CO2 Equivalent Research Articles

Climate change mitigation potentials of wood industry related measures in Hungary

Harvested wood products (HWPs) store a significant amount of carbon while long-lived products and wooden buildings can be among the most effective means for carbon storage. Wood products’ lifetime extension and appropriate waste management, recycling, and reuse can further contribute to the achievement of climate goals. In our study we projected under 10 different scenarios the carbon storage, carbon dioxide and methane emissions of the Hungarian HWP pool up to 2050 in order to find the combination of wood industry-related measures with the highest climate change mitigation effect. For the projection we used the country-specific HWP-RIAL model to predict emissions associated with the end-of-life and waste management of wood products. The main conclusion is that without additional measures the Hungarian HWP pool would turn from a carbon sink to a source of emissions by 2047. To maintain the Hungarian HWP pool to be a continuous carbon sink it is essential to implement additional climate mitigation measures including cascading product value chains, and approaches of a circular bioeconomy. We find the most effective individual measures are increasing product half-life, increasing recycling rate and increasing industrial wood production through increased industrial wood assortments and increased harvest. With the combination of these measures a maximum average annual climate change mitigation potential of 1.5 Mt CO2 equivalents could be reached during the 2022–2050 period.

Bioeconomic and sustainability performance of dairy-beef steer and heifer production systems differing in stocking rate

There is little published research on dairy-beef heifer systems or comparisons of heifer and steer dairy-beef production. Furthermore, given its impact on the productivity and economics of dairy-beef systems, any comparison of gender must also consider potential interactions with stocking rate (SR). The objective of this study was to evaluate the variability of physical and economic performance, greenhouse gas emissions, feed-food competition and pasture land-use of dairy-beef production steer and heifer systems at differing stocking rates. Performance data from a two (gender: Steers and Heifers) x two (SR: Low and High) x two (breed-types: Early-maturing (EM) and Late-maturing (LM) factorial experiment was used to parameterize a bio-economic farm systems model. Low SR animals were heavier, had higher fat scores and better conformed at slaughter. High stocking rate resulted in greater carcass output per hectare and subsequently were, on average, 22 % more profitable than their Low SR counterparts. Late-maturing animals were found to be more profitable than early-maturing, and steers were more profitable than heifers. GHG emissions of the eight treatments investigated ranged from 10.7 to 17.7 kgs of carbon dioxide equivalents (kg CO2eq) per kilogram of carcass weight produced, with both High SR and heifer systems having lower GHG emissions per kg of product than their Low SR and steer counterparts. Human edible protein efficiency was only favorable for the steer systems. High SR systems had, on average, lower land use per kg of product than their Low SR counterparts. Results from this study indicate that no single treatment was optimal across the range of performance metrics considered.

SLAPE solar panels: a possible solution for the future energy problems of our society

Today, the silicon photovoltaic cell (SPVC) solar panels are being deployed across the globe by all most all the governments to generate renewable carbon neutral electricity to use in place of the one generated at thermal power plants by burning fossil fuels. These SPVC solar panels generate electricity with less than 20% efficiency, and heat energy with more than 30% efficiency. This 10% excess heat energy released into the atmosphere can cause a very severe damage to the environment and ecology as it is million times higher than the one caused by the equivalent CO2 gas in the atmosphere with a concentration of about 421 ppm. To avoid the harmful and danger effects of heat energy released by these SPVC solar panels into the atmosphere, either they have to be stopped using or the heat generated by them has to be trapped to use for the beneficial purposes of the society or any other alternate safe solar panels have to be developed. In this study, for the first time, the SLAPE (Semiconductor and Liquid Assisted Photothermal Effect) solar panels are introduced to generate electricity from sunlight. In these new solar panels, a semiconducting material along with a stable organic solvent is employed to capture the sunlight reaching the earth surface and to convert it into the heat energy. This in situ generated heat energy is then converted into a rotational mechanical energy with the help of an heat engine, and then into electricity with the help of suitable electric generator. To establish the Proof of Concept (poc), in this study, SPV cells as semiconducting material and γ-butyrolactone were employed to fabricate a one square meter area SLAPE solar panel and generated about 17 V AC electricity with the help of a custom manufactured reciprocally moved steam engine (RMSE) and an electric generator. Thus obtained results are presented and discussed along this article.

Assessing the Carbon Footprint of Viticultural Production in Central European Conditions

A number of factors will increasingly play a role in the sustainability of wine production in the coming period. The current situation suggests that the analysis of energy consumption and greenhouse gas (GHG) emissions will play a particularly important role. The so-called carbon footprint, expressed in CO₂ equivalents, is used to express the sum of GHG emissions. This study presents an analysis of vine cultivation in a particular Central European region, with the main focus on quantifying the inputs, yield, fuel consumption, and GHG emissions. The emphasis was placed on conventional, integrated, and ecological production systems of growing, evaluated with the help of the developed AGROTEKIS version 5 software. A total of 30 wine-grower entities in the Morava wine-growing region, the subregion Velké Pavlovice, in the Czech Republic weather climate, were included in the input data survey. By analyzing the aggregated values, the real savings in energy and curbing of CO2 emissions of vineyards could be observed, relating to individual work procedures with lower energy demand used in the vineyard treatment as well as the amounts and doses of agrochemicals used. The average values of the total impacts did not show any statistically significant differences between the conventional (971 ± 78 kg CO2eq·ha−1·year−1) and integrated production systems (930 ± 62 kg CO2eq·ha−1·year−1), whereas the values for the ecological production system were significantly higher (1479 ± 40 kg CO2eq·ha−1·year−1). The results show that growing vines under ecological production conditions generates a higher proportion of the carbon footprint than under conventional production conditions. Overall, the best results can be achieved in an integrated production system.

Household Fuelwood Consumption and Its Implication for Carbon Dioxide Emission

This review paper aims to gather informative data on the impact of climate extremes on the physical environment, public health, and the livelihoods of people in Ethiopia. The primary sources of data for this review were peer-reviewed journal articles obtained from electronic databases such as PubMed, Central, Scopus, and Web of Science. Globally, the vast majority of households in developing countries depend on wood energy for their daily energy needs. Such consumption trends are expected to remain a common feature of traditional wood energy production and consumption, at least in the short- to medium-terms. This situation increases the demand for firewood and charcoal from the forest. The process of harvesting standing trees for charcoal and fire wood leads to forest degradation. Although woody biomass has the function of energy consumption, and as a source of income for rural villagers and urban poor dwellers practicing agriculture, wood energy generally has low priority in national policies of developing countries. However, unsustainable management and negative environmental consequences in humid and dry forests is derived from the use of fuel wood energy. Still now there is an unsystematic assessment of the economic contribution and environmental consequences of wood energy use, so its significance and consequences have been minimized. This deforestation and forest degradation contributes 1–2.4 Gt CO2e of greenhouse gases, which is 2–7% of global anthropogenic emissions, with global greenhouse gas emissions mostly CO2.

The Global Environmental Benefits of Halving Avoidable Consumer Food Waste.

Avoidable consumer food waste (ACFW) is a global environmental issue wasting key resources and causing emissions, especially in high food-producing nations. We trace ACFW to its origin to assess emissions, water use, and land use. We show that ACFW impacts are dominated by commodities like beef, dairy, rice, and wheat. Over 80% of impacts are domestic, but impacts embodied in trade affect a few major food-producing countries under environmental pressure. A 50% reduction in ACFW could save up to 198 Mt CO2eq in emissions, 30 Gm3 of blue water, and 99 Mha of land. Targeting key commodities in impactful countries (e.g., US beef waste) could achieve significant benefits. Sparing wasted land and returning it to its potential natural vegetation could sequester 26 Gt CO2eq long-term (17-35 Gt CO2eq). Finally, while the 50% ACFW reduction lines up with Sustainable Development Goal (SDG) 12.3b for the avoidable portion of food waste, a total of 276 Mt of unavoidable consumer food waste is also generated, which cannot be readily reduced. Achieving a 50% reduction in total food waste would require a 93% reduction in ACFW. Tracking the spatial impacts of ACFW can elucidate the concrete benefits of policies aiming at SDG 12.3b.

The carbon footprint of the perioperative transurethral resection of bladder tumour pathway.

To evaluate the carbon footprint of the perioperative transurethral resection of bladder tumour (TURBT) pathway from decision to treat to postoperative discharge, and model potential greenhouse gas (GHG) emissions reduction strategies. This process-based attributional cradle-to-grave life-cycle assessment (LCA) of GHG emissions modelled the perioperative TURBT pathway at a hospital in Southwest England. We included travel, energy and water use, all reusable and consumable items, and laundry and equipment sterilisation. Resource use for 30 patients undergoing surgery was recorded to understand average GHG emissions and the inter-case variability. Sensitivity analysis was performed for manufacturing location, pharmaceutical manufacturing carbon-intensity, and theatre list utilisation. The median (interquartile range) perioperative TURBT carbon footprint was 131.8 (119.8-153.6) kg of carbon dioxide equivalent. Major pathway categories contributing to GHG emissions were surgical equipment (22.2%), travel (18.6%), gas and electricity (13.3%), and anaesthesia/drugs and associated adjuncts (27.0%), primarily due to consumable items and processes. Readily modifiable GHG emissions hotspots included patient travel for preoperative assessment, glove use, catheter use, irrigation delivery and extraction, and mitomycin C disposal. GHG emissions were higher for those admitted as inpatients after surgery. This cradle-to-grave LCA found multiple modifiable GHG emissions hotspots. Key mitigation themes include minimising avoidable patient travel, rationalising equipment use, optimally filling operating theatre lists, and safely avoiding postoperative catheterisation and hospital admission where possible. A crucial next step is to design and deliver an implementation strategy for the environmentally sustainable changes demonstrated herein.

Application of building prefabricated diaphragm walls: Mechanics-carbon dual-control parametric segmentation decision-making framework

As a crucial innovation in building below-grade envelope structures, prefabricated diaphragm walls (PDWs) require the integration of multi-layer information for effective segmentation. Existing decision-making approaches rely on a single condition, leading to significant disparities between decision outcomes and actual requirements. This study introduces the mechanic-carbon dual-control parametric segmentation decision-making (MCSD) framework for PDWs to integrate multi-layer information. MCSD framework firstly performs parametric characterization of PDW component shapes and local transport constraints. Refined numerical modeling is next employed to identify the dominant mechanical factors influencing segmentation decision-making. Optimization algorithm is developed to automatically generate feasible schemes. Finally, carbon assessment is utilized to identify optimal segmentation schemes. MCSD framework is verified by actual engineering and the following key findings are obtained. Compared to empirical methods, MCSD could quantitatively determine feasible segmentation positions across the entire surface of PDWs. Notably, MCSD reveals the competitive relationship between horizontal and longitudinal joints for the first time. By incorporating this mechanism for decision optimization, carbon dioxide equivalent could be reduced by up to 29.3%. Ultimately, MCSD transcends the traditional boundary between mechanics and carbon, enabling automated planning of PDW segmentation. This study provides scientific and quantitative guideline for the segmentation decisions of building prefabricated enclosure structures.

Assessment of Municipal Solid Waste Management Scenarios in Metro Manila Using the Long-Range Energy Alternatives Planning-Integrated Benefit Calculator (LEAP-IBC) System

Short-lived climate pollutants (SLCPs) and municipal solid wastes (MSWs) have been found to be viable sources of clean energy. This study integrates the Intergovernmental Panel on Climate Change (IPCC) guidelines for methane flow rate estimation in the software Long-Range Energy Alternatives Planning-Integrated Benefit Calculator (LEAP-IBC) system to estimate and project the methane emissions coming from the waste generated by Metro Manila, disposed in sanitary landfills. It aims to analyze the environmental impacts of the emissions coming from the non-energy sector using the IBC feature of LEAP and by developing two scenarios with 2010 and 2050 as the base and end years: the baseline and methane recovery scenario, where the latter represents the solid waste management undertaken to counter the emissions. Under the baseline, 97.30 million metric tonnes of methane emissions are expected to be produced and are predicted to continuously increase. In the same scenario, the cities of Quezon, Manila, and Caloocan account for the biggest methane emissions. On the other hand, in the methane recovery scenario, the methane emissions are expected to have a decline of 36% from 127.036 to 81.303 million metric tonnes by 2025, 52% from 135.358 to 64.972 million metric tonnes by 2030, and 54% from 150.554 to 69.254 million metric tonnes by 2040. For the 40-year projection of the study under the 100-year global warming potential analysis, a total of 10,249 million metric tonnes of CO2 equivalent is avoided in the methane recovery compared to the BAU, and a maximum of 0.019 °C temperature increase can also be avoided. Moreover, electricity costs without LFG technology increase from 2.21 trillion to 8.75 trillion, while costs with LFG technology also rise but remain consistently lower, ranging from 2.20 trillion to 8.74 trillion. This consistent reduction in electricity costs underscores the long-term value and importance of adopting LFG technology, even as its relative savings impact diminishes over time. Finally, the fixed effects and random effects panel data regression analysis reinforces and asserts that the solid waste management is really improved by means of the methane recovery technology, leading the methane emissions to decrease.

Self-adaptive energy-efficient windows with enhanced synergistic regulation of broadband infrared thermal radiation

Effective management of both near-infrared (NIR) radiation and long-wavelength infrared (LWIR) thermal emission through window design holds tremendous promise for achieving carbon neutrality in the building sector. Compared to the traditional static low emissivity (Low-E) and solar regulating windows, emerging emissivity-altering windows can better adapt to varied weather. However, dynamic windows with self-adaptive solar radiation and emissivity control have long been challenging, primarily due to the intricate broadband spectrum manipulation requiring sophisticated material design. Herein, by employing the NIR transparent hydrogen-doped In2O3 (IHO) as a function layer (ε = 0.13, TNIR = 79.8 %), we present a broadband self-adaptive radiative thermal management (SRTM) window based on Fabry-Perot resonator. Compared to the common tin-indium oxide (ITO)-based counterpart, the IHO-based SRTM window shows a 70 % enhancement in NIR power regulation ability (10.9 %) with remaining emissivity regulation ability (0.26). It contributes significantly to energy conservation offering an annual energy saving and equivalent CO2 emissions reduction of up to 20 % (411 MJ·m−2) and 244 tons/yr, compared to traditional Low-E windows globally.

Greywater heat recovery to the refill water of a dishwasher via paraffin wax and steel wool aided segmental baffle heat exchanger

In this study, the recovery of household dishwasher greywater thermal energy into dishwashing water using paraffin wax and steel wool supported segmental heat exchanger was experimentally investigated. The heat exchange performance was 40% in rapid, economy, and intensive modes and the heat recovery was 0.048, 0.031 and 0.082 kWh, respectively. Efficiency increased by 5.01%, 3.84%, and 6.5%. Time and energy were saved, and hygienic washing was accomplished by raising the washing temperature and reducing the cycle time nearly 97, 113, and 240 s. It is estimated that by using heat exchangers on 16,954,196 dishwashers in use in Turkey, small, medium, and large families can save an average of 127.366, 254.733 and 509.466 GWh per year, respectively, provided they use the three dishwasher modes equally. The annual economic size of the gain and its contribution to emission reduction in CO2 equivalents are $15.793 million, $31.586 million, $63.173 million and 112.974 kt, 225.948 kt, 451.897 kt, respectively. Energy efficiency index of dishwasher increased from 48.84 to 46.97.

Environmental Impact of Footwear Using Life Cycle Assessment—Case Study of Professional Footwear

Life cycle assessment (LCA) is a method for assessing the environmental impact of a product, activity, or system across all the stages of its life cycle. LCA can identify the activities with a major impact on the environment throughout the life cycle of a product. To analyze the environmental implications of footwear, the LCA was applied to a pair of shoes designed for professional use. In this paper, the impact of a single pair of shoes was studied. Every year, footwear production worldwide is over 22 billion pairs, which has a significant impact on the environment. In this case study, the “cradle-to-grave” approach was used, which refers to all the activities involved in the life cycle of a footwear product, starting from raw material extraction, manufacturing, use, maintenance, and, in the end, disposal. The LCA was conducted using the SimaPro software. The environmental impact assessment of the analyzed shoe needed the acquisition of two crucial datasets. Background inventory data were sourced from the Ecoinvent database (version 3.3). The impact was quantified using the Global Warming Potential (GWP) metric, which calculates the contribution of emissions to global warming over a 100-year time limit according to the established values provided by the Intergovernmental Panel on Climate Change (IPCC). The impact of greenhouse gas (GHG) emissions was measured in relative carbon dioxide equivalents (kg CO2eq) to facilitate a standardized comparison. The results show that the total carbon footprint for a pair of safety boots is 18.65 kg of CO2eq with the “component manufacture” stage as a major contributor accumulating almost 80%.

Experimental Optimization of Natural Gas Injection Timing in a Dual-Fuel Marine Engine to Minimize GHG Emissions

Phased injection of natural gas into internal combustion marine engines is a promising solution for optimizing performance and reducing harmful emissions, particularly unburned methane, a potent greenhouse gas. This innovative practice distinguishes itself from continuous injection because it allows for more precise control of the combustion process with only a slight increase in system complexity. By synchronizing the injection of natural gas with the intake and exhaust valve opening and closing times while also considering the gas path in the manifolds, methane release into the atmosphere is significantly reduced, making a substantial contribution to efforts to address climate change. Moreover, phased injection improves the efficiency of marine engines, resulting in reduced overall fuel consumption, lower fuel costs, and increased ship autonomy. This technology was tested on a single-cylinder, large-bore, four-stroke research engine designed for marine applications, operating in dual-fuel mode with diesel and natural gas. Performance was compared with that of the conventional continuous feeding method. Evaluation of the effect on equivalent CO2 emissions indicates a potential reduction of up to approximately 20%. This reduction effectively brings greenhouse gas emissions below those of the diesel baseline case, especially when injection control is combined with supercharging control to optimize the air–fuel ratio. In this context, the boost pressure in DF was reduced from 3 to 1.5 bar compared with the FD case.

Carbon footprint of mixed farming crop-livestock rotational-based grazing beef systems using long term experimental data

In the context of ever-growing demand for food and associated concerns regarding the environmental impacts of high-input agricultural systems, there is growing interest in mixed farm enterprises to deliver greater sustainability compared with mono-enterprise production systems. However, assessments of such systems are complex and require high-resolution data to determine the true value and interconnectivity across enterprises. Given the scarcity of information on mixed crop–livestock systems and the difficulties of its analysis, we perform life cycle assessment using temporally high-resolution data (2019–2022) from a long-term experiment in South America to evaluate the ‘cradle-to-farmgate exit’ greenhouse gas emissions intensities of four rotational crop–livestock systems. Systems evaluated were continuous cropping: 2 years of continuous cropping; short rotation: 2-year continuous cropping plus 2-year pasture; long rotation: 2-year continuous cropping followed by 4-year pasture; and forage rotation: continuous pasture. Emissions intensities for beef throughput were reported as kilograms of carbon dioxide equivalents (CO2-eq) per kilogram of liveweight gain (LWG) using the Intergovernmental Panel for Climate Change’s Sixth Assessment Report (AR6 2021) CO2 characterisation factors. Point estimate results were found to be 11.3, 11.8, 11.8 and 16.4 kg CO2-eq/kg/LWG for continuous cropping, short rotation, long rotation and forage rotation, respectively. Emission averages arising from crops, which were separated from animal-based emissions using economic allocation, were 1.23, 0.53 and 0.52 kg CO2-eq/kg for soybean, wheat and oat, respectively. The inclusion of soil organic carbon stock changes had notable effects on reducing each system’s emissions: by 22.4%, 19.2%, 25.3% and 42.1% under continuous cropping, short rotation, long rotation and forage rotation, respectively, when soil organic carbon was included. Given there are few life cycle assessment studies available on such mixed-enterprise ‘semi-circular’ systems, particularly with novel primary data, this study adds critical knowledge to agri-food-related sustainability literature by addressing environmental issues in complex production systems compared to extant and broad coverage of mono-enterprise systems.

Energy, exergy, exergoeconomic, economic, and environmental analyses and multi-objective optimization of a novel combined cooling and power system with dual-pressure Kalina cycle-absorption refrigeration

A novel combined cooling and power system, the dual-pressure Kalina cycle-absorption refrigeration (DPKC-AR-CCP), is proposed for the cascade utilization of waste heat from high-temperature flue gas and jacket water from internal combustion engines. A pneumatic booster pump unit is employed to increase the inlet pressure of the low-pressure expander, with heat generated during the compression process utilized for preheating the ammonia/water mixture, and exhaust gas from the low-pressure expander is combined with driving gas for absorption refrigeration. By integrating the first and second laws of thermodynamics with the SPECO Methodology, models for energy, exergy, exergoeconomy, economy, and environment of the DPKC-AR-CCP system are developed. A multi-objective optimization model is formulated with maximum exergy efficiency, minimum total exergy cost rate, and maximum annual equivalent carbon dioxide (CO2) emission reduction as objective functions. MATLAB software (combined with REFPROP software) is utilized for simulation and multi-objective optimization. The performance of each component under specific conditions is assessed, and a comparison with the simple absorption refrigeration/Kalina cogeneration system (AR/KC) highlights the advantages of the DPKC-AR-CCP system; an investigation into the effects of different operating parameters on performance is conducted. The results indicate that, under identical operational parameters, the DPKC-AR-CCP system exhibits a substantial increase in net output power (230.2 %), cooling capacity (98.7 %), and exergy efficiency (148.8 %) compared to the simple AR/KC system; payback period is reduced by 64.8 %; and annual equivalent CO2 emissions are decreased by 202.2 %. However, there is an increase in the total exergy cost rate by 90.5 %. The optimal concentration of ammonia/water is determined to be 0.816/0.184, with a heat exchanger outlet temperature of 341.07 K, driving pressure of 0.654 MPa, and low-pressure expander inlet pressure of 5.064 MPa. Correspondingly, the optimal exergy efficiency is 87.2 %, the annual reduction in CO2 emissions is 5.53 × 107 kg, and the total exergy cost rate is 288.48$/h.

Methane in Dairy Farms in Aguascalientes: Corn Silage

Objective: To evaluate the potential methane gas production from corn silages (CS) intended for Holstein cattle in dairy farms in the state of Aguascalientes (Ags), Mexico. Design/Methodology/Approach: Methane (CH4) is one of the greenhouse gases, and worldwide plans and actions are being developed to monitor, control, and reduce their environmental impact. In Mexico, methane emissions from livestock are equivalent to 10.1% of CO2 equivalent are recorded. CS samples were collected from six municipalities in Ags, representing a total of 18 dairy farms. The in vitro gas production technique was used to determine methane gas production, employing a nested mixed model to compare variables between municipalities using residual maximum likelihood method. Results: The average methane production in CS was 29.3 mL/gDM. The Ags municipality showed significantly higher methane production (35.9 mL/gDM, p<0.05), while San Francisco de los Romo (SFR) displayed the lowest production (21.5 mL/gDM, p<0.05). In the state of Aguascalientes, CS-derived CH4 production was projected at approximately 2,884 metric tons (MT) annually. Study Limitations/Implications: There were no identified limitations in the study. Findings/Conclusions: The potential CH4 gas production derived from CS projected in the study represented 0.103% of what was reported by INEGyCEI in 2019.

Climate-Driven Increases in Source Water Natural Organic Matter: Implications for the Sustainability of Drinking Water Treatment.

This study presents an updated analysis spanning over two decades (1999-2023) of climate, water quality, and operational data from two drinking water facilities in Atlantic Canada that previously experienced gradual increases in the natural organic matter (NOM) concentration and brownification. The goal was to assess the impact of recent extreme weather events on acute NOM concentration increases and drinking water treatment processes. In 2023, a dry spring combined with a warm and wet summer caused NOM in the water supplies to increase by >67% (as measured by color). To mitigate increased NOM concentration, the alum dose nearly doubled in 2023 compared to that in 2022. Disinfection byproducts were elevated following the event but remained within the compliance levels. From 1999 to 2023, the two plants responded to gradual climate change impacts and brownification, with alum dose increases of between 4.1 and 8.3 times. Equivalent CO2 emissions were estimated for alum usage, which increased by 3 to 7-fold in 2023 compared to when the plants were commissioned decades prior. The plants were not only adversely impacted by climate change but also contributed to the global CO2 burden. Thus, a paradigm shift toward sustainable alternatives for NOM removal is required in the water sector, and climate change adaptation and mitigation principles are urgently needed.

Evaluation of parameters impacting grey H2 storage in coalbed methane formations

Injecting grey hydrogen into coalbed methane formations has the potential to transform coal into a geologically temporary “H2-Battery” and a permanent “CO2-sink”. This study aims to thoroughly evaluate crucial parameters-sorption, diffusion, and matrix swelling/shrinkage-that impact grey hydrogen injection in CH4-enriched coalbed formations. In terms of sorption capacity, CO2 exhibits the highest, followed by CH4 and then H2. Sorption data affirmed that anthracite coal has a certain degree of adsorption capacity for H2, with H2 demonstrating superior diffusive gas deliverability as indicated by its diffusion coefficient, which is approximately six times higher than that of CO2. These characteristic position coal as a promising candidate for temporary H2 storage and cleaning, optimizing injectivity and depletion efficiency. Interestingly, H2 adsorption induced matrix shrinkage in coal, in contrast to other strong sorption gases such as CH4 and CO2, which resulted in matrix swellings. Matrix deformations induced by H2–CO2 mixture (grey hydrogen) injection were conducted and quantified to evaluate grey hydrogen injection in future field trials. The results reveal that the majority of directional strains indicated that when the partial pressure of CO2 in the H2–CO2 mixture is equivalent to pure CO2 pressure, the latter case induces elevated swelling strains. This finding implicitly supports the hypothesis that H2–CO2 mixture injection causes less matrix swelling than pure CO2 injection at equivalent CO2 pressure. This work provides essential parameters to illustrate an enhanced synergism among hydrogen storage, carbon sequestration, and enhance coalbed methane recovery through grey hydrogen injection in coal formations.

Stochastic Capacity Optimization of an Integrated BFGCC–MSHS–Wind–Solar Energy System for the Decarbonization of a Steelmaking Plant

Deploying renewable generation to replace conventional fossil-fuel-based energy supplies provides an important pathway for the decarbonization of steelmaking plants. Meanwhile, it is also crucial to improve the flexibility of blast-furnace-gas-fired combined-cycle power plants (BFGCCs) to ease the accommodation of uncertain renewable generation. To this end, this paper proposes the deployment of a molten salt heat storage (MSHS) system in BFGCCs to store the heat of gas turbine flue gas so that the power–heat coupling of these BFGCCs can be unlocked to enhance the flexibility of the energy supply. A stochastic capacity optimization of an integrated BFGCC–MSHS–wind–solar (BMWS) energy system is presented to determine the optimal installed capacities of a BFG holder, MSHS, wind turbine, and PV panel, aiming to achieve an economic and safe energy supply for the entire system. Multiple scenarios considering uncertain fluctuations in load demands and renewable generation are generated with the Monte Carlo method based on a typical scenario. These scenarios are then reduced to representative scenarios using the synchronous substitution and reduction method for stochastic capacity optimization to enhance the reliability of the results. The case study results demonstrate that configuring MSHS reduces the total annualized cost of the BMWS system by 2.28%. Furthermore, considering the uncertainties of the power/heating load and wind/PV generation can reduce the expected annualized total cost of the BMWS system and the corresponding standard deviation by 5.66% and 81.45%, respectively. The BMWS system can achieve 730.68 tons of equivalent CO2 reduction in 24 h due to the successful utilization of renewable energy. This paper provides an effective approach for the decarbonization of energy generation systems in steelmaking plants.

Decreasing Greenhouse Gas Emissions from the Municipal Solid Waste Sector in Chinese Cites.

Municipal solid waste (MSW) management systems play a crucial role in greenhouse gas (GHG) emissions in China. Although the government has implemented many policies to improve the MSW management system, the impact of these improvements on city-level GHG emission reduction remains largely unexplored. This study conducted a comprehensive analysis of both direct and downstream GHG emissions from the MSW sector, encompassing sanitary landfill, dump, incineration, and biological treatment, across 352 Chinese cities from 2001 to 2021 by adopting inventory methods recommended by the Intergovernmental Panel on Climate Change (IPCC). The results reveal that (1) GHG emissions from the MSW sector in China peaked at 70.6 Tg of CO2 equiv in 2018, followed by a significant decline to 47.6 Tg of CO2 equiv in 2021, (2) cities with the highest GHG emission reduction benefits in the MSW sector were historical emission hotspots over the past 2 decades, and (3) with the potential achievement of zero-landfilling policy by 2030, an additional reduction of 203.7 Tg of CO2 equiv is projected, with the emission reduction focus toward cities in South China (21.9%), Northeast China (17.8%), and Southwest China (17.3%). This study highlights that, even without explicit emission reduction targets for the MSW sector, the improvements of this sector have significantly reduced GHG emissions in China.