Applications & Pathways

The popularity of hydrogen has been increasing globally as a promising sustainable energy source. However hydrogen needs to be produced and processed before it can be used in the energy sector. This paper uses total efficiency to evaluate the lifecycle of hydrogen-driven power generation. Total efficiency introduces the energy requirement of fuel preparation in conventional efficiency and is a reliable method to fairly compare different energy sources. Two case studies in Spain and Germany with nine scenarios each are defined to study different hydrogen-preparation routes. The scenarios include the main colors of hydrogen production (grey turquoise yellow and green) and different combinations of processing and transportation choices. In most cases the highest energy penalty in the overall preparation process of the fuel is linked to the production step. A large difference is found between fossil fuel-based hydrogen and green hydrogen derived from excess renewable energy with fossil fuel-based hydrogen resulting in significantly lower total efficiencies compared to green hydrogen. The use of natural gas as the primary source to generate hydrogen is found to be a critical factor affecting total efficiency particularly in cases where the gas must be transported from far away. This shows the value of using excess renewable energy in the production of hydrogen instead of grid power. Even in the most efficient scenario of green hydrogen studied total efficiency was found to be 7 % lower than the respective conventional efficiency that does not account for hydrogen generation. These results emphasize the importance of considering the impact of fuel preparation stages in comparative thermodynamic analyses and evaluations.

To support the energy transition in the area of defence we developed a tool and conducted a feasibility study to transform a military site from being a conventional energy consumer to becoming an energy-positive hub (or prosumer). Coupling a green energy source (e.g. photovoltaic wind) with fuel cells and hydrogen storage satisfied the dynamic energy consumption and dynamic hydrogen demand for both the civilian and military mobility sectors. To make the military sector independent of its civilian counterpart a military site was connected to a renewable energy hub. This made it possible to develop a stand-alone green-energy system transform the military site into a positive energy hub and achieve autonomous energy operation for several days or weeks. An environmental and economic assessment was conducted to determine the carbon footprint and the economic viability. The combined installed capacity of the solar power plant and the wind turbine was 2.5 times the combined peak consumption with about 19% of the total electricity and 7% of the hydrogen produced still available to external consumers.

With the development of hydrogen energy containerized hydrogen fuel cell systems are being used in distributed energy-supply systems. Hydrogen pipelines and electronic equipment of fuel cell containers can trigger hydrogen-explosion accidents. In the present study Computational Fluid Dynamics (CFD) software was used to calculate the affected areas of hydrogen fuel cell container-explosion accidents with and without protective walls. The protective effects were studied for protective walls at various distances and heights. The results show that strategically placing protective walls can effectively block the propagation of shock waves and flames. However the protective wall has a limited effect on the reduction of overpressure and temperature behind the wall when the protective wall is insufficiently high. Reflected explosion shock waves and flames will cause damage to the area inside the wall when the protective wall is too close to the container. In this study a protective wall that is 5 m away from the container and 3 m high can effectively protect the area behind the wall and prevent damage to the container due to the reflection of shock waves and flame. This paper presents a suitable protective wall setting scheme for hydrogen fuel cell containers.

This article describes the creation of a program that would be useful for calculating mathematical models in order to estimate the weight of aircraft components. Using several parameters it can calculate other parameters of civil transport aircraft powered by batteries or fuel cells. The main goals of this research were to add the missing dimensions and parameters to the aircraft database create a simple but effective program for creating mathematical models and use this program to find technological barriers to battery or hydrogen fuel-cell-powered aircraft concepts. The article introduces the reader to the problem of calculating OEW (operating empty weight) using Breguet– Leduc equations. A calculation model was created for OEW calculation. The result of this work is the verification of a mathematical model for battery-powered electric aircraft of the CS-23 (European Aviation Safety Agency Certification Specification for Normal Utility Aerobatic and Commuter Category Aeroplanes) category by comparing the program’s outputs with real aircraft. Subsequently the results of mathematical models are shown in graphs that specify the space of possible concepts of aircraft powered by batteries or fuel cells sorted by the number of passengers and the range of the aircraft delimited by two or three criteria respectively.

This paper investigates the performance of hydrogen-fueled spark-ignited single-cylinder Cooperative Fuel Research using experimental and numerical approaches. This study examines the effect of the air–fuel ratio on engine performance emissions and knock behaviour across different compression ratios. The results indicate that λ significantly affects both engine performance and emissions with a λ value of 2 yielding the highest efficiency and lowest emissions for all the tested compression ratios. Combustion analysis reveals normal combustion at λ ≥ 2 while knocking combustion occurs at λ < 2 irrespective of the tested compression ratios. The Livenwood–Wu integral approach was evaluated to assess the likelihood of end-gas autoignition based on fuel reactivity demonstrating that both normal and knocking combustion possibilities are consistent with experimental investigations. Combustion analysis at the ignition timing for maximum brake torque conditions demonstrates knock-free stable combustion up to λ = 3 with increased end-gas autoignition at lower λ values. To achieve knock-free combustion at those low λs the spark timings are significantly retarded to after top dead center crank angle position. Engine-out NOx emissions consistently increase in trend with a decrease in the air–fuel ratio of up to λ = 3 after which a distinct variation in NOx is observed with an increase in the compression ratio.

Sustainability is one of the main challenges the aviation industry is currently facing. In a global context of energy transition towards cleaner and renewable sources the sector is developing technologies to fly more efficiently and mitigate its environmental impact. Innovative propulsion alternatives such as biofuels electric aircraft and hydrogen engines are already a reality or are close to becoming so. To assess their feasibility a study is conducted on specific routes and aircraft across different flight ranges. The analysis focuses on the Canary Islands an outermost region of the EU with high mobility and no comparable alternative means of transport. For three routes flight profiles are analyzed obtaining the fuel consumption and emissions generated by the conventional propulsion and later applying the sustainable alternatives. The results indicate optimistic perspectives with reductions in environmental impact ranging between 40% and 75% compared to the present.

The impact of ship emission reductions can be maximised by considering climate health and environmental effects simultaneously and using solutions fitting into existing marine engines and infrastructure. Several options available enable selecting optimum solutions for different ships routes and regions. Carbon-neutral fuels including low-carbon and carbon-negative fuels from biogenic or non-biogenic origin (biomass waste renewable hydrogen) could resemble current marine fuels (diesel-type methane and methanol). The carbon-neutrality of fuels depends on their Well-to-Wake (WtW) emissions of greenhouse gases (GHG) including carbon dioxide (CO2) methane (CH4) and nitrous oxide emissions (N2O). Additionally non-gaseous black carbon (BC) emissions have high global warming potential (GWP). Exhaust emissions which are harmful to health or the environment need to be equally removed using emission control achieved by fuel engine or exhaust aftertreatment technologies. Harmful emission species include nitrogen oxides (NOx) sulphur oxides (SOx) ammonia (NH3) formaldehyde particle mass (PM) and number emissions (PN). Particles may carry polyaromatic hydrocarbons (PAHs) and heavy metals which cause serious adverse health issues. Carbon-neutral fuels are typically sulphur-free enabling negligible SOx emissions and efficient exhaust aftertreatment technologies such as particle filtration. The combinations of carbon-neutral drop-in fuels and efficient emission control technologies would enable (near-)zero-emission shipping and these could be adaptable in the short- to mid-term. Substantial savings in external costs on society caused by ship emissions give arguments for regulations policies and investments needed to support this development.

Ensuring the energy transition in order to decrease CO2 and volatile organic compounds emissions and improve the efficiency of energy processes requires the development of advanced materials and technologies for the electrical energy sector. The article reviews superconducting materials functional nanomaterials used in the power industry mainly due to their magnetic electrical optical and dielectric properties and the thin layers of amorphous carbon nitride which properties make them an important material from the point of view of environmental protection optoelectronic photovoltaic and energy storage. The superconductivity-based technologies material processing and thermal and nonthermal plasma generation have been reviewed as technologies that can be a solution to chosen problems in the electrical energy sector and environment. The study explains directly both—the basics and application potential of low and high-temperature superconductors as well as peculiarities of the related manufacturing technologies for Roebel cables 1G and 2G HTS tapes and superconductor coil systems. Among the superconducting materials particular attention was paid to the magnesium di-boride MgB2 and its potential applications in the power industry. The benefits of the use of carbon films with amorphous structures in electronics sensing technologies solar cells FETs and memory devices were discussed. The article provides the information about most interesting from the R&D point of view groups of materials for PV applications. It summarises the advantages and disadvantages of their use regarding commercial requirements such as efficiency lifetime light absorption impact on the environment costs of production and weather dependency. Silicon processing inkjet printing vacuum deposition and evaporation technologies that allow obtaining improved and strengthened materials for solar cell manufacturing are also described. In the case of the widely developed plasma generation field waste-to-hydrogen technology including both thermal and non-thermal plasma techniques has been discussed. The review aims to draw attention to the problems faced by the modern power industry and to encourage research in this area because many of these problems can only be solved within the framework of interdisciplinary and international cooperation.

In an effort to encourage industries to switch from fossil fuels to renewable energy resources for supplying their energy demands the exergy and financial aspects of a thermodynamic energy generation system were studied. The suggested system was modeled by MATLAB commercial software to assess the decision-making parameters affecting power generation cooling capacity and to produce hydrogen. The objective functions of this study were exergy efficiency and cost rate while the temperatures at the inlet of the turbine and the evaporator irradiated solar energy mass flow rate and surface area of the collector were the decision-making variables. The model was optimized via MOPSO and its results were compared with two widely utilized algorithms namely NSGA-II and SPEA-II. The comparison results indicated that MOPSO surpassed other two optimization algorithm resulting in exergy efficiency and cost rate of 2.11 % and 21.14 $/h respectively. According to this method the optimum generated power was equal to 21.01 kW. Eventually this system was utilized and evaluated in the city of Semnan Iran. The performance results of the system in Semnan showed that the annual power output taking into account the changes in radiation and ambient temperature is between 316667.4 and 428080.5 kW. Also the amount of hydrogen production is between 1503.66 and 1534.997 kg.

A clean energy revolution is occurring across the world. As iron and steelmaking have a tremendous impact on the amount of CO2 emissions there is an increasing attraction towards improving the green footprint of iron and steel production. Among reducing agents hydrogen has shown a great potential to be replaced with fossil fuels and to decarbonize the steelmaking processes. Although hydrogen is in great supply on earth extracting pure H2 from its compound is costly. Therefore it is crucial to calculate the partial pressure of H2 with the aid of reduction reaction kinetics to limit the costs. This review summarizes the studies of critical parameters to determine the kinetics of reduction. The variables considered were temperature iron ore type (magnetite hematite goethite) H2/CO ratio porosity flow rate the concentration of diluent (He Ar N2 ) gas utility annealing before reduction and pressure. In fact increasing temperature H2/CO ratio hydrogen flow rate and hematite percentage in feed leads to a higher reduction rate. In addition the controlling kinetics models and the impact of the mentioned parameters on them investigated and compared concluding chemical reaction at the interfaces and diffusion of hydrogen through the iron oxide particle are the most common kinetics controlling models.