Publications

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.

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.

Water electrolysis is a promising technology for sustainable energy conversion and storage of intermittent and fluctuating renewable energy sources and production of high-purity hydrogen for fuel cells and various industrial applications. Low-temperature electrochemical water splitting technologies include alkaline proton exchange membrane and anion exchange membrane water electrolyses which normally consist of two coupled half reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Despite the advances over decades formidable challenges still exist and hinder the practical application of large-scale energy-efficient and economically viable water electrolysis including large energy penalty sluggish kinetics high cost of precious metal based electrocatalysts possible H2/O2 gas crossover difficulty in storage and distribution of H2. Herein we first briefly introduce the fundamentals of water electrolysis summarize the recommended standardized electrochemical characterization protocols and demonstrate the metrics and key performance indicators that are used to evaluate the performances of HER and OER electrocatalysts and electrolyser cells. Then we present six new strategies to mitigate the technical challenges in conventional water electrolysis. These emerging strategies for disruptive innovation of water electrolysis technology include overall water electrolysis based on bifunctional nonprecious electrocatalysts (or pre-catalysts) magnetic field-assisted water electrolysis decoupled water electrolysis hybrid water electrolysis acid/alkaline asymmetric electrolyte electrolysis and tandem water electrolysis. Finally the remaining challenges perspectives and future directions are discussed. This review will provide guidance and inspire more endeavours to deepen the mechanistic understanding and advance the development of water electrolysis.

Hydrogen safety is a general concern because of the high reactivity compared to hydrocarbon-based fuels. The strength of knowledge in risk assessments related to the physical phenomena and the ability of models to predict the consequence of accidental releases is a key aspect for the safe implementation of new technologies. Nuclear safety considers the possibility of accidental leakages of hydrogen gas and subsequent explosion events in risk analysis. In many configurations the considered gaseous streams involve a large fraction of nitrogen gas mixed with hydrogen. This work presents the results of a large scale explosion experimental campaign for hydrogen-nitrogen-air mixtures. The experiments were performed in a 50 m3 vessel at Gexcon’s test site in Bergen Norway. The nitrogen fraction the equivalence ratio and the congestion level were investigated. The experiments are simulated in the FLACS-CFD software to inform about the current level of conservatism of the predictions for engineering application purposes. The study shows the reduced overpressure with nitrogen added to hydrogen mixtures and supports the use of FLACS-CFD-based risk analysis for hydrogen-nitrogen scenarios.

In response to the global climate change and the need for green and low-carbon development hydrogen energy has been recognized as a clean energy source that can achieve carbon neutrality unlike fossil fuels. As a country with a shortage of energy resources the development of hydrogen energy is of significant importance for China to adjust its energy structure and accelerate the new era of energy transformation. Based on the development of China’s hydrogen energy industry this paper elaborates on the current status and development trends of key technologies in the entire industrial chain of hydrogen energy in various stages including production storage transportation and application and identifies the problems and challenges of hydrogen energy development. The paper focuses on the analysis of hydrogen storage and transportation application scenarios and clarifies the selection of hydrogen storage and transportation technologies in different scenarios. To achieve healthy devel opment of China’s hydrogen energy industry it is necessary to strengthen top-level design make strategic planning encourage large-scale state-owned energy enterprises to play a leading role promote the development of the entire industry chain increase technological research and development efforts prevent the risk of core technology constraints and vigorously promote the application of hydrogen energy to realize the construction of a hydrogen energy society.

Unlocking the potential of offshore renewables for green hydrogen (GH2) production can be a game-changer empowering economies with their visionary clean energy policies amplifying energy security and promoting economic growth. However their novelty entails uncertainty and risk necessitating a robust framework for facility deployment and infrastructure planning. To optimize offshore GH2 infrastructure placement this work proposes a novel and robust GIS-based multi-criteria decision-making (MCDM) framework. Encompassing thirtytwo techno-socio-economic-safety factors and ocean environmental impact analysis this methodology facilitates informed decision-making for sustainable and safe GH2 development. Utilizing the synergies between offshore wind and solar resources this study investigates the potential of hybrid ocean technologies to enhance space utilization and optimize efficiency. To illustrate the practical application of the proposed framework a case study examining a GH2 system in Australia's marine region and its potential nexus with nearby offshore industries has been conducted. The performed life cycle assessment (LCA) explored various configurations of GH2 production storage and transportation technologies. A Bayesian objective weight integrating technique has been introduced and contrasted statistically with the hybrid CRITIC Entropy MEREC and MARCOS-based MCDM approaches. Various locations are ranked based on the net present value of life cycle cost GH2 production capacity risk availability and environment sustainability factors illustrating their compatibility. A sensitivity analysis is conducted to confirm that a Bayesian approach improves the decision-making outcomes through identifying optimal criteria weights and alternative ranks more effectively. Empowering strategic GH2 decisions globally the proposed approach optimizes system performances cost sustainability and safety excelling in harsh environments.

Hydrogen is an abundant element and a flexible energy carrier offering substantial potential as an environmentally friendly energy source to tackle global energy issues. When used as a fuel hydrogen generates only water vapor upon combustion or in fuel cells presenting a means to reduce carbon emissions in various sectors including transportation industry and power generation. Nevertheless conventional hydrogen production methods often depend on fossil fuels leading to carbon emissions unless integrated with carbon capture and storage solutions. Conversely green hydrogen is generated through electrolysis powered by renewable energy sources like solar and wind energy. This production method guarantees zero carbon emissions throughout the hydrogen’s lifecycle positioning it as a critical component of global sustainable energy transitions. In Africa where there are extensive renewable energy resources such as solar and wind power green hydrogen is emerging as a viable solution to sustainably address the increasing energy demands. This research explores the influence of policy frameworks technological innovations and market forces in promoting green hydrogen adoption across Africa. Despite growing investments and favorable policies challenges such as high production costs and inadequate infrastructure significantly hinder widespread adoption. To overcome these challenges and speed up the shift towards a sustainable hydrogen economy in Africa strategic investments and collaborative efforts are essential. By harnessing its renewable energy potential and establishing strong policy frameworks Africa can not only fulfill its energy requirements but also support global initiatives to mitigate climate change and achieve sustainable development objectives.

This paper presents the results of increasing the hydrogen concentration in natural gas distributed within the territory of the Slovak Republic. The range of hydrogen concentrations in the mathematical model is considered to be from 0 to 100 vol.% for the resulting combustion products temperature and heating value and for the scientific assessment of the environmental and economic implications. From a technical perspective it is feasible to consider enriching natural gas with hydrogen up to a level of 20% within the Slovak Republic. CO2 emissions are estimated to be reduced by 3.76 tons for every 1 TJ of energy at an operational cost of EUR 10000 at current hydrogen prices.

In the transition to sustainable public transportation with zero-emission buses hydrogen fuel cell electric buses have emerged as a promising alternative to traditional diesel buses. However assessing their economic viability is crucial for widespread adoption. This study carries out a comprehensive examination encompassing both sensitivity and probabilistic analyses to assess the total cost of ownership (TCO) for the bus fleet and its corresponding infrastructure. It considers various hydrogen supply options encompassing on-site electrolysis on-site steam methane reforming and off-site hydrogen procurement with both gaseous and liquid delivery methods. The analysis covers critical cost elements encompassing bus acquisition costs infrastructure capital expenses and operational and maintenance costs for both buses and infrastructure. This paper conducted two distinct case studies: one involving a current small bus fleet of five buses and another focusing on a larger fleet set to launch in 2028. For the current small fleet the off-site gray hydrogen purchase with a gaseous delivery option is the most cost-effective among hydrogen alternatives but it still incurs a 26.97% higher TCO compared to diesel buses. However in the case of the expanded 2028 fleet the steam methane-reforming method without carbon capture emerges as the most likely option to attain the lowest TCO with a high probability of 99.5%. Additionally carbon emission costs were incorporated in response to the growing emphasis on environmental sustainability. The findings indicate that although diesel buses currently represent the most economical option in terms of TCO for the existing small fleet steam methane reforming with carbon capture presents a 69.2% likelihood of being the most cost-effective solution suggesting it is a strong candidate for cost efficiency for the expanded 2028 fleet. Notably substantial investments are required to increase renewable energy integration in the power grid and to enhance electrolyzer efficiency. These improvements are essential to make the electrolyzer a more competitive alternative to steam methane reforming. Overall the findings in this paper underscore the substantial impact of the hydrogen supply chain and carbon emission costs on the TCO of zero-emission buses.

Hydrogen-fueled engines require large values of the excess air ratio in order to achieve high thermal efficiency. A low value of this coefficient promotes knocking combustion. This paper analyzes the conditions for the occurrence of knocking combustion in an engine with a turbulent jet ignition (TJI) system with a passive pre-chamber. A single-cylinder engine equipped with a TJI system was running with an air-to-fuel equivalence ratio λ in the range of 1.25–2.00 and the center of combustion (CoC) was regulated in the range of 2–14 deg aTDC (top dead center). Such process conditions made it possible to fully analyze the ascension of knock combustion until its disappearance with the increase in lambda and CoC. Measures of knock in the form of maximum amplitude pressure oscillation (MAPO) and integral modulus of pressure oscillation (IMPO) were used. The absolute values of these indices were pointed out which can provide the basis for the definition of knock combustion. Based on our own work the MAPO index > 1 bar was defined determining the occurrence of knocking (without indicating its quality). In addition taking into account MAPO it was concluded that IMPO > 0.13 bar·deg is the quantity responsible for knocking combustion.