by installing RES-based energy systems with hydrogen-battery storage. A national scale assessment is presented: first Norwegian islands are characterized and classified according to geographical location number of inhabitants key services and current electrification system. Then 138 suitable installation sites are pinpointed through a multiple-step sorting procedure and finally 10 reference islands are identified as representative case studies. A site-specific methodology is applied to estimate the electrical load profiles of all the selected reference islands. An optimization framework is then developed to determine the optimal system configuration that minimizes the levelized cost of electricity (LCOE) while ensuring a reliable 100% renewable power supply. The LCOE of the RES-based energy systems range from 0.21 to 0.63 €/kWh and a clear linear correlation with the wind farm capacity factor is observed (R2 equal to 0.87). Hydrogen is found to be crucial to prevent the oversizing of the RES generators and batteries and ensure long-term storage capacity. The techno-economic feasibility of alternative electrification strategies is also investigated: the use of diesel generators is not economically viable (0.87–1.04 €/kWh) while the profitability of submarine cable connections is highly dependent on the cable length and the annual electricity consumption (0.14–1.47 €/kWh). Overall the cost-effectiveness of RES-based energy systems for off-grid locations in Northern Europe can be easily assessed using the correlations derived in this analysis.

Clean hydrogen is a key pillar for the net zero economy which can be deployed by consistent utilization on heavy-duty transport. This study investigates a distributed green hydrogen infrastructure (DHI) for heavy-duty transportation consisting of on-site hydrogen production storage compression and refueling systems in Italy. Two options for energy supply are analyzed: grid connection using green energy via Power Purchasing Agreements (PPAs) and direct connection to the photovoltaic field respectively. Radiation data are representative of the three main Italian areas namely South (Catania) Center (Roma) and North (Milano). The sensitivity analysis varies the PPA value between 50 V/MWh and 200 V/MWh and the water electrolysis capacity factor between 20% and 100%. The study finds that the LCOH ranges from 7.4 V/kgH2 to 67.8 V/kgH2 for the first option and 5.5 V/kgH2 to 27.5 V/kgH2 for the second option with Southern Italy having the lowest LCOH due to higher solar irradiation. The research shows that a DHI can offer economic and technical benefits for heavy-duty mobility. However the performance is highly influenced by external conditions such as hydrogen demand and electricity prices. This study provides valuable insights into designing and operating a DHI for heavy-duty mobility promoting a carbon-free society.

The objective of the paper is to simulate the whole steelmaking process cycle based on Direct Reduced Iron and Electric Arc Furnace technologies by modeling for the first time the reduction furnace based on kinetic approach to be used as a basis for the environmental and techno-economic plant analysis by adopting different reducing gases. In addition the impact of carbon capture section is discussed. A complete profitability analysis has been conducted for the first time adopting a Monte Carlo simulation approach.<br/>In detail the use of syngas from methane reforming syngas and hydrogen from gasification of municipal solid waste and green hydrogen from water electrolysis are analyzed. The results show that the Direct Reduced Iron process with methane can reduce CO2 emissions by more than half compared to the blast furnace based-cycle and with the adoption of carbon capture greenhouse gas emissions can be reduced by an additional 40%. The use of carbon capture by amine scrubbing has a limited economic disadvantage compared to the scenario without it becoming profitable once carbon tax is included in the analysis. However it is with the use of green hydrogen from electrolyzer that greenhouse gas emissions can be cut down almost completely. To have an environmental benefit compared with the methane-based Direct Reduced Iron process the green hydrogen plant must operate for at least 5136 h per year (64.2% of the plant's annual operating hours) on renewable energy.<br/>In addition the use of syngas and separated hydrogen from municipal solid waste gasification is evaluated demonstrating its possible use with no negative effects on the quality of produced steel. The results show that hydrogen use from waste gasification is more economic with respect to green hydrogen from electrolysis but from the environmental viewpoint the latter results the best alternative. Comparing the use of hydrogen and syngas from waste gasification it can be stated that the use of the former reducing gas results preferable from both the economic and environmental viewpoint.

HyCARE project supported by the Clean Hydrogen Partnership of the European Union deals with a prototype of hydrogen storage tank using a solid-state hydrogen carrier. Up to 40 kilograms of hydrogen are stored in twelve tanks at less than 50 barg and less than 100 °C. The innovative design is based on a standard twenty-foot container including twelve TiFe-based metal hydride (MH) hydrogen storage tanks coupled with a thermal energy storage in phase change materials (PCM). This article aims at showing the main risks related to hydrogen storage in a MH system and the safety barriers considered based on HyCARE’s specific risk analysis.<br/>Regarding the TiFe MH material used to store hydrogen experimental tests showed that the exposure of the MH to air or water did not cause spontaneous ignition. Furthermore an explosion within the solid MH cannot propagate due to internal pore size. Additionally in case of leakage the speed of hydrogen desorption from the MH is self-limited which is an important safety characteristic since it reduces the potential consequences from the hydrogen release scenario.<br/>Regarding the integrated system the critical scenarios identified during the risk analysis were: explosion due to release of hydrogen inside or outside the container internal explosion inside MH tanks due to accidental mix of hydrogen and air and asphyxiation due to inert gas accumulation in the container. This identification phase of the risk analysis allowed to pinpoint the most relevant safety barriers already in place and recommend additional ones if needed to further reduce the risk that were later implemented.<br/>The main safety barriers identified were: material and component selection (including the MH selected) safety interlocks safety valves ventilation gas detection and safety distances.<br/>The risk management process based on risk identification and assessment contributed to coherently integrate inherently safe design features and safety barriers.

This paper presents an economic impact analysis and carbon footprint study of a hydrogenbased microgrid. The economic impact is evaluated with respect to investment costs operation and maintenance (O&M) costs as well as savings taking into account two different energy management strategies (EMSs): a hydrogen-based priority strategy and a battery-based priority strategy. The research was carried out in a real microgrid located at the University of Huelva in southwestern Spain. The results (which can be extrapolated to microgrids with a similar architecture) show that although both strategies have the same initial investment costs (EUR 52339.78) at the end of the microgrid lifespan the hydrogen-based strategy requires higher replacement costs (EUR 74177.4 vs. 17537.88) and operation and maintenance costs (EUR 35254.03 vs. 34877.08) however it provides better annual savings (EUR 36753.05 vs. 36282.58) and a lower carbon footprint (98.15% vs. 95.73% CO2 savings) than the battery-based strategy. Furthermore in a scenario where CO2 emission prices are increasing the hydrogen-based strategy will bring even higher annual cost savings in the coming years.

Roll-on/Roll-Off (Ro-Ro) vessels including those without and with passenger accommodation Roll-on/roll-off passenger (Ro-Pax) can be totally or partially retrofitted to reduce the greenhouse gas (GHG) emissions in maritime transport not only during hoteling operation at the dock but also during service. This study is based on data of the vessel routes connecting the Port of Piombino to the Elba Island in Italy. Three retrofitting scenarios have been considered: replacement of the main and auxiliary engines with fuel cells (FC) (full retrofitting) replacement of the auxiliary engines with FCs (partial retrofitting) and replacement of the auxiliary engines with FCs and hoteling only with auxiliary engines for one specific vessel. The amount of hydrogen the filling time and the energy needed for production compression and pre-cooling of hydrogen have been calculated for the different scenarios.

This paper proposes a numerical setup for 3D-CFD in-cylinder simulations of H2-fuelled internal combustion engines. The flamelet G-equation model based on Verhelst and Damkohler-like ¨ correlations for laminar and turbulent flame speeds respectively is used to reproduce the flame propagation. The validation against experimental data from a homogeneous-mixture port-injection engine enables a focus on combustion simulation by minimising stratification uncertainties. Accurate flame propagation modelling is identified as the main challenge. The results on different operating conditions confirm the predictive capabilities of the framework thanks to the agreement with the experimental pressure traces combustion indicators and flame imaging. Notably combustion rate predictions remain accurate even without considering the flame thermo-diffusive instability as the turbulence effect dominates at the investigated conditions. The combustion regime is analysed by a modified Borghi-Peters diagram and it ranges from flamelet to thin reaction zones. This highlights the numerical setup flexibility which accurately simulates combustion across different regimes.

The growing share of renewables in power grids increases the need for backup generators able to compensate production profiles whenever needed. Hydrogen internal combustion engines (H2 ICEs) offer a promising solution in terms of flexibility reduced capital cost and looser requirements on hydrogen purity. These systems are however still not well characterized. This study introduces a zero-dimensional (0D) model for a 100 % hydrogen engine calibrated using experimental data under varying loads and air-fuel ratios. Unlike existing models it proposes validated electrical efficiency data across multiple operating points. Efficiency curves are provided in quadratic and linear forms allowing integration into diverse energy system simulations including linear programming. The model performance is evaluated in a peak-shaving case study using real data from a remote site with limited grid supply. Three engine-generators are used to match single-minute resolution load demand. Compared to typical models that lack validation and ignore part-load efficiency losses the proposed model highlights differences in hydrogen consumption estimation up to 13.4 % thus offering improved accuracy for techno-economic analyses of hydrogen-based systems.

Through mathematical modeling this paper integrates economic safety and environmental assessments to evaluate alternative hydrogen supply options (on-site production and external supply) and various hydrogenbased system configurations for decarbonizing energy-intensive industries. The model is applied to a case study in the glass sector. While reliance on natural gas remains the most cost-effective and safest solution it does not align with decarbonization objectives. Assuming a complete hydrogen transition on-site production reduces emissions by 85 % compared to current levels and improves safety performance over external supply. External supply of grey hydrogen becomes counterproductive increasing emissions by 68 % compared to natural gas operations. Nevertheless hydrogen cost rises from 3.6 €/kg with external supply to 4.2 €/kg with on-site production doubling the fuel cost relative to natural gas. To address the trade-offs the paper explores how specific constraints influence system design. A sensitivity analysis on key factors affecting hydrogen-related decisions provides additional support for strategic decision-making.

The adoption of low-carbon fuels in maritime propulsion requires operational autonomy material suitability and compliance with safety standards making liquid fuels like LNG and LH2 the most viable options. LNG is widely used for reducing GHG NOx and SOx emissions while LH2 though new to the maritime sector leverages aerospace experience. This paper explores the operational requirements and challenges of LH2 cryogenic handling systems using LNG practices as a reference. Key comparisons are made between LNG and LH2 supply systems focusing on cryogenic materials hydrogen embrittlement and structural integrity under maritime conditions. Most maritime-approved materials are suitable for cryogenic use and hydrogen embrittlement is less critical at cryogenic temperatures due to reduced atomic mobility. Risk assessments suggest LH2’s safety record stems from limited operational data rather than superior inherent safety. The paper also addresses crucial safety and regulatory considerations for both fuels underscoring the need for strict adherence to standards to ensure the safe and compliant integration of LH2 in the maritime industry.

Green hydrogen obtained from renewable electricity can play an essential role in the decarbonization of different sectors. The reliability of the data used to model the entire supply chain is a crucial parameter in Life Cycle Assessment. In this study the authors show how photovoltaic and wind electricity supply chains influence the carbon footprint of green H2. While most published studies rely on default datasets from commercial libraries the current work exploits the actual supply chain of the PV panels and builds an updated average European wind turbine supply chain. The updated values for PV-based H2 experiencing a 40–60% reduction are 2.7 and 1.8 kg CO2 eq./kg H2 for the UK and Italy. The carbon footprint of UK offshore wind-based H2 can be reduced up to 24% and get close to 0.6 kg CO2 eq./kg H2. The findings emphasize the sensitivity of the final climate profile generated by the processes upstream of the electrolysis system.

Compression ignition engines will still be predominant in the naval sector: their high efficiency high torque and heavy weight perfectly suit the demands and architecture of ships. Nevertheless recent emission legislations impose limitations to the pollutant emissions levels in this sector as well. In addition to post-treatment systems it is necessary to reduce some pollutant species and therefore the study of combustion strategies and new fuels can represent valid paths for limiting environmental harmful emissions such as CO2 . The use of methane in dual fuel mode has already been implemented on existent vessels but the progressive decarbonization will lead to the utilization of carbon-neutral or carbon-free fuels such as in the last case hydrogen. Thanks to its high reactivity nature it can be helpful in the reduction of exhaust CH4 . On the contrary together with the high temperatures achieved by its oxidation hydrogen could cause uncontrolled ignition of the premixed charge and high emissions of NOx. As a matter of fact a source of ignition is still necessary to have better control on the whole combustion development. To this end an optimal and specific injection strategy can help to overcome all the before-mentioned issues. In this study three-dimensional numerical simulations have been performed with the ANSYS Forte® software (version 19.2) in an 8.8 L dual fuel engine cylinder supplied with methane hydrogen or hydrogen–methane blends with reference to experimental tests from the literature. A new kinetic mechanism has been used for the description of diesel fuel surrogate oxidation with a set of reactions specifically addressed for the low temperatures together with the GRIMECH 3.0 for CH4 and H2 . This kinetics scheme allowed for the adequate reproduction of the ignition timing for the various mixtures used. Preliminary calculations with a one-dimensional commercial code were performed to retrieve the initial conditions of CFD calculations in the cylinder. The used approach demonstrated to be quite a reliable tool to predict the performance of a marine engine working under dual fuel mode with hydrogen-based blends at medium load. As a result the system modelling shows that using hydrogen as fuel in the engine can achieve the same performance as diesel/natural gas but when hydrogen totally replaces methane CO2 is decreased up to 54% at the expense of the increase of about 76% of NOx emissions.

The agro-livestock sector produces about one third of global greenhouse gas (GHG) emissions. Since more energy is needed to meet the growing demand for food and the industrial revolution in agriculture renewable energy sources could improve access to energy resources and energy security reduce dependence on fossil fuels and reduce GHG emissions. Hydrogen production is a promising energy technology but its deployment in the global energy system is lagging. Here we analyzed the theoretical and practical application of green hydrogen generated by electrolysis of water powered by renewable energy sources in the agro-livestock sector. Green hydrogen is at an early stage of development in most applications and barriers to its large-scale deployment remain. Appropriate policies and financial incentives could make it a profitable technology for the future.

In recent years there has been a significant increase in research on hydrogen due to the urgent need to move away from carbon-intensive energy sources. This transition highlights the critical role of hydrogen storage technology where hydrogen tanks are crucial for achieving cleaner energy solutions. This paper aims to provide a general overview of hydrogen treatment from a mechanical viewpoint and to create a comprehensive review that integrates the concepts of hydrogen safety and storage. This study explores the potential of hydrogen applications as a clean energy alternative and their role in various sectors including industry automotive aerospace and marine fields. The review also discusses design technologies safety measures material improvements social impacts and the regulatory landscape of hydrogen storage tanks and safety technology. This work provides a historical literature review up to 2014 and a systematic literature review from 2014 to the present to fill the gap between hydrogen storage and safety. In particular a fundamental feature of this work is leveraging systematic procedural techniques for performing an unbiased review study to offer a detailed analysis of contemporary advancements. This innovative approach differs significantly from conventional review methods since it involves a replicable scientific and transparent process which culminates in minimizing bias and allows for highlighting the fundamental issues about the topics of interest and the main conclusions of the experts in the field of reference. The systematic approach employed in the paper was used to analyze 55 scientific articles resulting in the identification of six primary categories. The key findings of this review work underline the need for improved materials enhanced safety protocols and robust infrastructure to support hydrogen adoption. More importantly one of the fundamental results of the present review analysis is pinpointing the central role that composite materials will play during the transition toward hydrogen applications based on thin-walled industrial vessels. Future research directions are also proposed in the paper thereby emphasizing the importance of interdisciplinary collaboration to overcome existing challenges and facilitate the safe and efficient use of hydrogen.

Electro-fuels (E-fuels) represent a potential solution for decarbonizing the maritime sector including pleasure vessels. Due to their large energy requirements direct electrification is not currently feasible. E-fuels such as synthetic diesel methanol ammonia methane and hydrogen can be used in existing internal combustion engines or fuel cells in hybrid configurations with lithium batteries to provide propulsion and onboard electricity. This study confirms that there is no clear winner in terms of efficiency (the power-to-power efficiency of all simulated cases ranges from 10% to 30%) and the choice will likely be driven by other factors such as fuel cost onboard volume/mass requirements and distribution infrastructure. Pure hydrogen is not a practical option due to its large storage necessity while methanol requires double the storage volume compared to current fossil fuel solutions. Synthetic diesel is the most straightforward option as it can directly replace fossil diesel and should be compared with biofuels. CO2 emissions from E-fuels strongly depend on the electricity source used for their synthesis. With Italy’s current electricity mix E-fuels would have higher impacts than fossil diesel with potential increases between +30% and +100% in net total CO2 emissions. However as the penetration of renewable energy increases in electricity generation associated E-fuel emissions will decrease: a turning point is around 150 gCO2/kWhel.

This paper offers a set of comprehensive guidelines aimed at facilitating the widespread adoption of hydrogen in the industrial hard-to-abate sectors. The authors begin by conducting a detailed analysis of these sectors providing an overview of their unique characteristics and challenges. This paper delves into specific elements related to hydrogen technologies shedding light on their potential applications and discussing feasible implementation strategies. By exploring the strengths and limitations of each technology this paper offers valuable insights into its suitability for specific applications. Finally through a specific analysis focused on the steel sector the authors provide in-depth information on the potential benefits and challenges associated with hydrogen adoption in this context. By emphasizing the steel sector as a focal point the authors contribute to a more nuanced understanding of hydrogen’s role in decarbonizing industrial processes and inspire further exploration of its applications in other challenging sectors.

Nowadays one of the hottest topic in the automotive engineering community is the reduction of fossil fuels. Hydrogen is an alternative energy source that is already providing clean renewable and efficient power being used in fuel cells. Despite being developed since a few decades fuel cells are affected by several hurdles the most impacting one being their cost per unit power. While waiting for their cost reduction and mass-market penetration hydrogen-fueled internal combustion engines (H2ICEs) can be a rapidly applicable solution to reduce pollution caused by the combustion of fossil fuels. Such engines benefit from the advanced technology of modern internal combustion engines (ICEs) and the advantages related to hydrogen combustion although some modifications are needed for conventional liquid-fueled engines to run on hydrogen. The gaseous injection of hydrogen directly into the combustion chamber is a challenge both for the designers and for the injection system suppliers. To reduce uncertainties time and development cost computational fluid dynamics (CFD) tools appear extremely useful since they can accurately predict mixture formation and combustion before the expensive production/testing phase. The high-pressure gaseous injection which takes place in Direct-Injected H2ICEs promotes a super-sonic flow with very high gradients in the zone between the bulk of the injected hydrogen and the flow already inside the combustion chamber. To develop a methodology for an accurate simulation of these phenomena the SoPHy Engine of the Engine Combustion Network group (ECN) is used and presented. This engine is fed through a single nozzle H2-injector; planar laser-induced fluorescence (PLIF) data are available for comparison with the CFD outcomes.

This research investigated the suitability of air-to-water generator (AWG) technology to address one of the main concerns in green hydrogen production namely water supply. This study specifically addresses water quality and energy sustainability issues which are crucial research questions when AWG technology is intended for electrolysis. To this scope a reasoned summary of the main findings related to atmospheric water quality has been provided. Moreover several experimental chemical analyses specifically focused on meeting electrolysis process requirements on water produced using a real integrated AWG system equipped with certified materials for food contact were discussed. To assess the energy sustainability of AWGs in green hydrogen production a case study was presented regarding an electrolyzer plant intended to serve as energy storage for a 2 MW photovoltaic field on Iriomote Island. The integrated AWG used for the water quality analyses was studied in order to determine its performance in the specific island climate conditions. The production exceeded the needs of the electrolyzer; thus the overproduction was considered for the panels cleaning due to the high purity of the water. Due to such an operation the efficiency recovery was more than enough to cover the AWG energy consumption. This paper on the basis of the quantity results provides the first answers to the said research questions concerning water quality and energy consumption establishing the potential of AWG as a viable solution for addressing water scarcity and enhancing the sustainability of electrolysis processes in green hydrogen production.

To achieve sustainable development the transition from a fossil-based economy to a circular economy is essential. The use of renewable energy sources to make the overall carbon foot print more favorable is an important pre-requisite. In this context it is crucial to valorize all renewable resources through an optimized local integration. One opportunity arises through the synergy between bioresources and green hydrogen. Through techno-economic assessments this work analyzes four local case studies that integrate bio-based processes with green hydrogen produced via electrolysis using renewable energy sources. An analysis of the use of webGIS tools (i.e. Atlas of Biorefineries of IEA Bioenergy) to identify existing biorefineries that require hydrogen in relation to territories with a potential availability of green hydrogen has never been conducted before. This paper provides an evaluation of the production costs of the target products as a function of the local green hydrogen supply costs. The results revealed that the impact of green hydrogen costs could vary widely ranging from 1% to 95% of the total production costs depending on the bio-based target product evaluated. Additionally hydrogen demand in the target area could require an installed variable renewable energy capacity of 20 MW and 500 MW. On the whole the local integration of biorefineries and green hydrogen could represent an optimal opportunity to make hydrogenated bio-based products 100% renewable.

This study presents a techno-economic assessment of power-to-gas and power-to-liquid pathways within the Hydrogen Valley concept to support the decarbonization of local energy systems. Using the EnergyPLAN software both business-as-usual and Hydrogen Valley scenarios were analyzed by varying renewable energy electrolyzer capacity and hydrogen storage. The levelized costs of green hydrogen electrofuels and synthetic natural gas were estimated for both scenarios. A sensitivity analysis was conducted to assess the impact of cost parameters on the levelized costs of hydrogen and alternative fuel production. The findings indicate that the Hydrogen Valley scenario results in a 5.9% increase in total annual costs but achieves a 29.5% reduction in CO2 emissions compared to the business-as-usual scenario. Additionally utilizing excess energy for power-to-gas and power-to-liquid conversion in the Hydrogen Valley scenario lowers the levelized cost of electrofuels from 0.28 €·kWh−1 to 0.21 €·kWh−1 . Similarly the levelized cost of synthetic natural gas decreases from 0.33 €·kWh−1 to 0.25 €·kWh−1 when transitioning from the businessas-usual scenario to the Hydrogen Valley scenario. The results highlight that Hydrogen Valleys enable low-emission energy systems with cost-effective alternative fuels underscoring the tradeoffs between deep decarbonization and cost optimization in the transition to clean energy systems.

The automotive industry is under increasing pressure to develop cleaner and more efficient technologies in response to stringent emission regulations. Hydrogenpowered internal combustion engines represent a promising alternative offering the potential to reduce carbon-based emissions while improving efficiency. However the accurate estimation of in-cylinder pressure is crucial for optimizing the performance and emissions of these engines. While traditional simulation tools such as GT-POWER are widely utilized for these purposes recent advancements in artificial intelligence provide new opportunities for achieving faster and more accurate predictions. This study presents a comparative evaluation of the predictive capabilities of GT-POWER and an artificial neural network model in estimating in-cylinder pressure with a particular focus on improvements in computational efficiency. Additionally the artificial neural network is employed to predict the equivalent flame radius thereby obviating the need for repeated tests using dedicated high-speed cameras in optical access research engines due to the resource-intensive nature of data acquisition and post-processing. Experiments were conducted on a single-cylinder research engine operating at low-speed and low-load conditions across three distinct relative air–fuel ratio values with a range of ignition timing settings applied for each air excess coefficient. The findings demonstrate that the artificial neural network model surpasses GT-POWER in predicting in-cylinder pressure with higher accuracy achieving an RMSE consistently below 0.44% across various conditions. In comparison GT-POWER exhibits an RMSE ranging from 0.92% to 1.57%. Additionally the neural network effectively estimates the equivalent flame radius maintaining an RMSE of less than 3% ranging from 2.21% to 2.90%. This underscores the potential of artificial neural network-based approaches to not only significantly reduce computational time but also enhance predictive precision. Furthermore this methodology could subsequently be applied to conventional road engines exhibiting characteristics and performance similar to those of a specific optical engine used as the basis for the machine learning analysis offering a practical advantage in real-time diagnostics.

This paper aims at investigating clean hydrogen production from the large size (14 GW) hydroelectric power plant of Itaipu located on the border between Paraguay and Brazil the two countries that own and manage the plant. The hydrogen produced by a water electrolysis process is converted into ammonia through the well-known Haber-Bosch process. Hydraulic energy is employed to produce H2 and N2 respectively from a large-scale electrolysis system and an air separation unit. An economic feasibility analysis is performed considering the low electrical energy price in this specific scenario and that Paraguay has strong excess of renewable electrical energy but presents a low penetration of electricity. The proposal is an alternative to increase the use of electricity in the country. Different plant sizes were investigated and for each of them ammonia production costs were determined and considered as a term of comparison with traditional ammonia synthesis plants where H2 is produced from methane steam reforming and then purified. The study was performed employing a software developed by the authors’ research group at the University of Genoa. Finally an energetic environmental and economic comparison with the standard production method from methane is presented.

The use of highly efficient cogeneration systems fueled by pure hydrogen such as Solid Oxide Fuel Cells (SOFCs) in the residential sector is one of the new frontiers for achieving the net zero greenhouse gas emissions tran sitions. The lack of experimental studies in this area prompted the authors to propose the present paper. It refers to hydrogen-fueled SOFC 1 kW-sized integrated into the plant system of a single-family villa configurated as a nearly Zero Energy Building. The multiple objectives are: show the technical feasibility of this technology in building; analyse the data of a continuous monitoring campaign in wintertime; highlight the real performance compared to the manufacturer’s declaration. The results demonstrate that in particular conditions of photo voltaic production it is possible to meet the home electric loads and have a surplus of energy to store or send to the national power grid. The calculated electrical efficiency is equal to 0.47 ÷ 0.48 while the maximum overall efficiency is 0.93.

The effective storage of hydrogen is a critical challenge that needs to be overcome for it to become a widely used and clean energy source. Various methods exist for storing hydrogen including compression at high pressures liquefaction through extreme cooling (i.e. -253 °C) and storage with chemical compounds. Each method has its own advantages and disadvantages. MAST3RBoost (Maturing the Production Standards of Ultraporous Structures for High Density Hydrogen Storage Bank Operating on Swinging Temperatures and Low Compression) is a European funded Project aiming to establish a reliable benchmark for cold-adsorbed H2 storage (CAH2) at low compression levels (100 bar or below). This is achieved through the development of advanced ultraporous materials suitable for mobility applications such as hydrogen-powered vehicles used in road railway air and water transportation. The MAST3RBoost Project utilizes cutting-edge materials including Activated Carbons (ACs) and high-density MOFs (Metalorganic Frameworks) which are enhanced by Machine Learning techniques. By harnessing these materials the project seeks to create a groundbreaking path towards meeting industry goals. The project aims to develop the world's first adsorption-based demonstrator at a significant kg-scale. To support the design of the storage tank the project employs Computational Fluid Dynamics (CFD) software which allows for numerical investigations. In this paper a preliminary analysis of the tank refilling process is presented with a focus on the impact of the effect of the tank and hydrogen temperatures on quantity of hydrogen adsorbed.

This article analyzes the processes of compressing hydrogen in the gaseous state an aspect considered important due to its contribution to the greater diffusion of hydrogen in both the civil and industrial sectors. This article begins by providing a concise overview and comparison of diverse hydrogen-storage methodologies laying the groundwork with an in-depth analysis of hydrogen’s thermophysical properties. It scrutinizes plausible configurations for hydrogen compression aiming to strike a delicate balance between energy consumption derived from the fuel itself and the requisite number of compression stages. Notably to render hydrogen storage competitive in terms of volume pressures of at least 350 bar are deemed essential albeit at an energy cost amounting to approximately 10% of the fuel’s calorific value. Multi-stage compression emerges as a crucial strategy not solely for energy efficiency but also to curtail temperature rises with an upper limit set at 200 ◦C. This nuanced approach is underlined by the exploration of compression levels commonly cited in the literature particularly 350 bar and 700 bar. The study advocates for a three-stage compression system as a pragmatic compromise capable of achieving high-pressure solutions while keeping compression work below 10 MJ/kg a threshold indicative of sustainable energy utilization.

This paper intends to give an impression of new technologies and processes that are in development for application to achieve decarbonization and about which less or no experience on associated hazards exists in the process industry. More or less an exception is hydrogen technology because its hazards are relatively known and there is industry experience in handling it safely but problems will arise when it is produced stored and distributed on a large scale. So when its use spreads to communities and it becomes as common as natural gas now measures to control the risks will be needed. And even with hydrogen surprise findings have been shown lately e.g. its BLEVE behavior when in a liquified form stored in a vessel heated externally. Substitutes for hydrogen are not without hazard concern either. The paper will further consider the hazards of energy storage in batteries and the problems to get those hazards under control. Relatively much attention will be paid to the electrification of the process industry. Many new processes are being researched which given green energy will be beneficial to reduce greenhouse gases and enhance sustainability but of which hazards are rather unknown. Therefore as last chapter the developments with respect to the concept of hazard identification and scenario definition will be considered in quite detail. Improvements in that respect are also being possible due to the digitization of the industry and the availability of data and considering the entire life cycle all facilitated by the data model standard ISO 15926 with the scope of integration of life-cycle data for process plants including oil and gas production facilities. Conclusion is that the new technologies and processes entail new process and personal hazards and that much effort is going into renewal but safety analyses are scarce. Right in a period of process renewal attention should be focused on possibilities to implement inherently safer design.