Review of hydrogen economy in Malaysia and its way forward

Heavy fossil fuels consumption has raised concerns over the energy security and climate change while hydrogen is regarded as the fuel of future to decarbonize global energy use. Hydrogen is commonly used as feedstocks in chemical industries and has a wide range of energy applications such as vehicle fuel, boiler fuel, and energy storage. However, the development of hydrogen energy in Malaysia is sluggish despite the predefined targets in hydrogen roadmap. This paper aims to study the future directions of hydrogen economy in Malaysia considering a variety of hydrogen applications. The potential approaches for hydrogen production, storage, distribution and application in Malaysia have been reviewed and the challenges of hydrogen economy are discussed. A conceptual framework for the accomplishment of hydrogen economy has been proposed where renewable hydrogen could penetrate Malaysia market in three phases. In the first phase, the market should aim to utilize the hydrogen as feedstock for chemical industries. Once the hydrogen production side is matured in the second phase, hydrogen should be used as fuel in internal combustion engines or burners. In the final phase hydrogen should be used as fuel for automobiles (using fuel cell), fuel-cell combined heat and power (CHP) and as energy storage.     

Technological-economic assessment and optimization of hydrogen-based transportation systems in China: A life cycle perspective

Hydrogen energy is increasingly incorporated into long-distance transportation systems. Whether the coupled hydrogen-based transportation system can achieve a sustainable business operation mode requires quantification of environmental and economic performance by a comprehensive cost-benefit analysis. This study proposes a cost-based life cycle assessment method to evaluate the environmental and economic benefits of hydrogen-based long-distance transportation systems. The innovative cost assessment method introduces internal and external economic costs to conduct a multi-scenario assessment. According to the key factors of mileage, government subsidies and hydrogen fuel prices, this research identifies the key cost component of the hydrogen-based transportation system in China by using a multilevel comparison with cell-driven and oil-fueled vehicles. The results show that hydrogen fuel cell electric vehicles are competitive in terms of both fuel costs and environmental costs. As hydrogen costs are expected to be gradually reduced by 43% in the future, hydrogen logistics vehicles and heavy trucks are expected to have better life-cycle economics than other energy vehicles by approximately 2030. Hydrogen buses will outperform other vehicles by approximately 2033, while hydrogen passenger cars will have a reduced life-cycle cost per kilometre within 0.1 CHY/km compared to other vehicles by approximately 2035. Ultimately, fuel consumption, average annual mileage, and hydrogen fuel cell electric vehicle policy are three factors that have greater impacts. Policy implications are put forward to implement optimal investment plan for hydrogen transportation systems.     

Performance evaluation of a solarized gas turbine system integrated to a high temperature electrolyzer for hydrogen production

In this paper, the performance of a solar gas turbine (SGT) system integrated to a high temperature electrolyzer (HTE) to generate hybrid electrical power and hydrogen fuel is analyzed. The idea behind this design is to mitigate the losses in the electrical power transmission and use the enthalpy of exhaust gases released from the gas turbine (GT) to make steam for the HTE. In this context, a GT system is coupled with a solar tower including heliostat solar field and central receiver to generate electrical power. To make steam for the HTE, a flameless boiler is integrated to the SGT system applying the SGT extremely high temperature exhaust gases as the oxidizer. The results indicate that by increasing the solar receiver outlet temperature from 800 K to 1300 K, the solar share increases from 22.1% to 42.38% and the overall fuel consumption of the plant reduces from 7 kg/s to 2.7 kg/s. Furthermore, flameless mode is achievable in the boiler while the turbine inlet temperature (TIT) is maintained at the temperatures higher than 1314 K. Using constant amounts of the SGT electrical power, the HTE voltage decreases by enhancing the HTE steam temperature which result in the augmentation of the overall hydrogen production. To increase the HTE steam temperature from 950 K to 1350 K, the rate of fuel consumption in the flameless boiler increases from 0.1 m/s to 0.8 m/s; however, since the HTE hydrogen production increases from 4.24 mol/s to 16 mol/s it can be interpreted that the higher steam temperatures would be affordable. The presented hybrid system in this paper can be employed to perform more thermochemical analyses to achieve insightful understanding of the hybrid electrical power-hydrogen production systems.     

Determination of fuel utilisation and recirculated gas composition in dead-ended PEMFC systems

This work presents a fundamental theory and methods for understanding the gas composition dynamics in PEMFC anode fuel supply compartments operated dead-ended with recirculation. The methods are applied to measurement data obtained from a PEMFC system operated with a 1 kW short stack.We show how fuel utilisation and stack efficiency, two key factors determining how well a fuel supply system performs, are coupled through the anode gas composition.The developed methods allow determination of the anode fuel supply molar balance, giving access to the membrane crossover rates and the extent of recirculated gas exchanged to fresh fuel during a purge. A methane tracer gas is also evaluated for estimating fuel impurity enrichment ratios.The above theory and methods may be applied in modelling and experimental research activities related to defining hydrogen fuel quality standards, as well as for developing more efficient and robust PEMFC system operation strategies.     

Metaheuristic-based energy management strategies for fuel cell emergency power unit in electrical aircraft

This paper aims at presenting a comparative analysis of different metaheuristic algorithms in the application of energy management for fuel cell-based hybrid emergency power unit within electrical aircraft. Two energy management conventional strategies are employed while optimizing the operating temperature. Both the external energy maximization and the equivalent consumption minimization strategies are dealt with. The most efficient up-to-date metaheuristic techniques such as the artificial bee colony, the grey wolf optimization, the cuckoo search, the mine blast algorithm, the whale optimization algorithm, the moth swarm algorithm, the harmony search, the modified flower pollination algorithm and the electromagnetic field optimization are considered. The overall index of optimization performance is considered as a function of hydrogen consumption, overall system efficiency, variations of states of charge and stresses in different energy sources. The numerical simulations, through Matlab™/Simulink, highlights the capability of the different metaheuristic optimization techniques towards reducing the amount of consumed hydrogen in fuel cell-based emergency power unit in electrical aircrafts. The electromagnetic field optimization method results in significant hydrogen consumption reduction in comparison with the other proposed techniques.     

Hydrogen-powered vehicles for autonomous ride-hailing fleets

Autonomous ride-hailing fleets are approaching commercialization as an on-demand, low-cost transportation solution. Although battery electric vehicles (BEVs) are well-studied for this application, hydrogen fuel cell electric vehicles (FCEVs) may provide additional advantages that have not been sufficiently investigated. Here, we developed a stochastic ride-hailing autonomous vehicle (RHAV) model to compare these technologies and applied this model to seven BEVs and two FCEVs. FCEV fleets are 3–10% smaller than BEV fleets due to shorter refueling times and greater driving ranges, which enable greater fleet efficiency. The Hyundai Kona (BEV) provides the greatest fleet profitability; however, the Toyota Mirai (FCEV) is only 3% less profitable despite having a 25% higher purchase price. We demonstrate that FCEVs are economically competitive as RHAVs, and that expected price reductions can make them the most profitable technology. Furthermore, FCEV fleets provide qualitative benefits, including a substantial increase in local hydrogen demand to catalyze hydrogen infrastructure development.     

Reducing the fuel consumption and emissions with the use of an external fuel cell hybrid power unit for electric taxiing at airports

Airport ground operations have a great impact on the environment. Various innovative solutions have been proposed for aircraft to perform taxi movements by deactivating their main engines. Although these solutions are environmentally beneficial, onboard and external electric taxiing solutions that are actively used and planned to be used in airports are not completely carbon-free. The disadvantages of the existing solutions can be alleviated by using an external fuel cell hybrid power unit to meet the energy required for taxiing that does not put additional weight on the aircraft. To reveal the power and energy required by the system, Airbus A320-200, which is a narrow-body aircraft and frequently used in airports, has been considered in this study. To determine the physical requirements of the aircraft for taxiing, a total of 900 s taxi-out movement consisting of four different periods with different runway slope, headwind, and maximum speeds were examined. According to the determined physical requirements, the conceptual design of the proposed fuel cell battery system was created and the physical data of the system for each period were obtained using the Matlab Simulink environment. As a result of the simulation, it is seen that the system consumes approximately 1.96 g of hydrogen per second. In addition, it has been calculated that 578.34 kg of CO₂ is emitted during the taxi-out movement. The results also show that as a result of using the proposed system, approximately 14.6 million tons of CO₂ emission per year can be prevented.     

3D multiphysics modeling aided APU development for vehicle applications: A thermo-structural investigation

Solid oxide fuel cells (SOFC) are suitable for on-board electricity generation as Auxiliary Power Unit (APU) to support the electric power supply in heavy-duty vehicles. In order to satisfy the requirements of a lightweight fuel cell stack for mobile applications, thin-walled components must be used for the stack structure. This necessity is associated with material, process and design difficulties that must be solved in order to achieve a successful utilization. In this work a novel lightweight SOFC stack design with metal-supported cell was studied both numerically and experimentally. The metallic components are made from the Intermediate Temperature Metal (ITM), a high performance, high chromium ferritic stainless steels alloy. The multiphysics modeling approach (fluid dynamics, heat transfer, structural mechanics) was utilized in this work to predict the temperature distribution and the thermo-structural behavior of the new developed design. Geometric details of the fuel cell stack components as well as appropriate nonlinear, temperature and time-dependent constitutive models were developed to describe the material behavior. Experimental data were used to determine the material model parameters and validated the simulation results. The three-dimensional stress and deformation distributions in the individual stack components were evaluated and their maximum values for elements at risk were identified. Thus, the developed model enables the investigation of sustainability and serviceability of the structural elements to ensure a reliable operation of the stack. The developed computational model can be used as a design tool for parametric studies and optimization analysis to investigate the effects of process boundary conditions, material properties as well as geometrical design parameters and their variation on the induced thermal stresses.     

On the economics of a hydrogen bus fleet powered by a wind park – A case study for Austria

This paper investigates the economics of a fuel cell bus fleet powered by hydrogen produced from electricity generated by a wind park in Austria. The main research question is to simultaneously identify the most economical hydrogen generation business model for the electric utility owning wind power plants and to evaluate the economics of operating a fuel cell bus fleet, with the core objective to minimize the total costs of the overall fuel supply (hydrogen production) and use (bus and operation) system. For that, three possible operation modes of the electrolyzer have been identified and the resulting hydrogen production costs calculated. Furthermore, an in-depth economic analysis of the fuel cell buses as well as the electrolyzer technology has been conducted. Results show that investment costs are the largest cost factor for both technologies. Thus, continuous hydrogen production with the smallest possible electrolyzer is the economically most favorable option. In such an operation mode (power grid), the costs of production per kg/H₂ were the lowest. However, this means that the electrolyzer cannot be solely operated with electricity from the wind park, but is also dependent on the electricity mix from the grid. For fuel cell buses, the future cost development will depend very much on the respective policies and funding programs for the market uptake, as to date, the total cost of use for the fuel cell bus is more than two times higher than the diesel bus. The major final conclusion of this paper is that to make fuel cell electric busses competitive in the next years today severe policy interferences, such as subsidies for these busses as well as electrolyzers and bans for fossil energy, along with investments in the setup of a hydrogen infrastructure, are necessary.     

Consumer acceptance under hydrogen energy promotion policy: Evidence from Yangtze River Delta

Hydrogen fuel cell vehicle (HFCV) as an emerging industry with great potential have received great attention in the Yangtze River Delta, China. Under government's promotion of hydrogen energy, whether HFCV can be accepted by consumers is an important topic for future policymaking. Therefore, this study takes consumers' willingness to consume HFCV as the dependent variable and collects questionnaires from 21 cities in the Yangtze River Delta from 2020 to 2021. Based on Ordinary Least Squares (OLS) and Logit Regression, the evaluation was conducted from four perspectives: personal and family situation, environmental awareness, energy attitude and local product confidence. The results show that gender, age and income differences are not necessarily determinants of HFCV purchase, but educational level is a significant factor. Consistent with social-psychological studies, personal awareness of environmental protection and energy attitudes are the key factors that are significant affect HFCV purchase. Lastly, it is found that in the Yangtze River Delta, consumers' confidence in Chinese local hydrogen products is also a significant factor. This paper confirms that HFCV consumers have commonalities with other new energy consumers. However, due to the expectation of greater local production and development, enhancing the social recognition and confidence of local hydrogen technology may be one of the promotion approaches neglected.     

A techno-economic study for a hydrogen storage system in a microgrid located in baja California,Mexico. Levelized cost of energy for power to gas to power scenarios

In this work a techno economic feasibility study is carried out to implement a Hydrogen based Power to Gas to Power (P2G2P) in a Microgrid, located in a rural area in Baja California, Mexico. The study aims to define the feasibility to store energy throughout seasons with this novel alternative using an electrolyzer to produce green hydrogen from excess renewable energy in winter, to store it during months and re inject it to the grid as electricity by a fuel cell in the high energy demanding season. The Microgrid was modeled in Homer software and simulations of the P2G2P lead to Levelized Cost of Energy data to compare between the P2G2P scenarios and the current diesel-battery based solution to complete the high demand by the community. This study shows that using hydrogen and fuel cells to substitute diesel generators it is possible to reduce CO₂ emissions up to a 27% and that in order for the P2G2P to be cost competitive, the fuel cell should reduce its cost in 50%; confirming that, in the medium to long term, the hydrogen storage system is a coherent alternative towards decarbonization of the distributed energy generation.     

Reinforcement learning based energy management systems and hydrogen refuelling stations for fuel cell electric vehicles: An overview

This paper examines the current state of the art of hydrogen refuelling stations-based production and storage systems for fuel cell hybrid electric vehicles (FCHEV). Nowadays, the emissions are increasing rapidly due to the usage of fossil fuels and the demand for hydrogen refuelling stations (HRS) is emerging to replace the conventional vehicles with FCHEVs. Hence, the availability of HRS and its economic aspects are discussed. In addition, a comprehensive study is presented on the energy storage systems such as batteries, supercapacitors and fuel cells which play a major role in the FCHEVs. An energy management system (EMS) is essential to meet the load requirement with effective utilisation of power sources with various optimizing techniques. A detailed comparative analysis is presented on the merits of Reinforcement learning (RL) for the FCHEVs. The significant challenges are discussed in depth with potential solutions for future work.     

Hydrofluoroolefin-based mixed refrigerant for enhanced performance of hydrogen liquefaction process

Hydrogen has the highest gravimetric energy density of all fuels; however, it has a low volumetric energy density, unfavorable for storage and transportation. Hydrogen is usually liquefied to meet the bulk transportation needs. The exothermic interconversion of its spin isomers is an additional activity to an already energy-intensive process. The most significant temperature drop occurs in the precooling cycle (between ?150 °C and up to ?180 °C) and consumes more than 50% of the required energy. To reduce the energy consumption and improve the exergy efficiency of the hydrogen liquefaction process, a new high-boiling component, Hydrofluoroolefin (HFO-1234yf), is added to the precooled mixed refrigerant. As a result, the specific energy consumption of precooling cycle reduces by 41.8%, from 10.15 kWh/kg_LH2 to 5.90 kWh/kg_LH2, for the overall process. The exergy efficiency of the proposed case increases by 43.7%; however, the total equipment cost is also the highest. The inflated cost is primarily due to the added ortho-to-para hydrogen conversion reactor, boosting the para-hydrogen concentration. From the perspective of bulk storage and transportation of liquid hydrogen, the simplicity of design and low energy consumption build a convincing case for considering the commercialization of the process.     

A novel approach to ammonia synthesis from hydrogen sulfide

There are a number of shortcomings for currently-available technologies for ammonia production, such as carbon dioxide emissions and water consumption. We simulate a novel model for ammonia production from hydrogen sulfide through membrane technologies. The proposed production process decreases the need for external water and reduces the physical footprint of the plant. The required hydrogen comes from the separation of hydrogen sulfide by electrochemical membrane separation, while the required nitrogen is obtained from separating oxygen from air through an ion transport membrane. 10% of the hydrogen from the electrochemical membrane separation along with the separated oxygen from the ion transport membrane is sent to the solid oxide fuel cell for heat and power generation. This production process operates with a minimal number of processing units and in physical, kinetic, and thermal conditions in which a separation factor of ~99.99% can be attained.     

Barriers and strategies of hydrogen fuel cell power generation based on expert survey in South Korea

Recently, South Korea has become a pioneer in implementing hydrogen fuel cell energy production; however, sustainable development of hydrogen fuel cell as an energy source in South Korea remains limited. Hence, it is necessary to address these challenges that hinder such development. This study aims to identify the barriers to developing hydrogen fuel cell energy in South Korea and classify them. We used the combined qualitative methodology, which includes both expert Delphi surveys and Analytic Hierarchy Process techniques. Five factors were identified, each of which has three sub-factors derived for the Delphi survey. The results show that the most serious barriers are institutional and political factors; in addition, the cost of the unit and infrastructure of the fuel cell are significant barriers.     

Hydrogen fuel cell heavy-duty trucks: Review of main research topics

Road transportation is a significant source of CO₂ emissions and energy demand. Consequently, initiatives are being promoted to decrease the sector's emissions and comply with the Paris agreement. This article synthesizes the available information about heavy-duty fuel cell trucks as their deployment needs to be considered a complementary solution to decreasing CO₂ emissions alongside battery electric vehicles. A thorough evaluation of 95 relevant documents determines that the main research topics in the past ten years converge on public policies, hydrogen supply chain, environmental impact, drivetrain technology, fuel cell, and storage tank applications. The identified research gaps relate to expanding collaboration between institutions and governments in developing joint green macro policies focused on hydrogen heavy-duty trucks, scarce research about hydrogen production energy sources, low interest in documenting hydrogen pilot projects, and minimal involvement of logistic companies, which need to plan their diesel freight's conversion as soon as possible.     

Energy efficient hydrogen drying and purification for fuel cell vehicles

High-purity standards are required for hydrogen used in fuel cell vehicles. The relative abundance of contaminants is highly influenced by the production pathway. Hydrogen obtained from water electrolysis presents three main pollutants: Nitrogen, Oxygen and Water. Herein, the engineering and implementation of removal techniques in a commercial 50 kW alkaline electrolyzer are reported. The full system was characterized with various analytical techniques including gas chromatography and mass spectrometry. A reduction of contaminant levels compatible with ISO 14687:2019 standard was achieved. From cold start, 100 min of operation are required to reach the desired nitrogen levels. Oxygen was removed in one step with a catalytic converter. Drying of hydrogen was achieved by using an innovative vacuum assisted pressure swing adsorption system. Sub-ppm levels of water are obtained with a power consumption of only 0.5 kWh/kg H₂ and 98.4% of product recovery.     

A review of hydrogen usage in internal combustion engines (gasoline-Lpg-diesel) from combustion performance aspect

Demand for fossil fuels is increasing day by day with the increase in industrialization and energy demand in the world. For this reason, many countries are looking for alternative energy sources against this increasing energy demand. Hydrogen is an alternative fuel with high efficiency and superior properties. The development of hydrogen-powered vehicles in the transport sector is expected to reduce fuel consumption and air pollution from exhaust emissions. In this study, the use of hydrogen as a fuel in vehicles and the current experimental studies in the literature are examined and the results of using hydrogen as an additional fuel are investigated. The effects of hydrogen usage on engine performance and exhaust emissions as an additional fuel to internal combustion gasoline, diesel and LPG engines are explained. Depending on the amount of hydrogen added to the fuel system, the engine power and torque are increased at most on petrol engines, while they are decreased on LPG and diesel engines. In terms of chemical products, the emissions of harmful exhaust gases in gasoline and LPG engines are reduced, while some diesel engines increase nitrogen oxide levels. In addition, it is understood that there will be a positive effect on the environment, due to hydrogen usage in all engine types.     

Design and computational analysis of a metal hydride hydrogen storage system with hexagonal honeycomb based heat transfer enhancements-part A

In this study, design and performance analysis is carried out for a 10 kWh metal hydride based hydrogen storage system. The system is equipped with distinctive aluminium hexagonal honeycomb based heat transfer enhancements (HTE) having higher surface area to volume ratio for effective heat transfer combined with low system weight addition. The system performance was studied under different operating conditions. The optimum absorption condition was achieved at 35 bar with water at room temperature as heat transfer fluid where up to 90% absorption was completed in 7200 s. The performance of the reactor was observed to significantly improve upon the addition of the HTE network at a minimal system weight penalty.     

Optimisation of solar-hydrogen power system for household applications

A numerical method was developed for optimising solar–hydrogen energy system to supply renewable energy for typical household connected with the grid. The considered case study involved household located in Diyala Governorate, Iraq. The solar–hydrogen energy system was designed to meet the desired electrical load and increase the renewable energy fraction using optimum fuel cell capacity. The simulation process was conducted by MATLAB based on the experimental data for electrical load, solar radiation and ambient temperature at a 1-min time-step resolution. Results demonstrated that the optimum fuel cell capacity was approximately 2.25 kW at 1.8 kW photovoltaic power system based on the average of the daily energy consumption of 6.8 kWh. The yearly renewable energy fraction increased from 31.82% to 95.82% due to the integration of the photovoltaic system with a 2.25 kW fuel cell used as a robust energy storage unit. In addition, the energy supply, which is the economic aspect for the optimum system, levelised electricity cost by approximately $0.195/kWh. The obtained results showed that the proposed numerical analysis methodology offers a distinctive property that can be used effectively to optimise hybrid renewable energy systems.