Energy Conversion and Management-X最新文献

As consequence of the transition towards sustainable energy sources, the future production of liquid energy carriers (e.g. methanol) via H₂ supply pathways utilizing water electrolyzers (power-to-liquid) will most likely be based on fluctuating grid electricity or islanded renewable inputs. As a result, these production processes are subject to fluctuating operating conditions and varying production capacities, ultimately leading to uncertainties with respect to their process economics and profitability. Therefore, the impact of different electricity supply-side scenarios (static grid and intermittent grid or renewable supply) on the production economics of power-to-liquid processes needs to be assessed thoroughly for the upcoming decades. Methanol is considered as an essential base chemical which is widely known for its versatility and broad potential use contexts in future chemical industries and energy storage applications. Methanol production pathways powered by renewable electricity sources, also known as power-to-methanol processes, are characterized by low specific life-cycle emissions and are therefore of paramount interest. One possible renewable process chain features proton-conducting high temperature electrolyzers combined with a direct hydrogenation of CO₂. In this paper, a techno-economic forecast study of this process chain is presented and specific production costs of renewable methanol under different electricity supply scenarios are determined and discussed for the years 2030 and 2050. The studies showed that flexible grid-supported scenarios through direct spot-market participation and renewable scenarios based on wind onshore production enable the largest production cost reduction potential in the upcoming decades. Minimum production costs of 740 € t⁻¹_MeOH (2030) and 415 € t⁻¹_MeOH (2050) are determined for a flexible operation of the system with spot-market participation, benefitting from times of low or even negative electricity prices. Among the renewable production scenarios, islanded power-to-methanol systems coupled to wind onshore plants were identified as the most beneficial configuration with ascertained production costs as low as 820 € t⁻¹_MeOH and 353 € t⁻¹_MeOH by 2030 and 2050, respectively.

This experimental study aims to track the changes in electrical properties and energy behavior of two technically identical photovoltaic modules of the RAGGIE type (RG-M165W model) under different operating conditions. The first is the reference photovoltaic module, while the second is the targeted photovoltaic module. Both modules were tested under the same climatic conditions in the Algerian region of El-Oued. Numerous practical experiments were conducted to demonstrate the effect of using a solar tracking system (a horizontal single-axis tracking system manually moved from east to west), changing the tilt angle of the photovoltaic modules, and the cleanliness of the effective photovoltaic module area on their productivity. The study results showed a convergence between experimental and theoretical results. The optimal tilt angle of the photovoltaic modules in El-Oued during the study days is 33°, and any inaccurate selection of this angle results in an efficiency loss of 19.31 %. Additionally, manually tracking the solar path improved the photovoltaic module efficiency by 1.63 %. A decrease in energy productivity by 34.68 % was recorded due to dust deposition of 14.5 g.m⁻². Economically, it was shown that installing a photovoltaic system consisting of 14 RAGGIE modules can feed a typical Algerian house with 136.6 MWh over 25 years, with a Levelized Cost of Energy of $0.037/kWh, and the CO₂ mitigation is 59.15 tons with a saving of $858.

The food industry is a cornerstone of the global economy, supporting millions of jobs and generating substantial revenue annually. It also significantly influences public health, environmental sustainability, and social equity. As the world’s population continues to grow, the demand for food is increasing dramatically, necessitating substantial investments in agricultural productivity, infrastructure, and improved food distribution and access. Concurrently, addressing the resulting environmental impact and ensuring sustainability are crucial challenges. The inextricable link between energy, water, and waste in food production underscores the need to reduce loss and waste throughout the supply chain, enhance energy efficiency in food processes, and optimize resource utilization.

This work aims to extensively analyze the food industry, focusing on the energy and environmental dimensions. The study provides an in-depth exploration of the food market, employing a comprehensive review approach, with information on diverse geographic regions and major global markets. Moreover, the work sheds light on critical sections that present significant opportunities for efficiency improvements, emphasizing the intricate interplay between food and energy up to introducing a standardized taxonomy and energy planning framework. The paper highlights the environmental implications of food waste and the unsustainable utilization of energy resources and provides valuable insights into the feasibility and applicability of various conventional and innovative energy management strategies. The findings serve as a foundation to guide the development of efficient and sustainable solutions for a cleaner future.

Several factors affect engine performance, including fuel injection pressure, injection angle, and injector orifice diameter. Any deviation from normal conditions in any of these aspects can disrupt optimal engine performance, resulting in inefficient combustion and increased exhaust emissions. To investigate the effect of injector hole number, injection hole angle, and injection pressure on the performance and emissions of a diesel engine operating on a diesel/hydrogen blend (10 % hydrogen and 90 % diesel), a single-cylinder direct injection diesel engine was used. Three injector nozzle configurations just for diesel injector with different hole diameters (0.6, 0.3, and 0.2 mm) were used at injection angles of 0, 15, and 30 degrees, respectively. Three injection pressures (200, 400, and 600 bar) were tested, with results monitored for brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), smoke, and NOx emissions.

Optimal results were achieved with a maximum injection pressure of 400 bar and a nozzle angle of 15 degrees, resulting in improved engine performance and BTE, along with a 6.5 % reduction in BSFC. Increasing the number of injector holes, injection pressure, and injection angle resulted in reduced BSFC and smoke emissions, but with a significant increase in NOx emissions. Notably, this study deviates from traditional combustion methods by introducing air from a 1.1-atmosphere tank instead of relying solely on natural intake. In addition, hydrogen fuel is introduced into the air manifold via a separate injector with an injection pressure of 20 bar, while diesel fuel is injected directly into the combustion chamber.

Access to reliable energy is crucial for development, yet many rural areas in southern Bangladesh suffer from electricity shortages, impeding essential services and hindering social and economic progress. This paper proposes integrating renewable energy-based microgrids to provide sustainable and reliable electricity, thereby improving living conditions and boosting economic growth. A detailed survey in Ruma, Bandarban, was conducted for load estimation. Simulation results for on-grid and off-grid microgrids are obtained using HOMER Pro and PVsyst software. The off-grid system includes 21.8 kW of PV, 15 kW of hydro, and 222 kWh of battery storage, while the on-grid system includes a 200 kW PV system and a 15 kW hydro turbine. The levelized cost of energy (LCOE) is 0.15 USD/kWh off-grid and 0.03 USD/kWh on-grid. The on-grid system shows economic sustainability with a 6.8-year break-even point, 13 % IRR, and 8.7 % ROI. Environmental analysis shows significant greenhouse gas reductions, with CO₂ emissions decreasing from 227,778 kg/year to 199,016 kg/year. Additionally, a sensitivity analysis is conducted, which underscores the resilience of the proposed hybrid microgrid system to weather variations and cost fluctuations. This paper provides a comprehensive foundation for policymakers to consider renewable microgrids as a solution for rural electrification in southern Bangladesh, utilizing solar and hydropower resources.

Given the gradual nature of the energy transition, retrofitting coal-fired power plants with carbon capture technology is crucial. The calcium looping (CaL) process is a promising solution, with challenges like absorbent deactivation and reduced thermal efficiency mitigated by absorbent reactivation and heat recovery systems. This study evaluated the techno-economic feasibility of integrating a novel wet extraction and precipitation process for absorbent reactivation within a solar-assisted CaL system, alongside an existing coal power plant. The process incorporated a secondary steam cycle and an ammonia absorption chiller for enhanced heat recovery and district cooling. The integrated project could increase daily power generation by 50% and reduce CO₂ emissions from 820.4 g/kWh to 54.5 g/kWh. Over its lifespan, the reactivation facility could reduce limestone extraction by 21 Mt with 90% capture efficiency. With a levelized cost of electricity (LCOE) of 116.1 €/MWh and breakeven electricity selling price (BESP) of 56.6 €/MWh, the system demonstrated promising commercial viability, with the reactor and concentrated solar heating (CSH) system making up over 60% of investment costs. CSH cost and solar abundance were identified as key factors, indicating potential feasibility even in higher latitude regions. At CO₂ revenues of 150 €/t, a stand-alone capture project can break even based solely on CO₂ sales, demonstrating its potential for expansion to other areas. A case study highlighted the benefits of integrating absorbent reactivation and an ammonia absorption chiller, improving both economics and carbon capture efficiency. The study also confirmed the viability of solar-assisted projects in high-latitude regions, with optimistic future CO₂ revenues and advancements in carbon capture technology enhancing feasibility.

To fully realize the potential of solid oxide electrolysis (SOE) systems, improvements in long-term durability and scalability are required. Investigating and comparing different degradation mechanisms under different conditions is crucial. A multi-scale cell to system level time-dependent simulation framework for SOE systems including various degradation phenomena is presented. Galvanostatic, Potentiostatic, and Potentio-Galvanostatic operation, a combination of the two previous modes, are investigated. The time and space evolution of various performance and degradation parameters are compared. Potentio-Galvanostatic operation consistently maintains stable efficiency throughout its lifetime. Near thermoneutral condition is maintained in Potentiostatic and Potentio-Galvanostatic operations, while degradation eventually leads to exothermic operation in Galvanostatic mode. Cathode overpotential is higher in Galvanostatic operation, while in Potentio-Galvanostatic operation, it drops over time as the temperature increases. After 25,000 h of operation under specified conditions, the area-specific resistance (ASR) experiences a 51% and 62% increase in Galvanostatic and Potentiostatic operations, respectively, while Potentio-Galvanostatic operation results in only a 4% increase compared to the beginning of life. Interconnect oxidation is most pronounced in Potentio-Galvanostatic mode, highlighting the need for high-quality steels and coatings in this operation strategy. Over time, in Galvanostatic operation, the current density shifts from being highest at the inlet towards the outlet.

The challenges posed by power shortages, hot climates, heating demands, and water scarcity on island platforms significantly impede productivity and quality of life. Implementing a multi-energy supply system emerges as a promising solution to address these issues. In this study, we propose, analyze, and optimize a novel multigeneration system for cooling, heating, power, and desalinated water production, leveraging waste heat from a nuclear power plant. This innovative system integrates a recompression supercritical CO₂ (sCO₂) Brayton cycle, an Organic Rankine Cycle (ORC) with a booster-enhanced ejector refrigeration cycle (BERC), an absorber heat transformer (AHT) with a distillation unit, and a heating unit (HU). Harnessing energy cascading from nuclear power, the system efficiently recovers surplus heat generated by the sCO₂ cycle, which serves multiple purposes: powering the ORC generator for additional power generation, driving the BERC for user cooling, and fueling the AHT and HU systems for freshwater production and user heating, respectively. The system’s performance is rigorously evaluated through thermodynamic and exergoeconomic analyses, leveraging established and validated models. Parametric analysis reveals crucial trends in system performance with respect to eight key parameters. Additionally, single-objective and multi-objective optimizations, utilizing a weight coefficients approach, are conducted to maximize thermodynamic efficiency and minimize total product unit cost. Notably, the importance of balancing the sCO₂ compressor pressure ratio for optimal exergy efficiency or minimum total product cost is underscored. Exergoeconomic optimization demonstrates a substantial reduction (6.1% and 1.59%) in the overall cost of unit product compared to energy and exergy efficiency optimizations alone, while achieving optimal energy efficiency (62.54%), exergy efficiency (66.75%), and a sum unit cost of products of 10.02 $/GJ. Multi-objective optimization, treating all three objectives equally, yields impressive results, including an energy efficiency of 82.3%, exergy efficiency of 62.41%, and a sum unit cost of products of 10.58 $/GJ.

The microbial fuel cell (MFC), acknowledged as an innovative bioenergy conversion system, has attracted considerable attention in research. An MFC is a device that utilizes microorganisms to directly convert chemical energy present in organic compounds into electrical energy. This bioelectrochemical hybrid system functions not only as a power generation tool but also as an effective instrument for sewage treatment, incorporating nutrient recovery. Its noteworthy advantages encompass energy conservation, sludge reduction, and efficient energy conversion. This paper offers a comprehensive overview of recent cases that involve the synergistic treatment of MFC and traditional sewage treatment technologies. The integration of MFC with conventional sewage treatment processes has demonstrated greater efficiency compared to standalone MFC or traditional sewage treatment methods. This coupled system shows significant promise in converting waste into clean energy, optimizing resource utilization, and addressing the energy crisis. Significantly, the integration of MFC with anaerobic fermentation has attracted considerable attention owing to its distinctive advantages, positioning it as a potential future development trend. The paper concludes by analyzing the multifaceted benefits of this coupling system, providing valuable insights for future research on integrating MFC with other technologies.

Hybrid renewable energy systems with electric vehicle charging stations can provide reliable and environmentally friendly power output for telecom Base Transceiver Stations (BTS). This paper provides an optimized BTS telecom deployment method. The proposed framework uses actual load profiles to conduct a techno-economic assessment of 26 independent sites in North, South, and Central regions to reduce NPC, operational costs, LCOE, and diesel generator running hours. To complete this study’s financial model, these 26 BTS sites are connected to the grid for net metering and environmentally friendly electric vehicle (EV) charging stations, and incentives (bonus depreciation and investment tax credit) are added. Finally, numerous uncertain elements are sensitively analyzed, and a carbon emission reduction environmental evaluation is done. When connected to a grid for net metering, freestanding hybrid systems (diesel generator-photovoltaic-wind-battery) have a significantly lower LCOE. Standalone hybrid systems have LCOEs between 0.1096 and 0.2325 $/kWh. On-grid hybrid systems have an average LCOE of 0.004065 to 0.03559 $/kWh. After adding electric vehicle charging stations and incentives, the average LCOE drops further. Optimization and comparative studies reveal that the best grid expansion hybrid charging station is cheaper, greener, and more sustainable than the stand-alone hybrid system. The Sustainable Development Goals (SDGs) and governments and corporate investors can utilize the suggested studies to make decisions and optimize policies.