Brazil
Hydrogen-Rich Gaseous Mixture for Enhanced Combustion in a Flex-Fuel Engine: An Experimental Analysis
Nov 2025
Publication
This experimental study examines the effect of adding a hydrogen-enriched synthetic gaseous mixture (HGM’) on the combustion and fuel conversion efficiency of a singlecylinder research engine (SCRE). The work assesses the viability of using this mixture as a supplemental fuel for flex-fuel engines operating under urban driving cycling conditions. An SCRE the AVL 5405 model was employed operating with ethanol and gasoline as primary fuels through direct injection (DI) and a volumetric compression ratio of 11.5:1. The HGM’ was added in the engine’s intake via fumigation (FS) with volumetric proportions ranging from 5% to 20%. The tests were executed at 1900 rpm and 2500 rpm engine speeds with indicated mean effective pressures (IMEPs) of 3 and 5 bar. When HGM’s 5% v/v was applied at 2500 rpm the mean indicated effective pressure of 3 bar was observed. A decrease of 21% and 16.5% in the ISFC was observed when using gasoline and ethanol as primary fuels respectively. The usage of an HGM’ combined with gasoline or ethanol proved to be a relevant and economically accessible strategy in the improvement of the conversion efficiency of combustion fuels once this gaseous mixture could be obtained through the vapor-catalytic reforming of ethanol giving up the use of turbochargers or lean and ultra-lean burn strategies. These results demonstrated the potential of using HGM’ as an effective alternative to increase the efficiency of flex-fuel engines.
A Comparative Analysis of Conventional Thermal and Electrochemical Reforming Pathways for Hydrogen Production Towards Sustainable Aviation Fuels (SAF)
Oct 2025
Publication
H2 is increasingly recognized as a cornerstone of global decarbonization strategies including in hard-toabate sectors such as aviation. Its large-scale applicability remains limited owing to the limited diversity and maturity of low-carbon production pathways. Approximately 96% of global H2 production originates from non-renewable sources primarily through steam methane reforming (SMR) which remains the most commercially established route. Another critical barrier to the substitution of conventional aviation fuels lies in hydrogen storage as the current volumetric energy density and cryogenic storage requirements render onboard integration impractical for most aircraft configurations. To address these challenges this study developed a techno-economic and environmental benchmarking framework that compares conventional thermal reforming technologies (SMR autothermal and POX) with emerging electrochemical routes (water electrolysis and alcohol electro-oxidation) highlighting their potential roles in the transition toward sustainable aviation fuels (SAF). By normalizing efficiency energy intensity CO2 emissions and cost (USD kg 1 H2 and USD GJ 1 ) this study quantifies the trade-offs that define current and emerging pathways. SMR remains the industrial baseline (70%–85% thermal efficiency 1–2 USD kg−1 H2 9–12 kg CO2 kg−1 H2) whereas ethanol-based electrochemical reforming operates 0.3–0.9 V below conventional electrolysis achieving up to 40% lower electrical energy demand (∼2.4 kW h Nm−3 H2 with near-zero direct emissions. A sensitivity analysis demonstrates that a 60% reduction in catalyst cost or electricity prices below 0.03 USD (kW h)−1 could make electrochemical reforming cost-competitive with SMR. This study consolidates fragmented knowledge into a comprehensive roadmap that links catalyst performance and technology readiness for aviation decarbonization by integrating engineering metrics with policy and infrastructure perspectives to identify realistic transition pathways toward sustainable hydrogen and hybrid aviation fuels.
Green Hydrogen Market and Green Cryptocurrencies: A Dynamic Correlation Analysis
Nov 2025
Publication
The urgent need to mitigate climate change has elevated green hydrogen as a sustainable alternative to fossil fuels while green cryptocurrencies have emerged to address the environmental concerns of traditional cryptocurrency mining. This study investigates the dynamic correlation between the green hydrogen market and selected green cryptocurrencies (Cardano Stellar Hedera Algorand and Chia) from July 2021 to April 2024 utilizing the Dynamic Conditional Correlation GARCH (DCC-GARCH) model with robustness checks using EGARCH and GJR-GARCH specifications. Our findings reveal significant correlations with peaks reaching up to 50% in 2022 a period likely influenced by the Russia-Ukraine conflict. Subsequently a decline in these correlations was observed in 2023. These results underscore the interconnectedness of sustainability-driven markets suggesting potential contagion effects during periods of global instability. The high persistence of correlation shocks (α + β values approaching unity) indicates that correlation regimes tend to be long- lasting with important implications for portfolio diversification and risk management strategies. Robustness checks using EGARCH and GJR-GARCH specifications confirmed qualitatively similar patterns reinforcing the validity of our findings into the evolving landscape of green finance and energy
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