Publications

An integrated renewable system that utilizes solid waste-based biogas is important steps towards the sustainable energy solutions to rural off-grid communities in Bangladesh. In this study a hybrid energy system consisting of photovoltaic modules wind turbines biogas generators fuel cells and electrolyzer-hydrogen tank-based energy storage is optimized using non-dominated sorting genetic algorithm (NSGA-II). The hybrid system is optimized based on the cost of energy and human health damage as objective functions and a fuzzy decision-making technique is employed to determine the optimal solution to the multi-objective approach. Additionally several economic ecological and social indicators are also investigated while meeting a certain load reliability. An energy management strategy has been developed in the MATALB environment to satisfy the community load and the battery-driven electric vehicle load. Results from this comprehensive analysis suggest that the optimal configuration of PV/WT/FC/BG has an energy cost of 0.1634 $/kWh and an ecosystem damage of 0.00098 species.year. The human health damage and the human development index of the optimized system are 0.1732 DALYs and 0.696 DALYs respectively. Additionally the proposed system has a lifecycle emission of 123730 kg CO2-eq/year carbon emission penalties of $1856/year a job creation potential of 30 jobs/MW over the 25 years of project lifetime. The hybrid system oversees solid waste management solutions and provides the community with sustainable energy and vehicle recharge.

The weather-dependent nature of renewable energy production has led to periodic overproduction making hydrogen production a practical solution for storing excess energy. In addition to conventional storage methods such as physical tanks or chemical bonding using the existing natural gas network as a storage medium has also proven to be effective. Households can play a role in this process as well. The purpose of these experiments is to evaluate the parameters of a household heating device currently in use but not initially designed for hydrogen operation. The appliance used in the tests has a closed combustion chamber with a natural draft induced by a density difference which is a common type. The tests were conducted at nominal load with a mix of 0–40 V/V% hydrogen and natural gas; no flashbacks or other issues occurred. As the hydrogen ratio increased from 0 to 40 V/V% the input heat decreased from 3.9 kW to 3.4 kW. The NOx concentration in the flue gas dropped from 26.2 ppm to 14.2 ppm and the CO2 content decreased from 4.5 V/V% to 3.4 V/V%. However the CO con centration slightly increased from 40.0 ppm to 44.1 ppm. Despite these changes efficiency remained stable fluctuating between 86.9% and 87.0%. The internal flame cone height was 3.27 mm when using natural gas but reduced sharply to just 0.38 mm when using 62 V/V% hydrogen. In addition to the fact that the article examines a group of devices that has been rarely investigated but is also widely distributed it also provides valuable experience for other experiments since the experiments were carried out with a higher hydrogen ratio compared to previous works.

Hydrogen storage technologies are key enablers for the development of low-emission sustainable energy supply chains primarily due to the versatility of hydrogen as a clean energy carrier. Hydrogen can be utilized in both stationary and mobile power applications and as a lowenvironmental-impact energy source for various industrial sectors provided it is produced from renewable resources. However efficient hydrogen storage remains a significant technical challenge. Conventional storage methods such as compressed and liquefied hydrogen suffer from energy losses and limited gravimetric and volumetric energy densities highlighting the need for innovative storage solutions. One promising approach is hydrogen storage in metal hydrides which offers advantages such as high storage capacities and flexibility in the temperature and pressure conditions required for hydrogen uptake and release depending on the chosen material. However these systems necessitate the careful management of the heat generated and absorbed during hydrogen absorption and desorption processes. Thermal energy storage (TES) systems provide a means to enhance the energy efficiency and cost-effectiveness of metal hydride-based storage by effectively coupling thermal management with hydrogen storage processes. This review introduces metal hydride materials for hydrogen storage focusing on their thermophysical thermodynamic and kinetic properties. Additionally it explores TES materials including sensible latent and thermochemical energy storage options with emphasis on those that operate at temperatures compatible with widely studied hydride systems. A detailed analysis of notable metal hydride–TES coupled systems from the literature is provided. Finally the review assesses potential future developments in the field offering guidance for researchers and engineers in advancing innovative and efficient hydrogen energy systems.

This study investigates the feasibility of utilizing surplus hydropower from Ecuador’s major hydroelectric plants to produce green hydrogen a clean energy source that can be used to meet a large percentage of energy needs. Given Ecuador’s significant hydropower infrastructure this approach leverages untapped energy resources for hydrogen production with potential impacts on decarbonization strategies. A Pareto analysis identified five key hydroelectric plants that contribute the most to the national surplus. Using historical data from 2019 to 2023 a stochastic model was applied to estimate future surplus availability through 2030. The findings indicate that although Ecuador’s surplus hydropower peaked in 2021 the general trend shows a decline suggesting an urgent need to capitalize on these resources efficiently. The results indicate a projected annual surplus of hydroelectric energy in Ecuador ranging from 7475 to 3445 GWh over the next five years which could be utilized for green hydrogen production. Ecuador thus has promising potential to become a green hydrogen producer enhancing both regional energy security and carbon reduction goals. The reduction in energy availability for hydrogen production is attributed to the increasing energy demand and variable climatic conditions.

Fuel cell-based systems are emerging as the future focus for global adaptation and hydrogen compressors and turbines as economically critical versions are at the technological edge of product development of hydrogen-based energy systems in sustainable energy initiatives. As a novelty the paper deals with the issues behind implementing hydrogen machinery technologies to bring about a resilient hydrogen infrastructure also powered by fuel cells and it aims at strengthening the argument for evolving policies and comprehensive approaches that can cope with the technical infrastructural and market-related hurdles.<br/>More specifically the present paper analyzes several hydrogen compressor technologies with their unique advantages and disadvantages. Among them centrifugal compressors are seen to become their most efficient on the large-scale manufacture of hydrogen and allow compression ratios up to 30:1 with isentropic efficiencies between 70 and 90 %. On the other hand electrochemical hydrogen compressors exhibit operation with no vibration reduced noise and level of hydrogen purification among others and offer a plus in a module with lower energy consumption up to half value compared to mechanical compressors. Meanwhile hydrogen turbines are evolving to accommodate hydrogen mixes with the current technological activity in the turbine sector allowing for a blend of 30 % hydrogen and 70 % methane. In comparison prototypes have been already tested using 100 % hydrogen. Within this context this paper describes ongoing work related to efficiency improvements and cost reduction of hydrogen machinery.

Hydrogen embrittlement (HE) is a major concern when steel pipelines are used for hydrogen transportation and storage. The weldments of steel pipelines are of particular concern because they are reported to have higher HE susceptibility compare to the base metal. In this work targeted heat treatments were used to manipulate the microstructure in a pipeline steel weldment to examine the effects of different microstructural features on HE susceptibility. Complementary analyses of the microstructure mechanical testing and fracture surface identified inclusions and ferrite morphology as the most dominant microstructural features that affect the susceptibility to HE. Specimens with different microstructures but sharing similar Ti-rich inclusions exhibited significant re ductions in elongation to failure after hydrogen charging and showed brittle fracture surfaces decorated with multiple ‘fish-eye’ features. In addition co-existence of bainitic microstructure with Ti-rich inclusions resulted in the highest susceptibility to HE.

The International Maritime Organization (IMO) has set stringent regulations to reduce the carbon footprint of maritime transport using metrics such as the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII) to track progress. This study introduces a novel approach using deep reinforcement learning (DRL) to optimize energy efficiency across five types of vessels: cruise ships car carriers oil tankers bulk carriers and container ships under six different operational scenarios such as varying cargo loads and weather conditions. Traditional fuels like marine gas oil (MGO) and intermediate fuel oil (IFO) challenge compliance with these standards unless engine power restrictions are applied. This approach combines DRL with alternative fuels—bio-LNG and hydrogen—to address these challenges. The DRL algorithm which dynamically adjusts engine parameters demonstrated substantial improvements in optimizing fuel consumption and performance. Results revealed that while using DRL fuel efficiency increased by up to 10% while EEXI values decreased by 8% to 15% and CII ratings improved by 10% to 30% across different scenarios. Specifically under heavy cargo loads the DRL-optimized system achieved a fuel efficiency of 7.2 nmi/ton compared to 6.5 nmi/ton with traditional methods and reduced the EEXI value from 4.2 to 3.86. Additionally the DRL approach consistently outperformed traditional optimization methods demonstrating superior efficiency and lower emissions across all tested scenarios. This study highlights the potential of DRL in advancing maritime energy efficiency and suggests that further research could explore DRL applications to other vessel types and alternative fuels integrating additional machine learning techniques to enhance optimization.

The lack of clarity and uncertainty about hydrogen’s role demand applications and economics has been a barrier to the development of the hydrogen economy. In this paper an optimisation model for the integrated planning and operation of hydrogen and electricity systems is presented to identify the role of hydrogen technologies and linepack in decarbonising energy systems improving system flexibility and enhancing energy system security and resilience against extreme weather events. The studies are conducted on Great Britain’s (GB) 2050 net-zero electricity and gas transmission systems to analyse the hydrogen transport and capacity requirements within the existing infrastructure under different scenarios. This includes sensitivities on the level of flexibility high gas prices hydrogen production mixes enabled reversibility of electrolysers electricity generation cost and hydrogen storage facilities. In all sensitivity scenarios efficient hydrogen transport within the existing infrastructure is enabled by the optimal allocation of green and blue hydrogen sources distributed storage facilities and the intra-day flexibility provided by linepack. The findings highlight that increased renewable deployment transfers intermittency to the hydrogen network requiring greater linepack flexibility compared to the current paradigm (up to 83%). Furthermore the necessity of synergy between different gas and electricity systems components in providing flexibility security and resilience is quantified.

LNG carriers play a crucial role in the shipping industry meeting the global demand for natural gas (NG). However the energy losses resulting from the propulsion system and the excess boil-off gas (BOG) cannot be overlooked. The present article investigates the H2 production on board LNG carriers employing both the engine's waste heat (WH) and the excess BOG. Conventional (ORC) and dual-pressure (2P-ORC) organic Rankine cycles coupled separately with a solid oxide electrolysis (SOEC) have been simulated and compared. The hydrogen (H2) produced is then compressed at 150 bar for subsequent use as required. According to the results the 2P-ORC generates 14.79 % more power compared to ORC allowing for an increased energy supply to the SOEC; hence producing more H2 (34.47 kg/h compared to 31.14 kg/h). Including the 2P-ORC in the H2 production plant results in a cheaper H2 cost by 0.04 $/kgH2 compared to ORC a 1.13 %LHV higher system efficiency when leveraging all the available waste heat. The plant including 2P-ORC exploits more than 86 % of the of the available waste compared to 70 % when using ORC. Excluding the compression system decreases the capital cost by almost the half regardless of the WH recovery system used yet it plays in favour of the plant with ORC making the cost of H2 cheaper by 0.29 $/kgH2 in this case. Onboard H2 production is a versatile process independent from the propulsion system ensuring the ship's safety and availability throughout a sea journey.

This paper explores the current scope and direction of the emerging global governance of hydrogen within the broader context of the energy transition where technological innovation and institutional change intersect. Hydrogen as a critical yet complex energy vector requires coordinated governance efforts to navigate its development effectively. To this end we critically engage with key challenges facing the hydrogen sector and examine how institutional frameworks are addressing these issues. Departing from the broader scholarship on global energy governance we conceptually leverage the socio-technical transition and innovation system liter ature to understand the complexities underpinning the development of the global hydrogen economy. We identify three overarching issue areas pertaining to the nature and role of hydrogen in the global energy system: end-use sector development infrastructure and trade and environmental and socio-economic sustainability. Each of these areas presents distinct challenges to hydrogen’s global governance from stimulating supply and demand to managing geo-economic challenges and establishing comprehensive certification and standards. Through mapping multilateral institutions at the global and regional levels and their main objectives we offer insights into the emerging institutional architecture related to hydrogen and identify potential gaps in current governance. Our findings suggest that while newer hydrogen-specific institutions complement the broader agenda of the main established international organizations the overall global hydrogen structure remains a patchwork of diverse actors and frameworks each addressing hydrogen-related challenges to varying degrees. Our research contributes to a nuanced understanding of global governance in the hydrogen sector and advances scholarly discussions on how institutional and actor dynamics shape the emergence and development of new technologies.