Search Results (266)

Mining (1) operations in remote areas (2) face significant challenges related to energy supply, high fuel costs, and limited infrastructure. This study investigates the potential for achieving energy independence (3) and resilience (4) in such environments through the integration of renewable energy sources (5) and battery–electric mining equipment. Using the “Studena Vrila” underground bauxite mine as a case study, a comprehensive techno-economic and environmental analysis was conducted across three development models. These models explore incremental scenarios of solar and wind energy adoption combined with electrification of mobile machinery. The methodology includes calculating levelized cost of energy (LCOE), return on investment (ROI), and greenhouse gas (GHG) reductions under each scenario. Results demonstrate that a full transition to RES and electric machinery can reduce diesel consumption by 100%, achieve annual savings of EUR 149,814, and cut GHG emissions by over 1.7 million kg CO₂-eq. While initial capital costs are high, all models yield a positive Net Present Value (NPV), confirming long-term economic viability. This research provides a replicable framework for decarbonizing mining operations in off-grid and infrastructure-limited regions. Full article

The Union of the Comoros, located in the Indian Ocean, faces persistent energy challenges due to its geographic isolation, heavy dependence on imported fossil fuels, and underdeveloped electricity infrastructure. This study investigates the techno-economic optimization of a hybrid microgrid designed to supply electricity to a rural village in Grande Comore. The proposed system integrates photovoltaic (PV) panels, wind turbines, a diesel generator, and battery storage. Detailed modeling and simulation were conducted using HOMER Energy, accompanied by a sensitivity analysis on solar irradiance, wind speed, and diesel price. The results indicate that the optimal configuration consists solely of PV and battery storage, meeting 100% of the annual electricity demand with a competitive levelized cost of energy (LCOE) of 0.563 USD/kWh and zero greenhouse gas emissions. Solar PV contributes over 99% of the total energy production, while wind and diesel components remain unused under optimal conditions. Furthermore, the system generates a substantial energy surplus of 63.7%, which could be leveraged for community applications such as water pumping, public lighting, or future system expansion. This study highlights the technical viability, economic competitiveness, and environmental sustainability of 100% solar microgrids for non-interconnected island territories. The approach provides a practical and replicable decision-support framework for decentralized energy planning in remote and vulnerable regions. Full article

The utilization of thermal energy from co-produced water during natural gas production offers a promising pathway to enhance energy efficiency and reduce carbon emissions. This study proposes a techno-economic evaluation model to assess the feasibility and profitability of geothermal energy recovery from co-produced water in marginal gas wells. A wellbore fluid flow and heat transfer model is developed and validated against field data, with deviations in calculated wellhead temperature and pressure within 10%, demonstrating the model’s reliability. Sensitivity analyses are conducted to investigate the influence of key technical and economic parameters on project performance. The results show that electricity price, heat price, and especially government one-off subsidies have a significant impact on the net present value (NPV), whereas the effects of insulation length and annular fluid thermal conductivity are comparatively limited. Under optimal conditions—including 2048 m of insulated tubing, annular protection fluid with a thermal conductivity of 0.4 W/(m·°C), a 30% increase in heat and electricity prices, and a 30% government capital subsidy—the project breaks even in the 14th year, with the 50-year NPV reaching 0.896 M$. This study provides a practical framework for evaluating and optimizing geothermal energy recovery from co-produced water, offering guidance for future sustainable energy development. Full article

With rising energy costs and the need for sustainable power solutions in urban South African settings, grid-tied renewable energy systems have become viable alternatives for reducing dependence on traditional grid supply. This study investigates the techno-economic feasibility of a grid-connected hybrid photovoltaic (PV) and battery storage system designed for a commercial facility located in Johannesburg, South Africa—an area characterized by a subtropical highland climate. We conducted the analysis using the HOMER Grid software and evaluated the performance of the proposed PV/battery system against the baseline grid-only configuration. Simulation results indicate that the optimal systems, comprising 337 kW of flat-plate PV and 901 kWh of lithium-ion battery storage, offers a significant reduction in electricity expenditure, lowering the annual utility cost from $39,229 to $897. The system demonstrates a simple payback period of less than two years and achieves a net present value (NPV) of approximately $449,491 over a 25-year project lifespan. In addition to delivering substantial cost savings, the proposed configuration also enhances energy resilience. Sensitivity analyses were conducted to assess the impact of variables such as inflation rate, discount rate, and load profile fluctuations on system performance and economic returns. The results affirm the suitability of hybrid grid-tied PV/battery systems for cost-effective, sustainable urban energy solutions in climates with high solar potential. Full article

Municipal solid waste (MSW) and refuse-derived fuel (RDF) incineration generate over 20 million tons of residues annually in the EU. These include bottom ash (IBA), fly ash (FA), and air pollution control residues (APCr), which pose significant environmental challenges due to their leaching potential and hazardous properties. While these residues contain valuable metals and reactive mineral phases suitable for carbonation or alkaline activation, chemical, techno-economic, and policy barriers have hindered the implementation of sustainable, full-scale management solutions. Accelerated carbonation technology (ACT) offers a promising approach to simultaneously sequester CO₂ and enhance residue stability. This review provides a comprehensive assessment of waste incineration residue carbonation, covering 227 documents ranging from laboratory studies to field applications. The analysis examines reactor designs and process layouts, with a detailed classification based on material characteristics, operating conditions, investigated parameters, and the resulting pollutant stabilization, CO₂ uptake, or product performance. In conclusion, carbonation-based approaches must be seamlessly integrated into broader waste management strategies, including metal recovery and material repurposing. Carbonation should be recognized not only as a CO₂ sequestration process, but also as a binding and stabilization strategy. The most critical barrier remains chemical: the persistent leaching of sulfates, chromium(VI), and antimony(V). We highlight what we refer to as the antimony problem, as this element can become mobilized by up to three orders of magnitude in leachate concentrations. The most pressing research gap hindering industrial deployment is the need to design stabilization approaches specifically tailored to critical anionic species, particularly Sb(V), Cr(VI), and SO₄²⁻. Full article

Under the impetus of the global urbanization, the synergistic relationship between smart city policies and green innovation capabilities has emerged as a critical agenda for achieving sustainable development goals. While existing studies have explored the techno-economic effects of smart cities, systematic evidence remains scarce regarding their pathways and heterogeneous impacts on green growth. This study investigates the influence of smart city pilot policies on urban green growth trajectories and their heterogeneous characteristics. Leveraging panel data from 293 Chinese prefecture-level cities, we employ a multi-period difference-in-differences (DID) model with two-way fixed effects to control for unobserved city-specific and time-specific factors, complemented by robustness checks including parallel trend tests, placebo tests, and alternative dependent variable specifications. Data sources encompass the China City Statistical Yearbook, CNRDS, and CSMAR databases, covering core metrics such as green patent applications and grants, industrial upgrading indices, and environmental regulation intensity, with missing values being addressed via mean imputation. The findings demonstrate that smart city pilot policies significantly enhance green innovation levels in treated cities, with effects exhibiting pronounced spatial and resource-based heterogeneity; there are notably stronger impacts in non-resource-dependent cities and eastern regions. Mechanism analysis shows that policies are driven by a dual effect of industrial upgrading and environmental regulation. The former is manifested by the high substitution elasticity of the digital economy for traditional manufacturing, while the latter is reflected in the rising compliance costs of polluting enterprises. This research advances a cross-nationally comparable theoretical framework for understanding green transition mechanisms in smart city development while providing empirical benchmarks for policy design in emerging economies. Full article

Aviation is widely recognised as one of the most carbon-intensive modes of transport and among the most challenging sectors to decarbonise. The use of green hydrogen (H₂) in airside operations can help reduce emissions from air transport. While the pace and scalability of technology development, including H₂-powered and ground support equipment, will be key factors, other financial, regulatory, legal, organisational, behavioural, and societal issues must also be considered. This paper investigates the key opportunities and challenges of using H₂ in the aviation industry through eleven semi-structured interviews and a virtual expert workshop (N = 37) with key aviation industry stakeholders and academia. The results indicate that, currently, decarbonisation of the aviation sector faces several challenges, including socio-technical, techno-economic, and socio-political challenges, with socio-technical challenges being the most prominent barrier. This study shows that decarbonisation will not occur until the UK government is ready to have all the required infrastructure and capacity in place. Governments can play a significant role in directing the necessary ‘push’ and ‘pull’ to develop and promote zero-carbon emission aircraft in the marketplace and ensure safe implementation. Full article

The agriculture sector is a major contributor to the economy of Alberta, Canada, accounting for almost 2.8% of the total GDP. Considering its importance, implementing efficient and cost-effective irrigation systems is vital for promoting sustainable agriculture in semi-arid regions like Lethbridge County, Alberta, Canada. Although irrigation is primarily carried out using the Oldman River and its allied reservoirs, groundwater pumping becomes a supplementary necessity during periods of limited surface water availability or droughts. This research investigates the potential of renewable energy resources, such as wind and solar energy, to meet the energy requirements for crop irrigation. The study begins by identifying and calculating the water requirements for major crops in Lethbridge County, such as wheat and barley, using the United Nations Food and Agriculture Organization’s CROPWAT 8.0 software. Subsequently, energy calculations were conducted to meet the specific crop water demand through the design of a hybrid energy system using Homer Pro 3.16.2. A technoeconomic analysis of the renewable hybrid system has been carried out to demonstrate the efficiency and novelty of the proposed work. Outcomes revealed that the proposed system is both efficient and economical in fulfilling the crop water requirement through groundwater pumping, promoting sustainable agriculture, and helping to ensure food security in the region. Full article

The sustainability of the natural gas-to-methanol (NGTM) and methanol-to-gasoline (MTG) processes are assessed in this systematic review as a potential substitute in the global energy transition. Methanol offers itself as a versatile and less carbon-intensive substitute for conventional gasoline in light of growing environmental concerns and the demand for cleaner fuels. This review’s rationale is to assess MTG’s ability to lessen environmental impact while preserving compatibility with current fuel infrastructure. The goal is to examine methanol and gasoline’s effects on the environment, society, and economy throughout their life cycles. This review used a two-phase systematic literature review methodology, filtering and evaluating studies that were indexed by Scopus using bibliometric and thematic analysis. A total of 25 documents were reviewed, in which 22 documents analyzed part of this study, and 68% employed LCA or techno-economic analysis, with the U.S. contributing 35% of the overall publications. A comparative analysis of the reviewed literature indicates that methanol-based fuels offer significantly lower greenhouse gas (GHG) emissions and life cycle environmental impacts than gasoline, particularly when combined with carbon capture and renewable feedstocks. This review also highlights benefits, such as improved safety and energy security, while acknowledging challenges, including high production costs, infrastructure adaptation, and toxicity concerns. Several drawbacks are high manufacturing costs, the necessity to adjust infrastructure, and toxicity issues. The report suggests investing in renewable methanol production, AI-driven process optimization, and robust legislative frameworks for integrating green fuels. The life cycle sustainability assessment (LCSA) of NGTM and MTG systems should be investigated in future studies, particularly in light of different feedstock and regional circumstances. The findings emphasize NGTM and MTG’s strategic role in aligning with several UN Sustainable Development Goals (SDGs) and add to the worldwide conversation on sustainable fuels. A strong transition necessitates multi-stakeholder cooperation, innovation, and supporting policies to fully realize the sustainability promise of cleaner fuels like methanol. Full article

South Africa’s persistent energy shortages and high utility costs have led to increased interest in rooftop solar photovoltaic (PV) systems. However, understanding their economic and environmental viability in urban residential contexts remains limited. This study investigates the feasibility of integrating rooftop solar PV systems with local energy storage and grid electricity in residential housing complexes in Benoni, Gauteng Province. A hybrid energy system was proposed and modeled using detailed consumption data from a typical community in Benoni. The system includes rooftop PV installations, lithium-ion storage, and connection to the national grid. A techno-economic analysis was conducted over a 25-year project lifespan to evaluate energy cost, payback period, net present cost, and carbon dioxide emissions. The optimal system configuration—Solar PV + Storage + Grid—achieved average annual utility bill savings of USD 30,207, with a payback period of 1.0 year, a net present cost (NPC) of USD 40,782, and an internal rate of return (IRR) of 101.7%. Annual utility costs were reduced from USD 30,472 to USD 267, and the system resulted in a net reduction of 130 metric tons of CO₂ emissions per year. The levelized cost of energy (LCOE) was USD 0.0071/kWh. The integration of rooftop solar PV and energy storage with grid electricity presents a highly cost-effective and environmentally sustainable solution for residential communities in urban South Africa. The findings support policy initiatives aligned with Sustainable Development Goal (SDG) 7: “Affordable and Clean Energy”. Full article

The cement industry faces increasing energy costs and environmental pressures, driving the adoption of alternative fuels derived from waste materials. In Togo, approximately 350,000 t of end-of-life tires (ELT) are generated annually, creating significant environmental and health hazards through uncontrolled disposal and burning practices. This study investigated the technical feasibility and economic viability of incorporating waste tires as an alternative fuel in cement manufacturing. Tire-derived fuel (TDF) performance was evaluated by comparing pre-processed industrial tires with unprocessed ones, focusing on clinker production loss, elemental composition, heating values, and bulk density. The results demonstrate that TDF exhibits superior performance characteristics, with the highest heating values, and meets all the required specifications for cement production. In contrast, whole tire incineration fails to satisfy the recommended criteria, necessitating blending with conventional fuels to maintain clinker quality and combustion efficiency. The investigation revealed no significant adverse effects on production processes or clinker quality while achieving substantial reductions in nitrogen and sulfur oxide emissions. The experimental results were compared with the theoretical burnout times to optimize the shredding operations and injection methods. However, several challenges remain unaddressed, including the absence of streamlined handling processes, limited understanding of long-term ecological and health impacts, and insufficient techno-economic assessments. Future research should prioritize identifying critical aging points, investigating self-rejuvenating behaviors, and quantifying long-term environmental implications. These findings provide a foundation for developing computational models to optimize the mixing ratios of alternative and fossil fuels in cement manufacturing, offering significant environmental, economic, and societal benefits for the cement industry. Full article

In recent decades, the attention of researchers has been directed towards the study of the dehydration of isopropanol (IPA) through different techniques. Besides its multiple uses in the chemical industry, IPA is also a potential bio-component in eco-friendly gasolines. Extractive distillation is a successful technique for separating IPA from a minimum boiling azeotrope with water. However, the major challenge is the production of fuel-grade IPA (minimum 99.92 mol%) with low expenses. As a consequent step in the investigation of IPA dehydration with propylene glycol as extractive solvent, the present study compares its efficiency and economic viability with two other extractive solvents, namely ethylene glycol (EG) and dimethyl sulfoxide (DMSO). A systematic and comprehensive methodology was developed to design a three-column extractive distillation (TCED) for each investigated solvent. A techno-economic assessment of all the investigated processes concluded that ethylene glycol, followed by propylene glycol, seems to be the most promising solvent in the IPA dehydration process. Further, the heat integration of hot streams (SH flowsheets) demonstrated improvements over 17% in the case of ethylene glycol solvent, around 16% in the case of propylene glycol (PG) solvent, and only 10% (in the case of DMSO solvent) reduction in utility consumption, improving the energy efficiency of TCED processes. Furthermore, SH flowsheets yield a 14% cost saving obtained in terms of total annualized cost (TAC) and, respectively, 8.69%, by comparison with TCED processes. In the case of DMSO solvent, the TAC reduction is only 3.54% due to the capital cost, which has an increase of 3% mainly due to the high solvent cost. Full article

Environmentally friendly and low-emission extraction methods are needed to meet worldwide rare earth element (REE) demand. Within a greenhouse setting, this study aims to investigate the REE hyperaccumulation ability of four plant species (e.g., Phalaris arundinacea, Solanum nigrum, Phytolacca americana, and Brassica juncea) and the impact of amending REE-rich soil with biochar or fertilizer and watering with citric acid solution. Harvested samples were pyrolyzed, and the resulting bio-ores were acid-digested and underwent elemental analysis to determine REE content. Amending soil with fertilizer and biochar increased bio-ore production, while plant species explained the most variation in bioaccumulation factor. The results indicate that Phalaris arundinacea achieved the highest average REE concentration of 27,940 µg/g for the targeted REEs (comprising cerium, lanthanum, neodymium, praseodymium, and yttrium) and 37,844 µg/g for total REEs. It is also found that soil amendment and plant species are critical parameters in the design and implementation of Idaho-based REE phytomining operations. The life cycle assessment study estimated that the electricity demand of the greenhouse contributed the most to GHG emissions during the greenhouse study. Within the field study, electricity demand of the pyrolysis reactor was determined to be the largest producer of GHGs. The techno-economic analysis estimated that the total cost of growing P. arundinacea for six weeks on a one-acre field area is USD 6213, including 39%, 22%, 21%, and 18% of that cost derived from cultivation, biomass processing, soil treatment with fertilizer, and pyrolysis, respectively. It is concluded that the proposed low-emission extraction pathway, which combines phytomining, drying, and pyrolysis, is a promising sustainable approach for REE extraction, especially from REE-rich soil sourced in Idaho. Full article

The life-cycle economics and greenhouse-gas (GHG) emissions of forest biomass harvesting and utilization for value-added bioproducts were comprehensively evaluated via the development of an integrated modeling framework. Taking the eastern U.S. as the case region, the model innovatively integrated field studies, a Bayesian-based statistical learning model, techno-economic analysis, and life-cycle assessment. In specific, by investigating and summarizing the typical forest biomass harvesting systems across the region, the forest biomass harvesting costs were spatially grouped and mapped for four classified subregions across the eastern US. Overall, with 95% confidence the forest biomass harvesting cost is between USD 21.99 and USD 44.33/dry Mg, while the GHG emissions are between 14.79 and 98.80 kg CO₂ eq./dry Mg. Furthermore, for the forest biomass utilization for four alternative value-added bioproducts, the minimum selling price (MSP) is USD 177.82/Mg for pellet fuel, USD 110.24/MWh for biopower, USD 1059.4/Mg for biochar, and USD 4.98/gallon for aviation fuel. The life-cycle GHG emissions are 149.80 kg CO₂ eq./Mg pellet fuel, 52.22 kg CO₂ eq./MWh biopower, 792.12 kg CO₂ eq./Mg biochar, and 2.13 kg CO₂ eq./gallon aviation fuel, respectively. Considering the uncertainties, 95% confidence intervals of MSPs range from USD 164.77 to USD 190.97/Mg for pellet fuel with an 81.85% probability to be profitable, from USD 100.20 to USD 120.21/MWh for biopower with a 49.38% probability to be profitable, from USD 1000.91 to USD 1109.25/Mg for biochar with a 79.51% probability to be profitable, from USD 4.86 to USD 5.54/gallon for aviation fuel with an 0.03% probability to be profitable. Moreover, the MSPs of pellet fuel and biochar are much less affected by the market changes than those of biopower and aviation fuel. However, the production of biopower and aviation fuel has lower carbon intensities than that of pellet fuel and biochar. Full article

While the application of antibiotics in livestock production has undeniably propelled the rapid growth of animal husbandry, the escalating crisis of antimicrobial resistance stemming from antibiotic use poses significant threats to global public health and sustainable agricultural development. To address this critical challenge, multifaceted strategies have been implemented through coordinated policy interventions and scientific innovations. This review systematically examines two pivotal dimensions: (1) evolving regulatory frameworks governing antibiotic usage and (2) emerging non-antibiotic alternatives, with a particular focus on their implementation mechanisms and technological maturation. The analysis of transnational antibiotic governance encompasses comparative policy evolution in the European Union, the United States, and China. These regulatory paradigms address critical control points including registration management policies, usage monitoring systems, and integrated surveillance programs. Concerning technological alternatives, six categories of antibiotic substitutes are critically evaluated: Chinese herbal formulations, plant-derived essential oils, antimicrobial peptides, microecological agents, acidifiers, and enzyme preparations. These solutions are functionally categorized into prophylactic agents (enhancing disease resilience) and zootechnical additives (optimizing feed efficiency). These antibiotic alternatives demonstrate certain efficacy in alleviating the challenges of antibiotic overuse, yet they still face multiple implementation barriers. Further investigations are warranted to establish standardized efficacy evaluation protocols and conduct technoeconomic feasibility assessments under commercial-scale production conditions. Ultimately, resolving the antibiotic dilemma requires synergistic collaboration between regulatory bodies, pharmaceutical innovators, and academic researchers. This work emphasizes the crucial interplay between evidence-based policymaking and technological advancement in shaping sustainable livestock production systems. Full article