Green Energy and Resources最新文献

Energy storage is a crucial solution for the intermittency and instability of renewable energy. Carnot batteries, a novel electrical energy storage technology, promise to address the challenges of renewable electrical energy storage worldwide. Rankine-based Carnot batteries, which are geographically unconstrained and effectively store energy at low temperatures, have attracted considerable attention in recent years. In this study, a mathematical model was developed, and a multi-objective optimization with power-to-power-efficiency, exergy efficiency, and levelized cost of storage was performed. Moreover, the investment cost and exergy loss of the optimized system components were investigated in detail and analyzed. The results showed that the optimal power-to-power-efficiency, exergy efficiency, and levelized cost of the storage system can be achieved at 60.3%, 33%, and 0.373 $/kWh based on single-objective optimization, and the operating parameters of the proposed system are different. Therefore, there is a strong trade-off relationship between the three objective functions mentioned above. Under the same weighting for the two approaches, they are 25.8%, 23%, and 0.437 $/kWh, and 39.3%, 29.1%, and 0.549 $/kWh, respectively. Furthermore, this study observed that the exergy destruction in the charge mode was nearly 95 kW larger than that in the discharge mode, and the exergy destruction of the throttle valve was the largest at 95.83 kW, accounting for 28.32%. The expander was the component with the highest cost (35.84% of the total cost) in the proposed system, followed by the compressor.

Developing countries face challenges in maintaining a reliable power supply due to factors such as ageing infrastructure and rapid urbanization. Relying on backup diesel generators during outages is not only ecologically hazardous but also economically inefficient. Integrating multiple renewable sources with conventional energy systems is crucial to meeting growing energy demands and reducing carbon emissions. This study assesses dispatch strategies for optimal operation in hybrid renewable energy systems (HRES) connected to an unreliable national grid (GRD). An enhanced combined dispatch (ECD) strategy is introduced for effective energy distribution, considering load demands, energy resource availability, and grid unreliability. Compared to load following (LF) and cycle charging (CC) strategies, the ECD strategy proves superior, resulting in an optimized HRES configuration with a 248 kW solar PV array, a 2 kW wind turbine (WDT), a 22 kW biogas generator (BGG), a 92 kW diesel generator (DiG), and a 658 kWh battery storage (BSS). Achieving a low Levelized Cost of Energy (LCOE) at 0.148 USD per kilowatt-hour and a Net Present Cost (NPC) of 1.99 million USD. Adopting the ECD strategy also exhibits substantial reductions in CO₂, CO, SO₂, and NO_x emissions when compared to CC and LF. ECD achieves approximately 25% lower CO₂ emissions, 34% lower CO emissions, and a 40% reduction in SO₂ and NO_x emissions. These findings highlight the ECD strategy's potential for effective, economically viable, and environmentally conscious energy solutions, particularly relevant in developing nations like Nigeria, where Hybrid Renewable Energy Systems could play a crucial role in the energy sector.

Increasingly stringent emission standards have led shippers and port operators to consider alternative energy sources which can reduce emissions while minimizing capital investment. It is essential to understand whether there is a certain economic investment gap for alternative energy. The present work mainly focuses on the simulation study of ships using ammonia and hydrogen fuels arriving at Guangzhou Port to investigate the emission advantages and cost-benefit analysis of ammonia and hydrogen as alternative fuels. By collecting actual data and fuel consumption emissions of ships arriving at Guangzhou Port, the present study calculated the pollutant emissions and cost of ammonia and hydrogen fuels substitution. As expected, it is shown that with the increase of NH₃ in fuel, mixed fuels will effectively reduce CO and CO₂ emissions. Compared to conventional fuel, the injection of NH₃ increases the NO_x emission. However, the cost savings of ammonia fuel for CO₂, SO_x and PM₁₀ reduction are higher than that for NO_x. In terms of pollutants, ammonia is less expensive than conventional fuels when applied to the Guangzhou Port. However, the cost of fuel supply is still higher than conventional energy as ammonia has not yet formed a complete fuel supply and storage system for ships. On the other hand, hydrogen is quite expensive to store and transport, resulting in higher overall costs than ammonia and conventional fuels, even if no pollutants are produced. At present, conventional fuels still have advantage in terms of cost. With the promotion of ammonia fuel technology and application, the cost of supply will be reduced. It is predicted that by 2035 ammonia will not only have emission reduction benefits, but also will have a lower overall economic cost than conventional fuels. Hydrogen energy will need longer development and technological breakthroughs due to the limitation of storage conditions.

In recent years, ion-selective capacitive deionization (CDI) technology has been used to selectively separate ions from multi-ion composition solutions. Innovative ion-selective electrode materials have been widely used in the fields of recovery of high-value ions and removal of toxic and harmful ions. Developments of electrode materials and their structure-chemical activity relationships were reviewed and analyzed. Moreover, anticipatory observations and challenges regarding the future of ion-selective CDI devices are discussed. Ultimately, this comprehensive review aims to provide meaningful insights and directions in the exploration for ideal ion-selective electrode materials, propelling further advancements in CDI systems.

Photo-thermal catalytic CO₂ hydrogenation to value-added products is considered a viable strategy for CO₂ conversion, whereas the unsatisfactory selectivity and conversion efficiency hinder its practical applications. Herein, Pt nanoparticles supported on LaCoO₃ with different loadings were prepared for photo-thermal catalytic CO₂ hydrogenation. Transmission Electron Microscope (TEM) images revealed that the Pt nanoparticles (about 2∼4 nm) were evenly dispersed on the surface of rhomboid-phased LaCoO₃ supports. X-ray photoelectron spectroscopy (XPS) studies showed that in the composited catalysts, electron transfer from LaCoO₃ to Pt occurred, suggesting a strong interaction between Pt and LaCoO₃. In result, 0.6 Pt/LaCoO₃ showed a remarkable CH₄ production rate of 119.8 mmol g_cat⁻¹ h⁻¹ with 87% selectivity at 250°C under visible light irradiation. Additionally, the in situ diffuse reflectance infrared Fourier transformations spectroscopy (DRIFTS) indicated that formate is the main intermediate species in the photo-thermal catalytic CO₂ hydrogenation process and illumination could promote the conversion of intermediate species without changing the reaction pathway, thus increasing the yield of CH₄. Given that the catalyst preparation approaches could be easily scaled up and the conversion efficiency of CO₂ is satisfactory, it is confident that this research will offer valuable guidance for the future industrialization of CO₂ conversion.

The growing demand for sodium-ion batteries (SIBs) in commercial applications has made it imperative to meet the commercial requirements. However, SIBs face significant challenges because of their poor cyclability and low reversible capacity compared with their rival lithium-ion batteries (LIBs). To address these challenges, various techniques, design strategies, surface engineering, and structural modifications have been developed to enhance the electrochemical performance of SIBs. This review focuses on recent developments in improving the electrochemical performance and cyclability of novel promising electrode materials for SIBs. We discuss several unique state-of-the-art research studies of the past five years that demonstrated excellent electrochemical performance through effective methodologies, surface modulations, and substitution of novel elements into the structure, and boosted the efficiency of the materials. Furthermore, we propose that it is important to adopt a nuanced approach when designing SIBs. Rather than copying the designs and methods used for LIBs, ideas should be absorbed from them and approaches should be tailored to meet the specific requirements of SIBs. This will enable the development of SIBs that are optimized for their intended applications and will avoid the challenges that have hindered the commercial success of earlier attempts at constructing SIBs. Thus, the key to creating high-performance SIBs is to draw inspiration from the best practices used in LIBs, while simultaneously innovating and developing new approaches tailored to the unique characteristics of SIBs.

Melting furnace slag (MFS) is a potentially active by-product of the synergistic treatment of iron and steel dust sludge and Municipal Solid Waste (MSW) incineration fly ash in the flue gas magnetization fusion separator furnace of the “fire method + wet method”. This paper focuses on the MFS reactivated by mechanical grinding, and the reactivity of MFS is synergistically enhanced by alkaline, sulfate-based solid wastes. The particle size distribution, specific surface area, morphology, and physical phase composition of MFS with different grinding times resulted in the best performance of MFS when mechanically ground for 80 min and the specific surface area reached 450 m²/kg, and the reactivity indexes reached 100.94% and 103.7% for 7 and 28 d, respectively. The synergistic activation of steel slag and flue-gas desulfurization gypsum can play an effective role in stimulating the MFS, and the optimal proportion is m (MFS): m (SS): m (FGDG) = 42%: 42%: 16%. The reactivity enhancement mechanism of the ternary slag-based system on MFS: SS provides high alkalinity hydration reaction conditions for MFS and FGDG provides SO₄²⁻, which continuously promotes the hydrolysis of MFS under the synergistic reactivity stimulation to generate AFt and C–S–H gels.

Anaerobic digestion presents a viable approach for managing biodegradable waste. However, the process generates a significant amount of digestate, which, if not appropriately managed, can contribute to eutrophication and salinization. This research explores the integration of hydrothermal carbonization (HTC) and pyrolysis as a potential solution for digestate management, emphasizing volume reduction and energy recovery. The study specifically focuses on the production of biochar from agricultural waste digestate (AWD) in an energy-efficient manner. Utilizing HTC as a pretreatment was found to enhance the heating value of both the AWD and the subsequent pyrolytic char, and it also improved the carbonization degree of the resulting char. Energy balance analysis revealed that the pyrolysis of AWD shifted from an endothermic to an exothermic reaction upon HTC pretreatment. This transition decreased the reaction's energy absorption from 41.1 to 1557.6 MJ to an energy release of 685.1 to 960.6 MJ per ton of digestate, thereby optimizing energy consumption in digestate management. Additionally, it was noted that using acetone as a solvent in gas chromatography for biooil samples with high ammonia content led to the formation of diacetonamine, an outcome that is deemed undesirable.

The electro-synthesis of hydrogen peroxide has attracted extensive research interest and is expected to replace conventional chemical processes as a mild and safe approach. Single-atom catalysts (SACs) have been applied in a wide variety of thermo- and electro-chemical reactions due to their high atom utilization and highly tunable electronic structure. Herein, an in-depth discussion on recent advances of SACs in the field of hydrogen peroxide electro-synthesis is summarized, specifically on the surface structure and electronic effects that enable high activity and selectivity of SACs. Different synthesis and modification strategies of SACs are discussed in detail, emphasizing the remarkable versatility of SACs utilization in this field. Finally, the opportunities and challenges of SACs for electrocatalytic synthesis of hydrogen peroxide are summarized in terms of rational design, controlled synthesis, and the stability of operation at high current densities of SACs to meet practical requirements.