Search Results (1,924)

This paper investigates technological pathways for the conversion of coal-fired power plants toward sustainable energy sources, using an integrated multi-criteria decision-making approach that combines Proknow-C, AHP, and PROMETHEE. Eight alternatives were identified: full conversion to natural gas, full conversion to biomass, coal and natural gas hybridization, coal and biomass hybridization, electricity and hydrogen cogeneration, coal and solar energy hybridization, post-combustion carbon capture systems, and decommissioning with subsequent reuse. The analysis combined bibliographic data (26 scientific articles and 13 patents) with surveys from 14 energy experts, using Total Decision version 1.2.1041.0 and Visual PROMETHEE version 1.1.0.0 software tools. Based on six criteria (environmental, structural, technical, technological, economic, and social), the most viable option was full conversion to natural gas (ϕ = +0.0368), followed by coal and natural gas hybridization (ϕ = +0.0257), and coal and solar hybridization (ϕ = +0.0124). These alternatives emerged as the most balanced in terms of emissions reduction, infrastructure reuse, and cost efficiency. In contrast, decommissioning (ϕ = −0.0578) and carbon capture systems (ϕ = −0.0196) were less favorable. This study proposes a structured framework for strategic energy planning that supports a just energy transition and contributes to the United Nations Sustainable Development Goals (SDGs) 7 and 13, highlighting the need for public policies that enhance the competitiveness and scalability of sustainable alternatives. Full article

In the last decades, small satellites such as CubeSats and PocketQubes have become popular platforms for scientific and applied missions in low Earth orbit (LEO). However, prolonged exposure to atomic oxygen, ultraviolet radiation, and thermal cycling in LEO leads to gradual degradation of onboard solar panels, reducing mission lifetime and performance. This study addresses the need to quantify and compare the degradation behavior of different solar cell technologies and protective coatings used in nanosatellites and pico-satellites. The aim is to evaluate the in-orbit performance of monocrystalline silicon (Si), gallium arsenide (GaAs), triple-junction (TJ) structures, and copper indium gallium selenide (CIGS) cells under varying orbital and satellite parameters. Telemetry data from recent small satellite missions launched after 2020, combined with numerical modeling in GNU Octave, were used to assess degradation trends. The models were validated using empirical mission data, and statistical goodness-of-fit metrics (RMSE, R²) were applied to evaluate linear and exponential degradation patterns. Results show that TJ cells exhibit the highest resistance to LEO-induced degradation, while Si-based panels experience more pronounced power loss, especially in orbits below 500 km. Furthermore, smaller satellites (<10 kg) display higher degradation rates due to lower thermal inertia and limited shielding. These findings provide practical guidance for the selection of solar cell technologies, anti-degradation coatings, and protective strategies for long-duration CubeSat missions in diverse LEO environments. Full article

This study analyses the potential electricity output from different bio wastes using various energy conversion technologies to enhance the share of renewable energy. Furthermore, it evaluates the carbon emissions mitigated by replacing fossil fuels with bioenergy, contributing to efforts to reduce environmental pollution. The findings reveal that Egypt’s annual biomass waste (BW) could total approximately 80 million tons, with the most significant contributions from agricultural crop residues and municipal solid waste (MSW). MSW incineration and crop residue combustion were found to have the highest power generation compared to other techniques. Additionally, the anaerobic digestion of various biomass types offers the benefits of lower greenhouse gas emissions while still generating significant energy. The electricity generation from different BW sources is approximately 49.14 TWh/year. This energy can be predominantly generated through direct combustion of agricultural crop residues (66%), incineration of MSW (29%), anaerobic digestion of sewage sludge (3%), and animal waste (2%). Furthermore, the reduction in carbon emissions from substituting fossil fuels with bioenergy is estimated at up to 30.47 million tons of CO₂ annually, supporting efforts to mitigate climate change and combat global warming. Full article

The Middle East and North Africa region has not played a major role in climate action so far, and several countries depend economically on fossil fuel exports. However, this is a region with vast solar energy resources, which can be exploited affordably for power generation and hydrogen production at scale to eventually reach carbon neutrality. In this paper, we elaborate on the case of the United Arab Emirates and explore the aspirations and feasibility of its net-zero by 2050 target. While we affirm the concept per se, we also highlight the technological complexity and economic dimensions that accompany such transformation. We expect the UAE’s electricity demand to triple between today and 2050, and the annual green hydrogen production is expected to reach 3.5 Mt, accounting for over 40% of the electricity consumption. Green hydrogen will provide power-to-fuel solutions for aviation, maritime transport and hard-to-abate industries. At the same time, electrification will intensify—most importantly in road transport and low-temperature heat demands. The UAE can meet its future electricity demands primarily with solar power, followed by natural gas power plants with carbon capture, utilization and storage, while the role of nuclear power in the long term is unclear at this stage. Full article

Facing challenges of low efficiency and severe wear in deep hard formations with conventional drilling bits, this study investigates the synergistic rock-breaking technology combining a pulsed CO₂ laser with mechanical bits. The background highlights the need for novel methods to enhance drilling speed in high-strength, abrasive strata where traditional bits struggle. The theoretical analysis explores the thermo-mechanical coupling mechanism, where pulsed laser irradiation rapidly heats the rock surface, inducing thermal stress cracks, micro-spallation, and strength reduction through mechanisms like mineral thermal expansion mismatch and pore fluid vaporization. This pre-damage layer facilitates subsequent mechanical fragmentation. The research employs finite element numerical simulations (using COMSOL Multiphysics with an HJC constitutive model and damage evolution criteria) to model the coupled laser–mechanical–rock interaction, capturing temperature fields, stress distribution, crack propagation, and assessing efficiency. The results demonstrate that laser pre-conditioning significantly achieves 90–120% higher penetration rates compared to mechanical-only drilling. The dominant spallation mechanism proves energy-efficient. Conclusions affirm the feasibility and significant potential of CO₂ laser-assisted drilling for deep formations, contingent on optimized laser parameters, composite bit design (incorporating laser transmission, multi-head layout, and environmental protection), and addressing challenges, like high in-situ stress and drilling fluid interference through techniques like gas drilling. Future work should focus on high-power laser downhole transmission, adaptive control, and rigorous field validation. Full article

This study examines the issue of wind power smoothing in renewable-energy-grid integration scenarios. Under the “dual-carbon” policy initiative, large-scale renewable energy integration (particularly wind power) has become a global focus. However, the intermittency and uncertainty of wind power output exacerbate grid power fluctuations, posing challenges to power system stability. Consequently, smoothing strategies for wind power energy storage systems are desperately needed to improve operational economics and grid stability. According to current research, single energy storage technologies are unable to satisfy both the system-level economic operating requirements and high-frequency power fluctuation compensation at the same time, resulting in a trade-off between economic efficiency and precision of frequency regulation. Therefore, hybrid energy storage technologies have emerged as a key research focus in wind power energy storage. This study employs the SE-SGMD method, utilizing the distinct characteristics of lithium batteries and supercapacitors to decompose frequency regulation commands into low- and high-frequency components via frequency separation strategies, thereby controlling the output of supercapacitors and lithium batteries, respectively. Additionally, the GA-GWO algorithm is applied to optimize energy-storage-system configuration, with experimental validation conducted. The theoretical contributions of this study include the following: (1) introducing the SE-SGMD frequency separation strategy into hybrid energy storage systems, overcoming the performance limitations of single energy storage devices, and (2) developing a power allocation mechanism on the basis of the inherent properties of energy storage devices. In terms of methodological innovation, the designed hybrid GA-GWO algorithm achieves a balance between optimization accuracy and efficiency. Compared to PSO-DE and GWO-PSO, the GA-GWO energy storage system demonstrates improvements of 21.10% and 17.47% in revenue, along with reductions of 6.26% and 12.57% in costs, respectively. Full article

This script discusses a qualitative analysis of the characteristics of coals burned in the combustion chambers of thermal power plants in Serbia. The study includes the following coal characteristics (mass fraction): moisture ($W\%$) ash ($A\%$), combustible materials ($V_g\%$) and lower heating power ($H_d(\mathrm{kJ}·{\mathrm{kg}}^{-1})$). Based on the collected data, statistical modeling was conducted, which included the calculation of the mean value ($\overline{X}$), standard deviation ($S$), and coefficient of variation ($C_v$) for each of the listed characteristics. The results indicate that all analyzed characteristics exhibit significant deviations from their mean values, as confirmed by the high values of the coefficient of variation (moisture 70.20%, ash 62.21%, combustible matter 43.33%, and lower heating value 44.10%). Large mass fraction deviations ($W$), ($A$), $(V_g)$ and $H_d$ around the mean value may negatively impact the operation of boiler plants and electrostatic precipitators of thermal power plants in Serbia, where the considered coals are burned. Large oscillations of ash (62.21%) around the mean value (17.00%) suggests that it is not feasible to implement dry flue-gas desulfurization (FGD) processes, due to the additional amount of ash. Distribution testing confirmed that all examined parameters can be reasonably approximated by a normal distribution. Subsequent statistical modeling using Student’s t-test at a 0.05 significance level demonstrated strong agreement between the coal characteristics from Serbia and corresponding parameters of coals from Bosnia and Herzegovina and Montenegro. The obtained results enable reliable quality comparison of coals, particularly lignites, across different basins. These findings establish a solid foundation for further energy and technological valorization of these fuel resources. Full article

This paper presents the design and implementation of an ultra-wideband (UWB) and flat gain low noise amplifier (LNA) using 0.15 µm GaAs pHEMT technology, specifically tailored for applications that benefit from multi-band capability, such as satellite communication. The designed LNA consists of three stages: Two stages are cascoded using source degeneration with a resistor for low noise and high linearity, and the third cascaded stage is utilized for high gain. The designed UWB LNA exhibits a measured gain of 17.4 ± 1 dB between 312 and GHz and a 3 dB bandwidth of 12.4 GHz (1.6–14 GHz). It achieves a noise figure (NF) of 2.5–4.3 dB and an output P1dB of 15 dBm. The chip size is $3\times 1$${\mathrm{mm}}^2$, and it operates without the need for any external components. When compared to LNAs in the literature, the proposed design stands out for its flat gain in the specified frequency band, making the LNA particularly attractive for volume-limited and power-constrained applications. Full article

In this study, the effects of non-thermal pretreatment such as corona discharge plasma (CDP-21 kV), dielectric barrier discharge plasma (DBDP-32 kV), and ultrasonic waves of different powers (US-180 W, 210 W, 240 W) on hot-air drying of ferruginous yam were compared. The regulatory effects of ultrasonic and cold plasma pretreatment on the drying characteristics and quality of yam were systematically evaluated by determining the drying kinetic parameters, physicochemical indexes, volatile components, and energy consumption. The results showed that ultrasonic pretreatment significantly improved the drying performance of yam compared with different cold plasma treatments, with the highest drying rate and effective moisture diffusion coefficient in the US-180 W group. In terms of quality, this treatment group exhibited better color retention, higher total phenol content (366 mg/100 g) and antioxidant activity, and optimal rehydration performance. Low-field nuclear magnetic resonance (NMR) analyses showed a more homogeneous water distribution, and gas chromatography–mass spectrometry (GC-MS) identified 55 volatile components. This study confirms that the US-180 W ultrasonic pretreatment technology can effectively improve the drying efficiency and product quality of yam and at the same time reduce the energy consumption. The results of this study provide a practical solution for the optimization of a process that can be replicated in the food drying industry. Full article

Perfluoromethyl vinyl ether (PMVE) has recently emerged as a promising environmentally friendly insulating gas with potential for practical applications in the power industry. When mixed with CO₂, the PMVE/CO₂ mixture exhibits an elevated liquefaction temperature and enhanced insulation performance, making it suitable for engineering use. In this study, density functional theory (DFT) calculations were employed to investigate the reactive sites of PMVE molecules. The results indicate that the C₂–O and C₃–O bonds are the most susceptible to breakage, highlighting their high reactivity. The optimal insulation performance of the PMVE/CO₂ mixture is achieved at a CO₂ concentration of approximately 60%, with significant molecular decomposition observed at temperatures exceeding 2600 K. The primary decomposition products include C₂F₂, COF₃, COF₂, F, C₂F₃, CO, CF₃, and C₂F₄. Both high temperature and elevated CO₂ content accelerate the decomposition process. These findings provide valuable insights into the insulation properties and thermal stability of the PMVE/CO₂ system, offering theoretical support for its potential application in eco-friendly high-voltage insulation technologies. Full article

As a major source of carbon emissions, the carbon-based power generation industry requires a scientifically robust environmental performance evaluation system to facilitate its green transition and sustainable development. Focusing on unique transition dynamics across four carbon-based power generation formats, this study compares environmental dimension indicators across typical ESG evaluation frameworks and proposes an innovative evaluation index model of environmental performance based on common metrics, with a particular emphasis on their contribution potential to the “Dual Carbon Goals”. The framework’s core innovation lies in its Dual Carbon-focused indicator system, which evaluates three critical indicators overlooked by mainstream ESG methodologies. It extends to include upstream/downstream processes, addressing gaps in current evaluation systems. The findings reveal that core environmental issues, such as climate change, pollution emissions, and resource utilization, exhibit broad commonality in ESG evaluations. Among the assessed indicators, carbon emission intensity carries the highest weight, underscoring its centrality in each power generation sector’s efforts to align with the Dual Carbon Goals. Furthermore, the analysis demonstrates that underground coal gasification combined cycle power generation has a relatively favorable environmental performance, ranking slightly below natural gas combined cycle but above shale gas combined cycle power generation. In contrast, traditional coal-fired power generation exhibits significantly poorer environmental outcomes, highlighting both the efficacy of technological upgrades in reducing emissions and the urgent need for transitioning away from conventional coal-based power. Full article

In the context of advancing sustainable energy solutions, this paper provides a detailed modelling study of the process integration of biomass gasification to produce syngas and subsequent methanation for methane production. The process is assumed to take place in a circulating fluidised bed and three adiabatic fixed-bed reactors. To address the low H₂/CO ratio of syngas produced from biomass gasification using air, three pre-methanation scenarios were evaluated: water gas shift reaction (scenario 1), H₂ addition through Power-to-Gas (scenario 2), and splitting syngas into pure H₂ and CO and then recombining them in a 3:1 ratio (scenario 3). The findings reveal that each scenario presents a unique balance of efficiency, decarbonisation potential, and technological integration. Scenario 2 achieves the highest overall efficiency at 62%, highlighting the importance of integrating renewable electricity into the methane industry. Scenario 1, which incorporates WGS and CO₂ capture, offers an environmentally friendly solution with an overall efficiency of 59%. In contrast, Scenario 3, involving H₂/CO separation and recombination, achieves only 44.4% efficiency due to energy losses during separation, despite its operational simplicity. Methane yields were highest in Scenario 1, while Scenario 2 offers the most significant potential for integration with decarbonised power systems. The model was validated using published data and feedstock characteristics from experimental work and industrial projects. The results showed good agreement and supported the accuracy of the simulation in reflecting realistic biomass processing for methane production. Full article

This research introduces a two-stage, low-carbon industrial heating process, leveraging advanced waste heat recovery (WHR) technologies and exploiting waste heat (WH) to drive decentralised hydrogen production. This study is supported by a data-driven analysis of individual technologies, followed by 0D modelling of the integrated system for technical and feasibility assessment. Within 10 years, the EU industry will be supported by two main strategies to transition to low-carbon energy: (a) shifting from grid-mix electricity towards fully renewable sources, and (b) expanding low-carbon hydrogen infrastructure within industrial clusters. On the demand side, process heating in the industrial sector accounts for 70% of total energy consumption in industry. Almost one-fifth of the energy consumed to fulfil the process heat demand is lost as waste. The proposed heating solution is tailored for process heat in industry and stands apart from the dual-mode residential heating system (i.e., heat pump and gas boiler), as it is based on integrated and simultaneous operation to meet industry-level reliability at higher temperatures, focusing on WHR and low-carbon hydrogen. The solution uses a cascaded heating approach. Low- and medium-temperature WH are exploited to drive high-temperature heat pumps (HTHPs), followed by hydrogen burners fuelled by hydrogen generated on-site by electrolysers, which are powered by advanced WHR technologies. The results revealed that the deployment of the solution at scale could fulfil ~14% of the process heat demand in EU/UK industries by 2035. Moreover, with further availability of renewable energy sources and clean hydrogen, it could have a higher contribution to the total process heat demand as a low-carbon solution. The economic analysis estimates that adopting the combined heating solution—benefiting from the full capacity of WHR for the HTHP and on-site hydrogen production—would result in a levelised cost of heat of ~EUR 84/MWh, which is lower than that of full electrification of industrial heating in 2035. Full article

To meet the high standards required for the liquefaction process by the Floating Liquefied Natural Gas System (FLNG), including low power consumption, compact footprint, high safety, resistance to waves, and portability, this paper proposes a novel FLNG liquefaction process which combines the supersonic swirling separation technology with pressurized liquefaction technology. The process is simulated and optimized using Aspen HYSYS V10 software and genetic algorithms. The results indicate that the specific power consumption of this liquefaction process is only 0.208 kWh/m³, with the cooler, expander, and compressor being the main equipment responsible for exergy losses, accounting for 28.85%, 26.48%, and 21.70%, respectively. This liquefaction process is relatively adaptable to changes in feed gas pressure, temperature, and methane content. The specific power consumption slightly increases with the increasing feed gas pressure and temperature, while it exhibits some fluctuations with the increasing methane content. The process requires a low CO₂ removal rate, possesses moisture pretreatment capability, has fewer pieces of equipment, and saves a significant amount of valuable space. It combines low specific power consumption, minimal impact from swaying, and high safety, providing considerable application potential in future offshore natural gas development. Full article

We present a highly sensitive and selective gas sensor based on an advanced silicon-on-insulator tunnel field-effect transistor (SOI-TFET) architecture, enhanced through the integration of customized conducting polymers. In this design, traditional metal gates are replaced with distinct functional polymers—PPP-TOS/AcCN, PP-TOS/AcCN, PP-FE(CN)₆³⁻/H₂O, PPP-TCNQ-TOS/AcCN, and PPP-ClO₄/AcCN—which enable precise molecular recognition and discrimination of various target gases. To further enhance sensitivity, the device employs an oppositely doped source region, significantly improving gate control and promoting stronger band-to-band tunneling. This structural modification amplifies sensing signals and improves noise immunity, allowing reliable detection at trace concentrations. Additionally, optimization of the subthreshold swing contributes to faster switching and response times. Thermal stability is addressed by embedding a P-type buffer layer within the buried oxide, which increases thermal conductivity and reduces lattice temperature, further stabilizing device performance. Experimental results demonstrate that the proposed sensor outperforms conventional SOI-TFET designs, exhibiting superior sensitivity and selectivity toward analytes such as methanol, chloroform, isopropanol, and hexane. Beyond gas sensing, the unique polymer-functionalized gate design enables integration of microbial biosensing capabilities, making the platform highly versatile for biochemical detection. This work offers a promising pathway toward ultra-sensitive, low-power sensing technologies for environmental monitoring, industrial safety, and medical diagnostics. Full article