Publications

MgH2 shows significant potential for a solid-state hydrogen storage medium due to the advantages of high hydrogen capacity excellent reversibility and low cost. However its large-scale application still requires overcoming significant thermodynamic and kinetic hurdles. Catalyst design and optimization enhancements are crucial for the hydrogen storage properties of MgH2 wherein single-atom catalysts characterized by their small size and high proportion of unsaturated coordination sites have recently demonstrated a significant advance and considerable promise in this regard. This review presents recent progress on state-of-the-art single-atom catalysts for enhancing MgH2 hydrogen storage examining both supported and unsupported catalyst types i.e. transition metal @ N-modified carbon materials and transition metal @ transition metal compounds and metallene-derived compounds and single-atom alloys respectively. We systematically discussed the single-atom catalysts in MgH2 hydrogen storage systems focusing on synthesis strategies characterization techniques catalytic mechanisms as well as existing challenges and future perspectives. We aimed to provide a comprehensive and cohesive understanding for researchers in the field and promote the development of single-atom catalysts and their significant optimization of the hydrogen storage performance of MgH2.

In the pursuit of establishing a sustainable fuel cell (FC) energy system this review highlights the necessity of examining the operational principles technical details environmental consequences and economic concerns collectively. By adopting an integrated approach the review research into various fuel cells types extending their applications beyond transportation and evaluating their potential for seamless integration into sustainable practices. A detailed analysis of the technical aspects including FC membranes performance and applications is presented. The environmental impact of hydrogen generation through fuel cell/electrolyzer is quantitatively assessed emphasizing a comparative emission footprint against traditional hydrogen generation methods. Economic considerations of fuel cell technology adoption are explored through an extensive examination of market growth and forecasts and investments into the FC systems. Some flagship commercial projects of FC technology are also discussed along with their future prospective. The article concludes with a thorough analysis of challenges associated with FC adoption encompassing membrane research performance hurdles infrastructure development and application-specific challenges. This all-round review serves as an indispensable tool for academicians and policymakers providing a directed and comprehensive FC perspective.

In the twenty-first century global energy consumption is rapidly increasing particularly in emerging nations hastening the depletion of fossil fuel reserves and emphasizing the vital need for sustainable and renewable energy sources. This study aims to analyze hybrid renewable energy systems (HRESs) that use solid waste to generate power focusing on difficulties linked to intermittent renewable sources using a techno-economic framework. Employing the HOMER Pro software prefeasibility analysis is performed to meet the energy needs of an Indian community. System architecture optimization depends on factors like minimizing net present cost (NPC) achieving the lowest cost of energy (COE) and maximizing renewable source utilization. This study evaluates the technical economic and environmental feasibility of a hybrid renewable energy system (HRES) comprising a 400-kW solar photovoltaic (PV) array a 100-kW wind turbine (WT) a 100-kW electrolyzer 918 number of 12V batteries a 200-kW converter a 200-kW reformer and a 15-kg hydrogen tank (H-tank). This optimal configuration has the lowest NPC of $26.8 million and COE of $4.32 per kilowatt-hour and a Renewable Fraction (RF) of 100%. It can provide a dependable power supply and satisfy 94% of the daily onsite load demand which is 1080 kilowatt-hours per day. The required electricity is sourced to load demand entirely from renewable energy at the given location. Additionally the study highlights the benefits of HRES in solid waste management considering technological advancements and regulatory frameworks. Furthermore sensitivity analysis is conducted to measure economic factors that influence HRES accounting for fluctuations in load demand project lifespan diesel fuel costs and interest rates. Installing an HRES custom-made to the local environmental conditions would provide a long-lasting reliable and cost-effective energy source. The results show that the optimal HRES system performs well and is a viable option for sustainable electrification in rural communities.

The study presents the development of a novel integrated wind-biomass energy system designed for sustainable urban development leveraging municipality waste and wind power energy sources. This innovative system is capable of producing multiple forms of energy including electricity cooling heat and hydrogen addressing the diverse energy needs of urban communities. It integrates advanced thermodynamic cycles like Kalina and water electrolysis via an alkaline electrolyzer. In addition the system uniquely combines power and refrigeration while utilizing landfills as an energy source. The designed system is thermodynamically modeled using the Engineering Equation Solver and process wise simulated by the Aspen Plus software to ensure better performance. By integrating advanced thermodynamic cycles such as the Kalina and combined power and refrigeration system the overall system is designed to maximize the utilization of biomass energy content and enhances overall performance. The thermodynamic analysis results reveal that the system achieved remarkable results with an energy efficiency of 67.60% and an exergy efficiency of 59.7% demonstrating its tangible performance compared to other standalone energy systems. The refrigeration system itself achieves an energetic COP of 5.41 and an exergetic COP of 1.7. Additionally the system's hydrogen production facilitated by an alkaline electrolyzer reaches a rate of 5.38 kg/h highlighting its potential to contribute to clean hydrogen energy solutions. Moreover the exergo-environmental assessment shows that the system is environmentally friendly. The cost assessment shows that the system reaches profitability in 7 years and demonstrates growth achieving a substantial NPV of 192.39 million by 30 years highlighting its long-term financial viability.

Hydrogen is a promising carbon-free energy carrier for large-scale applications yet its adoption faces unique safety challenges. Microscopic physicochemical properties such as high diffusivity low ignition energy and distinct chemical pathways alter the safety of hydrogen systems. Analyzing the HIAD 2.0 incident database an occurrence-based review of past hydrogen incidents shows that 59% arise from general industrial failures common to other hydrocarbon carrier systems. Of the remaining 41% only 15% are unequivocally linked to the fuel’s unique properties. This study systematically isolates hazards driven by hydrogen’s intrinsic properties by filtering out confounding factors and provides an original clear characterization of the different failure mechanisms of hydrogen systems. These hydrogen-specific cases are often poorly described limiting their contribution to safety strategies and regulations improvement. A case study on pipeline failures illustrates how distinguishing hydrogen-specific hazards supports targeted risk mitigation. The findings highlight the need for evidence-based regulation over broadly precautionary approaches.

The teams sits down with Johannah Christensen to discuss regulatory policies and risk mitigation for vessel owners switching to green fuels and what we can do to encourage that jump as well as ensure a Just Transition.

The podcast can be found on their website.

Hydrogen-fueled Internal Combustion Engines (H2-ICEs) are typically operated with lean mixtures to minimize NOx emissions and reduce the risk of abnormal combustion events. Due to hydrogen’s low Lewis number premixed hydrogen-air flames in lean conditions exhibit strong thermodiffusive instabilities which make the numerical simulation of the combustion process particularly challenging. Indeed the intensity of these instabilities is significantly influenced by thermodynamic parameters – such as mixture temperature pressure and dilution rate – resulting in substantial variations in combustion behaviour across different operating conditions. Therefore they have to be properly considered not only to ensure model robustness but also to improve model accuracy over a wider range of operations. In this study the combustion process in a Direct Injection H2-ICE was analyzed using 3D-CFD simulations relying on a flamelet-based combustion model. Two sets of lookup flame speed maps were defined: laminar flame speed (SL) maps derived from standard 1D-CFD simulations in homogeneous reactor and freely propagating flame speed (SM) maps which account for the effects of thermodiffusive instabilities. The model that uses SL maps required the recalibration of some combustion model parameters when changing the dilution rate to ensure consistency with experimental data. Instead the model relying on SM maps featured a noticeable accuracy across different air-to-fuel ratios without the need for recalibration any combustion model parameter highlighting the key role of thermodiffusive flame instabilities on the combustion process. Based on these findings the impact of such instabilities was evaluated throughout the entire combustion process from both global and local perspectives. The relevance of thermodiffusive instabilities was observed to increase with the air-to-fuel ratio thereby enhancing combustion speed in leaner mixtures. Additionally the implementation of thermodiffusive instabilities was found to affect also preferred direction of flame propagation as stronger instabilities were identified in the leanest and low-temperature portions of the flame front. Novelty and significance This study addresses a critical knowledge gap regarding the role of thermodiffusive flame instabilities in accurately replicating the combustion process of a direct-injection internal combustion engine within a RANS simulation framework. Indeed while these instabilities have been shown to significantly enhance the mixture consumption rate in quiescent environments at low to moderate pressures and temperatures particularly in lean mixtures their impact on the burn rate under engine-like conditions has not yet been systematically investigated to the best of the authors’ knowledge. This work provides a comprehensive analysis of the significance of these instabilities in the combustion process of a direct-injection hydrogen internal combustion engine. The analysis is conducted from both a global perspective assessing their overall influence on the combustion process and a local perspective examining how they alter flame front characteristics when incorporated into the model.

Alternative fuel opportunities can satisfy energy security and reduce carbon emissions. In this regard the hydrogen fuel is derived from the source of environmental pollutants like sewage and algae wastewater through hydrothermal gasification technique using a KOH catalyst with varied gasification process parameters of duration and temperature of 6–30 min and 500-800 ◦C. The novelty of the work is to identify the optimum gasification process parameter for obtaining the maximum hydrogen yield using a KOH catalyst as an alternative fuel for agricultural engine applications. Influences of gasification processing time and temperature on H2 selectivity Carbon gasification efficiency (CE) Lower heating value (LHV) Hydrogen yield potential (HYP) and gasification efficiency (GE) were studied. Its results showed that the gasifier operated at 800 ◦C for 30 min offering maximum hydrogen yield (26 mol/kg) and gasification efficiency (58 %). The synthesized H2 was an alternative fuel blended with diesel fuel/TiO2 nanoparticles. It was experimentally studied using an internal combustion engine. Influences of H2 on engine perfor mance like brake-specific fuel consumption brake thermal efficiency and emission performances were measured and compared with diesel fuel. The results showed that DH20T has the least (420g/kWh) brake-specific fuel consumption (BSFC) and superior brake thermal efficiency of about 25.2 %. The emission results revealed that the DH20T blend showed the NOX value increased by almost 10.97 % compared to diesel fuel whereas the CO UHC and smoke values reduced by roughly 31.25 28.34 and 42.35 %. The optimum fuel blend (DH20T) result is rec ommended for agricultural engine applications.

Climate change and global warming concerns promote interest in alternative fuels especially zero-carbon fuels like hydrogen. Modifying existing combustion engines for dual-fuel operation can decrease emissions of vehicles that are already on the road. The procedure of a deep learning-based model predictive control as a machine learning implementation practical for complex nonlinear systems with input and state constraints has been developed and tested on a hydrogen/diesel dual-fuel (HDDF) engine application. A nonlinear model predictive controller (NMPC) utilizing a deep neural network (DNN) process model is proposed to control the injected hydrogen and diesel. This DNN model has eight inputs and four outputs and has a short computational time compared to the physics-based model. The architecture and hyperparameters of the DNN model of the HDDF process are optimized through a two-stage Bayesian optimization to achieve high accuracy while minimizing the complexity of the model described. The final DNN architecture has two hidden layers with 31 and 23 neurons. A modified engine capable of HDDF operation is compared to standard diesel operation to evaluate the engine performance and emissions. During experimental engine testing the controller required an average computational time of 2 ms per cycle on a low-cost processor satisfying the real-time requirements and was faster than recurrent networks. The control performance of the DNN-NMPC for the HDDF engine showed a mean absolute error of 0.19 bar in load tracking while maximizing average hydrogen energy share (68%) and reducing emissions. Specifically the particulate matter emissions decrease by 87% compared to diesel operation.

An increasing demand for energy coupled with rising pollution levels is driving the search for environmentally clean alternative energy resources to replace fossil fuels. Hydrogen has emerged as a promising clean energy carrier and raw material for various applications. However its environmental benefits depend on sustainable production methods. The rapid development of nanomaterials (NMs) has opened new avenues for the conversion and utilization of renewable energy (RE). NMs are becoming increasingly important in addressing challenges related to hydrogen (H₂) generation. This review provides an overview of current advancements in H₂ production from biomass via thermochemical (TC) and biological (BL) processes including associated costs and explores the applications of nanomaterials in these methods. Research indicates that biological hydrogen (BL-H₂) production remains costly. The challenges associated with the TC conversion process are examined along with potential strategies for improvement. Finally the technical and economic obstacles that must be overcome before hydrogen can be widely adopted as a fuel are discussed.