Hydrogen energy technology—Update 1976

Hydrogen, a chemical commodity and fuel now produced from natural gas, could, in the future, become a widely used fuel produced from water and diverse energy sources. Since the initial flurry of interest in “hydrogen economy” concepts, serious feasibility studies, technology assessments, and experimental studies have identified economic and technological problem areas. Production now appears to be the focus of most hydrogen research and development efforts as shown by a review of the technical papers presented at the First World Hydrogen Energy Conference. Specific industrial uses, electric power storage, and perhaps additions of hydrogen to supplement the natural gas supply appear to be near-term prospects for hydrogen utilization.     

Exergy analysis of an integrated fuel processor and fuel cell (FP–FC) system

Fuel cells have great application potential as stationary power plants, as power sources in transportation, and as portable power generators for electronic devices. Most fuel cells currently being developed for use in vehicles and as portable power generators require hydrogen as a fuel. Chemical storage of hydrogen in liquid fuels is considered to be one of the most advantageous options for supplying hydrogen to the cell. In this case a fuel processor is needed to convert the liquid fuel into a hydrogen-rich stream. This paper presents a second-law analysis of an integrated fuel processor and fuel cell system. The following primary fuels are considered: methanol, ethanol, octane, ammonia, and methane. The maximum amount of electrical work and corresponding heat effects produced from these fuels are evaluated. An exergy analysis is performed for a methanol processor integrated with a proton exchange membrane fuel cell, for use as a portable power generator. The integrated FP–FC system, which can produce 100 W of electricity, is simulated with a computer model using the flow-sheeting program Aspen Plus. The influence of various operating conditions on the system efficiency is investigated, such as the methanol concentration in the feed, the temperature in the reformer and in the fuel cell, as well as the fuel cell efficiency. Finally, it is shown that the calculated overall exergetic efficiency of the FP–FC system is higher than that of typical combustion engines and rechargeable batteries.     

Potential of molten carbonate fuel cells to enhance the performance of CHP plants in sewage treatment facilities

In spite of its slow commercial deployment, fuel cells are amongst the most efficient and environmentally friendly electric power generators. The case of Molten Carbonate Fuel Cells is even more interesting since, in addition to these features that are common to all fuel cells, these systems can be used as active carbon capture devices due to their capability to migrate carbon dioxide from one electrode (cathode) to another (anode). In this context, this work presents the operation of a fuel cell of this type coupled to a combined heat and power plant based on gas reciprocating engines as typically used in wastewater treatment plants. The biogas produced in the water sludge digestion process is burnt in the reciprocating engines, whose exhaust gases are mixed with air and blown into the fuel cell cathode. The carbon dioxide contained in this stream is conveyed in the form of carbonate ions (CO₃⁼) through the electrolyte to the anode where it reacts with the hydrogen fuel, being released as carbon dioxide. The exhaust gases from the anode comprise carbon dioxide, water steam and a small fraction of unspent hydrogen fuel. The combustion of the latter species with pure oxygen followed by a cooling process permits separating a gaseous stream of pure carbon dioxide from a liquid stream of water.     

Hydrogen as a fuel

Hydrogen, used as fuel, has a number of attractive features that make it a leading candidate in the search for an alternative to the dwindling and progressively less reliable supply of fluid hydrocarbon fuels. Hydrogen produced by electrolysis using hydro- or nuclear-generated electricity will be available in Canada at prices competitive with other portable forms of energy before the end of the century. This paper examines the use of carbon-free electrolytic hydrogen as a motor vehicle fuel and as a fuel for fuel cells. A review of onboard hydrogen storage systems indicates that the propulsion power unit of hydrogen-fueled vehicles must be considerably more efficient than present gasoline-fueled internal combustion engines in order to compensate for the larger size and greater weight of hydrogen storage systems. Hydrogen-fueled internal combustion engines are more efficient than similar gasoline-fueled engines, but the improvement is not sufficient to offset the storage system limitation. Fuel cells operate with much higher efficiency than internal combustion engines, especially at partial loads. A comparison between H₃PO₄ and KOH fuel cells show that where carbon-free hydrogen is available from the onboard storage system, the KOH fuel cell offers the higher level of performance.     

Examining the trends of technological development in hydrogen energy using patent co-word map analysis

Hydrogen fuel is a zero CO₂ emission fuel which uses in electrochemical cells, or internal combustion engines, to power vehicles and electric devices. It is also can potentially be mass-produced for various applications and be used in propulsion of spacecraft with safely high pressure storage. Therefore, it is an interesting subject to identify the technological trends of hydrogen energy. This study suggests a patent co-word map analysis (PCMA) to examine the trends of technological development in the area of hydrogen energy. The PCMA provides a systematic procedure to demonstrate the overall relationship among patents and produces the important technological insights regarding hydrogen energy. The results of analysis firstly indicate that the technological trends of worldwide hydrogen energy focus on the converting and application of hydrogen. Furthermore, critical technologies obtained from three patent sub-maps can be identified as the production, storage and conversion for hydrogen energy. Finally, hydrogen application is taken for the key factor in sustainable energy research works to improve the use for hydrogen.     

Preparation of Li-Mg-N-H hydrogen storage materials for an auxiliary power unit

Solid hydrogen storage materials as H₂ supply for PEM fuel cells have been attempted over the past decades because of their high efficiencies in H₂ storage. However, most investigations were focused on the stage of tank design for the storage materials. The Li-Mg-N-H hydrogen storage system was for the first time integrated into a HT-PEM fuel cell stack for a prototype auxiliary power unit, the maximum working temperature being 200 °C. With a designed output of 1 kW, a few kilograms of storage materials are needed. By using commercially available raw materials, an up-scaled preparation of the storage material was performed using laboratory facilities. Preparation conditions were established with the aid of FTIR, TG-DSC and x-ray diffraction to ensure the desired quality of materials. Prior to power the fuel cell stack, the storage materials need to go through an exothermic metathesis, and severe temperature overshooting is expected, which may cause deterioration in material performance and safety issue. Operation conditions were tested and the temperature overshooting could be effectively prevented under adequate conditions.     

Hydrogen generation from LiBH4 solution catalyzed by multiwalled carbon nanotubes supported Co–B nanocatalysts for a portable micro proton exchange membrane fuel cell application

LiBH₄ has high hydrogen storage capacities, and could potentially serve as a superior hydrogen storage material. In the hydrolytic process, however, incomplete hydrolysis caused by the agglomeration of its hydrolytic product and un-reacted LiBH₄ limits its full utilization. Furthermore, application of hydrogen generated from LiBH₄ aqueous solution for proton exchange membrane fuel cell (PEMFC) has not been reported yet. In this paper, CNTs-supported Co–B nanocatalyst was used for hydrogen generation from LiBH₄ solution. 22 wt% LiBH₄ alkaline solution can fully release its stoichiometric amount of hydrogen and supply a 2.3 W portable PEMFC stack to run stably. The overall power density of the PEMFC/LiBH₄ solution system with Co–B/CNTs addition is 1020 Wh L⁻¹. Due to the high gravimetric and volumetric hydrogen capacities, the LiBH₄ solution could be used as a promising liquid hydrogen storage material for hydrogen fuel cells-based devices.     

Metal organic frameworks for hydrogen purification

High purity hydrogen is one of the key factors in determining the lifetime of proton exchange membrane (PEM) fuel cells. However, the current industrial processes for producing high purity hydrogen are not only expensive, but also come with low energy efficiencies and productivity. Finding more cost-effective methods of purifying hydrogen is essential for ensuring wider scale deployment of PEM fuel cells. Among various hydrogen purification methods, adsorption in porous materials and membrane technologies are seen as two of the most promising candidates for the current industrial hydrogen purification methods, with metal organic frameworks (MOF) being particularly popular in research over the last decade. Despite many available reviews on MOFs, most focus on synthesis and production, with few reports focused on performance for hydrogen purification. This review describes the working principle and performance parameters of adsorptive separations and membrane materials and identifies MOFs that have been reported for hydrogen purification. The MOFs are summarised and their performance in separating hydrogen from common impurities (CO₂, N₂, CH₄, CO) is compared systematically. The challenges of commercial application of MOFs for hydrogen purification are discussed.     

Fuel cells for low power applications

Electronic devices show an ever-increasing power demand and thus, require innovative concepts for power supply. For a wide range of power and energy capacity, membrane fuel cells are an attractive alternative to conventional batteries.The main advantages are

• •the flexibility with respect to power and capacity achievable with different devices for energy conversion and energy storage,
• •the long lifetime and long service life,
• •the good ecological balance,
• •very low self-discharge.

Therefore, the development of fuel cell systems for portable electronic devices is an attractive, although also a challenging, goal. The fuel for a membrane fuel cell might be hydrogen from a hydride storage system or methanol/water as a liquid alternative. The main differences between the two systems are

• •the much higher power density for hydrogen fuel cells,
• •the higher energy density per weight for the liquid fuel,
• •safety aspects and infrastructure for fuel supply for hydride materials.

For different applications, different system designs are required. High power cells are required for portable computers, low power methanol fuel cells required for mobile phones in hybrid systems with batteries and micro-fuel cells are required, e.g. for hand held PCs in the sub-Watt range. All these technologies are currently under development. Performance data and results of simulations and experimental investigations will be presented.     

Estimation of indirect CO2 emissions of a hydrogen‐powered medium size vehicle for the NEDC cycle

Reduction in greenhouse effect gases emission is a major source of concern nowadays. Internal combustion engines, as the most widely used power generation mean for transportation, represent a large share of such gases, which motivates active research efforts for alternative solutions. In this regard, PEM fuel cells represent a promising prospect and are thoroughly investigated, whether experimentally or through numerical simulation. The present work presents a simulation of the power potential of a PEM fuel cell, which is integrated to the full power electric traction chain of a medium size car. The cell potential is modelled by taking into account the different types of polarization. The driving performances of the vehicle and its hydrogen consumption are evaluated through a simple mathematical model and an application is performed for the New European Driving Cycle (NEDC) standard driving cycle. A preliminary sizing of the proton exchange membrane fuel cell (PEMFC) membrane area for the chosen vehicle is presented, along with that of a hydrogen storage tank for a typical autonomy. The main goal of the simulation is to estimate CO₂ indirect emissions due to the production of the needed hydrogen for the cycle via an electrolyser, compared with the case of a gasoline fueled vehicle. This is performed solely on a ‘fuel tank to wheel’ basis in order to have comparable figures. The results indicate that the environmental advantage of hydrogen cars is quite questionable if hydrogen is produced using carbon‐based energy sources. Copyright © 2009 John Wiley & Sons, Ltd.     

The fuel cell electric vehicles: The highlight review

Transportation sector is the important sector and consumed the most fossil fuel in the world. Since COVID-19 started in 2019, this sector had become the world connector because every country relies on logistics. The transportation sector does not only deal with the human transportation but also relates to logistics. Research in every country has searched for alternative transportation to replace internal combustion engines using fossil fuel, one of the most prominent choices is fuel cells. Fuel cells can use hydrogen as fuel. Hydrogen can be fed to the fuel cells to provide electric power to drive vehicles, no greenhouse gas emission and no direct combustion required. The fuel cells have been developed widely as the 21st century energy-conservation devices for mobile, stationary, and especially vehicles. The fuel cell electric vehicles using hydrogen as fuel were also called hydrogen fuel cell vehicles or hydrogen electric vehicles. The fuel cells were misconceived by several people that they were batteries, but the fuel cells could provide electric power continuously if their fuel was provided continuously. The batteries could provide electric power as their only capacities, when all ions are released, no power could be provided. Because the fuel cell vehicles play important roles for our future transportation, the overall review for these vehicles is significantly interesting. This overall review can provide general and technical information, variety of readers; vehicle users, manufacturers, and scientists, can perceive and understand the fuel cell vehicles within this review. The readers can realize how important the fuel cell technologies are and support research around the world to drive the fuel cell vehicles to be the leading vehicles in our sustainable developing world.     

Investigations on fabrication and lifetime performance of self – air breathing direct hydrogen micro fuel cells

There is an ever – increasing demand for more powerful, compact and longer – life power modules for portable electronic devices for leisure, communication and computing. Micro fuel cells have the potential to replace battery packs for portable electronic appliances because of their high power density, longer operating and standby times, and substantially shorter recharging times. However, fuel cells have stringent operating requirements, including no fuel leakage, water formed in the electrochemical reactions, heat dissipation, robustness, easy and safe use, and reliability. Due to the large market potential, several companies are currently involved in the development of micro fuel cells. For application of fuel cells as a battery charger or in a battery replacement market, the cells require simplification in terms of their construction and operation and must have volumetric power densities equivalent to or better than those of existing battery power packs. This paper discusses results of investigation on methods and materials for direct hydrogen micro fuel cells as well as the lifetime performance of single cells and 2 W_e arrays. The paper also reviews the global technology development status for the direct hydrogen micro fuel cell and compares its salient features with other types of micro fuel cells.     

Macroscale evaluation and testing of chemically hydrogenated graphene for hydrogen storage applications

The effective storage of H₂ gas represents one of the major challenges in the wide spread adoption of hydrogen powered fuel cells for light vehicle transportation. Here, we investigate the merits of chemically hydrogenated graphene (graphane) as a means to store high-density hydrogen fuel for on demand delivery. In order to evaluate hydrogen storage at the macroscale, 75 g of hydrogenated graphene was synthesized using a scaled up Birch reduction, representing the largest reported synthesis of this material to date. Covalent hydrogenation of the material was characterized via Raman spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). We go on to demonstrate the controlled release of H₂ gas from the bulk material using a sealed pressure reactor heated to 600 °C, identifying a bulk hydrogen storage capacity of 3.2 wt%. Additionally, we demonstrate for the first time, the successful operation of a hydrogen fuel cell using chemically hydrogenated graphene as a power source. This work demonstrates the utility of chemically hydrogenated graphene as a high-density hydrogen storage medium, and will be useful in the design of prototype hydrogen storage systems moving forward.     

An experimental investigation on hydroxy (HHO) enriched ammonia as alternative fuel in gas turbine

Today, the important challenges with the utilization of hydrogen in power-producing applications (internal combustion engines and fuel cells) are its delivery and storage and these create a big hesitation regarding the application safety. Ammonia, which can be regarded as the most promising alternative fuel to hydrogen, provides the possibility of storage in liquid form at low pressures and high temperatures. This study was carried out to investigate how to compensate the drawbacks of using ammonia as the main fuel in a gas turbine by hydrogen and hydroxy-gas enrichment. During the experiments, propane that is standard working fuel of the gas turbine, neat ammonia, as well as a 10 L/min ammonia fuel enriched with 3 L/min, 5 L/min, and 7 L/min hydroxy gas, were utilized. The results show that hydroxy enrichments cause improvements in the performance data as well as emission values due to the absence of any carbon emissions. When the performance outputs are examined, it has been shown that the power values of NH₃ + 3 HHO and NH₃ + 5 HHO fuels are 10.98% and 3.65% lower than propane, whereas NH₃ + 7 HHO fuel produces 4.12% more power, and the desired performance values are reached. It has been also fund that NO_x emissions should be kept under control in addition to the increase in the performance and elimination of the carbon emissions.     

Performance and cost of fuel cells for off-road heavy-duty vehicles

Replacing hydrocarbon-powered off-road vehicles with hydrogen fuel cell-powered off-road vehicles can reduce carbon dioxide and criteria pollutant emissions in the agriculture, construction, and mining industries. Off-road vehicles perform challenging work in harsh environments that complicate deployment of their fuel cell-powered counterparts. Customers and vehicle manufacturers recognize the health and environmental benefits of emissions reductions but are compelled by the total cost of ownership of their vehicles. This study provides a novel technoeconomic comparison of hydrogen fuel cell + battery hybrid powertrains to traditional diesel powertrains for three hallmark off-road vehicles: tractors, wheel loaders, and excavators. Performance metrics include fuel cell engine power, hydrogen consumption rate, hydrogen storage system volume, energy-regenerative drivetrain efficiency, cost of capital, operating and maintenance cost, fuel cost, and fuel storage cost. Results demonstrate that state-of-the-art fuel cell-powered wheel loaders and excavators are currently cost competitive with diesel platforms by total cost of ownership: compact wheel loaders are 19% less expensive, large wheel loaders are equally expensive, mini/compact excavators are 11% more expensive, and standard/full excavators are 9% less expensive. If targeted improvements to cost, performance, and durability of fuel cell stacks and storage systems are achieved, fuel cell systems would be cost competitive for tractors and significantly lower total cost of ownership options for wheel loaders and excavators. This study also elucidates the relationship between performance, cost, and vehicle duty cycle and provides guidance for optimal deployment of fuel cell off-road vehicles.     

Significance of CO2-free hydrogen globally and for Japan using a long-term global energy system analysis

In this paper, the significance of CO₂-free hydrogen is discussed using a long-term global energy system. The energy demand–supply system including CO₂-free hydrogen was assumed, though there are still large uncertainties as to whether a global CO₂-free hydrogen energy system will be deployed. System analysis was conducted using the global and long-term intertemporal optimization energy model GRAPE under severe CO₂ emission constraints. Applied global CO₂ constraints for 2050 were a 50% reduction from 1990 levels. CO₂ constraints accounting for Intended Nationally Determined Contributions (INDCs) in each region were also considered. A variety of energy resources and technologies were considered in this model. Hydrogen can be produced from low-grade coal or natural gas with CO₂ capture and electricity from renewable energy. The hydrogen CIF (cost, insurance, and freight) price for Japan was about 3.2 cents/MJ in 2030. Hydrogen demand technologies considered in this paper are hydrogen-fired power plants, direct combustion, combined heat and power (fuel cells, gas engines, and gas turbines), fuel cell vehicles, and hydrogen internal combustion engine vehicles. The majority of CO₂-free hydrogen was deployed in the transportation sector. CO₂-free hydrogen was utilized in the power sector, where deployment of other zero emission technology has some constraints. From an economic viewpoint, CO₂-free hydrogen can reduce the global energy system cost. From the viewpoint of a localized region, such as Japan, deployment of CO₂-free hydrogen can improve energy security and environmental indicators.     

Impact of hydrogen energy storage on California electric power system: Towards 100% renewable electricity

Decarbonization of the power sector is a key step towards greenhouse gas emissions reduction. Due to the intermittent nature of major renewable sources like wind and solar, storage technologies will be critical in the future power grid to accommodate fluctuating generation. The storage systems will need to decouple supply and demand by shifting electrical energy on many different time scales (hourly, daily, and seasonally). Power-to-Gas can contribute on all of these time scales by producing hydrogen via electrolysis during times of excess electrical generation, and generating power with high-efficiency systems like fuel cells when wind and solar are not sufficiently available. Despite lower immediate round-trip efficiency compared to most battery storage systems, the combination of devices used in Power-to-Gas allows independent scaling of power and energy capacities to enable massive and long duration storage. This study develops and applies a model to simulate the power system balance at very high penetration of renewables. Novelty of the study is the assessment of hydrogen as the primary storage means for balancing energy supply and demand on a large scale: the California power system is analyzed to estimate the needs for electrolyzer and fuel cell systems in 100% renewable scenarios driven by large additions of wind and solar capacities. Results show that the transition requires a massive increase in both generation and storage installations, e.g., a combination of 94 GW of solar PV, 40 GW of wind, and 77 GW of electrolysis systems. A mix of generation technologies appears to reduce the total required capacities with respect to wind-dominated or solar-dominated cases. Hydrogen storage capacity needs are also evaluated and possible alternatives are discussed, including a comparison with battery storage systems.     

Design and set up of a hybrid power system (PV-WT-URFC) for a stand-alone application in Mexico

The Mexican territory has a large potential for renewable energy development, such as geothermal, hydro, biofuels, wind and solar. Thus, a 2.5 kW hybrid power system (solar, wind and hydrogen) was designed and installed to meet the power demand for a stand-alone application at the University of Zacatecas. The hybrid unit integrates three power energy sources –a photovoltaic system (PV), a micro-wind turbine (WT), a prototype of a unitized regenerative fuel cell (URFC) and energy storage devices (batteries)– in addition to their interaction methodology. The main contribution of this work is the URFC integration to a hybrid power system for the production of H₂ (water electrolyzer mode) and energy (fuel cell mode). These three energy technologies were connected in parallel, synchronized to the energy storage system and finally coupled to a power conversion module. To achieve the best performance and energy management, an energy management and control strategy was developed to the properly operation of the power plant. A meteorological station that has wireless sensors for the temperature, the humidity, the solar radiation and the wind speed provides the necessary information (in real time) to the monitor and control software, which computes and executes the short and mid–term decisions about the energy management and the data storage for future analysis.     

Review on key technologies and applications of hydrogen energy storage system

随着国内以风电,太阳能为主的可再生能源快速增长,可再生能源消纳能力不足和并网困难等问题愈发突出,大规模储能系统被证实是解决该问题的有效方法.本文回顾了现有成熟储能系统的不足与限制,分析氢储能的优势特点,构建了电能链和氢产业链融合的氢储能系统,为可再生能源的进一步发展提供良策.随后对氢储能系统三个环节(制氢,储运氢,氢发电)关键技术进行了梳理,对电解槽技术,燃料电池技术和储氢材料中的关键性能进行了比较和评估.在氢储能领域,部分发达国家已经初步形成了从基础研究,应用研究到示范演示的全方位格局,本文对德国和法国的重点示范工程进行了调研,为我国未来发展氢储能的提供参考.     

Heat exchanger design for autothermal reforming of diesel

The increasing electrification of vehicles for passenger and heavy duty transport requires the deployment of efficient, low-emission power sources. Auxiliary Power Units (APUs) based on fuels cells offer an excellent solution, especially for supplying power during idling mode. For urban transport applications, gaseous hydrogen appears to be the best fuel option, whereas long-distance applications are better served by a liquid energy carrier. The autothermal reforming of liquid fuels such as diesel presents a simple and efficient method for producing hydrogen for fuel cell APUs. Heat integration for steam generation and air pre-warming are the key elements to a compact autothermal reformer design. With the aid of intense CFD simulations, a reformer construction was achieved with the high power density of 3.3 kW_th/l. Experimental validation indicates high hydrogen concentrations of between 32 and 36%, depending on diesel quality. In combination with already existing results, the newest autothermal reformer (ATR) generation enables the set-up of a complete APU system, fulfilling the U.S. Department of Energy (DOE) targets for fuel cell-based APUs.