Publications

When the renewable energy is used the challenge is match the supply of intermittent energy with the demand for energy therefore the energy storage solutions should be used. This paper is dedicated to hydrogen accumulation from wind sources. The case study investigates the conceptual system that uses intermitted renewable energy resources to produce hydrogen (power-to-gas concept) and fuel (power-to-liquid concept). For this specific case study hydrogen is produced from surplus electricity generated by wind power plant trough electrolysis process and fuel is obtained by upgrading biogas to biomethane using hydrogen. System dynamic model is created for this conceptual system. The developed system dynamics model has been used to simulate 2 different scenarios. The results show that in both scenarios the point at which the all electricity needs of Latvia are covered is obtained. Moreover the methodology of system dynamics used in this paper is white-box model that allows to apply the developed model to other case studies and/or to modify model based on the newest data. The developed model can be used for both scientific research and policy makers to better understand the dynamic relation within the system and the response of system to changes in both internal and external factors.

This study analyzes the optimal sizing design of a stand-alone solar hydrogen hybrid energy system for a house in Afyon Turkey. The house is not connected to the grid and the proposed hybrid system meets all its energy demands; therefore it is considered a zero-energy building. The designed system guarantees uninterrupted and reliable power throughout the year. Since the reliability of the power supply is crucial for the house optimal sizing of the components photovoltaic (PV) panels electrolyzer storage tank and fuel cell stack is critical. Determining the sufficient number of PV panels suitable electrolyzer model and size number of fuel cell stacks and the minimum storage tank volume to use in the proposed system can guarantee an uninterrupted energy supply to the house. In this study a stand-alone hybrid energy system is proposed. The system consists of PV panels a proton exchange membrane (PEM) electrolyzer a storage tank and a PEM fuel cell stack. It can meet the continuous energy demand of the house is sized by using 10 min of averaged solar irradiation and temperature data of the site and consumption data of the house. Present results show that the size of each component in a solar hydrogen hybrid energy system in terms of power depends on the size of each other components to meet the efficiency requirement of the whole system. Choosing the nominal electrolyzer power is critical in such energy systems

Hydrogen is acknowledged as a potential and appealing energy carrier for decarbonizing the sectors that contribute to global warming such as power generation industries and transportation. Many people are interested in employing low-carbon sources of energy to produce hydrogen by using water electrolysis. Additionally the intermittency of renewable energy supplies such as wind and solar makes electricity generation less predictable potentially leading to power network incompatibilities. Hence hydrogen generation and storage can offer a solution by enhancing system flexibility. Hydrogen saved as compressed gas could be turned back into energy or utilized as a feedstock for manufacturing building heating and automobile fuel. This work identified many hydrogen production strategies storage methods and energy management strategies in the hybrid microgrid (HMG). This paper discusses a case study of a HMG system that uses hydrogen as one of the main energy sources together with a solar panel and wind turbine (WT). The bidirectional AC-DC converter (BAC) is designed for HMGs to maintain power and voltage balance between the DC and AC grids. This study offers a control approach based on an analysis of the BAC’s main circuit that not only accomplishes the function of bidirectional power conversion but also facilitates smooth renewable energy integration. While implementing the hydrogen-based HMG the developed control technique reduces the reactive power in linear and non-linear (NL) loads by 90.3% and 89.4%.

The author discusses in this paper the potential of a micro gas turbine (MGT) combustor when operated under unconventional fuel supplied. The combustor of C30 gas turbine is a reverse flow annular combustor. The CFD analysis of the reacting flow is performed with the 3D ANSYS-FLUENT solver. Specific computational experiments refer to the use of hydrogen – natural gas mixtures in order to define the optimal conditions for pilot and main injections in terms of combustion stability and NOx production. The author's methodology relies on an advanced CFD approach that compares different schemes like eddy dissipation concept together with the flamelet- PDF based approach coupled with an accurate study of the turbulent chemistry interaction. Extended kinetic mechanisms are also included in the combustion model. Some test cases are examined to make a comparison of combustion stability and efficiency and pollutant production with high hydrogen / natural gas ratios.

The shipping industry has reached a higher level of maturity in terms of its knowledge and awareness of decarbonization challenges. Carbon-free or carbon-neutralized green fuel such as green hydrogen green ammonia and green methanol are being widely discussed. However little attention has paid to the green fuel pathway from renewable energy to shipping. This paper therefore provides a review of the production methods for green power (green hydrogen green ammonia and green methanol) and analyzes the potential of green fuel for application to shipping. The review shows that the potential production methods for green hydrogen green ammonia and green methanol for the shipping industry are (1) hydrogen production from seawater electrolysis using green power; (2) ammonia production from green hydrogen + Haber–Bosch process; and (3) methanol production from CO2 using green power. While the future of green fuel is bright in the short term the costs are expected to be higher than conventional fuel. Our recommendations are therefore as follows: improve green power production technology to reduce the production cost; develop electrochemical fuel production technology to increase the efficiency of green fuel production; and explore new technology. Strengthening the research and development of renewable energy and green fuel production technology and expanding fuel production capacity to ensure an adequate supply of low- and zero-emission marine fuel are important factors to achieve carbon reduction in shipping.

The steel industry represents about 7% of the world’s anthropogenic CO2 emissions due to the high use of fossil fuels. The CO2 -lean direct reduction of iron ore with hydrogen is considered to offer a high potential to reduce CO2 emissions and this direct reduction of Fe2O3 powder is investigated in this research. The H2 reduction reaction kinetics and fluidization characteristics of fine and cohesive Fe2O3 particles were examined in a vibrated fluidized bed reactor. A smooth bubbling fluidization was achieved. An increase in external force due to vibration slightly increased the pressure drop. The minimum fluidization velocity was nearly independent of the operating temperature. The yield of the direct H2 -driven reduction was examined and found to exceed 90% with a maximum of 98% under the vibration of ~47 Hz with an amplitude of 0.6 mm and operating temperatures close to 500 ◦C. Towards the future of direct steel ore reduction cheap and “green” hydrogen sources need to be developed. H2 can be formed through various techniques with the catalytic decomposition of NH3 (and CH4 ) methanol and ethanol offering an important potential towards production cost yield and environmental CO2 emission reductions.

Liquid organic hydrogen carriers (LOHC) can be used as a lossless form of hydrogen storage at ambient conditions. The storage cycle consists of the exothermic hydrogenation of a hydrogen-lean molecule at the start of the transport usually the hydrogen production site becoming a hydrogen-rich molecule. This loaded molecule can be transported long distances or be used as long-term storage due to its ability to not lose hydrogen over long periods of time. At the site or time of required hydrogen production the hydrogen can be released through an endothermic dehydrogenation reaction. LOHCs show similar properties to crude oils such as petroleum and diesel allowing easy handling and possibilities of integration with current infrastructure. Using this background this paper reviews a variety of aspects of the LOHC life cycle with a focus on currently studied materials. Important factors such as the hydrogenation and dehydrogenation requirements for each material are analysed to determine their ability to be used in current scenarios. Toluene and dibenzyltoluene are attractive options with promising storage attributes however their dehydrogenation enthalpies remain a problem. The economic feasibility of LOHCs being used as a delivery device were briefly analysed. LOHCs have been shown to be the cheapest option for long distance transport (>200 km) and are cheaper than most at shorter distances in terms of specifically transport costs. The major capital cost of an LOHC delivery chain remains the initial investment for the raw materials and the cost of equipment for performing hydrogenation and dehydrogenation. Finally some studies in developing the LOHC field were discussed such as microwave enhancing parts of the process and mixing LOHCs to acquire more advantageous properties.

This paper explores the skills landscape of the emerging green hydrogen industry in Australia drawing on data collected from a study that gathered insights on training gaps from a range of hydrogen industry participants. A total of 41 industry participants completed a survey and 14 of those survey respondents participated in industry consultations. The findings revealed widespread perceptions of training and skilling as being very important to the industry but under-provisioned across the sector. Data were analysed to consider the problem of skilling the green hydrogen industry and the barriers and enablers as perceived by industry stakeholders. In this paper we argue that urgent cross-sector attention needs to be paid to hydrogen industry training and skill development systems in Australia if the promise of green hydrogen as a clean energy source is to be realised.

This paper shows the results of an in-depth techno-economic analysis of the public transport sector in a small to midsize city and its surrounding area. Public battery-electric and hydrogen fuel cell buses are comparatively evaluated by means of a total cost of ownership (TCO) model building on historical data and a projection of market prices. Additionally a structural analysis of the public transport system of a specific city is performed assessing best fitting bus lines for the use of electric or hydrogen busses which is supported by a brief acceptance evaluation of the local citizens. The TCO results for electric buses show a strong cost decrease until the year 2030 reaching 23.5% lower TCOs compared to the conventional diesel bus. The optimal electric bus charging system will be the opportunity (pantograph) charging infrastructure. However the opportunity charging method is applicable under the assumption that several buses share the same station and there is a “hotspot” where as many as possible bus lines converge. In the case of electric buses for the year 2020 the parameter which influenced the most on the TCO was the battery cost opposite to the year 2030 in where the bus body cost and fuel cost parameters are the ones that dominate the TCO due to the learning rate of the batteries. For H2 buses finding a hotspot is not crucial because they have a similar range to the diesel ones as well as a similar refueling time. H2 buses until 2030 still have 15.4% higher TCO than the diesel bus system. Considering the benefits of a hypothetical scaling-up effect of hydrogen infrastructures in the region the hydrogen cost could drop to 5 €/kg. In this case the overall TCO of the hydrogen solution would drop to a slightly lower TCO than the diesel solution in 2030. Therefore hydrogen buses can be competitive in small to midsize cities even with limited routes. For hydrogen buses the bus body and fuel cost make up a large part of the TCO. Reducing the fuel cost will be an important aspect to reduce the total TCO of the hydrogen bus.

Global transitions from carbon- to hydrogen-based economies are an essential component of curbing greenhouse gas emissions and climate change. This study provides an investigative review of the technological development trends within the overall hydrogen value chain in terms of production storage transportation and application with the aim of identifying patterns in the announcement and execution of hydrogen-based policies both domestically within Korea as well as internationally. The current status of technological trends was analyzed across the three areas of natural hydrogen carbon dioxide capture utilization and storage technology linked to blue hydrogen and green hydrogen production linked to renewable energy (e.g. water electrolysis). In Korea the establishment of underground hydrogen storage facilities is potentially highly advantageous for the storage of domestically produced and imported hydrogen providing the foundations for large-scale application as economic feasibility is the most important national factor for the provision of fuel cells. To realize a hydrogen economy pacing policy and technological development is essential in addition to establishing a roadmap for efficient policy support. In terms of technological development it is important to prioritize that which can connect the value chain all of which will ultimately play a major role in the transformation of human energy consumption.

To situate its low-carbon transition process in longer-term real-world business contexts this article makes a longitudinal analysis of the UK petrochemical industry focusing on changing economic and socio-political environments and company strategies in the last 50 years. Using the Triple Embeddedness Framework the paper identifies two parallel and conflicting reorientation processes in the UK petrochemical industry. The first one which started in the 1970s and is driven by long-standing competitiveness problems led to retrenchment in the 1980s exit of incumbent companies (BP Shell ICI) and the entry of new firms (INEOS SABIC) in the 1990s and 2000s and diversification into upstream fossil fuel production and ethane imports in the 2010s. The second reorientation process which started in the 2010s is driven by climate change considerations and has led petrochemical firms to reluctantly explore low-carbon alternatives. Despite advancing ambitious visions and plans companies are weakly committed to low-carbon reorientation because this is layered on top of and conflicts with the deeper economically-motivated reorientation process. The paper further concludes that the industry's low-carbon plans and visions are partial because they focus more on some innovations (hydrogen-as-fuel CCS) than on other innovations (recycling bio-feedstocks synthetic feedstocks). Despite exploring alternatives firms also use political resistance strategies to hamper and delay deeper low-carbon reorientation

In this episode titled "The Commission's support to the hydrogen ecosystem" our CEO Jorgo Chatzimarkakis discusses with Rosalinde van der Vlies Clean Planet Director DG RTD - European Commission. Starting off on how Rosalinde joined the Commission the two speakers discuss the Commission's support in developing a hydrogen ecosystem also in light of its participation in the Clean Hydrogen Partnership and the implications arising from the REPowerEU.

The impact of hydrogen added to natural gas on the performance of commercial domestic water heating devices has been discussed in several recent papers in the literature. Much of the work focuses on performance at specific hydrogen levels (by volume) up to 20–30% as a near term blend target. In the current work new data on several commercial devices have been obtained to help quantify upper limits based on flashback limits. In addition results from 39 individual devices are compiled to help generalize observations regarding performance. The emphasis of this work is on emissions performance and especially NOx emissions. It is important to consider the reporting bases of the emissions numbers to avoid any unitended bias. For water heaters the trends associated with both mass per fuel energy input and concentration-based representation are similar For carbon free fuels bases such as 12% CO2 should be avoided. In general the compiled data shows that NOx NO UHC and CO levels decrease with increasing hydrogen percentage. The % decrease in NOx and NO is greater for low NOx devices (meaning certified to NOx <10 ng/J using premixing with excess air) compared to conventional devices (“pancake burners” partial premixing). Further low NOx devices appear to be able to accept greater amounts of hydrogen above 70% hydrogen in some cases without modification while conventional water heaters appear limited to 40–50% hydrogen. Reporting emissions on a mass basis per unit fuel energy input is preferred to the typical dry concentration basis as the greater amount of water produced by hydrogen results in a perceived increase in NOx when hydrogen is used. While this effort summarizes emissions performance with added hydrogen additional work is needed on transient operation higher levels of hydrogen system durability/reliability and heating efficiency.

Transportation is one of the largest sources of CO2 emissions accounting for more than 20% of worldwide emissions. However it is one of the areas where decarbonization presents the greatest hurdles owing to its capillarity and the benefits that are associated with the use of fossil fuels in terms of energy density storage and transportation. In order to accomplish comprehensive decarbonization in the transport sector it will be required to encourage a genuine transition to low-carbon fuels and the widespread deployment of the necessary infrastructures to allow for a large-scale innovation. Renewable hydrogen shows potential for sustainable transportation applications whether in fuel cell electric vehicles (FCEVs) such as automobiles trucks and trains or as a raw material for ship and airplane synthetic fuels. The present paper aims to present how hydrogen-fuel cell hybrid powertrains for road vehicles work in terms of conceptual layouts and operating strategies. A comprehensive overview of real and current applications is presented concerning existing prototypes and commercially available vehicles with a focus on the main key performance indicators such as efficiency mileage and energy consumption.

In this paper the design of fuel cells for the main energy supply of passenger transportation aircraft is discussed. Using a physical model of a fuel cell general design considerations are derived. Considering different possible design objectives the trade-off between power density and efficiency is discussed. A universal cost–benefit curve is derived to aid the design process. A weight factor wP is introduced which allows incorporating technical (e.g. system mass and efficiency) as well as non-technical design objectives (e.g. operating cost emission goals social acceptance or technology affinity political factors). The optimal fuel cell design is not determined by the characteristics of the fuel cell alone but also by the characteristics of the other system components. The fuel cell needs to be designed in the context of the whole energy system. This is demonstrated by combining the fuel cell model with simple and detailed design models of a liquid hydrogen tank. The presented methodology and models allows assessing the potential of fuel cell systems for mass reduction of future passenger aircraft.

Hydrogen is considered the fuel of the future due to its cleaner nature compared to methane and gasoline. Therefore renewable hydrogen production technologies and long-term affordable and safe storage have recently attracted significant research interest. However natural underground hydrogen production and storage have received scant attention in the literature despite its great potential. As such the associated formation mechanisms geological locations and future applications remain relatively under-explored thereby requiring further investigation. In this review the global natural hydrogen formation along with reaction mechanisms (i.e. metamorphic processes pyritization and serpentinization reactions) as well as the suitable geological locations (i.e. ophiolites organic-rich sediments fault zones igneous rocks crystalline basements salt bearing strata and hydrocarbon-bearing basins) are discussed. Moreover the underground hydrogen storage mechanisms are detailed and compared with underground natural gas and CO2 storage. Techno-economic analyses of large-scale underground hydrogen storage are presented along with the current challenges and future directions.

This review article provides a comprehensive overview of the fundamentals modelling approaches experimental studies and challenges associated with hydrogen gas flow in pipelines. It elucidates key aspects of hydrogen gas flow including density compressibility factor and other relevant properties crucial for understanding its behavior in pipelines. Equations of state are discussed in detail highlighting their importance in accurately modeling hydrogen gas flow. In the subsequent sections one-dimensional and three-dimensional modelling techniques for gas distribution networks and localized flow involving critical components are explored. Emphasis is placed on transient flow friction losses and leakage characteristics shedding light on the complexities of hydrogen pipeline transportation. Experimental studies investigating hydrogen pipeline transportation dynamics are outlined focusing on the impact of leakage on surrounding environments and safety parameters. The challenges and solutions associated with repurposing natural gas pipelines for hydrogen transport are discussed along with the influence of pipeline material on hydrogen transportation. Identified research gaps underscore the need for further investigation into areas such as transient flow behavior leakage mitigation strategies and the development of advanced modelling techniques. Future perspectives address the growing demand for hydrogen as a clean energy carrier and the evolving landscape of hydrogen-based energy systems.

Across the globe energy production and usage cause the greatest greenhouse gas (GHG) emissions which are the key driver of climate change. Therefore countries around the world are aggressively striving to convert to a clean energy regime by altering the ways and means of energy production. Hydrogen is a frontrunner in the race to net-zero carbon because it can be produced using a diversity of feedstocks has versatile use cases and can help ensure energy security. While most current hydrogen production is highly carbon-intensive advances in carbon capture renewable energy generation and electrolysis technologies could help drive the production of low-carbon hydrogen. However significant challenges such as the high cost of production a relatively small market size and inadequate infrastructure need to be addressed before the transition to a hydrogen-based economy can be made. This review presents the state of hydrogen demand challenges in scaling up low-carbon hydrogen possible solutions for a speedy transition and a potential course of action for nations.

Dynamically-operated water electrolyzers enable the production of green hydrogen for cross-sector applications while simultaneously stabilizing power grids. In this study the start-up phase of polymer electrolyte membrane (PEM) water electrolyzers is investigated in the context of intermittent renewable energy sources. During the start-up of the electrolysis system the temperature increases which directly influences hydrogen production efficiency. Experiments on a 100 kWel electrolyzer combined with simulations of electrolyzers with up to 1 MWel were used to analyze the start-up phase and assess its implications for operators and system designers. It is shown that part-load start-up at intermediate cell voltages of 1.80 V yields the highest efficiencies of 74.0 %LHV compared to heat-up using resistive electrical heating elements which reaches maximum efficiencies of 60.9 %LHV. The results further indicate that large-scale electrolyzers with electrical heaters may serve as flexible sinks in electrical grids for durations of up to 15 min.

Hydrogen is emerging as one of the most promising energy carriers for a decarbonised global energy system. Transportation and storage of hydrogen are critical to its large-scale adoption and to these ends liquid hydrogen is being widely considered. The liquefaction and storage processes must however be both safe and efficient for liquid hydrogen to be viable as an energy carrier. Identifying the most promising liquefaction processes and associated transport and storage technologies is therefore crucial; these need to be considered in terms of a range of interconnected parameters ranging from energy consumption and appropriate materials usage to considerations of unique liquid-hydrogen physics (in the form of ortho–para hydrogen conversion) and boil-off gas handling. This study presents the current state of liquid hydrogen technology across the entire value chain whilst detailing both the relevant underpinning science (e.g. the quantum behaviour of hydrogen at cryogenic temperatures) and current liquefaction process routes including relevant unit operation design and efficiency. Cognisant of the challenges associated with a projected hydrogen liquefaction plant capacity scale-up from the current 32 tonnes per day to greater than 100 tonnes per day to meet projected hydrogen demand this study also reflects on the next-generation of liquid-hydrogen technologies and the scientific research and development priorities needed to enable them.

To realize a hydrogen economy many studies are being conducted regarding the development and analysis of hydrogen carriers. Recently formic acid has been receiving attention as a potential hydrogen carrier due to its high volumetric energy density and relatively safe characteristics. However hydrogen refueling systems using formic acid are very different from conventional hydrogen refueling stations and quantitative risks assessments need to be conducted to verify their safe usage. In this study a comparative safety analysis of a formic acid hydrogen refueling station (FAHRS) and a gaseous hydrogen refueling station (GHRS) was conducted. Since there is no FAHRS under operation a process simulation model was developed and integrated with quantitative risk assessment techniques to perform safety analysis. Results of the analysis show that the FAHRS poses less risk than the GHRS where the vapor cloud explosion occurring in the buffer tank is of greatest consequence. A GHRS poses a greater risk than an FAHRS due to the high pressure required to store hydrogen in the tube trailer. The mild operating conditions required for storage and dehydrogenation of formic acid contribute to the low risk values of an FAHRS. For risk scenarios exceeding the risk limit risk mitigation measures were applied to design a safe process for GHRS. The results show that the installation of active safety systems for the GHRS allow the system to operate within acceptable safety regions.

The emerging energy transition is particularly described as a move towards a cleaner lower-carbon system. In the context of the global shift towards sustainable energy sources this paper reviews the potential and roadmap for hydrogen energy as a crucial component of the clean energy landscape. The primary objective is to present a comprehensive literature overview illuminating key themes trends and research gaps in the scientific discourse concerning hydrogen production and energy policy. This review focuses particularly on specified geographic contexts with an emphasis on understanding the unique energy policies related to renewable energy in Brazil Austria and Germany. Given their distinct social systems and developmental stages this paper aims to delineate the nuanced approaches these countries adopt in their pursuit of renewable energy and the integration of hydrogen within their energy frameworks. Brazil exhibits vast renewable energy potential particularly in wind and solar energy sectors positioning itself for substantial growth in the coming years. Germany showcases a regulatory framework that promotes innovation and technological expansion reflecting its highly developed social system and commitment to transitioning away from fossil fuels. Austria demonstrates dedication to decarbonization particularly through the exploration of biomethane for residential heating and cooling.

This work compares the costs of three electrolysis-based hydrogen supply systems for heavy road transportation: a decentralized off-grid system for hydrogen production from wind and solar power (Dec-Sa); a decentralized system connected to the electricity grid (Dec-Gc); and a centralized grid-connected electrolyzer with hydrogen transported to refueling stations (Cen-Gc). A cost-minimizing optimization model was developed in which the hydrogen production is designed to meet the demand at refueling stations at the lowest total cost for two timeframes: one with current electricity prices and one with estimated future prices. The results show that: For most of the studied geographical regions Dec-Gc gives the lowest costs of hydrogen delivery (2.2e3.3V/kgH2) while Dec-Sa entails higher hydrogen production costs (2.5e6.7V/kgH2). In addition the centralized system (Cen-Gc) involves lower costs for production and storage than the grid-connected decentralized system (Dec-Gc) although the additional costs for hydrogen transport increase the total cost (3.5e4.8V/kgH2).

Focusing on technological innovation and convergence is crucial for utilizing hydrogen energy an emerging infrastructure area. This research paper analyzes the extent of technological capabilities in a region that could accelerate the occurrence of technological convergence in the fields related to hydrogen energy through the use of triadic patents their citation information and their regional information. The results of the Bayesian spatial model indicate that the active exchange of diverse original technologies could facilitate technological convergence in the region. On the other hand it is difficult to achieve regional convergence with regard to radical technology. The findings could shed light on the establishment of an R&D strategy for hydrogen technologies. This study could contribute to the dissemination and utilization of hydrogen technologies for sustainable industrial development.

The sustainable development goals concept towards zero carbon emission set forth by the Paris Agreement is the foundation of decarbonisation implemented in most developed countries worldwide. One of the efforts in the decarbonisation of the environment is through hydrogen fuel cell technology. A fuel cell is an energy converter device that produces electricity via the electrochemical reaction with water as the by-product. The application of fuel cells is strongly related to the economic aspect including local and infrastructure costs making it more relevant to be implemented in a developed country. This work presents a short review of the development and progress of hydrogen fuel cells in a developed country such as Japan Germany USA Denmark and China (in transition between developing to developed status); which championed hydrogen fuel cell technology in their region.

The environment is seriously threatened by the rising energy demand and the use of conventional energy sources. Renewable energy sources including hydro solar and wind have been the focus of extensive research due to the proliferation of energy demands and technological advancement. Wind energy is mostly harvested in coastal areas and little work has been done on energy extraction from winds in a suburban environment. The fickle behavior of wind makes it a less attractive renewable energy source. However an energy storage method may be added to store harvested wind energy. The purpose of this study is to evaluate the feasibility of extracting wind energy in terms of hydrogen energy in a suburban environment incorporating artificial intelligence techniques. To this end a site was selected latitude 33.64◦ N longitude 72.98◦ N and elevation 500 m above mean sea level in proximity to hills. One year of wind data consisting of wind speed wind direction and wind gust was collected at 10 min intervals. Subsequently long short-term memory (LSTM) support vector regression (SVR) and linear regression models were trained on the empirically collected data to estimate daily hydrogen production. The results reveal that the overall prediction performance of LSTM was best compared to that of SVR and linear regression models. Furthermore we found that an average of 6.76 kg/day of hydrogen can be produced by a 1.5 MW wind turbine with the help of an artificial intelligence method (LSTM) that is well suited for time-series data to classify process and predict.

The recent strong increase in the penetration of renewable energy sources (RESs) in medium-voltage distribution grids (MVDNs) has raised the need for congestion management in such grids as they were not designed for this new condition. This paper examines to what extent producing green hydrogen through electrolyzers can profitably contribute to congestion alleviation in MVDNs in the presence of high amounts of RES as well as flexible consumers of electricity and a local heat system. To address this issue an incentive-based method for improving flexibility in MVDNs is used which is based on a single-leader–multiple-followers game formulated by bi-level mathematical programming. At the upper level the distribution system operator who is the leader of this game determines dynamic prices as incentives at each node based on the levels of generation and load. Next at the lower level providers of flexibility including producers using electrolyzers price-responsive power consumers heat consumers as well as heat producers respond to these incentives by reshaping their output and consumption patterns. The model is applied to a region in the North of The Netherlands. The obtained results demonstrate that converting power to hydrogen can be an economically efficient way to reduce congestion in MVDNs when there is a high amount of RES. However the economic value of electrolyzers as providers of flexibility to MVDNs decreases when more other options for flexibility provision exist.

In an actual thermal power plant deep peak shaving will cause thermal power units to run under non-nominal conditions for an extended period resulting in serious problems such as increased equipment wearing low equipment utilization efficiency and decreased benefits. To this end in this work both the design and optimization method for a coal to hydrogen system which is coupled with the expected non-nominal operation of thermal power units are proposed. Aiming towards maximum profit in the context of thermal power plants a mathematical optimization model for a coal to hydrogen system based on the multi-period operating conditions of thermal power plants is established. The corresponding optimal design scheme of the coal to hydrogen system is determined using variable operating conditions. The superiority of the integrated system compared with an independent system is explored and the feasibility of the proposed method is verified by using the case study of an actual thermal power plant. The results show that compared with the independent system the economic benefits of the integrated system can increase by 13.56% where the sale of hydrogen in the coal to hydrogen system accounts for 60.3% of the total benefit. The main expenditure associated with the system is the purchase cost of feedstock coal accounting for 91.8%. Since the required power and medium-pressure steam in the coal to hydrogen process are provided by thermal power units the minimum operating load of the thermal power plant in the integrated system increases from 40% to 60.1% which significantly improves the utilization efficiency and service life of the generator units. In addition the proposed integration scheme of the system is simple and controllable which can contribute to the maintenance of the safe and stable operation of power generation and hydrogen production processes. These results are expected to provide the necessary methodological guidance for the integration and optimization of coal-fired power plants and coal to hydrogen systems.

Water electrolysis based on solid oxide electrolysis cell (SOEC) exhibits high conversion efficiency due to part of energy demand can be derived from thermal energy. Therefore it can be integrated with other sources of thermal energy to reduce the consumption of electrical energy. In this paper a diesel engine is integrated with the SOEC stacks for heat recovery steam generator (HRSG). The thermal energy from the engine exhaust gas used to heat the inlet H2O of the SOEC is carried out as the integration case. A SOEC plant using electricity as the thermal heat input is selected as the base case. Thermodynamic analysis of the benchmark and integration scheme reveals that an electrical efficiency of 73.12% and 85.17% can be achieved respectively. The diesel to power efficiency can be increased to 70% when the exhaust gas is completely utilized by the SOEC system. The impacts of some key parameters including current density and operating temperature on system performance have also been conducted and found that the system has optimized parameters of current density and operating temperature to achieve better performance.

The International Maritime Organization (IMO) has set decarbonisation goals for the shipping industry. As a result shipowners and operators are preparing to use low- or zero-carbon alternative fuels. The greenhouse gas (GHG) emission performances are fundamental for choosing suitable marine fuels. However the current regulations adopt tank-to-wake (TTW) emission assessment methods that could misrepresent the total climate impacts of fuels. To better understand the well-to-wake (WTW) GHG emission performances this work applied the life cycle assessment (LCA) method to a very large crude carrier (VLCC) sailing between the Middle East and China to investigate the emissions. The life cycle GHG emission impacts of using alternative fuels including liquified natural gas (LNG) methanol and ammonia were evaluated and compared with using marine gas oil (MGO). The bunkering site of the VLCC was in Zhoushan port China. The MGO and LNG were imported from overseas while methanol and ammonia were produced in China. Four production pathways for methanol and three production pathways for ammonia were examined. The results showed that compared with MGO using fossil energy-based methanol and ammonia has no positive effect in terms of annual WTW GHG emissions. The emission reduction effects of fuels ranking from highest to lowest were full solar and battery-based methanol full solar and battery-based ammonia and LNG. Because marine ammonia-fuelled engines have not been commercialised laboratory data were used to evaluate the nitrous oxide (N2O) emissions. The GHG emission reduction potential of ammonia can be exploited more effectively if the N2O emitted from engines is captured and disposed of through after-treatment technologies. This paper discussed three scenarios of N2O emission abatement ratios of 30% 50% and 90%. The resulting emission reduction effects showed that using full solar and battery-based ammonia with 90% N2O abatement performs better than using full solar and battery-based methanol. The main innovation of this work is realising the LCA GHG emission assessment for a deep-sea ship.

Recently hydrogen and fuel cells have gained interest as an emerging technology to mitigate the effects of climate change caused by the aviation sector. The aim of this work is to evaluate the applicability of this technology to an existing regional aircraft in order to assess its electrification with the aim of reducing greenhouse gas emissions and achieving sustainability goals. The design of a proton-exchange membrane fuel cell system (PEMFC) with the inclusion of liquid hydrogen storage is carried out. Specifically a general mathematical model is developed which involves multiple scales ranging from individual cells to aircraft scale. First the fuel cell electrochemical model is developed and validated against published polarization curves. Then different sizing approaches are used to compute the overall weight of the hydrogen-based propulsion system in order to optimize the system and minimize its weight. Crucially this work underscores that the feasibility of hydrogenbased fuel cell systems relies not only on hydrogen storage but especially on the electrochemical cell performance which influences the size of the balance of plant and especially its thermal management section. In particular the strategic significance of working with fuel cells at partial loads is demonstrated. This entails achieving an optimal balance between the stacks oversizing and the weights of both hydrogen storage and balance of plant thereby minimizing the overall weight of the system. It is thus shown that an integrated approach is imperative to guide progress towards efficient and implementable hydrogen technology in regional aviation. Furthermore a high-performance PEMFC is analyzed resulting in an overall weight reduction up to nearly 10% compared to the baseline case study. In this way it is demonstrated as technological advancements in PEMFCs can offer further prospects for improving system efficiency.

In this episode Steffan Eldred Hydrogen Knowledge Transfer Manager and Debra Jones Chemistry Knowledge Transfer Manager from Innovate UK KTN talk about hydrogen combustion with special guest Duncan Engeham European Research and Development Director at Cummins Inc.

The podcast can be found on their website.

Using hydrogen fuel cells for power systems temperature conditions are important for efficient and reliable operations especially in low-temperature environments. A heating system with an electrical energy buffer is therefore required for reliable operation. There is a research gap in finding an appropriate control strategy regarding energy efficiency and reliable operations for different environmental conditions. This paper investigates heating strategies for the subfreezing start of a fuel cell for portable applications at an early development stage to enable frontloading in product engineering. The strategies were investigated by simulation and experiment. A prototype for such a system was built and tested for subfreezing start-ups and non-subfreezing start-ups. This was done by heating the fuel cell system with different control strategies to test their efficiency. It was found that operating strategies to heat up the fuel cell system can ensure a more reliable and energy efficient operation. The heating strategy needs to be adjusted according to the ambient conditions as this influences the required heating energy efficiency and reliable operation of the system. A differentiation in the control strategy between subfreezing and non-subfreezing temperatures is recommended due to reliability reasons.

Green steel produced using renewable energy and hydrogen presents a promising avenue to decarbonize steel manufacturing and expand the hydrogen industry. Australia endowed with abundant renewable resources and iron ore deposits is ideally placed to support this global effort. This paper's two-step analytical approach offers the first comprehensive assessment of Australia's potential to develop green steel as a value-added export commodity. The Economic Fairways modelling reveals a strong alignment between prospective hydrogen hubs and current and future iron ore operations enabling shared infrastructure development and first-mover advantages. By employing a site-based system optimization that integrates both wind and solar power sources the cost of producing green steel could decrease significantly to around AU$900 per tonne by 2030 and AU$750 per tonne by 2050. Moreover replacing 1% of global steel production would require 35 GW of well-optimized wind and solar photovoltaics 11 GW of hydrogen electrolysers and 1000 square kilometres of land. Sensitivity analysis further indicates that iron ore prices would exert a long-term influence on green steel prices. Overall this study highlights the opportunities and challenges facing the Australian iron ore industry in contributing to the decarbonization of the global steel sector underscoring the crucial role of government support in driving the growth and development of the green steel industry.

Renewable energy supply is essential for carbon neutrality; however technologies aiming to optimally utilize renewable energy sources remain insufficient. Seasonal variability in renewable energy is a key issue which many studies have attempted to overcome through operating systems and energy storage. Currently hydrogen is the only technology that can solve this seasonal storage problem. In this study the amount of hydrogen required to circumvent the seasonal variability in renewable energy supply in Korea was quantified. Spatiotemporal analysis was conducted using renewable energy resource maps and power loads. It was predicted that 50% of the total power demand in the future will be met using solar and wind power and a scenario was established based on the solar-to-wind ratio. It was found that the required hydrogen production differed by approximately four-times depending on the scenarios highlighting the importance of supplying renewable energy at an appropriate ratio. Spatially wind power was observed to be unsuitable for the physical transport of hydrogen because it has a high potential at mountain peaks and islands. The results of this study are expected to aid future hydrogen research and solve renewable energy variability problems.

Hydrogen is a promising future fuel to enable the transition of transportation sector toward carbon neutrality. The direct utilization of H2 in internal combustion engines (ICEs) faces three major challenges: high NOx emissions severe pressure rise rates and pre-ignition at mid to high loads. In this study the potential of H2 combustion in a truck-size engine operated in spark ignition (SI) and pre-chamber (PC) mode was investigated. To mitigate the high pressure rise rate with the SI configuration the effects of three primary parameters on the engine combustion performance and NOx emissions were evaluated including the compression ratio (CR) the air–fuel ratio and the spark timing. In the simulations the severity of the pressure rise was evaluated based on the maximum pressure rise rate (MPRR). Lower compression ratios were assessed as a means to mitigate the auto-ignition while enabling a wider range of engine operation. The study showed that by lowering CR from 16.5:1 to 12.5:1 an indicated thermal efficiency of 47.5% can be achieved at 9.4 bar indicated mean effective pressure (IMEP) conditions. Aiming to restrain the auto-ignition while maintaining good efficiency growth in λ was examined under different CRs. The simulated data suggested that higher CRs require a higher λ and due to practical limitations of the boosting system λ at 4.0 was set as the limit. At a fixed spark timing using a CR of 13.5 combined with λ at 3.33 resulted in an indicated thermal efficiency of 48.6%. It was found that under such lean conditions the exhaust losses were high. Thus advancing the spark time was assessed as a possible solution. The results demonstrated the advantages of advancing the spark time where an indicated thermal efficiency exceeding 50% was achieved while maintaining a very low NOx level. Finally the optimized case in the SI mode was used to investigate the effect of using the PC. For the current design of the PC the results indicated that even though the mixture is lean the flame speed of H2 is sufficiently high to burn the lean charge without using a PC. In addition the PC design used in the current work induced a high MPRR inside the PC and MC leading to an increased tendency to engine knock. The operation with PC also increased the heat transfer losses in the MC leading to lower thermal efficiency compared to the SI mode. Consequently the PC combustion mode needs further optimizations to be employed in hydrogen engine applications.

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.

This paper focuses on developing a fast-solving open-source model for dynamic power-to-X plant techno-economic analysis and analysing the method bias that occurs when using other state-of-the-art power-to-X cost calculation methods. The model is a least-cost optimisation of investments and operation-costs taking as input techno-economic data varying power profiles and hourly grid prices. The fuel analysed is ammonia synthesised from electrolytic hydrogen produced with electricity from photovoltaics wind turbines or the grid. Various weather profiles and electrolyser technologies are compared. The calculated costs are compared with those derived using methods and assumptions prevailing in most literature. Optimisation results show that a semi-islanded set-up is the cheapest option and can reduce the costs up to 23% compared to off-grid systems but leads to e-fuels GHG emissions similar to fossil fuels with today’s electricity blend. For off-grid systems estimating costs using solar or wind levelized cost of electricity and capacity factors to derive operating hours leads to costs overestimation up to 30%. The cheapest off-grid configuration reaches production costs of 842 e/t3 . For comparison the "grey" ammonia price was 250 e/t3 in January 2021 and 1500 e/t3 in April 2022 (Western Europe). The optimal power mix is found to always include photovoltaic with 1-axis tracking and sometimes different types of onshore wind turbines at the same site. For systems fully grid connected approximating a highly fluctuating electricity price by a yearly average and assuming a constant operation leads to a small cost.

This paper examines the prospect of PEM (Proton Exchange Membrane) electrolyzers and fuel cells to partake in European electrical ancillary services markets. First the current framework of ancillary services is reviewed and discussed emphasizing the ongoing European harmonization plans for future frequency balancing markets. Next the technical characteristics of PEM hydrogen technologies and their potential uses within the electrical power system are discussed to evaluate their adequacy to the requirements of ancillary services markets. Last a case study based on a realistic representation of the transmission grid in the north of the Netherlands for the year 2030 is presented. The main goal of this case study is to ascertain the effectiveness of PEM electrolyzers and fuel cells for the provision of primary frequency reserves. Dynamic generic models suitable for grid simulations are developed for both technologies including the required controllers to enable participation in ancillary services markets. The obtained results show that PEM hydrogen technologies can improve the frequency response when compared to the procurement with synchronous generators of the same reserve value. Moreover the fast dynamics of PEM electrolyzers and fuel cells can help mitigate the negative effects attributed to the reduction of inertia in the system.

The fishing sector is faced with emission problems arising from the extensive use of diesel engines as prime movers. Energy efficiency environmental performance and minimization of operative costs through the reduction of fuel consumption are key research topics across the whole maritime sector. Ship emissions can be determined at different levels of complexity and accuracy i.e. by analyzing ship technical data and assuming its operative profile or by direct measurements of key parameters. This paper deals with the analysis of the environmental footprint of a fishing trawler operating in the Adriatic Sea including three phases of the Life-Cycle Assessment (manufacturing Well-to-Pump (WTP) and Pump-to-Wake (PTW)). Based on the data on fuel consumption the viability of replacing the conventional diesel-powered system with alternative options is analyzed. The results showed that fuels such as LNG and B20 represent the easiest solution that would result in a reduction of harmful gases and have a positive impact on overall costs. Although electrification and hydrogen represent one of the cleanest forms of energy due to their high price and complex application in an obsolete fleet they do not present an optimal solution for the time being. The paper showed that the use of alternative fuels would have a positive effect on the reduction of harmful emissions but further work is needed to find an environmentally acceptable and economically profitable pathway for redesigning the ship power system of fishing trawlers.

Not only due to the energy crisis European policymakers are exploring options to substitute natural gas with renewable hydrogen. A condition for the application of hydrogen is a functioning transportation infrastructure. However the most efficient transport of large hydrogen quantities is still unclear and deeper analyses are missing. A promising option is converting the existing gas infrastructure. This study presents a novel approach to develop hydrogen networks by applying the Steiner tree algorithm to derive candidates and evaluate their costs. This method uses the existing grid (brownfield) and is compared to a newly built grid (Greenfield). The goal is the technical and economic evaluation and comparison of hydrogen network candidates. The methodology is applied to the German gas grid and demand and supply scenarios covering the industry heavy-duty transport power and heating sector imports and domestic production. Five brownfield candidates are compared to a greenfield candidate. The candidates differ by network length and pipeline diameters to consider the transported volume of hydrogen. The economic evaluation concludes that most brownfield candidates’ cost is significantly lower than those of the greenfield candidate. The candidates can serve as starting points for flow simulations and policymakers can estimate the cost based on the results.

Land available for energy production is limited in cities owing to high population density. To reach the net zero goal cities contributing 70% of overall greenhouse gas emissions need to dramatically reduce emissions and increase self-sufficiency in energy production. Environmental infrastructures such as sewage treatment and incineration plants can be used as energy production facilities in cities. This study attempted to examine the effect of using environmental infrastructure such as energy production facilities to contribute toward the carbon neutrality goal through urban energy systems. In particular since the facilities are suitable for hydrogen supply in cities the analysis was conducted focusing on the possibility of hydrogen production. First the current status of energy supply and demand and additional energy production potential in sewage treatment and incineration plants in Seoul were analyzed. Then the role of these environmental infrastructures toward energy self-sufficiency in the urban system was examined. This study confirmed that the facilities can contribute to the city’s energy self-sufficiency and the achievement of its net-zero goal.

The environmental and societal challenges of our contemporary society are leading us to reconsider our approaches to vehicle design. The aim of this article is to provide the reader with the essential knowledge needed to responsibly design a vehicle equipped with a hydrogen fuel cell system. Two pivotal aspects of hydrogen-electric powertrain eco-design are examined. First the global warming potential is assessed for both PEMFC systems and Type IV hydrogen tanks accounting for material extraction production and end-of-life considerations. The usage phase was omitted from the study in order to facilitate data adaptation for each type of use. PEMFC exhibits a global warming potential of about 29.2 kgCO2eq/kW while the tank records 12.4 kgCO2eq/kWh with transportation factors considered. Secondly the societal and governmental impacts are scrutinized with the carbon-intensive hydrogen tank emerging as having the most significant societal and governmental risks. In fact on a scale of 1–5 with 5 representing the highest level of risk the PEMFC system has a societal impact and governance risk of 2.98. The Type IV tank has a societal impact and governance risk of 3.31. Although uncertainties persist regarding the results presented in this study the values obtained provide an overview of the societal and governmental impacts of the hydrogen ecosystem in the transportation sector. The next step will be to compare for the same usage which solution between hydrogen-electric and 100% battery is more respectful of humans and the environment.

Developing a thriving hydrogen industry will depend on public and community support. Past research mainly focusing on the acceptance of hydrogen fuelling stations and cars suggests that people generally support hydrogen energy technology (HET). Few studies have however considered how people think about other components of the hydrogen supply chain (i.e. technologies required to make store transport and use hydrogen). Moreover there has been limited research investigating how people interpret and develop beliefs about HET after being presented with technical information. This paper attempts to address these research gaps by presenting the findings from four face-to-face focus group discussions conducted in Australia. The findings suggest that people have differing views about HET which depends on the type of technology and these views influence levels of support. The study also revealed concerns about a range of other factors that have yet to be considered in hydrogen acceptance research (e.g. perceived water use efficiency and indirect benefits). The findings highlight the value of qualitative research for identifying salient beliefs that shape attitudes towards HET and provide recommendations for future research and how to effectively communicate with the public and communities about an emerging hydrogen industry.

The present research work aims to present a uniquely designed renewable energy-based integrated system along with an equilibrium model for the processing of feedstock by following a hybrid route of thermochemical and biochemical ways. In this regard Canadian maple leaves and plastic wastes are selected as potential feedstocks for co-pyrolysis and syngas fermentation. The influence of co-pyrolysis process parameters on the overall system performance is investigated and assessed. Also several sensitivity analyses are performed to determine the optimal operating parameters that can generate maximum yields of hydrogen and ethanol. The present system is further investigated thermodynamically in terms of energetic and exergetic approaches and efficiencies. The present study shows that a molar flow ratio of 1:1 for maple leaves to plastic wastes a temperature of 1000◦C temperature and a pressure of 1 bar appear to be the most suitable operating conditions with the net production capacities of 7.43 tons/day for hydrogen and 8.72 tons/day for ethanol. The cold gas efficiency and LHV of the syngas produced are found to be 57.23% and 19.96 MJ/kg respectively. The overall energetic and exergetic efficiencies of the present system are found to be 30.98% and 26.88% respectively.

Ammonia is a pollutant present in wastewater and is also a valuable carbon-free hydrogen carrier. Stripping recovery and anodic oxidation of ammonia to produce hydrogen via electrolysis is gaining momentum as a technology yet the development of an inexpensive stable catalytic material is imperative to reduce cost. Here we report on a new nickel copper (NiCu) catalyst electrodeposited onto a high surface area nickel felt (NF) as an anode for ammonia electrolysis. Cyclic voltammetry demonstrated that the catalyst/substrate combination reached the highest current density (200 mA cm2 at 20 C) achieved for a non-noble metal catalyst. A NiCu/NF electrode was tested in an anion exchange membrane electrolyser for 50 h; it showed good stability and high Faradaic efficiency for ammonia oxidation (88%) and hydrogen production (99%). We demonstrate that this novel electrode catalyst/substrate material combination can oxidise ammonia in a scaled system and hydrogen can be produced as a valuable by-product at industrial-level current densities and cell voltages lower than that for water electrolysis.

The present study investigates four factors that govern the ability to supply hydrogen at a low cost in Europe: the scale of the hydrogen demand; the possibility to invest in large-scale hydrogen storage; process flexibility in hydrogen-consuming industries; and the geographical areas in which hydrogen demand arises. The influence of the hydrogen demand on the future European zero-emission electricity system is investigated by applying the cost-minimising electricity system investment model eNODE to hydrogen demand levels in the range of 0–2500 TWhH2. It is found that the majority of the future European hydrogen demand can be cost-effectively satisfied with VRE assuming that the expansion of wind and solar power is not hindered by a lack of social acceptance at a cost of around 60–70 EUR/MWhH2 (2.0–2.3 EUR/kgH2). The cost of hydrogen in Europe can be reduced by around 10 EUR/MWhH2 if the hydrogen consumption is positioned strategically in regions with good conditions for wind and solar power and a low electricity demand. The cost savings potential that can be obtained from full temporal flexibility of hydrogen consumption is 3-fold higher than that linked to strategic localisation of the hydrogen consumption. The cost of hydrogen per kg increases and the value of flexibility diminishes as the size of the hydrogen demand increases relative to the traditional demand for electricity and the available VRE resources. Low-cost hydrogen is thus achieved by implementing efficiency and flexibility measures for hydrogen consumers as well as increasing acceptance of VRE.

South Korea ranking ninth among the largest energy consumers and seventh in carbon dioxide emissions from 2016 to 2021 faces challenges in energy security and climate change mitigation. The primary challenge lies in transitioning from fossil fuel dependency to a more sustainable and diversified energy portfolio while meeting the growing energy demand for continued economic growth. This necessitates fostering innovation and investment in the green energy sector. This study examines the potential impact of green energy expansion (through integrating renewable energy and hydrogen production) and gas import reduction on South Korea’s economic growth using a system dynamics approach. The findings indicate that increasing investment in green energy can result in significant growth rates ranging from 7% to 35% between 2025 and 2040. Under the expansion renewable energy scenario (A) suggests steady but sustainable economic growth in the long term while the gas import reduction scenario (B) displays a potential for rapid economic growth in the short term with possible instability in the long term. The total production in Scenario B is USD 2.7 trillion in 2025 and will increase to USD 4.8 trillion by 2040. Scenario C which combines the effects of both Scenarios A and B results in consistently high economic growth rates over time and a substantial increase in total production by 2035–2040 from 20% to 46%. These findings are critical for policymakers in South Korea as they strive for sustainable economic growth and transition to renewable energy.

The present study enters in the context of reducing harmful emissions of the marine fleet by using three of the most promising alternative fuels namely methanol ammonia and hydrogen. These fuels are to be examined from the perspective of both the first and second laws of thermodynamics when employed in turbocharged and intercooled Homogeneous Charge Compression Ignition Engines (HCCI) under various values of ambient temperature and equivalence ratio. Results showed that the highest engine performance values favour using ammonia as fuel followed in order by hydrogen and methanol. Furthermore most of the exergy destruction rates (65.26% ammonia to 84.02% for hydrogen) of the exergy destruction rate occurring in the engine take place in the HCCI engine.

Recent drastic increases in natural gas prices have brought into sharp focus the inherent tensions between net zero transitions energy security and affordability. We investigate the impact of different fuel prices on the energy system transition explicitly accounting for the increasingly coupled power and heating sectors and also incorporate the emerging hydrogen sector. The aim is to identify low-regret decisions and optimal energy system transitions for different fuel prices. We observe that the evolution of the heating sector is highly sensitive to the gas price whereas the composition of the power sector is not qualitatively impacted by gas prices. We also observe that bioenergy plays an important role in the energy system transition and the balance between gas price and biomass prices determines the optimal technology portfolios. The future evolution of the prices of these two resources is highly uncertain and future energy systems must be resilient to these uncertainties.