Search Results (1,950)

Standalone DC microgrids offer a promising solution for providing reliable and sustainable electricity to remote communities in developing countries. However, the intermittent nature of solar and wind resources, combined with continuously varying load demand, presents considerable operational challenges in maintaining real-time power balance, stable DC bus voltage, and ensuring reliable continuous supply. Therefore, there is dire need for user-friendly control solutions tailored to the specific needs of isolated communities. As such, this paper presents a coordinated control and power management strategy for an isolated hybrid solar–wind–battery integrated DC microgrid for rural electrification applications. A comprehensive mathematical model of the standalone DC microgrid incorporating photovoltaic generation, wind energy conversion, battery storage, bidirectional DC-DC conversion, and common DC bus dynamics is developed at the very first stage of the proposed coordinated control framework. The framework utilizes principal local device loops and a secondary dynamic power management strategy to ensure efficient renewable power extraction, dynamic source–storage–load coordination, stable DC bus voltage, and real-time energy management within the developed standalone DC microgrid. It is worthwhile to mention that, instead of using synthesized or online available wind speed and solar irradiance data, this research utilized real-time recorded metrological data obtained from the Mehran University Jamshoro, Pakistan. The obtained results establish a stable DC bus voltage regulation within acceptable operating limits, continuous power balance, seamless bidirectional battery operation, and safe battery state-of-charge (SoC) management to prevent deep discharging or overcharging, thus ensuring reliable operation. The overall performance confirms the technical robustness, operational flexibility, and practical suitability of the proposed standalone hybrid DC microgrid architecture for its resilient operation and rural electrification applications. Full article

This study presents an integrated and sustainable approach for the valorization of polystyrene (PS) plastic waste into methanol, contributing to circular carbon utilization and waste-to-fuel strategies. Two simulation models were developed in Aspen plus. In Case 1, PS is converted to syngas through steam gasification, followed by its conversion into methanol. In Case 2, a steam methane reforming (SMR) unit is integrated with the gasification unit, using the heat from the gasifier-derived syngas to boost hydrogen production and overall methanol yield. This integration boosts the hydrogen-to-carbon ratio, doubling methanol production in Case 2 compared to Case 1. In terms of energy performance, Case 2 exhibits a process efficiency of 81% and exergy efficiency of 73%, both significantly higher than 48% and 60%, compared to Case 1. From an economic standpoint, Case 2 requires greater capital investment and annual operational expenditure, yet it proves to be more cost-effective in the long run compared to Case 1 due to the higher methanol production. The methanol production cost is reduced by 50%, from $1.001/kg in Case 1 to $0.505/kg in Case 2. These improvements are driven by increased throughput and process integration that supports sustainable and circular carbon management. Full article

The rise in the need for sustainable energy has facilitated the advancement of perovskite solar cells (PSCs) as potential substitutes for traditional photovoltaic technologies. Nevertheless, their performance is very sensitive to environmental factors, especially temperature, which influences the charge transport and recombination processes. This paper examines the thermal effect on the electrical characteristics and impedance response of lead-free PSCs in accordance with the FTO/ETL (C₆₀, PCBM, SnS₂, ZnSe)/CH₃NH₃SnBr₃/Cu₂O configuration. The experiments were performed with SCAPS-1D under usual illumination, using a combination of current-voltage analysis and impedance spectroscopy between 270 and 400 K. The findings indicate that there is a significant reduction in open-circuit voltage with higher temperature, whereas the short-circuit current density does not change much. The enhancement of the fill factor increases and then decreases with increased temperature, leading to a net decrease in power conversion efficiency because of the increased recombination. The impedance analysis is also an indicator of lower recombination resistance and accelerated charge carrier dynamics. These results demonstrate that thermal control and interface optimization can be important for enhancing PSC performance. Full article

The urgent need for bio-based functional materials has driven a shift away from fossil-fuel-sourced materials toward renewable lignocellulosic biomass (LCB). This comprehensive review explores the advancements in LCB carbonization between 2020 and 2026, marking a shift from traditional, low-yield combustion processes toward highly selective and sustainable thermochemical conversion pathways. The primary objective of this review is to evaluate the integration of green pretreatment strategies, conversion technologies, and efficient valorization of the aqueous effluents and by-products. The goal of green pretreatment is to overcome the inherent recalcitrance of LCB without the use of harsh chemicals and reaction conditions, specifically highlighting the effectiveness of deep eutectic solvents (DESs) and ionic liquids (ILs). The review also evaluates the emerging conversion technologies, including hydrothermal carbonization (HTC), microwave-assisted pyrolysis (MAP), and the synergistic co-pyrolysis of LCB with synthetic polymeric wastes. Another novel concept in preparing hard carbon and other related materials is the “lignin-first” biorefinery strategy, which facilitates the subsequent production of high-value aromatic monomers, platform chemicals, and biofuels. The engineered carbon materials are increasingly utilized well beyond their traditional use as solid fuels. The products have been proven to be excellent for use in high-performance energy conversion and storage, serving as renewable bio-based electrode materials for supercapacitors and carbon electrodes in next-generation batteries. Full article

The rapid development of wearable electronics has created a demand for flexible, lightweight, and sustainable power-supply technologies. The persistent temperature difference between the human body and the environment provides a low-grade thermal source for thermoelectric energy harvesting. However, traditional flexible thermoelectric devices still face limited self-supporting capabilities and difficulties in maintaining sufficiently low cold-side temperatures. Here, we designed a passively radiative-cooled thermoelectric film (PRT film) by integrating a PAM/PEDOT:PSS self-supporting thermoelectric composite layer with a polymer metamaterial radiative cooling (PMRC) film. The PAM/PEDOT:PSS layer serves as a self-supporting thermoelectric conversion component for harvesting low-grade heat, while the PMRC film layer acts as a passive cold-side regulator without energy input to lower the cold-side temperature and enhance the temperature gradient. By optimizing the PAM content, the PAM/PEDOT:PSS composite material with 85 wt% PAM achieved the highest power factor of 72.3 μW m⁻¹ K⁻². Under a temperature difference of 39 °C, the optimized PAM/PEDOT:PSS sample provided an open-circuit voltage of 0.47 V, a maximum output power of 1.1 μW, and a power density of 11.2 μW cm⁻². According to the temperature-difference enhancement measured in experiments and the independently obtained load characteristics, the integration of PMRC films is expected to increase the maximum output power from 1.1 to 1.4 μW, with the corresponding power density rising from 11.2 to 14.25 μW cm⁻², representing a 27.2% enhancement. This work demonstrates the feasibility of passive radiative cold-side regulation in enhancing low-level thermoelectric energy harvesting for wearable applications. Full article

Energy efficiency (EE) is integral to a sustainable energy system and can play a significant role in climate mitigation by reducing energy consumption and the adverse effects of climate change. This paper examines the association between CO₂ emissions, EE, environmentally related taxes (ERTs), renewable energy (RE), and non-renewable energy consumption (EC) in Australia from 1990 to 2020. Using a dynamic ARDL model, the empirical findings show that adopting EE (β = −0.14, p = 0.000), ERT (β = −0.08, p = 0.071), and RE (β = −0.008, p = 0.007) is associated with lower carbon emissions, particularly in the short run. Conversely, EC impedes climate mitigation, as revealed by the substantial positive and significant coefficient of 1.4%. Notably, EE has the largest short-run coefficient among the mitigating variables, indicating that energy efficiency is the most significant mitigator of carbon emissions in Australia in the short run. The ARDL bounds test confirms the existence of a long-run equilibrium relationship among the variables. However, in the long run, EE, ERT, and RE do not mitigate carbon emissions, given their statistically insignificant coefficients, whereas EC remains strongly positively related to CO₂ emissions. Results from the FMOLS and DOLS estimates largely support the ARDL findings, though some sensitivity is observed for ERT. Consequently, this paper proposes a comprehensive policy direction for governments and international organizations, emphasizing the importance of reducing energy intensity and promoting EE as core climate mitigation instruments to foster a green, sustainable environment. Full article

Microbial fuel cells (MFCs) are promising bioelectrochemical systems for converting organic matter into electrical energy, but their practical relevance depends on both functional performance and sustainability-oriented viability. This study evaluated the bioelectrochemical behavior of double-chamber MFCs inoculated with kefir, comparing graphene and graphite anodes under fed-batch operation. A total of 33 MFC series were monitored longitudinally through voltage, current, power output, substrate consumption, and oxidation-reduction potential. Under the LED-connected closed-circuit configuration used here, kefir-inoculated reactors exhibited a reproducible electrical response together with near-complete substrate depletion. These findings support kefir as a workable mixed inoculum for comparative reactor operation under the tested conditions, although direct extracellular electron transfer and exclusive microbial causation of the measured signal were not demonstrated. Graphene showed higher early and mean electrical performance than graphite, particularly in power-related metrics, although this advantage decreased over time and did not result in a categorical separation of final batch-level outcomes. In contrast, substrate consumption remained highly similar between anode materials, indicating that the main material effect was expressed in electrochemical translation rather than in overall substrate conversion. Taxonomic profiling supported the presence of a metabolically complementary consortium dominated by lactic acid bacteria, acetic acid bacteria, Gram-negative bacteria, and yeasts. Deterministic sensitivity analysis and Monte Carlo-based LCA/TEA screening further showed that the most sustainable scenario was not necessarily the one with the highest electrical response, highlighting the importance of integrating performance, material burden, and uncertainty in MFC assessment. Full article

The growing share of photovoltaic generation in power grids intensifies the need for converter architectures capable of combining efficient energy conversion, DC-bus stability, and ancillary service provision at the grid coupling point. This paper presents the modeling, implementation, and simulation-based evaluation of a 91 kWp three-phase photovoltaic (PV) system integrated with a battery energy storage system (BESS), developed in the PLECS environment. The proposed architecture comprises three interleaved Boost stages for maximum power point tracking (MPPT), a DC bus regulated at 600 V, three independent bidirectional buck–boost converters for LiFePO${}_4$ bank management, and a two-level three-phase voltage source inverter (VSI) with an LC output filter. The control is organized in cascade voltage–current loops for the DC–DC stages and in vector control within the synchronous reference frame (SRF) for the inverter, with synchronization via SRF-PLL. A C-Script supervisory block integrates the Perturb and Observe (P&O) MPPT algorithm, independent state of charge (SOC) estimation per bank via coulomb counting, and Volt–VAR reactive power reference generation with a dead band of 0.90–1.10 pu. Five scenarios are analyzed for validation: DC-bus regulation under irradiance transients; reactive power support during undervoltage and overvoltage events (0.80–0.85 pu and 1.15–1.20 pu); BESS operation as an active DC-link support element; and PV curtailment with fully charged banks. All five scenarios were additionally corroborated on a Typhoon HIL402 Pro 2 hardware-in-the-loop platform, reproducing the PLECS waveforms within the amplitude and timing resolution of the oscilloscope captures. Across all scenarios, the DC bus is held within $\pm 15$ V (2.5%) of the 600 V reference, with the worst-case transient recovering in 80–100 ms; under a sustained 9 s bidirectional disturbance, redirecting PV surplus to BESS charging in both the undervoltage and overvoltage segments—with no externally imposed active-current limit—keeps the current-vector magnitude $\sqrt{i_d^2+i_q^2}$ below the 335 A rating throughout (≈271 A and ≈242 A, respectively), while the available reactive margin $Q_{disp}$ reaches ≈78– 80 kVAr in both segments and the bank SOC advances by ≈$0.03$ pu; and supervisory curtailment under a sustained overvoltage ride-through with a saturated bank keeps the per-bank SOC dispersion within $4\times {10}^{-5}$ pu while expanding the available reactive margin $Q_{disp}$ from ≈50 to ≈90 kVAr. Full article

Background: Corporate energy transition can create efficiency, financing, and valuation benefits, but it also exposes firms to implementation, information, and transition risks. This study examines whether digital transformation helps firms convert energy-transition strategies into financial value. Unlike prior studies that mainly treated digitalization or sustainability as broad direct predictors, this study examines an implementation-based, multidimensional digital capability as a boundary condition across three distinct energy-transition strategies and both accounting- and market-based financial outcomes. Methods: Using an unbalanced panel of 30 firms associated with Indonesia’s LQ45 Low Carbon Leaders Index (120 firm years, 2020–2025), we construct a 30-item implementation-based Digital Transformation Index and estimate two-way fixed-effects models with firm-level wild-cluster-bootstrap inference, conditional marginal effects, false-discovery-rate adjustment, and prespecified robustness checks. Results: Clean energy use is positively associated with return on assets, return on equity, and Tobin’s Q. Low-carbon operational efficiency is most clearly associated with return on assets, whereas renewable energy use is primarily reflected in Tobin’s Q. Digital transformation is positively associated with all three outcomes and selectively strengthens the financial effects of the three transition strategies. Conclusions: Digital transformation is not a universal performance amplifier. It functions as a strategy- and outcome-specific value-conversion and risk-management capability that improves the monitoring, coordination, financing, verification, and communication of energy-transition investments. Full article

The maritime sector is increasingly focused on green propulsion technologies to address stringent regulations on greenhouse gas emissions and other pollutants. In recent years, research has proposed novel electric and hybrid propulsion architectures and advanced energy management systems. This paper reviews the fundamentals and the most recent developments of hybrid and electric propulsion technologies, evaluating their environmental and economic implications. Particular attention is given to the various onboard energy storage, conversion, and generation technologies, outlining their potential and limitations. Through the analysis of numerous research studies in alternative marine propulsion, the suitability of Li-ion batteries, supercapacitors, flywheels, and different types of fuel cells for maritime transport needs is evaluated, along with the possibilities offered by renewable energy to reduce the environmental impact of marine energy systems. Additionally, it discusses important future directions, research gaps, and emerging paradigms in sustaining maritime eco-systems. Unlike previous reviews that mainly focus on individual technologies, this study provides an integrated analysis connecting propulsion architectures, energy storage systems, fuel cells, alternative fuels, renewable energy integration, and energy management strategies. The review also discusses technology limitations, operational suitability for different vessel categories, and future research challenges toward maritime decarbonization. In presenting these issues, the author’s intention is to promote interdisciplinary cooperation between shipbuilders, policymakers, and researchers for the benefit of more sustainable development of the maritime industry. Full article

South Africa possesses substantial bioenergy potential derived from agricultural residues, forestry by-products, municipal organic waste, wastewater sludge, and dedicated energy crops, positioning bioenergy as a potentially important contributor to the country’s low-carbon energy transition. Despite more than two decades of supportive policy, modern bioenergy remains a marginal contributor to the country’s energy system. Although previous studies have examined individual bioenergy technologies, feedstocks, environmental impacts, or policy frameworks, a comprehensive assessment of the alignment between policy ambition, technological readiness, implementation outcomes, and emerging sustainable development opportunities in South Africa remains lacking. This review presents a systematic integrative review of bioenergy development in South Africa, evaluating the alignment between policy ambition, technological readiness, and implementation outcomes. Literature published between 2000 and 2025 was systematically reviewed using Scopus, Web of Science, Google Scholar, and institutional publications. A PRISMA-informed screening process identified 427 records, of which 116 studies met the inclusion criteria for detailed synthesis. Evidence was synthesized across three interconnected dimensions: (i) policy and regulatory frameworks, (ii) feedstock availability and technological readiness, and (iii) deployment outcomes, implementation challenges, and future development opportunities. The findings reveal a persistent implementation gap despite abundant biomass resources and commercially established bioenergy conversion technologies Although global biofuel production exceeded 180 billion liters in 2023, South Africa’s installed bioenergy electricity capacity remains approximately 265 MW, representing less than 0.5% of the country’s approximately 60 GW installed electricity generation capacity. By comparison, installed solar and wind capacities exceed 8 GW and 3 GW, respectively. The review identifies fragmented governance, limited investment incentives, regulatory uncertainty, infrastructure constraints, and inadequate integration of bioenergy into national energy planning as the principal barriers to deployment. The review concludes that South Africa’s principal challenge is not biomass availability or technological capability, but translating policy ambition into coordinated implementation capable of scaling sustainable bioenergy deployment. Full article

Background/Objectives: This study examines the effectiveness of calorie labeling on restaurant menus by investigating how visual attention is allocated between calorie information and food cues. Although calorie labeling policies are widely implemented, prior research suggests limited impact on reducing energy intake. Methods: Using eye-tracking technology, this study explored how menu design factors (specifically visual food cues) influence attention. Results: Results from a within-subject experiment (N = 82) indicated that calorie labels received significantly fewer visual fixations (in terms of frequency and duration) when food images were present. Conversely, calorie labels did not reduce attention to food cues, highlighting an asymmetry in attentional allocations. Interestingly, restricted eaters were associated with more frequent attention to calorie labels but not with longer sustained attention to those labels. Conclusions: Overall, findings suggest that the motivational responses elicited by food cues undermine the effectiveness of calorie labeling by diverting attention away from nutritional information, limiting its utility as a public health intervention. Full article

Perovskite tandem solar cells (TSCs) have emerged as a transformative photovoltaic technology, offering a viable pathway to surpass the Shockley-Queisser limit of single-junction devices by enabling broader solar spectrum utilization and reduced thermalization losses. This review provides a comprehensive overview of recent progress in perovskite-based TSCs, covering four major device architectures: perovskite/silicon, perovskite/CIGS, all-perovskite, and perovskite/organic TSCs. We systematically discuss the fundamental working principles, including bandgap engineering, charge generation and separation, and current-voltage matching, followed by an in-depth analysis of strategies for perovskite layer regulation, interface engineering, and transport-layer optimization. Key advancements, such as compositional engineering, defect passivation, crystallization control, and optical management, have synergistically pushed power conversion efficiencies (PCEs) beyond 34% for perovskite/silicon TSCs and over 28% for all-perovskite and perovskite/organic configurations. Despite these achievements, critical challenges remain, including material instability, halide phase segregation, lead toxicity, scalable fabrication, and cost-effective integration. This review also outlines future perspectives, emphasizing the development of lead-free perovskites, novel charge-transport materials, advanced encapsulation techniques, and large-area manufacturing processes. With continued interdisciplinary efforts, perovskite TSCs hold great promise for driving the global transition toward sustainable and low-carbon energy systems. Full article

Efficient utilization of agricultural residues plays an important role in advancing sustainable bioenergy development in China. This study established a multi-criteria evaluation framework integrating energy quality, economic performance, and environmental impact to assess three representative straw-to-energy pathways: direct combustion for power generation, anaerobic digestion for biogas production, and lignocellulosic ethanol production. The Analytic Hierarchy Process (AHP) was applied to determine indicator weights and calculate composite scores using operational and pilot-scale data obtained for each pathway. The results showed that anaerobic biogas achieved the highest overall performance (composite score 0.41), with balanced performance in economic viability, energy utilization efficiency, and environmental performance. Direct combustion demonstrated favorable economic performance (0.37) but exhibited higher process emissions, whereas lignocellulosic ethanol showed superior environmental performance but suffered from low energy conversion efficiency and negative economic returns (0.00). Sensitivity analysis confirmed the stability of the pathway ranking and highlighted the dominant influence of economic and energy-related indicators on the overall sustainability assessment. The study demonstrated that anaerobic biogas exhibited the most balanced performance among the evaluated pathways under the investigated technological and economic conditions, while integrated biorefining approaches, such as co-production of ethanol and biogas, showed potential for further enhancing resource efficiency and sustainability. Full article

Molybdenum carbide (MoC) thin films were deposited by dual-target magnetron co-sputtering and investigated as platinum-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The effects of Mo target power and film thickness on structural evolution, electrical transport properties, and photovoltaic performance were systematically examined. Raman analysis revealed progressive modifications in the carbon bonding structure, accompanied by variations in the G-band position and an overall reduction in the I_D/I_G ratio. These structural changes were correlated with increased hardness, reduced electrical resistivity, and decreased surface wettability, indicating improved structural integrity and electrical transport characteristics of the MoC films. The optimized films exhibited a resistivity as low as 2.04 mΩ·cm and improved charge-transport behavior. DSSCs employing the optimized MoC CEs achieved a maximum power conversion efficiency of 4.13%. The photovoltaic performance trends were consistent with the evolution of the electrical transport properties of the MoC thin films, suggesting a close relationship between electrode structure, charge transport, and device operation. The results demonstrate that sputtered MoC thin films are promising functional materials for Pt-free DSSC CEs and provide insight into structure–transport–performance correlations relevant to sustainable photovoltaic energy-conversion systems. Full article