Publications

Clean hydrogen is expected to play a crucial role in the future decarbonized energy mix. This places the gasification of biomass as a critical conversion pathway for hydrogen production owing to its carbon neutrality. However there is limited research on the direction of the body of literature on this subject matter. Utilising the Bibliometrix package R this paper conducts a systematic review and bibliometric analysis of the literature on gasification-derived hydrogen production over the previous three decades. The results show a decade-wise spike in hydrogen research mostly contributed by China the United States and Europe whereas the scientific contribution of Africa on the topic is limited with less than 6% of the continent’s research output on the subject matter sponsored by African institutions. The current trend of the research is geared towards alignment with the Paris Agreement through feedstock diversification to include renewable sources such as biomass and municipal solid waste and decarbonising the gasification process through carbon-capture technologies. This review reveals a gap in the experimental evaluation of heterogenous organic municipal solid waste for hydrogen production through gasification within the African context. The study provides an incentive for policy actors and researchers to advance the green hydrogen economy in Africa.

The production of green hydrogen requires renewable electricity and a supply of sustainable water. Due to global water scarcity using seawater to produce green hydrogen is particularly important in areas where freshwater resources are scarce. This study establishes a system model to simulate and optimize the integrated technology of seawater desalination by membrane distillation and hydrogen production by alkaline water electrolysis. Technical economics is also performed to evaluate the key factors affecting the economic benefits of the coupling system. The results show that an increase in electrolyzer power and energy efficiency will reduce the amount of pure water. An increase in the heat transfer efficiency of the membrane distillation can cause the breaking of water consumption and production equilibrium requiring a higher electrolyzer power to consume the water produced by membrane distillation. The levelized costs of pure water and hydrogen are US$1.28 per tonne and $1.37/kg H2 respectively. The most important factors affecting the production costs of pure water and hydrogen are electrolyzer power and energy efficiency. When the price of hydrogen rises the project’s revenue increases significantly. The integrated system offers excellent energy efficiency compared to conventional desalination and hydrogen production processes and advantages in terms of environmental protection and resource conservation.

Ammonia is a particularly promising hydrogen carrier due to its relatively low cost high energy density its liquid storage and to its production from renewable sources. Thus in recent years great attention is devoted to this fuel for realizing next generation refueling stations according to a carbon-free energy economy. In this paper a distributed onsite refueling station (200 kg/day of hydrogen filling 700-bar HFCEVs (Hybrid Fuel Cell Electric Vehicles) with about 5 kg of hydrogen in 5 min) based on ammonia feeding is studied from the energy and economic point of views. The station is designed with a modular configuration consisting of more sections: i) the hydrogen production section ii) the electric energy supplier section iii) the compression and storage section and the refrigeration/dispenser section. The core of the station is the hydrogen production section that is based on an ammonia cracking reactor and its auxiliaries; the electric energy demand necessary for the station operation (i.e. the hydrogen compression and refrigeration) is satisfied by a PEMFC (Proton-Exchange Membrane Fuel Cell) power module. Energy performance according to the hydrogen daily demand has been evaluated and the estimation of the levelized cost of hydrogen (LCOH) has been carried out in order to establish the cost of the hydrogen at the pump that can assure the feasibility of this novel refueling station.

The increasing global demand for sustainable energy solutions has intensified the need to replace fossil fuels in gas turbines particularly in aviation and power generation where alternatives to gas turbines are currently limited. This review explores the feasibility of utilizing sustainable liquid and gaseous fuels in gas turbines by evaluating their environmental impacts performance characteristics and technical integration potential. The study examines a broad range of alternatives including biofuels hydrogen alcohols ethers synthetic fuels and biogas focusing on their production methods combustion behavior and compatibility with existing turbine technology. Key findings indicate that several bioderived and synthetic fuels can serve as viable drop-in replacements for conventional jet fuels especially under ASTM D7566 standards. Hydrogen and other gaseous alternatives show promise for industrial applications but require significant combustion system adaptations. The study concludes that a transition to sustainable fuels in gas turbines is achievable through coordinated advancements in combustion technology fuel infrastructure and regulatory support thus enabling meaningful reductions in greenhouse gas emissions and advancing global decarbonization efforts.

Hydrogen is a promising fuel to decarbonise aviation. Storage in liquid form is favoured for long-haul aircraft; storage as a high-pressure gas is preferred otherwise. The exergy expended during the compression or liquefaction process is stored as physical exergy in the fuel. Most discussions around hydrogen-fuelled aviation ignore this very significant exergy content. When combusted in an engine the chemical energy of hydrogen can produce around 60 MJ of work per kg. The work that can be extracted from the physical exergy depends strongly on the method used. This paper presents an exergy analysis considering a range of storage conditions operating conditions and work-extraction methods. For reasonable gas-turbine operating conditions upwards of 16 MJ/kg might be extracted from compressed hydrogen (at 700 bar) and 30 MJ/kg from LH2. This additional work representing 25–50 % of the shaft work produced by combustion has been by and large neglected.

This study presents the design and techno-economic comparison of two standalone photovoltaic (PV) systems each supplying a 1 kW critical load with 100% reliability under Cairo’s climatic conditions. These systems are modeled for both the constant and the night load scenarios accounting for the worst-case weather conditions involving 3.5 consecutive cloudy days. The primary comparison focuses on traditional lead-acid battery storage versus green hydrogen storage via electrolysis compression and fuel cell reconversion. Both the configurations are simulated using a Python-based tool that calculates hourly energy balance component sizing and economic performance over a 21-year project lifetime. The results show that the PV/H2 system significantly outperforms the PV/lead-acid battery system in both the cost and the reliability. For the constant load the Levelized Cost of Electricity (LCOE) drops from 0.52 USD/kWh to 0.23 USD/kWh (a 56% reduction) and the payback period is shortened from 16 to 7 years. For the night load the LCOE improves from 0.67 to 0.36 USD/kWh (a 46% reduction). A supplementary cost analysis using lithium-ion batteries was also conducted. While Li-ion improves the economics compared to lead-acid (LCOE of 0.41 USD/kWh for the constant load and 0.49 USD/kWh for the night load) this represents a 21% and a 27% reduction respectively. However the green hydrogen system remains the most cost-effective and scalable storage solution for achieving 100% reliability in critical off-grid applications. These findings highlight the potential of green hydrogen as a sustainable and economically viable energy storage pathway capable of reducing energy costs while ensuring long-term resilience.

Stringent CO2 reduction targets and tightening emission regulations have intensified interest in hydrogen internal combustion engines (H2ICEs) as a clean and robust solution for the heavy-duty (HD) sector. This study experimentally compares port fuel injection (PFI) early low-pressure direct injection (LPDI) and late LPDI strategies on a single-cylinder HD H2ICE under steady-state medium and high loads. The injection timing and fuel pressure are varied to study the overall influences on a single-cylinder heavy-duty H2ICE. PFI and early LPDI deliver high charge homogeneity but reduced volumetric efficiency compared to late LPDI. At medium load all three strategies achieve ~41 % gross indicated thermal efficiency (gITE). Increasing LPDI pressure from 12.8 to 20 bar enhances mixture uniformity cutting BSNOx emissions by up to 75 %. At high load early LPDI reaches 41.7 % gITE with low NOx (0.72 g/kWh) while late LPDI benefits from reduced heat transfer loss and compression work achieving 42.4 % gITE. However late injection also increases BSNOx (9.3 g/kWh) unburnt H2 (435 ppm) and pressure rise rate (19.7 bar/◦CA). These results highlight LPDI’s potential for high efficiency with injection timing and pressure as key levers to balance emissions and performance.

Global climate change caused by geological processes is one of the main causes of the 5 global mass extinctions in geological history. Human industrialization activities have caused serious damage to the ecosystem the greenhouse effect of atmospheric CO2 has intensified and the living environment is facing threats and challenges. Carbon neutrality is the active action and common goal of mankind in the face of the climate change crisis therefore probing into its theoretical and technological connotation scientific and technological innovation system has far-reaching significance and broad prospects. Studies indicate that (1) Carbon neutrality reflects the theoretical connotations of “energy science” and “carbon neutrality science” including technical connotations of carbon emission reduction zero carbon emission negative carbon emission and carbon trading. (2) Carbon neutrality spawns new industries such as carbon industry centering on CO2 capture utilization and storage (CCUS or CO2 capture and storage CCS) and hydrogen industry centering on green hydrogen. “Gray carbon” and “black carbon” are the two application attributes of CO2. “Carbonþ” “Carbon” and “Carbon¼” are three carbon-neutral products and technologies. (3) China faces three major challenges in achieving the goal of carbon neutrality: first energy transition is large in scale and the cycle is short; Second there are many problems in the process of energy transition such as security uncertainties economic utilization and unpredictable disruptive technologies; Third after transition we may face new key techno-logical “bottlenecks” and “broken chain” of key mineral resources. (4) Based on current knowledge to predict the top 10 disruptive technologies and industries in the energy field: underground coal gasification in-situ conversion process of medium and low-mature shale oil CCUS/CCS hydrogen energy and fuel cells bio-photovoltaic power generation space-based solar power generation optical storage smart micro-grid super energy storage controllable nuclear fusion wisdom energy Internet. Five strategic projects will be implemented including energy conservation and efficiency improvement carbon reduction and sequestration scientific and technological innovation emergency reserve and policy support. (5) In the future different types of energy will have different orientations. Coal will play the role of ensuring the national energy strategy “reserve” and “guarantee the bottom line”. Petroleum will play the role of ensuring national energy security “urgent need” and the “cornerstone” of raw materials in people's livelihood. Natural gas will play the role in ensuring national energy “safety” and “best partner” of new energy. New energy will play the role in ensuring the “replacement” and “main force” of the national energy strategy. (6) Carbon neutrality is a major practice of the green industrial revolution carbon reduction energy revolution and ecological technology revolution which will bring new and profound changes to human society the environment and the economy. (7) Carbon neutrality needs to follow the four principles of “disruptive breakthroughs in technology guarantee of energy security realization of economic feasibility and controllable social stability”. We should rely on technological innovation and management changes to ensure the realization of national energy “independence” and carbon neutrality goal and make China's contribution to the construction of a livable earth green development and ecological civilization.

In this paper we analyze the autothermal reforming (ATR) of methane through Gibbs energy minimization and entropy maximization methods to analyze isothermic and adiabatic systems respectively. The software GAMS® 23.9 and the CONOPT3 solver were used to conduct the simulations and thermodynamic analyses in order to determine the equilibrium compositions and equilibrium temperatures of this system. Simulations were performed covering different pressures in the range of 1 to 10 atm temperatures between 873 and 1073 K steam/methane ratio was varied in the range of 1.0/1.0 and 2.0/1.0 and oxygen/methane ratios in the feed stream in the range of 0.5/1.0 to 2.0/1.0. The effect of using pure oxygen or air as oxidizer agent to perform the reaction was also studied. The simulations were carried out in order to maintain the same molar proportions of oxygen as in the simulated cases considering pure oxygen in the reactor feed. The results showed that the formation of hydrogen and synthesis gas increased with temperature average composition of 71.9% and 56.0% using air and O2 respectively. These results are observed at low molar oxygen ratios (O2/CH4 = 0.5) in the feed. Higher pressures reduced the production of hydrogen and synthesis gas produced during ATR of methane. In general reductions on the order of 19.7% using O2 and 14.0% using air were observed. It was also verified that the process has autothermicity in all conditions tested and the use of air in relation to pure oxygen favored the compounds of interest mainly in conditions of higher pressure (10 atm). The mean reductions with increasing temperature in the percentage increase of H2 and syngas using air under 1.5 and 10 atm at the different O2/CH4 ratios were 5.3% 13.8% and 16.5% respectively. In the same order these values with the increase of oxygen were 3.6% 6.4% and 9.1%. The better conditions for the reaction include high temperatures low pressures and low O2/CH4 ratios a region in which there is no swelling in terms of the oxygen source used. In addition with the introduction of air the final temperature of the system was reduced by 5% which can help to reduce the negative impacts of high temperatures in reactors during ATR reactions.

Due to increasing energy demand limited fossil fuels and increasing greenhouse gasses people is in need for alternative energy sources to have a sustainable world. The objective of this study is to look for alternative solutions and design a hybrid energy system to meet any energy needs of a single family house including both utility and transportation. The system is designed and optimized using HOMER software. According to the optimization studies levelized cost of electricity and hydrogen production was found to be 0.685$/kWh and 6.85$/kg respectively and the cost of hydrogen which is half of its market price is very attractive. To project possible future costs in advance sensitivity analysis was carried out and the results show that when the main components’ price decays to the half both costs of energy will be reduced by 26.4%. This implies that further decrease on the components’ cost would bring the cost of energy to the level of energy produced by fossil fuels or even lower. Hydrogen would also be produced with much lower and tempting price. It is important to note that energy used by residential electrical load and fuel cell electric car in this study was generated by sole renewable energies and the system consumes zero fossil fuels thus emitting no greenhouse gasses. The study considering both utility and transportation simultaneously is believed to be the first on a small scale and to attract the interest of everyone.