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Many efforts have been made to assess the potential of green hydrogen production at global, regional, and national levels using Geographic Information Systems (GIS); however, many dismiss the possibility of producing hydrogen in urban settlements. In order to reveal the true potential of these areas, it is essential to provide arguments that allow evaluation of the feasibility of promoting and impulsing the concept of hydrogen cities. Based on this idea, this work assesses the monthly and annual potential of solar hydrogen in urban areas of Mexico using actual measurements of sunshine duration as electrolyzer production times. Moreover, as light transportation is crucial for cities, we examine the substitution of gasoline with hydrogen and its cost throughout the year. These constitute the main contribution of the present work. This study departs from the geographical and technical potential of solar energy, and by using GIS, the amount of hydrogen production per unit of area (Ton/(km2 year)) was computed. The levelized cost of hydrogen production (LCOH) is also evaluated, using two of the most popular and commercial electrolysis technologies: PEM and Alkaline. Our results revealed that Mexican urban areas have a high potential to produce solar hydrogen, having an average annual production that varies from 1991.8 Ton/km2 to 4338.3 Ton/km2 according to the region. The total solar hydrogen potential of all Mexican urban places is 9.39 MTon/year, which could satisfy up to 42.6 times the 2020 hydrogen demand of Mexico. We found that the national gasoline consumption could be replaced by H 2 , requiring between 42% and 52% of the total urban production. Additionally, the national average of LCOH was found to be about 6.25 USD/kg for alkaline electrolyzer and 9.50 USD/kg for PEM technology, considering the yearly average sunshine duration of 3237 h/year, which means that Mexico could be competitive at large-scale hydrogen production by using Alkaline technology. Our findings have the potential to impact positively on the country since they provide information to facilitate the derivation of public policies from a rigorous and technical perspective. [Display omitted] • Urban hydrogen potential could satisfy up to 42.6 times the 2020 Mexico's hydrogen demand. • Light transportation would require between 46.1% and 54.7% of the total hydrogen produced. • Spring and summer had the largest production, between 0.52 MTon/month and 0.81 MTon/month. • LCOH was estimated to be between 6.25 USD/kg and 9.50 USD/kg for Alkaline and PEM technologies. • Alkaline electrolyzers resulted in a more feasible technology in the short term. [ABSTRACT FROM AUTHOR]

The effect of the energy interchange dynamics on the Zero-Energy Hydrogen Economy (ZEH2E) of households with Fuel-cell Hybrid Electric Vehicles (FCHEV) is investigated in this work. An isolated grid constituted of a household, a battery bank, a PEMFC, a PEM electrolyzer, and PV panels were used as a rig for the study together with an optimal energy management strategy, which guaranteed ≥100% PV self-sufficiency index of the household load and hydrogen harvesting for electrical transportation. Global horizontal irradiance and temperature data, measured every 10 min for 365 days in three different locations of Mexico and Hardware-in-the-loop experiments were used in the analysis. Short and long-term effects of the energy storage system and their importance for achieving ZEH2E conditions were identified. Proposed solar, and battery utilization indexes revealed the short-term effect of the battery storage, imperceptible even in daily average values. Hydrogen production and vehicle autonomy values strongly depended on the season of the year, location, vehicle characteristics, driving cycle, and household load, therefore two indexes were proposed to compare the different scenarios: the hydrogen production-to - average household power load ratio (m H 2 -to-load) and the average vehicle power per traveled distance. These indexes allowed us to reveal low effective load-location pairs for hydrogen production and low effective driving cycle-vehicle pairs for hydrogen utilization. Our results revealed that the average data to analyze ZEH2E conditions is not enough and that detailed data is necessary. [Display omitted] • The effect of the energy dynamics on ZEH2E of households with FCHEV is studied. • Hardware-in-the-Loop experiments as well as real solar irradiance and temperature data are used. • 3 locations, 2 household electric load profiles, 4 vehicle types are tested. • Proposed indexes revealed short-term and long-term actions of the energy sources. • 0.36–1 g of H 2 per load power were found and autonomy values from 52 to 116 km per day. [ABSTRACT FROM AUTHOR]

The Opuntia genus, whose origin is in Mexico where several species grow wild, is taxonomically diverse and has become an important crop worldwide. The aim of this work was to assess the molecular composition of five Opuntia species and three different varieties of each taxonomically identified species with different domestication gradients (from the wildest to the most domesticated O. ficus-indica ). Data were subjected to chemometric evaluation using principal component analysis (PCA), which showed that O. ficus-indica seems to fall far outside of the current domestication gradient that has been proposed, and its ancestor is still unclear. Phenolic compounds showed major (eucomic acid, kaempferol 3-O-robinobioside-7-O-arabinofuranoside, isorhamnetin 3-O-galactoside, and isorhamnetin 3-O-rhamnoside-7-O-(rhamnosyl-hexoside)) and minor compounds that were present only in wild (kaempferol 3-O-arabinofuranoside) or domesticated (quercetin 3-O-rhamnosyl-(1→2)-[rhamnosyl-(1→6)]-glucoside) species. This information could be very useful for authentication of Opuntia species and the identification of species with the highest potential as sources of compounds with nutritional and therapeutic properties. [ABSTRACT FROM AUTHOR]