Applications & Pathways

This paper provides a comprehensive review and critical analysis of the latest research results in addition to an overview of the future challenges and opportunities regarding the use of hydrogen to power internal combustion engines (ICEs). The experiences and opinions of various international research centers on the technical possibilities of using hydrogen as a fuel in ICE are summarized. The advantages and disadvantages of the use of hydrogen as a solution are described. Attention is drawn to the specific physical chemical and operational properties of hydrogen for ICEs. A critical review of hydrogen combustion concepts is provided drawing on previous research results and experiences described in a number of research papers. Much space is devoted to discussing the challenges and opportunities associated with port and direct hydrogen injection technology. A comparison of different fuel injection and ignition strategies and the benefits of using the synergies of selected solutions are presented. Pointing to the previous experiences of various research centers the hazards related to incorrect hydrogen combustion such as early pre‐ignition late pre‐ignition knocking combustion and backfire are described. Attention is focused on the fundamental importance of air ratio optimization from the point of view of combustion quality NOx emissions engine efficiency and performance. Exhaust gas scrubbing to meet future emission regulations for hydrogen powered internal combustion engines is another issue that is considered. The article also discusses the modifications required to adapt existing engines to run on hydrogen. Referring to still‐unsolved problems the reliability challenges faced by fuel injection systems in particular are presented. An analysis of more than 150 articles shows that hydrogen is a suitable alternative fuel for spark‐ignition engines. It will significantly improve their performance and greatly reduce emissions to a fraction of their current level. However its use also has some drawbacks the most significant of which are its high NOx emissions and low power output and problems in terms of the durability and reliability of hydrogen‐fueled engines.

As the use of fossil fuels becomes more and more restricted there is a need for alternative fuels also at sea. For short sea distance travel purposes batteries may be a solution. However for longer distances when there is no possibility of recharging at sea batteries do not have sufficient capacity yet. Several projects have demonstrated the use of compressed hydrogen (CH₂) as a fuel for road transport. The experience with hydrogen as a maritime fuel is very limited. In this paper the similarities and differences between liquefied hydrogen (LH₂) and liquefied natural gas (LNG) as a maritime fuel will be discussed based on literature data of their properties and our system knowledge. The advantages and disadvantages of the two fuels will be examined with respect to use as a maritime fuel. Our objective is to discuss if and how hydrogen could replace fossil fuels on long distance sea voyages. Due to the low temperature of LH₂ and wide flammability range in air these systems have more challenges related to storage and processing onboard than LNG. These factors result in higher investment costs. All this may also imply challenges for the LH₂ supply chain.

It is now well established that electrochemical systems can optimally perform only within a narrow range of temperature. Exposure to temperatures outside this range adversely affects the performance and lifetime of these systems. As a result thermal management is an essential consideration during the design and operation of electrochemical equipment and can heavily influence the success of electrochemical energy technologies. Recently significant attempts have been placed on the maturity of cooling technologies for electrochemical devices. Nonetheless the existing reviews on the subject have been primarily focused on battery cooling. Conversely heat transfer in other electrochemical systems commonly used for energy conversion and storage has not been subjected to critical reviews. To address this issue the current study gives an overview of the progress and challenges on the thermal management of different electrochemical energy devices including fuel cells electrolysers and supercapacitors. The physicochemical mechanisms of heat generation in these electrochemical devices are discussed in-depth. Physics of the heat transfer techniques currently employed for temperature control are then exposed and some directions for future studies are provided.

Using electricity for heating can contribute to decarbonization and provide flexibility to integrate variable renewable energy. We analyze the case of electric storage heaters in German 2030 scenarios with an open-source electricity sector model. We find that flexible electric heaters generally increase the use of generation technologies with low variable costs which are not necessarily renewables. Yet making customary night-time storage heaters temporally more flexible offers only moderate benefits because renewable availability during daytime is limited in the heating season. Respective investment costs accordingly have to be very low in order to realize total system cost benefits. As storage heaters feature only short-term heat storage they also cannot reconcile the seasonal mismatch of heat demand in winter and high renewable availability in summer. Future research should evaluate the benefits of longer-term heat storage.

The percentage of the population in urban areas has increased by ten points from 2000 (46%) to 2020 (56%); it is expected to reach up to 70% by 2050. This undoubtedly will encourage society to use alternative transports. On the other hand the widespread fear of pandemics seems to be here to stay and it is causing most people to leave public transport to use private cars and a few have chosen unipersonal electric vehicles. As a consequence the decision of using private cars negatively affects the air quality and consequently urban population health. This paper aims to demonstrate a sustainable solution for urban mobility based on a hydrogen powered unipersonal electric vehicle which as shown provides great advantages over the conventional battery powered unipersonal electric vehicle. To show this the authors have developed both vehicles in comparable versions using the same platform and ensuring that the total weight of the unipersonal electric vehicle was the same in both cases. They have been subjected to experimental tests that support the features of the hydrogen-based configuration versus the battery-based one including higher specific energy more autonomy and shorter recharge time.

In recent years the frequency of power demand imbalance and negative price phenomenon has risen due to the rapid expansion of renewable energy sources (RES). Because of this a means to reduce the curtailment of RES by utilizing surplus energy is essential. This paper focuses on reducing the curtailment of wind turbines (WT) with high output intermittency and minimizing the investment cost of IES via an integrated energy system (IES). The IES operation seeks to improve the acceptability and efficiency of the RES as it supports the integration of various energies mix such as electricity heat hydrogen. This paper proposes an optimal facility combination set (FCS) of IES that satisfies the requirements of ISO and IPP using Multi-Objective Optimization Programming (MOP). The case study is based on a wind farm in South Korea set in Aewol-eup Jeju-Island. The case study results provide the best configuration of the IES energy mix with the best economic value and efficiency while satisfying ISO and IPP perspectives.

The use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality. However due to its physical characteristics storage is still a challenge. There is an innovative way presented in this study to store hydrogen in conventional vehicles propelled by spark-ignition reciprocating engines and fuel cells using hydrogen as fuel; the storage of hydrogen will be at high pressure within small spheres randomly packed in a tank like the conventional tank of fuel used nowadays in current vehicles. Therefore the main purpose of the present study is to assess the performance of this storage system and compare it to others already applied by car manufacturers in their cars. In order to evaluate the performance of this storage system some parameters were taken into account: The energy stored by volume and stored by weight hydrogen leakage and compliance with current standards. This system is safer than conventional storage systems since hydrogen is stored inside small spheres containing small amounts of hydrogen. Besides its gravimetric energy density (GED) is threefold and the volumetric energy density (VED) is about half when compared with homologous values for conventional systems and both exceed the targets set by the U.S. Department of Energy. Regarding the leakage of hydrogen it complies with the European Standards provided a suitable choice of materials and dimensions is made.

Delft University of Technology under its ‘‘Green Village” programme has an initiative to build a power plant (car parking lot) based on the fuel cells used in vehicles for motive power. It is a trigeneration system capable of producing electricity heat and hydrogen. It comprises three main zones: a hydrogen production zone a parking zone and a pump station zone. This study focuses mainly on the hydrogen production zone which assesses four different system designs in two different operation modes of the facility: Car as Power Plant (CaPP) mode corresponding to the open period of the facility which uses fuel cell electric vehicles (FCEVs) as energy and water producers while parked; and Pump mode corresponding to the closed period which compresses the hydrogen and pumps to the vehicle’s fuel tank. These system designs differ by the reforming technology: the existing catalytic reformer (CR) and a solid oxide fuel cell operating as reformer (SOFCR); and the option of integrating a carbon capture and storage (CCS). Results reveal that the SOFCR unit significantly reduces the exergy destruction resulting in an improvement of efficiency over 20% in SOFCR-based system designs compared to CR-based system designs in both operation modes. It also mitigates the reduction in system efficiency by integration of a CCS unit achieving a value of 2% whereas in CR-based systems is 7–8%. The SOFCR-based system running in Pump mode achieves a trigeneration efficiency of 60%.

Automotive proton-exchange membrane fuel cells (PEMFCs) have finally reached a state of technological readiness where several major automotive companies are commercially leasing and selling fuel cell electric vehicles including Toyota Honda and Hyundai. These now claim vehicle speed and acceleration refueling time driving range and durability that rival conventional internal combustion engines and in most cases outperform battery electric vehicles. The residual challenges and areas of improvement which remain for PEMFCs are performance at high current density durability and cost. These are expected to be resolved over the coming decade while hydrogen infrastructure needs to become widely available. Here we briefly discuss the status of automotive PEMFCs misconceptions about the barriers that platinum usage creates and the remaining hurdles for the technology to become broadly accepted and implemented.

The information in this report covers the period January 2019 – December 2019. The technology and market module of the FCHO presents a range of statistical data as an indicator of the health of the sector and the progress in market development over time. This includes statistical information on the size of the global fuel cell market including number and capacity of fuel cell systems shipped in a calendar year. For this first edition data to the end of 2019 is presented where possible alongside analysis of key sector developments. Fuel cell system shipments for each calendar year are presented both as numbers of units and total system megawatts. The data are further divided and subdivided by: • Application: Total system shipments are divided into Transport Stationary and Portable applications • Fuel cell type: Numbers are provided for each of the different fuel cell chemistry types • Region of integration: Region where the final manufacturer – usually the system integrator – integrates the fuel cell into the final product • Region of deployment: Region where the final product was shipped to for deployment The data is sourced directly from industry players as well as other relevant sources including press releases associations and other industry bodies.