Turkey

Diesel engines are inevitable parts of our daily life and will be in the future. Expensive after-treatment technologies to fulfil normative legislations about the harmful tail-pipe emissions and fuel price increase in recent years created expectations from researchers for alternative fuel applications on diesel engines. This study investigates hydrogen as additive fuel in diesel engines. Hydrogen was introduced into intake manifold using gas injectors as additive fuel in gaseous form and also diesel fuel was injected into cylinder by diesel injector and used as igniter. Energy content of introduced hydrogen was set to 0% 25% and 50% of total fuel energy where the 0% references neat diesel operation without hydrogen injection. Test conditions were set to full load at 750 900 1100 1400 1750 and finally 2100 r/min engine speed. Variation in engine performance emissions and combustion characteristics with hydrogen addition was investigated. Hydrogen introduction into the engine by 25% and 50% of total charge energy reveals significant decrease in smoke emissions while dramatic increase in nitrogen oxides. With increasing hydrogen content a slight rise is observed in total unburned hydrocarbons although CO2 and CO gaseous emissions reduced considerably. Maximum in-cylinder gas pressure and rate of heat release peak values raised with hydrogen fraction.

This paper aims to expand current thinking about the future of energy and water utility provision by presenting a radical idea: it proposes a combined delivery system for household energy and water utilities which is inspired by an analogy with the human body. It envisions a multi-functional infrastructure for cities of the future modelled on the human circulatory system. Red blood cells play a crucial role as energy carriers in biological energy distribution; they are suspended in the blood and distributed around the body to fuel the living cells. So why not use an analogous system e an urban circulatory system or “city blood” e to deliver energy and water simultaneously via one dedicated pipeline system? This paper focuses on analysing the scientific technological and economic feasibilities and hurdles which would need to be overcome in order to achieve this idea.<br/>We present a rationale for the requirement of an improved household utility delivery infrastructure and discuss the inspirational analogy; the technological components required to realise the vignette are also discussed. We identify the most significant advance requirement for the proposal to succeed: the utilisation of solid or liquid substrate materials delivered through water pipelines; their benefits and risks are discussed.

The virtual energy storage system (VESS) is one of the emerging novel concepts among current energy storage systems (ESSs) due to the high effectiveness and reliability. In fact VESS could store surplus energy and inject the energy during the shortages at high power with larger capacities compared to the conventional ESSs in smart grids. This study investigates the optimal operation of a multi-carrier VESS including batteries thermal energy storage (TES) systems power to hydrogen (P2H) and hydrogen to power (H2P) technologies in hydrogen storage systems (HSS) and electric vehicles (EVs) in dynamic ESS. Further demand response program (DRP) for electrical and thermal loads has been considered as a tool of VESS due to the similar behavior of physical ESS. In the market three participants have considered such as electrical thermal and hydrogen markets. In addition the price uncertainties were calculated by means of scenarios as in stochastic programming while the optimization process and the operational constraints were considered to calculate the operational costs in different ESSs. However congestion in the power systems is often occurred due to the extreme load increments. Hence this study proposes a bi-level formulation system where independent system operators (ISO) manage the congestion in the upper level while VESS operators deal with the financial goals in the lower level. Moreover four case studies have considered to observe the effectiveness of each storage system and the simulation was modeled in the IEEE 33-bus system with CPLEX in GAMS.

The corrosion morphology in grade 2205 duplex stainless steel wire was studied to understand the nature of pitting and the causes of the ferrite phase’s selective corrosion in acidic (pH 3) NaCl solutions at 60 °C. It is shown that the corrosion mechanism is always pitting which either manifests lacy cover perforation or densely arrayed selective cavities developing selectively on the ferrite phase. Pits with a lacy metal cover form in concentrated chloride solutions whereas the ferrite phase’s selective corrosion develops in diluted electrolytes showing dependency on the chloride-ion concentration. The pit perforation is probabilistic and occurs on both austenite and ferrite grains. The lacy metal covers collapse in concentrated solutions but remain intact in diluted electrolytes. The collapse of the lacy metal cover happens due to hydrogen embrittlement. Pit evolution is deterministic and occurs selectively in the ferrite phase in light chloride solutions.

Today with the increasing transition to electric vehicles (EVs) the design of highly energy-efficient vehicle architectures has taken precedence for many car manufacturers. To this end the energy consumption and recovery rates of different powertrain vehicle architectures need to be investigated comprehensively. In this study six different powertrain architectures—four independent in-wheel motors with regenerative electronic stability control (RESC) and without an RESC one-stage gear (1G) transmission two-stage gear (2G) transmission continuously variable transmission (CVT) and downsized electric motor with CVT—were mathematically modeled and analyzed under real road conditions using nonlinear models of an autonomous hydrogen fuel-cell electric vehicle (HFCEV). The aims of this paper were twofold: first to compare the energy consumption performance of powertrain architectures by analyzing the effects of the regenerative electronic stability control (RESC) system and secondly to investigate the usability of a downsized electrical motor for an HFCEV. For this purpose all the numerical simulations were conducted for the well-known FTP75 and NEDC urban drive cycles. The obtained results demonstrate that the minimum energy consumption can be achieved by a 2G-based powertrain using the same motor; however when an RESC system is used the energy recovery/consumption rate can be increased. Moreover the results of the article show that it is possible to use a downsized electric motor due to the CVT and this powertrain significantly reduces the energy consumption of the HFCEV as compared to all the other systems. The results of this paper present highly significant implications for automotive manufacturers for designing and developing a cleaner electrical vehicle energy consumption and recovery system.

The Energy Management Strategy (EMS) in Fuel Cell Hybrid Electric Vehicles (FCHEVs) is the key part to enhance optimal power distribution. Indeed the most recent works are focusing on optimizing hydrogen consumption without taking into consideration the degradation of embedded energy sources. In order to overcome this lack of knowledge this paper describes a new health-conscious EMS algorithm based on Model Predictive Control (MPC) which aims to minimize the battery degradation to extend its lifetime. In this proposed algorithm the health-conscious EMS is normalized in order to address its multi-objective optimization. Then weighting factors are assigned in the objective function to minimize the selected criteria. Compared to most EMSs based on optimization techniques this proposed approach does not require any information about the speed profile which allows it to be used for real-time control of FCHEV. The achieved simulation results show that the proposed approach reduces the economic cost up to 50% for some speed profile keeping the battery pack in a safe range and significantly reducing energy sources degradation. The proposed health-conscious EMS has been validated experimentally and its online operation ability clearly highlighted on a PEMFC delivery postal vehicle.

In recent years there has been great interest in Wankel-type rotary engines which are one of the most suitable power sources for unmanned aerial vehicle (UAV) applications due to their high power-to-size and power-to-weight ratios. The purpose of the present study was to investigate the potential of a hydrogen enrichment strategy for the improvement of the performance and reduction of the emissions of Wankel engines. The main motivation behind this study was to make Wankel engines which are already very advantageous for UAV applications even more advantageous by applying the hydrogen enrichment technique. In this study hydrogen addition was implemented in a spark-ignition rotary engine model operating at a constant engine speed of 6000 rpm. The mass fraction of hydrogen in the intake gradually increased from 0% to 10%. Simulation results revealed that addition of hydrogen to the fuel accelerated the flame propagation and increased the burning speed of the fuel the combustion temperature and the peak pressure in the working chamber. These phenomena had a very positive effect on the performance and emissions of the Wankel engine. The indicated mean effective pressure (IMEP) increased by 8.18% and 9.68% and the indicated torque increased by 6.15% and 7.99% for the 5% and 10% hydrogen mass fraction cases respectively compared to those obtained with neat gasoline. In contrast CO emissions were reduced by 33.35% and 46.21% and soot emissions by 11.92% and 20.06% for 5% and 10% hydrogen additions respectively. NOx emissions increased with the application of the hydrogen enrichment strategy for the Wankel engine.

With the synthesis of ammonia with chemical methods global carbon emission is the biggest threat to global warming. However the dependence of the agricultural industry on ammonia production brings with it various research studies in order to minimize the carbon emission that occurs with the ammonia synthesis process. In order to completely eliminate the carbon emissions from ammonia production both the hydrogen and the energy needed for the operation of the process must be obtained from renewable sources. Thus hydrogen can be produced commercially in a variety of ways. Many processes are discussed to accompany the Haber Bosch process in ammonia production as potential competitors. In addition to parameters such as temperature and pressure various plasma catalysts are being studied to accelerate the ammonia production reaction. In this study various alternative processes for the capture storage and complete removal of carbon gas released during the current ammonia production are evaluated and the current conditions related to the applicability of these processes are discussed. In addition it has been discussed under which conditions it is possible to produce larger capacities as needed in the processes studied in order to reduce carbon gas emissions during ammonia production in order to provide raw material source for fertilizer production and energy sector. However if the hydrogen gas required for ammonia production is produced using a solid oxide electrolysis cell the reduction in the energy requirement of the process and in this case the reduction of energy costs shows that it will play an important role in determining the method to be used for ammonia production. In addition it is predicted that working at lower temperature (<400 °C) and pressure (<10 bar) values in existing ammonia production technologies despite increasing possible energy costs will significantly reduce process operating costs.

Hydrogen is known to be the carbon-neutral alternative energy carrier with the highest energy density. Currently more than 95% of hydrogen production technologies rely on fossil fuels resulting in greenhouse gas emissions. Water electrolysis is one of the most widely used technologies for hydrogen generation. Nuclear power a renewable energy source can provide the heat needed for the process of steam electrolysis for clean hydrogen production. This review paper analyses the recent progress in hydrogen generation via high-temperature steam electrolysis through solid oxide electrolysis cells using nuclear thermal energy. Protons and oxygen-ions conducting solid oxide electrolysis processes are discussed in this paper. The scope of this review report covers a broad range including the recent advances in material development for each component (i.e. hydrogen electrode oxygen electrode electrolyte interconnect and sealant) degradation mechanisms and countermeasures to mitigate them.

In recent years the growing concern for air quality has led to the development of sustainable vehicles to replace conventional internal combustion engine (ICE) vehicles. Currently the most widespread technology in Europe and Portugal is that of Battery Electric Vehicles (BEV) or plug‐in HEV (PHEV) electric cars but hydrogen‐based transport has also shown significant growth in the commercialization of Fuel Cell Electric Vehicles (FCEV) and in the development of new infrastructural schemes. In the current panorama of EV particular attention should be paid to hydrogen technology i.e. FCEVs which is potentially a valid alternative to BEVs and can also be hybrid (FCHEV) and plug‐in hybrid (FCPHEV). Several sources cited show a positive trend of hydrogen in the transport sector identifying a growing trend in the expansion of hydrogen infrastructure although at this time it is still at an early stage of development. At the moment the cost of building the infrastructure is still high but on the basis of medium/long‐term scenarios it is clear that investments in hydrogen refueling stations will be profitable if the number of Fuel Cell vehicles increases. Conversely the Fuel Cell vehicle market is hampered if there is no adequate infrastructure for hydrogen development. The opportunity to use Fuel Cells to store electrical energy is quite fascinating and bypasses some obstacles encountered with BEVs. The advantages are clear since the charging times are reduced compared to charging from an electric charging post and the long‐distance voyage is made easier as the autonomy is much larger i.e. the psycho‐ sociological anxiety is avoided. Therefore the first part of the paper provides an overview of the current state of electric mobility in Portugal and the strategies adopted by the country. This is necessary to have a clear vision of how a new technology is accepted by the population and develops on the territory that is the propensity of citizens to technological change. Subsequently using current data on EV development and comparing information from recent years this work aims to investigate the future prospects of FCEVs in Portugal by adopting a dynamic model called SERA (Scenario Evaluation and Regionalization Analysis) with which it is possible to identify the Portuguese districts and cities where an FC charging infrastructure is expected to be most beneficial. From the results obtained the districts of Lisbon Porto and Aveiro seem to be the most interested in adopting FC technology. This analysis aims to ensure a measured view of the credible development of this market segment.

With rising temperatures extreme weather events and environmental challenges there is a strong push towards decarbonization and an emphasis on renewable energy with wind energy emerging as a key player. The concept of multi-energy systems offers an innovative approach to decarbonization with the potential to produce hydrogen as one of the output streams creating another avenue for clean energy production. Hydrogen has significant potential for decarbonizing multiple sectors across buildings transport and industries. This paper explores the integration of wind energy and hydrogen production particularly in areas where clean energy solutions are crucial such as impoverished villages in Africa. It models three systems: distinct configurations of micro-multi-energy systems that generate electricity space cooling hot water and hydrogen using the thermodynamics and cost approach. System 1 combines a wind turbine a hydrogen-producing electrolyzer and a heat pump for cooling and hot water. System 2 integrates this with a biomass-fired reheat-regenerative power cycle to balance out the intermittency of wind power. System 3 incorporates hydrogen production a solid oxide fuel cell for continuous electricity production an absorption cooling system for refrigeration and a heat exchanger for hot water production. These systems are modeled with Engineering Equation Solver and analyzed based on energy and exergy efficiencies and on economic metrics like levelized cost of electricity (LCOE) cooling (LCOC) refrigeration (LCOR) and hydrogen (LCOH) under steady-state conditions. A sensitivity analysis of various parameters is presented to assess the change in performance. Systems were optimized using a multiobjective method with maximizing exergy efficiency and minimizing total product unit cost used as objective functions. The results show that System 1 achieves 79.78 % energy efficiency and 53.94 % exergy efficiency. System 2 achieves efficiencies of 55.26 % and 27.05 % respectively while System 3 attains 78.73 % and 58.51 % respectively. The levelized costs for micro-multi-energy System 1 are LCOE = 0.04993 $/kWh LCOC = 0.004722 $/kWh and LCOH = 0.03328 $/kWh. For System 2 these values are 0.03653 $/kWh 0.003743 $/kWh and 0.03328 $/kWh. In the case of System 3 they are 0.03736 $/kWh 0.004726 $/kWh and 0.03335 $/kWh and LCOR = 0.03309 $/kWh. The results show that the systems modeled here have competitive performance with existing multi-energy systems powered by other renewables. Integrating these systems will further the sustainable and net zero energy system transition especially in rural communities.

In this study the electrical electrochemical and thermodynamic performance of a PV/T electrolyzer system was investigated and the experimental results were verified with a numerical model. The annual amounts of electrical and thermal energy from the PV/T electrolyzer system were calculated as 556.8 kWh and 1912 kWh respectively. In addition the hydrogen production performance for the PV/T electrolyzer was compared with that of a PV electrolyzer system. The amount of hydrogen was calculated as 3.96 kg annually for the PV system while this value was calculated as 4.49 kg for the PV/T system. Furthermore the amount of hydrogen production was calculated as 4.59 kg for a 65 ◦C operation temperature. The electrical thermal and total energy efficiencies of the PV/T system which were obtained hourly on a daily basis were calculated and varied between 12–13.8% 36.1–45.2% and 49.1–58.4% respectively. The hourly exergy analyses were also carried out on a daily basis and the results showed that the exergy efficiencies changed between 13.8–14.32%. The change in the electrolysis voltage was investigated by changing the current and temperature in the ranges of 200–1600 mA/cm2 A and 30–65 ◦C respectively. While the current and the water temperature varied in the ranges of 400–2350 mA/cm2 and 28.1–45.8 ◦C respectively energy efficiency and exergy efficiency were in the ranges of 57.85–69.45% and 71.1–79.7% respectively.

Hydrogen is a promising zero-carbon fuel for internal combustion engines; however the geometric optimization of injectors for low-pressure direct-injection (LPDI) systems under lean-burn conditions remains underexplored. This study presents a high-fidelity optimization framework that couples a validated computational fluid dynamics (CFD) combustion model with a surrogate-assisted multi-objective genetic algorithm (MOGA). The CFD model was validated using particle image velocimetry (PIV) data from non-reacting flow experiments conducted in an optically accessible research engine developed by Sandia National Laboratories ensuring accurate prediction of in-cylinder flow structures. The optimization focused on two critical geometric parameters: injector hole count and injection angle. Partial indicated mean effective pressure (pIMEP) and in-cylinder NOx emissions were selected as conflicting objectives to balance performance and emissions. Adaptive mesh refinement (AMR) was employed to resolve transient in-cylinder flow and combustion dynamics with high spatial accuracy. Among 22 evaluated configurations including both capped and uncapped designs the injector featuring three holes at a 15.24◦ injection angle outperformed the baseline delivering improved mixture uniformity reduced knock tendency and lower NOx emissions. These results demonstrate the potential of geometrybased optimization for advancing hydrogen-fueled LPDI engines toward cleaner and more efficient combustion strategies.

This study seeks to find the appropriate strategies necessary to make sustainable and effective hydrogen energy investments. Within this scope nine different criteria are defined regarding social managerial and financial factors. A hesitant interval-valued intuitionistic fuzzy (IVIF) decision-making trial and evaluation laboratory (DEMATEL) methodology is considered to calculate the degree of importance of the criteria. Additionally impact relation maps are also generated to visualize the causality relationship between the factors. The findings indicate that the technical dimension has the greatest importance in comparison to managerial and financial factors. Furthermore it is also concluded that storage and logistics research and development and technological infrastructure are the most significant factors to be considered when defining hydrogen energy investment strategies. Hence before investing in hydrogen energy necessary actions should be taken to minimize the storage and logistic costs. Among them building the production site close to the usage area will contribute significantly to this purpose. In this way possible losses during the transportation of hydrogen can be minimized. Moreover it is essential to identify the lowest-cost hydrogen storage method by carrying out the necessary research and development activities thereby increasing the sustainability and effectiveness of hydrogen energy investment projects.

Turquoise hydrogen is produced from methane cracking a cleaner alternative to steam methane reforming. This study looks at two proposed systems based on solar methane cracking for low-carbon fuel production. The systems utilize different pathways to convert the hydrogen into a suitable form for transportation and utilize the carbon solid by-product. A direct carbon fuel cell is integrated to utilize the carbon and capture the CO2 emissions. The CO2 generated is utilized for fuel production using CO2 hydrogenation or co-electrolysis. An advanced exergetic analysis is conducted on these systems using Aspen plus simulations of the process. The exergetic efficiency waste exergy ratio exergy destruction ratio exergy recoverability ratio environmental effect factor and the exergetic sustainability index were determined for each system and the subsystems. Solar methane cracking was found to have an environmental effect factor of 0.08 and an exergetic sustainability index of 12.27.

Hydrogen is believed to be the future energy carrier that will reduce environmental pollution and solve the current energy crisis especially when produced from a renewable energy source. Solar energy is a renewable source that has been commonly utilized in the production process of hydrogen for years because it is inexhaustible clean and free. Generally hydrogen is produced by means of a water splitting process mainly electrolysis which requires energy input provided by harvesting solar energy. The proposed model integrates the solar harvesting system into a conventional Rankine cycle producing electrical and thermal power used in domestic applications and hydrogen by high temperature electrolysis (HTE) using a solid oxide steam electrolyzer (SOSE). The model is divided into three subsystems: the solar collector(s) the steam cycle and an electrolysis subsystem where the performance of each subsystem and their effect on the overall efficiency is evaluated thermodynamically using first and second laws. A parametric study investigating the hydrogen production rate upon varying system operating conditions (e.g. solar flux and area of solar collector) is conducted on both parabolic troughs and heliostat fields as potential solar energy harvesters. Results have shown that heliostat-based systems were able to attain optimum performance with an overall thermal efficiency of 27% and a hydrogen production rate of 0.411 kg/s whereas parabolic trough-based systems attained an overall thermal efficiency of 25.35% and produced 0.332 kg/s of hydrogen.

Hydrogen has attracted growing research interest due to its exceptionally high energy per mass content and being a clean energy carrier unlike the widely used hydrocarbon fuels. With the possibility of long-term energy storage and re-electrification hydrogen promises to promote the effective utilization of renewable and sustainable energy resources. Clean hydrogen can be produced through a renewable-powered water electrolysis process. Although alkaline water electrolysis is currently the mature and commercially available electrolysis technology for hydrogen production it has several shortcomings that hinder its integration with intermittent and fluctuating renewable energy sources. The proton exchange membrane water electrolysis (PEMWE) technology has been developed to offer high voltage efficiencies at high current densities. Besides PEMWE cells are characterized by a fast system response to fluctuating renewable power enabling operations at broader partial power load ranges while consistently delivering high-purity hydrogen with low ohmic losses. Recently much effort has been devoted to improving the efficiency performance durability and economy of PEMWE cells. The research activities in this context include investigations of different cell component materials protective coatings and material characterizations as well as the synthesis and analysis of new electrocatalysts for enhanced electrochemical activity and stability with minimized use of noble metals. Further many modeling studies have been reported to analyze cell performance considering cell electrochemistry overvoltage and thermodynamics. Thus it is imperative to review and compile recent research studies covering multiple aspects of PEMWE cells in one literature to present advancements and limitations of this field. This article offers a comprehensive review of the state-of-the-art of PEMWE cells. It compiles recent research on each PEMWE cell component and discusses how the characteristics of these components affect the overall cell performance. In addition the electrochemical activity and stability of various catalyst materials are reviewed. Further the thermodynamics and electrochemistry of electrolytic water splitting are described and inherent cell overvoltage are elucidated. The available literature on PEMWE cell modeling aimed at analyzing the performance of PEMWE cells is compiled. Overall this article provides the advancements in cell components materials electrocatalysts and modeling research for PEMWE to promote the effective utilization of renewable but intermittent and fluctuating energy in the pursuit of a seamless transition to clean energy.

In this study the Bald Eagle Search Algorithm performed hydrogen consumption and battery cycle optimization of a fuel cell electric vehicle. To save time and cost the digital vehicle model created in Matlab/Simulink and validated with real-world driving data is the main platform of the optimization study. The digital vehicle model was run with the minimum and maximum battery charge states determined by the Bald Eagle Search Algorithm and hydrogen consumption and battery cycle values were obtained. By using the algorithm and digital vehicle model together hydrogen consumption was minimized and range was increased. It was aimed to extend the life of the parts by considering the battery cycle. At the same time the number of battery packs was included in the optimization and its effect on consumption was investigated. According to the study results the total hydrogen consumption of the fuel cell electric vehicle decreased by 57.8% in the hybrid driving condition 23.3% with two battery packs and 36.27% with three battery packs in the constant speed driving condition.

This paper aims to holistically study hydrogen production options essential for a sustainable and carbon-free future. This study also outlines the benefits and challenges of hydrogen production methods to provide sustainable alternatives to fossil fuels by meeting the global energy demand and net-zero targets. In this study sixteen hydrogen production methods are selected for sustainability investigation based on seven different criteria. The criteria selected in the comparative evaluation cover various dimensions of hydrogen production in terms of economic technical environmental and thermodynamic aspects for better sustainability. The current study results show that steam methane reforming with carbon capture could provide sustainable hydrogen in the near future while the other technologies’ maturity levels increase and the costs decrease. In the medium- and long-terms photonic and thermal-based hydrogen production methods can be the key to sustainable hydrogen production.

Apart from many limitations the usage of hydrogen in different day-to-day applications have been increasing drastically in recent years. However numerous techniques available to produce hydrogen electrolysis of water is one of the simplest and cost-effective hydrogen production techniques. In this method water is split into hydrogen and oxygen by using external electric current. In this research a novel hydrogen production system incorporated with Photovoltaic – Thermal (PVT) solar collector is developed. The influence of different parameters like solar collector tilt angle thermal collector design and type of heat transfer fluid on the performance of PVT system and hydrogen production system are also discussed. Finally thermal efficiency electrical efficiency and hydrogen production rate have been predicted by using the Adaptive Neuro-Fuzzy Inference System (ANFIS) technique. Based on this study results it can be inferred that the solar collector tilt angle plays a significant role to improve the performance of the electrical and thermal performance of PVT solar system and Hydrogen yield rate. On the other side the spiral-shaped thermal collector with water exhibited better end result than the other hydrogen production systems. The predicted results ANFIS techniques represent an excellent agreement with the experimental results. In consequence it is suggested that the developed ANFIS model can be adopted for further studies to predict the performance of the hydrogen production system.

Solar energy is important for the future as it provides a clean renewable source of electricity that can help combat climate change by reducing reliance on fossil fuels via implementing various solar-based energy systems. In this study a unique configuration for a parabolic-trough-based solar system is presented that allows energy storage for periods of time with insufficient solar radiation. This model based on extensive analysis in MATLAB utilizing real-time weather data demonstrates promising results with strong practical applicability. An organic Rankine cycle with a regenerative configuration is applied to produce electricity which is further utilized for hydrogen generation. A proton exchange membrane electrolysis (PEME) unit converts electricity to hydrogen a clean and versatile energy carrier since the electricity is solar based. To harness the maximum value from this system additional energy during peak times is used to produce clean water utilizing a reverse osmosis (RO) desalination unit. The system’s performance is examined by conducting a case study for the city of Antalya Turkey to attest to the unit’s credibility and performance. This system is also optimized via the Grey Wolf multi-objective algorithm from energy exergy and techno-economic perspectives. For the optimization scenario performed the energy and exergy efficiencies of the system and the levelized cost of products are found to be approximately 26.5% 28.5% and 0.106 $/kWh respectively.

The production of green hydrogen the cleanest energy source plays a crucial role in enhancing the efficiency of renewable energy systems by utilizing surplus energy that would otherwise be wasted. With the global shift towards sustainability and the rising adoption of renewable energy sources green hydrogen is gaining significant importance as both an energy carrier and a storage solution. However determining the optimal locations for green hydrogen production facilities remains a complex challenge due to the interplay of technical economic logistical and environmental factors. This study introduces the City Location Evaluation Optimization for Green Hydrogen (CELO_GH) algorithm a novel heuristic approach designed to address this challenge. Unlike conventional multi-criteria decision-making (MCDM) models CELO_GH dynamically evaluates cities by considering renewable energy surplus proximity to industrial hydrogen demand port and pipeline accessibility and economic viability. A case study conducted in Turkey demonstrates the effectiveness of the approach by identifying optimal cities for green hydrogen production based on real-world energy and infrastructure data. The problem was also solved with the genetic algorithm and the results were compared and it was seen that the proposed heuristic provides the lowest cost location selection. A geographically flexible methodology as the proposed algorithm can be applied globally to regions with high renewable energy potential ensuring scalability and adaptability for future energy transition strategies. The results provide valuable insights for policy-makers energy investors and industrial planners aiming to optimize green hydrogen infrastructure while ensuring cost efficiency and sustainability.

In this study the annual electricity consumption of nine real houses from different cities in Türkiye was recorded on a monthly basis. The feasibility of meeting the electrical energy needs of houses with hydrogen and supplying the energy required for hydrogen production using solar panels is examined. The annual electricity consumption of the houses was normalized based on house size. The solar panel area for hydrogen production needed for these houses was defined. Additionally it was calculated that the average volumetric amount of hydrogen produced per hour during peak sun hours in the investigated cities was 1 m3/h. This approach reduced the solar panel area for hydrogen production by a factor of 1.7.

Fossil fuels have been the conventional source of energy that has driven economic growth and industrial development for a long time. However their extensive use has led to immense environmental problems especially concerning the emission of greenhouse gases. These problems have stimulated researchers to turn their attention to renewable alternative fuels. Hydrogen has risen in recent years as a prospective energy carrier because it is possible to produce it in an environmentally friendly manner and because it is the most common element. Hydrogen may be used in diesel engines in a dual-fuel mode. Hydrogen has a higher heating value flame speed and diffusivity in air. These superior fuel properties can enhance performance and combustion efficiency. Hydrogen can decrease carbon monoxide unburned hydrocarbons and soot emissions due to the absence of carbon in hydrogen. However hydrogen-fuelled diesel engines have problems such as engine knocking and high nitrogen oxide emission. This paper presents a comprehensive review of the recent literature on the performance combustion and emission characteristics of hydrogen-fuelled diesel engines. Moreover this paper discusses the long-term sustainability of hydrogen production methods nitrogen oxide emission reduction techniques challenges to the large-scale use of hydrogen economic implications of hydrogen use safety issues in hydrogen applications regulations on hydrogen safety conflicting NOx emission results in the literature and material incompatibility issues in hydrogen applications. This study highlights state-of-the-art developments along with critical knowledge gaps that will be useful in guiding future research. These findings can support researchers and industry professionals in the integration of hydrogen into both existing and future diesel engine technologies. According to the literature the use of hydrogen up to 46% decreased smoke emissions by over 75% while CO2 and CO emissions significantly decreased. Moreover hydrogen addition improved thermal efficiency up to 7.01% and decreased specific fuel consumption up to 7.19%.

The use of energy in the built environment contributes to over one-third of the world’s carbon emissions. To reduce that effect two primary solutions can be adopted i.e. (i) renovation of old buildings and (ii) increasing the renewable energy penetration. This review paper focuses on the latter. Renewable energy sources typically have an intermittent nature. In other words it is not guaranteed that these sources can be harnessed on demand. Thus complement solutions should be considered to use renewable energy sources efficiently. Hydrogen is recognized as a potential solution. It can be used to store excess energy or be directly exploited to generate thermal energy. Throughout this review various research papers focusing on hydrogen-based heating systems were reviewed analyzed and classified from different perspectives. Subsequently articles related to machine learning models optimization algorithms and smart control systems along with their applications in building energy management were reviewed to outline their potential contributions to reducing energy use lowering carbon emissions and improving thermal comfort for occupants. Furthermore research gaps in the use of these smart strategies in residential hydrogen heating systems were thoroughly identified and discussed. The presented findings indicate that the semi-decentralized hydrogen-based heating systems hold significant potential. First these systems can control the thermal demand of neighboring homes through local substations; second they can reduce reliance on power and gas grids. Furthermore the model predictive control and reinforcement learning approaches outperform other control systems ensuring energy comfort and cost-effective energy bills for residential buildings.

Innovative green vehicle concepts have become increasingly prevailing in consumer purchasing habits as technology evolves. The global transition towards sustainable transportation indicates an increase in new-generation vehicles including both fuel-cell electric vehicles (FCEVs) and plug-in electric vehicles (PEVs) that will take on roads in the future. This change requires new-generation stations to support electrification. This study introduced a prominent multi-energy system concept with a hydrogen refueling station. The proposed multi-energy system (MES) consists of green hydrogen production a hydrogen refueling station for FCEVs hydrogen injection into natural gas (NG) and a charging station for PEVs. An on-site renewable system projected at the station and a polymer electrolyte membrane electrolyzer (PEM) to produce hydrogen for two significant consumers support MES. In addition the MES offers the ability to conduct two-way trade with the grid if renewable energy systems are insufficient. This study develops a comprehensive multi-energy system with an economically optimized energy management model using a mixed-integer linear programming (MILP) approach. The determinative datasets of vehicles are generated in a Python environment using Gauss distribution. The fleet of FCEVs and PEVs are currently available on the market. The study includes fleets of the most common models from well-known brands. The results indicate that profits increase when the storage capacity of the hydrogen tank is higher and natural gas injections are limitless. Optimization results for all cases tend to choose higher-priced natural gas injections over hydrogen refueling because of the difference in costs of refueling and injection expenses. The analyses reveal the highest hydrogen sales to the natural gas (NG) grid by consuming 2214.31 kg generating a revenue of $6966 and in contrast the lowest hydrogen sales to the natural gas grid at 1045.38 kg resulting in a revenue of $3286. Regarding electricity the highest sales represent revenue of $7701 and $2375 for distribution system consumption and electric vehicles (EV) respectively. Conversely Cases 1 and 2 have achieved sales to EV of $2286 and $2349 respectively but do not have any sales to distribution system consumption regarding the constraints. Overall the optimization results show that the solution is optimal for a multi-energy system operator to achieve higher profits and that all end-user parties are satisfied.

This study examines the steps to lower air emissions in South Korea’s domestic shipping sector. It highlights the significant contributions of the sector to air pollution and greenhouse gas emissions emphasizing its impact on environmental sustainability and climate change mitigation. By looking at the current shipping energy use and emissions the research identifies ways to reduce the environmental impact of domestic shipping. Data was collected from domestic ferry routes and the fuel use was reviewed with respect to existing global technologies for reducing emissions. The results show that operational changes and current energy-efficient technologies can quickly cut emissions. Furthermore a long-term plan is suggested involving the development of new ship designs and the use of net-zero fuels like biofuels methanol hydrogen and ammonia. These efforts aim to meet climate goals targeting a 40% reduction in greenhouse emissions by 2030 and a 70% reduction by 2050 making South Korea’s shipping industry more sustainable and resilient.

While fossil fuels continue to be used and to increase air pollution across the world hydrogen gas has been proposed as an alternative energy source and a carrier for the future by scientists. Water electrolysis is a renewable and sustainable chemical energy production method among other hydrogen production methods. Hydrogen production via water electrolysis is a popular and expensive method that meets the high energy requirements of most industrial electrolyzers. Scientists are investigating how to reduce the price of water electrolytes with different methods and materials. The electrolysis structure equations and thermodynamics are first explored in this paper. Water electrolysis systems are mainly classified as high- and low-temperature electrolysis systems. Alkaline PEM-type and solid oxide electrolyzers are well known today. These electrolyzer materials for electrode types electrolyte solutions and membrane systems are investigated in this research. This research aims to shed light on the water electrolysis process and materials developments.

Integration of hydrogen into the existing natural gas infrastructure is considered a potential pathway that can accelerate the incorporation of hydrogen into the energy sector. While blending renewable hydrogen with natural gas offers advantages such as reduced carbon intensity and the ability to utilize existing infrastructure for hydrogen storage and transportation there are several concerns including leakage and associated issues. Un derstanding the behavior of hydrogen blended with natural gas in the existing infrastructure is crucial to ensure safe and efficient integration. In this study the leakage rates of mixtures of hydrogen and methane at different molar concentrations (5% 10% 20% and 50% hydrogen) through both precision machined orifices and com mon pipe fitting threads were investigated. The experiments showed that the leakage rates of these mixtures increased as the hydrogen content increased; however gas chromatography (GC) analysis showed that hydrogen did not leak preferentially at a greater rate than methane. The results indicate that mixing hydrogen with methane can increase the volume of gas leakage under the same pressure conditions. These findings suggest that mixing hydrogen with natural gas may result in increased volumetric flow rate of gas leaks but hydrogen alone does not leak preferentially to methane.

One of the most important problems in the widespread use of electric vehicles is the lack of charging infrastructure. Especially in tourist areas where historical buildings are located the installation of a power grid for the installation of electric vehicle charging stations or generating electrical energy by installing renewable energy production systems such as large-sized PV (photovoltaic) and wind turbines poses a problem because it causes the deterioration of the historical texture. Considering the need for renewable energy sources in the transportation sector our aim in this study is to model an electric vehicle charging station using PVPS (photovoltaic power system) and FC (fuel cell) power systems by using irradiation and temperature data from historical regions. This designed charging station model performs electric vehicle charging meeting the energy demand of a house and hydrogen production by feeding the electrolyzer with the surplus energy from producing electrical energy with the PVPS during the daytime. At night when there is no solar radiation electric vehicle charging and residential energy demand are met with an FC power system. One of the most important advantages of this system is the use of hydrogen storage instead of a battery system for energy storage and the conversion of hydrogen into electrical energy with an FC. Unlike other studies in our study fossil energy sources such as diesel generators are not included for the stable operation of the system. The system in this study may need hydrogen refueling in unfavorable climatic conditions and the energy storage capacity is limited by the hydrogen fuel tank capacity.

Due to increasing energy demand limited fossil fuels and increasing greenhouse gasses people is in need for alternative energy sources to have a sustainable world. The objective of this study is to look for alternative solutions and design a hybrid energy system to meet any energy needs of a single family house including both utility and transportation. The system is designed and optimized using HOMER software. According to the optimization studies levelized cost of electricity and hydrogen production was found to be 0.685$/kWh and 6.85$/kg respectively and the cost of hydrogen which is half of its market price is very attractive. To project possible future costs in advance sensitivity analysis was carried out and the results show that when the main components’ price decays to the half both costs of energy will be reduced by 26.4%. This implies that further decrease on the components’ cost would bring the cost of energy to the level of energy produced by fossil fuels or even lower. Hydrogen would also be produced with much lower and tempting price. It is important to note that energy used by residential electrical load and fuel cell electric car in this study was generated by sole renewable energies and the system consumes zero fossil fuels thus emitting no greenhouse gasses. The study considering both utility and transportation simultaneously is believed to be the first on a small scale and to attract the interest of everyone.

Hydrogen energy one of the renewable energy sources plays a crucial role in combating climate change since its usage aims to reduce carbon emissions and enhance energy security. As the global energy trend moves toward cleaner alternatives countries start to adapt their energy strategies. In this transition hydrogen is one of the energy sources with the potential to increase long-term energy security. Developing countries face challenges such as high energy import dependency rising industrial demand and the need for infrastructure modernization making hydrogen valleys one of the viable solutions since they integrate hydrogen production storage distribution and utilization at one facility. However establishing small-scale hydrogen valleys requires a comprehensive decision-making strategy consisting of technical financial environmental social and political factors while addressing uncertainties in the system. To systematically manage the process this study proposes a Z-numberbased fuzzy cognitive mapping approach which models the interdependencies among success factors supported by Z-number Decision-Making Trial and Evaluation Laboratory for structured prioritization with a multi-expert perspective. The results indicate that Financial Factors emerged as the most critical category with Government Incentives Infrastructure Investment Cost and Land Acquisition Cost ranking as the top three sub-success factors. Availability of Skilled Workforce and Regional Energy Supply followed in importance which demonstrates the importance of social and technical dimensions in the hydrogen valley development. These findings demonstrate the critical role of policy support infrastructure readiness and workforce availability in the design process. Sensitivity analyses are also conducted to present robustness of the given decisions for the analysis of the results. Based on the results and analyses possible implications based on the policy and practical dimensions are also discussed. By integrating fuzzy logic and Z-numbers the study aims to minimize loss of information enhances the analytical background for decision-making and provides a strategic roadmap for hydrogen valley development.

This study develops a photovoltaic (PV)-based hydrogen production system specifically designed for university campuses which is expected to lead in sustainability efforts. The proposed system aims to meet the electricity demand of a Hydrogen Research Center while supplying energy to an electric charging station and a hydrogen refueling station for battery-electric and fuel-cell electric vehicles operating within the campus. In this integrated system the electricity generation capacity of PV panels installed on the research center’s roof is determined and the surplus electricity after meeting the energy demand is allocated to cover the varying proportions needed for both electric charging station and hydrogen production system. The green hydrogen produced by the system is compressed to 100 350 and 700 bar with intermediate cooling stages where the heat generated at the compressor outlet is absorbed by a cooling fluid and repurposed in a condenser for domestic hot water production. A full thermodynamic analysis of this entirely renewable energy-powered system is conducted by considering a 9-hour daily operational period from 8:00 AM to 5:00 PM. The average incoming solar radiation is determined to be 484.63 W/m2 resulting in an annual electricity generation capacity of 494.86 MWh. Based on the assumptions and data considered the energy and exergy efficiencies of the proposed system are calculated as 17.71 % and 17.01 % respectively with an annual hydrogen production capacity of 3.642 tons. Various parametric studies are performed for varying solar intensity values and PV surface areas to investigate how the overall system capacities and efficiencies are affected. The results show that an integration of hydrogen production systems with solar energy offers significant advantages including mitigating intermittency issues found in standalone renewable systems reducing carbon emissions compared to fossil-based alternatives and enhancing the flexibility of energy systems.

Hydrogen recirculation is essential for maintaining fuel efficiency and durability in Proton Exchange Membrane Fuel Cell (PEMFC) systems particularly in automotive range extender applications. This study presents the design simulation and experimental validation of a dry all-metal scroll pump developed for hydrogen recirculation in a 5 kW PEMFC system. The pump operates without oil or polymer seals offering long-term compatibility with dry hydrogen. Two prototypes were fabricated: SP1 incorporating PTFE-bronze tip seals and SP2 a fully metallic seal-free design. A fully deterministic one-dimensional (1D) model was developed to predict thermodynamic performance including leakage and heat transfer effects and validated against experimental results. SP1 achieved higher flow rates due to reduced axial leakage but experienced elevated friction and temperature. In contrast SP2 provided improved thermal stability and lower friction with slightly reduced flow performance. The pump demonstrated a maximum flow rate of 50 l/min and an isentropic efficiency of 82.2 % at 2.5 bara outlet pressure. Simulated performance showed strong agreement with experimental results with deviations under 5 %. The findings highlight the critical role of thermal management and manufacturing tolerances in dry scroll pump design. The seal-free liquid-cooled scroll architecture presents a promising solution for compact oil-free hydrogen recirculation in low-power fuel cell systems.

Electrolysis utilizing renewable electricity is an environmentally friendly non-polluting and sustainable method of hydrogen production. Seawater is the most desirable and inexpensive electrolyte for this process to achieve commercial acceptance compared to competing hydrogen production technologies. We reviewed metal–organic frameworks as possible electrocatalysts for hydrogen production by seawater electrolysis. Metal–organic frameworks are interesting for seawater electrolysis due to their large surface area tunable permeability and ease of functional processing which makes them extremely suitable for obtaining modifiable electrode structures. Here we discussed the development of metal– organic framework-based electrocatalysts as multifunctional materials with applications for alkaline PEM and direct seawater electrolysis for hydrogen production. Their advantages and disadvantages were examined in search of a pathway to a successful and sustainable technology for developing electrode materials to produce hydrogen from seawater.

This extensive study delves into analyzing carbon dioxide (CO2)-capturing green hydrogen plant exploring its operation using multiple electrolysis techniques and examining their efficiency and impact on environment. The solar energy is used for the electrolysis to make hydrogen. Emitted CO2 from thermal power plants integrate with green hydrogen and produces methanol. It is a process crucial for mitigating environmental damage and fostering sustainable energy practices. The findings demonstrated that solid oxide electrolysis is the most effective process by which hydrogen can be produced with significant rate of 90 % efficiency. Moreover proton exchange membrane (PEM) becomes a viable and common method with an 80 % efficiency whereas the alkaline electrolysis has a moderate level of 63 % efficiency. Additionally it was noted that the importance of seasonal fluctuations where the capturing of CO2 is maximum in summer months and less in the winter is an important factor to consider in order to maximize the working of the plant and the allocation of resources.

This study presents the design and techno-economic optimization of a hybrid renewable energy system (HRES) for a coastal hotel in Manavgat Türkiye. The system integrates photovoltaic (PV) panels wind turbines (WT) pumped hydro storage (PHS) hydrogen storage (electrolyzer tank and fuel cell) batteries a fuel cell-based combined heat and power (CHP) unit and a boiler to meet both electrical and thermal demands. Within this broader optimization framework six optimal configurations emerged representing gridconnected and standalone operation modes. Optimization was performed in HOMER Pro to minimize net present cost (NPC) under strict reliability (0% unmet load) and renewable energy fraction (REF > 75%) constraints. The grid-connected PHS–PV–WT configuration achieved the lowest NPC ($1.33 million) and COE ($0.153/kWh) with a renewable fraction of ~96% and limited excess generation (~21%). Off-grid PHS-based and PHS–hydrogen configurations showed competitive performance with slightly higher costs. Hydrogen integration additionally provides complementary storage pathways coordinated operation waste heat utilization and redundancy under component unavailability. Battery-only systems without PHS or hydrogen storage resulted in 37–39% higher capital costs and ~53% higher COE confirming the economic advantage of long-duration PHS. Sensitivity analyses indicate that real discount rate variations notably affect NPC and COE particularly for battery-only systems. Component cost sensitivity highlights PV and WT as dominant cost drivers while PHS stabilizes system economics and the hydrogen subsystem contributes minimally due to its small scale. Overall these results confirm the techno-economic and environmental benefits of combining seawater-based PHS with optional hydrogen and battery storage for sustainable hotel-scale applications.