Applications & Pathways

The rapid expansion of renewable energies has the potential to decarbonize the electricity supply. This is more challenging in difficult-to-electrify sectors. The use of hydrogen provides a massive potential for this issue. However expanding hydrogen production increases electricity demand while providing additional flexibility to the electricity market. This paper mainly aims to analyze the economic effects of this sector coupling between the European electricity and national hydrogen markets. The developed energy market model jointly considers both markets to reach an overall welfare optimum. A novel modeling approach allows the interaction of these markets without the need for several iterative optimization runs. This allows for a detailed analysis of various market participants’ changes in consumer and producer surpluses. The optimization is conducted in 13 connected Central European countries to account for various power plant fleets generation mixes and electricity prices. Results show an overall welfare increase of EUR 4 to 28 billion in 2030 and an EUR 5 to 158 billion increase in 2040. However there is a surplus shift from consumers to producers. The consumer surplus is reduced by up to EUR 44 billion in 2030 and EUR 60 billion while producers benefit to achieve the overall welfare benefits. The reduction of consumer surplus changes if significant price peaks occur. Fuel cell applications can avoid these price peaks resulting in a surplus shift from thermal power plants to consumers. Hence consumer surplus can increase by up to EUR 146 billion in the respective 2040 scenarios. Pink hydrogen accounts for a sizable portion of total hydrogen production up to 58 percent in 2030 and up to 30 percent in 2040. As a result nuclear power plants that are nearly entirely allocated in France stand to benefit greatly from this sector coupling. Additional efforts could be made to address the link between hydrogen and natural gas prices. Furthermore the potential for cross-border hydrogen trade and the implementation of national legal and regulatory frameworks could be assessed.

This paper provides a comprehensive overview of the physical properties and applications of natural gas (NG) and hydrogen as fuels in internal combustion (IC) engines. The paper also meticulously examines the use of both NG and hydrogen as a fuel in vehicles their production physical characteristics and combustion properties. It reviews the current experimental studies in the literature and investigates the results of using both fuels. It further covers the challenges associated with injectors needle valves lubrication spark plugs and safety requirements for both fuels. Finally the challenges related to the storage production and safety of both fuels are also discussed. The literature review reveals that NG in spark ignition (SI) engines has a clear and direct positive impact on fuel economy and certain emissions notably reducing CO2 and non-methane hydrocarbons. However its effect on other emissions such as unburnt hydrocarbons (UHC) nitrogen oxides (NOx) and carbon monoxide (CO) is less clear. NG which is primarily methane has a lower carbon-to-hydrogen ratio than diesel fuel resulting in lower CO2 emissions per unit of energy released. In contrast hydrogen is particularly well-suited for use in gasoline engines due to its high self-ignition temperature. While increasing the hydrogen content of NG engines reduces torque and power output higher hydrogen input results in reduced fuel consumption and the mitigation of toxic exhaust emissions. Due to its high ignition temperature hydrogen is not inherently suitable for direct use in diesel engines necessitating the exploration of alternative methods for hydrogen introduction into the cylinder. The literature review suggests that hydrogen in diesel engines has shown a reduction in specific exhaust emissions and fuel consumption and an increase in NOx emissions. Overall the paper provides a valuable and informative overview of the challenges and opportunities associated with using hydrogen and NG as fuels in IC engines. It highlights the need for further research and development to address the remaining challenges such as the development of more efficient combustion chambers and the reduction of NOx emissions.

Direct gaseous fuel injection in internal combustion engines is a potential strategy for improving in-cylinder combustion processes and performance while reducing emissions and increasing hydrogen energy share (HES). Through use of numerical modelling the current study explores combustion in a compression ignition engine utilising a late compression/early power stroke direct gaseous hydrogen injection ignited by a diesel pilot at up to 99% HES. The combustion process of hydrogen in this type of engine is mapped out and compared to that of the same engine using methane direct injection. Four distinct phases of combustion are found which differ from that of pure diesel operation. Interaction of the injected gas jet with the chamber walls is found to have a considerable impact on performance and emission characteristics and is a factor which needs to be explored in greater detail in future studies. Considerable performance increase and carbon-based emission reductions are identified at up to 99% HES at high load but low load performance greatly deteriorated when 95% HES was exceeded due to a much reduced diesel pilot struggling to ignite the main hydrogen injection.

The majority of rail vehicles worldwide use diesel as a primary fuel source. Diesel engine carbon emissions harm the environment and human health. Although railway electrification can reduce emissions it is not always the most economical option especially on routes with low vehicle demand. As a result interest in hydrogen-powered trains as a way to reduce greenhouse gas (GHG) emissions has steadily grown in recent years. In this paper we discuss advancements made in hydrogen-powered freight and commuter trains as well as the technology used in some aspects of hydrogen-powered vehicles. It was observed that hydrogen-powered trains are already in use in Europe and Asia unlike most developing countries in Africa. Commuter trains have received most of the research and development (R&D) attention but interest in hydrogen-powered freight trains has recently picked up momentum. Despite the availability and use of gray and blue hydrogen green hydrogen is still the preferred fuel for decarbonizing the rail transport sector.

The use of hydrogen fuel produced from renewable energy sources is an effective way to reduce well-to-wheel CO2 emissions from automobiles. In this study the performance of a hydrogen-powered series hybrid vehicle was compared with that of other powertrains such as gasoline-powered hybrid fuel cell and electric vehicles in a simulation that could estimate CO2 emissions under real-world driving conditions. The average fuel consumption of the hydrogenpowered series hybrid vehicle exceeded that of the gasoline-powered series hybrid vehicle under all conditions and was better than that of the fuel cell vehicle under urban and winding conditions with frequent acceleration and deceleration. The driving range was longer than that of the batterypowered vehicle but approximately 60% of that of the gasoline-powered series hybrid. Regarding the life-cycle assessment of CO2 emissions fuel cell and electric vehicles emitted more CO2 during the manufacturing process. Regarding fuel production CO2 emissions from hydrogen and electric vehicles depend on the energy source. However in the future this problem can be solved by using carbon-free energy sources for fuel production. Therefore hydrogen-powered series hybrid vehicles show a high potential to be environmentally friendly alternative fuel vehicles.

Interest in more sustainable energy sources has increased rapidly in the maritime industry and ambitious goals have been set for decreasing ship emissions. All industry stakeholders have reacted to this with different approaches including the optimisation of ship power plants the development of new energy-improving sub-systems for existing solutions or the design of entirely novel power plant concepts employing alternative fuels. This paper assesses the feasibility of different ship energy sources for an icebreaking Arctic research ship. To that end possible energy sources are assessed based on fuel infrastructure availability and operational endurance criteria in the operational area of interest. Promising alternatives are analysed further using the evidence-based Strengths Weaknesses Opportunities and Threats (SWOT) method. Then a more thorough investigation with respect to the required fuel tank space life cycle cost and CO2 emissions is implemented. The results demonstrate that marine diesel oil (MDO) is currently still the most convenient solution due to the space operational range and endurance limitations although it is possible to use liquefied natural gas (LNG) and methanol if the ship’s arrangement is radically redesigned which will also lead to reduced emissions and life cycle costs. The use of liquefied hydrogen as the only energy solution for the considered vessel was excluded from the potential options due to low volumetric energy density and high life cycle and capital costs. Even if it is used with MDO for the investigated ship the reduction in CO2 emissions will not be as significant as for LNG and methanol at a much higher capital and lifecycle cost. The advantage of the proposed approach is that unrealistic alternatives are eliminated in a systematic manner before proceeding to detailed techno-economic analysis facilitating the decision-making and investigation of various options in a more holistic manner.

Compression ignition engines will still be predominant in the naval sector: their high efficiency high torque and heavy weight perfectly suit the demands and architecture of ships. Nevertheless recent emission legislations impose limitations to the pollutant emissions levels in this sector as well. In addition to post-treatment systems it is necessary to reduce some pollutant species and therefore the study of combustion strategies and new fuels can represent valid paths for limiting environmental harmful emissions such as CO2 . The use of methane in dual fuel mode has already been implemented on existent vessels but the progressive decarbonization will lead to the utilization of carbon-neutral or carbon-free fuels such as in the last case hydrogen. Thanks to its high reactivity nature it can be helpful in the reduction of exhaust CH4 . On the contrary together with the high temperatures achieved by its oxidation hydrogen could cause uncontrolled ignition of the premixed charge and high emissions of NOx. As a matter of fact a source of ignition is still necessary to have better control on the whole combustion development. To this end an optimal and specific injection strategy can help to overcome all the before-mentioned issues. In this study three-dimensional numerical simulations have been performed with the ANSYS Forte® software (version 19.2) in an 8.8 L dual fuel engine cylinder supplied with methane hydrogen or hydrogen–methane blends with reference to experimental tests from the literature. A new kinetic mechanism has been used for the description of diesel fuel surrogate oxidation with a set of reactions specifically addressed for the low temperatures together with the GRIMECH 3.0 for CH4 and H2 . This kinetics scheme allowed for the adequate reproduction of the ignition timing for the various mixtures used. Preliminary calculations with a one-dimensional commercial code were performed to retrieve the initial conditions of CFD calculations in the cylinder. The used approach demonstrated to be quite a reliable tool to predict the performance of a marine engine working under dual fuel mode with hydrogen-based blends at medium load. As a result the system modelling shows that using hydrogen as fuel in the engine can achieve the same performance as diesel/natural gas but when hydrogen totally replaces methane CO2 is decreased up to 54% at the expense of the increase of about 76% of NOx emissions.

To cope with the growing penetration rate of renewable energy and to enhance the absorption capacity of wind power this paper investigates the applications of an Integrated Energy System (IES) Hydrogen Compressed Natural Gas (HCNG) and power-to-hydrogen (P2H) devices within the IES. It employs power-to-gas and gas blending with hydrogen to construct an efficient electricity–gas–electricity energy flow loop establishing a Natural Gas–Electricity Coupling System (NGECS) model. On this basis a coordinated scheduling method for gas–electric coupling systems using gas blended with hydrogen is proposed. A carbon trading mechanism is introduced to constrain carbon emissions further reducing the system’s carbon footprint. Multiple scenarios are set up for a comparative analysis in order to validate the effectiveness of the proposed model. This study also analyzes the impact of different hydrogen blending ratios and methods on the low-carbon and economic performance of IES.

Reducing industrial emissions to achieve net-zero targets by the middle of the century will require profound and sustained changes to how energy intensive industries operate. Preliminary activity is now underway with governments of several developed economies starting to implement policy and providing funding to support the deployment of low carbon infrastructure into high emitting industrial clusters. While clusters appear to offer the economies of scale and institutional capacity needed to kick-start the industrial transition to date there has been little systematic assessment of the factors that may influence the success of these initiatives. Drawing from academic and grey literature this paper presents a rapid evidence assessment of the approaches being used to drive the development of low carbon industrial clusters internationally. Many projects are still at the scoping stage but it is apparent that current initiatives focus on the deployment of carbon capture technologies alongside hydrogen as a future secondary revenue stream. This model of decarbonisation funnels investment into large coastal clusters with access to low carbon electricity and tends to obscure questions about the integration of these technologies with other decarbonisation interventions such as material efficiency and electrification. The technology focus also omits the importance that a favourable location and shared history and culture appears to have played in helping progress the most advanced initiatives; factors that cannot be easily replicated elsewhere. If clusters are to kick-start the low-carbon industrial transition then greater attention is needed to the social and political dimensions of this process and to a broader range of decarbonisation interventions and cluster types than represented by current projects.

Investing in green hydrogen systems has become a global objective to achieve the net-zero emission goal. Therefore it is seen as the primary force behind efforts to restructure the world’s energy lessen our reliance on gas attain carbon neutrality and combat climate change. This paper proposes a power management for a net zero emission PV microgrid-based decentralized green hydrogen system. The hybrid microgrid combines a fuel cell battery PV electrolyzer and compressed hydrogen storage (CHSU) unit aimed at power sharing between the total components of the islanded DC microgrid and minimizing the equivalent hydrogen consumption (EHC) by the fuel cell and the battery. In order to minimize the EHC and maintain the battery SOC an optimization-based approach known as the Equivalent Consumption Minimization Strategy (ECMS) is used. A rulebased management is used to manage the power consumed by the electrolyzer and the CHSU by the PV system in case of excess power. The battery is controlled by an inverse droop control to regulate the dc bus voltage and the output power of the PV system is maximized by the fuzzy logic controller-based MPPT. As the hybrid microgrid works in the islanded mode a two-level hierarchical control is applied in order to generate the voltage and the frequency references. The suggested energy management approach establishes the operating point for each system component in order to enhance the system’s efficiency. It allows the hybrid system to use less hydrogen while managing energy more efficiently.