Search Results (46)

It is a well-known fact that proper nutrition is essential for human beings to live healthy lives. For thousands of years, it has been considered that dates are one of the best nutrient providers. To have better-quality dates and to enhance the shelf life of dates, it is vital to preserve dates in optimal conditions that contribute to food security. Hence, it is crucial to know the shelf life of different types of dates. In current practice, shelf life assessment is typically based on manual visual inspection, which is subjective, error-prone, and requires considerable expertise, making it difficult to scale across large storage facilities. Traditional cold storage systems, whilst being capable of monitoring temperature and humidity, lack the intelligence to detect spoilage or predict shelf life in real-time. In this study, we present a novel IoT-based shelf life estimation system that integrates multichannel gas sensors and a lightweight machine learning model deployed on an edge device. Unlike prior approaches, our system captures the real-time emissions of spoilage-related gases (methane, nitrogen dioxide, and carbon monoxide) along with environmental data to classify the freshness of date fruits. The model achieved a classification accuracy of 91.9% and an AUC of 0.98 and was successfully deployed on an Arduino Nano 33 BLE Sense board. This solution offers a low-cost, scalable, and objective method for real-time shelf life prediction. This significantly improves reliability and reduces postharvest losses in the date supply chain. Full article

Gas hydrates have been identified as one of the leading candidates for future energy sources. According to conservative estimates, the energy contained in natural hydrates is double that of the fossil fuel that has been explored. This substantial energy storage motivates the investigation of natural hydrates. Prior research on mechanical/material properties has assumed that the lattice would be the smallest unit and averaged all the features within the lattice, disregarding smaller-scale geometric properties. We investigated the geometric features of sI methane hydrate under pressure. The sI methane hydrate is made up of two kinds of cages (polyhedrons) with two kinds of faces (polygons), and the vertices of the polygons are occupied by water oxygen atoms. Based on these three categories, we examined the cage integrity, face deformation, and water oxygen atom bond lengths and angles within and beyond the stability limits. The presence of forbidden zones was confirmed in bond length and angle distributions, validating the effects of geometric features. The predictive nature of water molecule angular displacement with pressure was validated. This multiscale computational materials science methodology describes and defines the range of the elastic stability of gas hydrates, a crucial contribution to energy materials science and engineering. Full article

Orphaned and abandoned wells in the United States pose significant environmental risks, including methane emissions, groundwater contamination, and ecosystem degradation. These wells also threaten the integrity of carbon capture and storage (CCS) projects by providing potential leakage pathways for stored CO₂, particularly if they lack proper plugging and well integrity. Although the exact number of orphaned and abandoned wells is uncertain due to poor historical documentation, recent estimates suggest there could be as many as 3.9 million such wells nationwide, emitting approximately 3.2 Teragram (Tg) of methane annually. This study investigates the distribution of orphaned and abandoned wells across the United States, presenting new estimates of documented wells and exploring their methane emissions. Through state-level data analysis, the number of documented orphan wells is estimated to be significantly higher than previously reported. A machine learning model, specifically a RandomForestRegressor, was employed to predict the locations of potential orphan wells, enhancing the ability to target monitoring and remediation efforts. Full article

Bioenergy with carbon capture and storage (BECCS) or utilization (BECCU) allows net zero or negative carbon emissions and can be a breakthrough technology for climate change mitigation. This work consists of an energetic, exergetic, and economic analysis of an integrated process based on chemical looping combustion of solar-torrefied agro-industrial residues, followed by methanation of the concentrated CO₂ stream with green H₂. Four agro-industrial residues and four Italian site locations are considered. Depending on the considered biomass, the integrated plant processes about 18–93 kg h⁻¹ of raw biomass and produces 55–70 t y⁻¹ of synthetic methane. Global exergetic efficiencies ranged within 45–60% and 67–77% when neglecting and considering, respectively, the valorization of torgas. Sugar beet pulp and grape marc required a non-negligible input exergy flow for the torrefaction, due to the high moisture content of the raw biomasses. However, for these biomasses, the water released during drying/torrefaction and CO₂ methanation could be recycled to the electrolyzer to eliminate external water consumption, thus allowing for a more sustainable use of water resources. For olive stones and hemp hurd, this water recycling brings, instead, a reduction of approximately 65% in water needs. A round-trip electric efficiency of 28% was estimated assuming an electric conversion efficiency of 40%. According to the economic analysis, the total plant costs ranged within 3–5 M€ depending on the biomass and site location considered. The levelized cost of methane (LCOM) ranged within 4.3–8.9 € kg_CH4⁻¹ but, if implementing strategies to avoid the use of a large temporary H₂ storage vessel, can be decreased to 2.6–5.3 € kg_CH4⁻¹. Lower values are obtained when considering hemp hurd and grape marc as raw biomasses, and when locating the PV field in the south of Italy. Even in the best scenario, values of LCOM are out of the market if compared to current natural gas prices, but they might become competitive with the introduction of a carbon tax or through government incentives for the purchase of the PV field and/or electrolyzer. Full article

This investigation ventures into the nuanced porosity traits of shallow shale gas reservoirs, pinpointing the critical determinants of their gas content with a nuanced touch. By harnessing sophisticated microscopy and analytical methods, we embarked on an exploration into the porosity architecture of shale, identifying the distinct pore spaces that harbor shale gas and applying gas adsorption techniques to evaluate its storage potential. Noteworthy is our utilization of diverse adsorption mechanisms and models to accurately fit methane adsorption data while carefully considering the influence of marine shallow shale’s pore structure peculiarities, total organic carbon (TOC) content, and clay mineral content on its adsorption prowess. We introduce a refined model for appraising gas adsorption volumes, an innovative stride toward bolstering the precise estimation of reserves in marine dam shallow shale gas and shedding light on accurate gas adsorption volume calculations in analogous shallow shale gas scenarios. This manuscript offers profound insights into the sophisticated interplay between shale porosity and gas storage, enriching our understanding and enabling more accurate future resource estimations. Full article

The global climate crisis forces mankind to develop carbon storage technologies. “Ladoga” carbon monitoring site is part of the Russian climate project “Carbon Supersites”, which aims to develop methods and technologies to control the balance of greenhouse gases in various ecosystems. This article shows the condition of soil and vegetation cover of the carbon polygon “Ladoga” using the example of a typical southern taiga ecosystem in the Leningrad region (Russia). It is revealed that soils here are significantly disturbed as a result of agrogenic impact, and the vegetation cover changes under the influence of anthropogenic activity. It has been found that a considerable amount of carbon is deposited in the soils of the carbon polygon; its significant part is accumulated in peat soils (60.0 ± 19.8 kg × m⁻² for 0–100 cm layer). In agrogenically disturbed and pristine soils, carbon stocks are equal to 12.8 ± 2.9 kg × m⁻² and 8.3 ± 1.3 kg × m⁻² in the 0–100 cm layer, respectively. Stocks of potentially mineralizable organic matter (0–10 cm) in peat soils are 0.48 ± 0.01 kg × m⁻²; in pristine soils, it is 0.58 ± 0.06 kg × m⁻². Peat soils are characterized by a higher intensity of carbon mineralization 9.2 ± 0.1 mg × 100 g⁻¹ × day⁻¹ with greater stability. Carbon in pristine soils is mineralized with a lower rate—2.5 ± 0.2 mg × 100 g⁻¹ × day⁻¹. The study of microbial diversity of soils revealed that the dominant phyla of microorganisms are Actinobacteria, Bacteroidetes, and Proteobacteria; however, methane-producing Archaea—Euryarchaeota—were found in peat soils, indicating their potentially greater emission activity. The results of this work will be useful for decision makers and can be used as a reference for estimating the carbon balance of the Leningrad region and southern taiga boreal ecosystems of the Karelian Isthmus. Full article

The production of biohydrogen with negative CO₂ emissions through the steam methane reforming of biomethane, coupled with carbon capture and storage, represents a promising technology, particularly for industries that are difficult to electrify. In spite of the maturity of this technology, which is currently employed in the production of grey and blue hydrogen, a detailed cost model that considers the entire supply chain is lacking in the literature. This study addresses this gap by applying correlations derived from actual facilities producing grey and blue hydrogen to calculate the CAPEX, while exploring various feedstock combinations for biogas generation to assess the OPEX. The analysis also includes logistic aspects, such as decentralised biogas production and the transportation and storage of CO₂. The levelized cost of golden hydrogen is estimated to range from EUR 1.84 to 2.88/kg, compared to EUR 1.47/kg for grey hydrogen and EUR 1.93/kg for blue hydrogen, assuming a natural gas cost of EUR 25/MWh and excluding the CO₂ tax. This range increases to between 3.84 and 2.92, with a natural gas cost of EUR 40/MWh with the inclusion of the CO₂ tax. A comparison with conventional green hydrogen is performed, highlighting both prices and potential, thereby offering valuable information for decision-making. Full article

Underground Hydrogen Storage (UHS) provides a large-scale and safe solution to balance the fluctuations in energy production from renewable sources and energy consumption but requires a proper and detailed characterization of the candidate reservoirs. The scope of this study was to estimate the hydrogen diffusion coefficient for real caprock samples from two natural gas storage reservoirs that are candidates for underground hydrogen storage. A significant number of adsorption/desorption tests were carried out using a Dynamic Gravimetric Vapor/Gas Sorption System. A total of 15 samples were tested at the reservoir temperature of 45 °C and using both hydrogen and methane. For each sample, two tests were performed with the same gas. Each test included four partial pressure steps of sorption alternated with desorption. After applying overshooting and buoyancy corrections, the data were then interpreted using the early time approximation of the solution to the diffusion equation. Each interpretable partial pressure step provided a value of the diffusion coefficient. In total, more than 90 estimations of the diffusion coefficient out of 120 partial pressure steps were available, allowing a thorough comparison between the diffusion of hydrogen and methane: hydrogen in the range of 1 × 10⁻¹⁰ m²/s to 6 × 10⁻⁸ m²/s and methane in the range of 9 × 10⁻¹⁰ m²/s to 2 × 10⁻⁸ m²/s. The diffusion coefficients measured on wet samples are 2 times lower compared to those measured on dry samples. Hysteresis in hydrogen adsorption/desorption was also observed. Full article

During LNG storage and transportation by ship, a fraction of the LNG in the cryogenic tanks evaporates due to heat ingress through the insulation, resulting in boil-off gas (BOG) production and a change in LNG composition, a phenomenon known as LNG ageing. Common practice is to assume that BOG composition and related density are identical to the initial LNG or pure methane, resulting in inaccuracy in BOG mass flow measurements. This is particularly important regarding LNG shipping economics and the utilization of BOG as a fuel for ship propulsion. This work investigates the influence of LNG ageing on the produced BOG thermodynamic properties relevant to the mentioned inaccuracies’ estimation and correction. An established, simplified, dynamic boil-off model is utilized for the simulation of LNG and BOG properties’ changes during the voyage. Four cases represented by limiting the minimum and maximum values of methane and nitrogen content are used to estimate the general influence of the compositional variability over the whole range of practically possible LNG source mixtures. Research results provide an insight into the relevant BOG properties’ variability and confirm that BOG flow measurements should be corrected with dynamic model simulations results due to significant differences between the total BOG mixture and forced BOG mixture corresponding to the LNG composition. Full article

The aim of the publication was to analyze investments in biogas plants with a cogeneration unit for an average size dairy farm. The basis for the calculation was the use of cow manure as the only substrate in methane fermentation. The economic balance also includes ecological and service aspects. The study also shows how much energy and quality potential is lost due to improper manure management and what impact a single farm with dairy cows has on the emission of carbon dioxide equivalent. It has been estimated that as a result of improper storage of manure, even 2/3 of its fertilizing, energy and economic value can be lost, while causing damage to the environment. It has been estimated that for a single farm with 100 cows, without government mechanisms subsidizing investments in RES, the payback period exceeds 15 years, and the Return of Capital Employed is slightly more than 6%. Full article

Quantities of waste generation are drastically increasing every day, and most of the waste is disposed of through open dumps and landfilling. Methane, carbon dioxide, and nitrous oxide are major greenhouse gases (GHGs) produced from landfill sites. However, the global-warming potential of methane is 21 times higher than that of carbon dioxide. Hence, there is immense concern for its utilization from landfill sites. In developing countries, the composition of municipal solid waste (MSW) has high amounts of biodegradable waste (50–60%). This leads to higher emissions of GHGs a per ton of MSW compared to the developed world. In this study, the attempt will be made to estimate the amount of carbon stored in MSW burial in landfills. Tests were conducted in two different locations at the Mavallipura landfill. MSW samples were collected for every meter interval (1–2 m, 2–3 m and so on) up to 6 m. The result shows that carbon stored in organic matter increases with depth from approximately 2.2% at 1.0 m depth to 4.8% at 6 m depth. Based on MSW’s carbon storage factor and data on MSW generation, global carbon sequestration from MSW burial in the Mavallipura landfill is estimated to be at least 10 million metric tons per year. In additional, the study aims to quantify methane-gas production from the ward levels and the Mavallipura landfill site in India. Full article

This study addresses the use of former gas storage facilities as short-term storage for renewable energy through power-to-gas (PtG) technology in Germany. Three test cases with coupled thermal-hydromechanical (THM) modelling were conducted to evaluate short-term injection and production schedules. The operating rates were controlled by the upper and lower limits of the wellbore pressure. The maximum difference in pore pressure and effective stress was 0.6 MPa in all cases. Fault reactivation analysis was performed on the THM models to estimate fault stability. The critical pore pressure for safe reservoir operation was determined to be 1.25 times the original pore pressure, corresponding to a WBHP value of 20.25 MPa. The upper limit of the gas injection rate for safe storage operation was estimated to be between 100,000 and 150,000 m³/day. The thermal stresses were found to be negligible for short-term cases. The storage capacity of PtG technology was reported to be up to 1,322,400 kWh/d of renewable electricity, which can contribute to Germany becoming a greenhouse gas neutral country by 2050. The workflows and results of the study are applicable to all gas storage in a porous medium, including methane, CO₂, and hydrogen. Full article

Significant stress changes caused by sorption-induced swelling raise the coal wellbore failure potential, which directly impacts the safety and sustainability of CO₂ enhanced coalbed methane (CO₂-ECBM). Additionally, a mixture gas (CO₂/N₂) injection is recommended due to the sharp decline of permeability with pure CO₂ injection. In this study, incorporating the impacts of mixture gas adsorption and poroelastic effects, a semi-analytical model of coal wellbore stability during mixture gas injection is proposed. Model results indicate that the stress field is significantly influenced by the boundary condition and sorption effect. In addition, parametric studies are performed to determine the influence of adsorption parameters, mechanical properties, and gas composition on the stress distribution and then on the wellbore failure index. Furthermore, mixture gas injection with a large proportion of CO₂ or N₂ both cause wellbore instability. Significant compressive hoop stress and shear failure are caused by the mixture gas injection with a large proportion of CO₂. In contrast, the displacement of CH₄ with weakly adsorptive N₂ will result in less compressive and even tensile hoop stress, so shear or tensile failure may occur. Thus, mixture gas (including pure CO₂/N₂) injection must be controlled by coal wellbore failure, providing an accurate estimation of in-situ coal seams’ CO₂ storage capacity from the perspective of wellbore stability. Full article

California is the leading dairy state in the United States. The total sale of milk and its products represents about $6.3 billion annually out of the $50 billion generated from all agricultural production in the state. However, methane emissions from dairy manure and enteric fermentation represented nearly half of all annual methane emissions in California, with dairy manure accounting for 25%, and enteric fermentation for 20%. Methane emissions originating from manure are produced primarily from anaerobic settling basins and lagoons, which are the most common manure storage systems in the state. To achieve sustainability on dairy farms and to comply with state regulations for air and climate pollutants, dairy farms have implemented technologies such as anaerobic digestion and alternative manure management technologies. In addition, governmental incentive programs have been deployed to partially fund these technologies for eligible dairies in the state. The present article reviews the design and operations, effectiveness, and economics of the most common technologies employed in Californian dairies in reducing methane emissions. The technologies studied include anaerobic digesters, mechanical separators, compost-bedded pack barns, manure vacuuming followed by drying, and weeping walls. The current status and estimated effectiveness of government incentive programs are reviewed and recommendations for improvements presented. Finally, future trends and research needs for mitigating the emissions in Californian dairies are identified. Full article

Several research and development efforts have been made to ensure food security in developing countries. Dissemination of improved agricultural technologies was used as the main avenue through which some increases in food supply have been achieved. However, food insecurity remains a major challenge. This paper argues and provides empirical evidence that reducing food loss and waste can be an effective food and energy security, and natural resource, and environmental conservation strategy. Following the life cycle framework, the annual amount of wheat-based food lost or wasted from farm-to-fork in Morocco was estimated at 4 million tons (equivalent to 36% of total supply) valued at US$1.0 billion. Among all nodes, the magnitudes of farm management-related losses, wastage during consumption, and storage losses rank first to third accounting for about 17.4%, 7.92%, and 7.06%, respectively of total wheat supply in the country. Were these losses and wastes entirely prevented, Morocco would have been able to feed 29.3 million more people, or save 1.79 million hectares of land, 2.66 billion m3 of water, and 64.28 million GJ of energy, and prevented the emission from landfills of at least 16.61 million kg of methane annually. Besides the ongoing efforts to disseminate agricultural technologies, the Moroccan government needs to develop short- and medium-term national strategies to reduce food losses and wastage particularly targeting the storage and consumption nodes. Replacing bread subsidy with food vouchers targeting only the needy and creation of public awareness about the magnitudes and consequences of food loss and wastage alone may go long way in reducing them. Full article