Energy Generation Research Articles

Evaluation of the Interconnection of a Biomethane Microturbine in an Absorption Refrigeration System

This article evaluates the performance and environmental impact of a combined system of natural gas microturbine and absorption refrigeration system. The objective of the study is to evaluate the interconnection of a biomethane microturbine in an absorption refrigeration system. The study applies energy and exergy balances to each component of the system, using EES software for the simulation. The microturbine is a Capstone C600s model with a nominal power of 600 kW, and the absorption chiller is a single-stage LiBr-H2O system with a cooling capacity of 680.7 kW. The results show that the microturbine achieves a thermal efficiency of 34%, an exergetic efficiency of 86%, and a net power output of 585.4 kW. At the same time the absorption chiller has a coefficient of performance (COP) of 0.7 and 680.7 kW with generator water temperature inlet of 100 °C. On the other hand, this study identifies the most efficient points of interconnection between the two systems. The combined system reduces the CO2 equivalent emissions by 700 to 900 tons/year compared to conventional systems. The behaviour of the interconnection heat exchanger is also evaluated using Computed Fluid Dynamics. The investigation concludes that the interconnection of a natural gas microturbine and an absorption refrigeration system is a promising alternative that can optimize both technical and economic aspects of energy generation and utilization, while mitigating environmental problems.

Power Quality State Estimation for Distribution Grids Based on Physics-Aware Neural Networks—Harmonic State Estimation

In the transition from traditional electrical energy generation with mainly linear sources to increasing inverter-based distributed generation, electrical power systems’ power quality requires new monitoring methods. Integrating a high penetration of distributed generation, which is typically located in medium- or low-voltage grids, shifts the monitoring tasks from the transmission to distribution layers. Compared to high-voltage grids, distribution grids feature a higher level of complexity. Monitoring all relevant nodes is operationally infeasible and costly. State estimation methods provide knowledge about unmeasured locations by learning a physical system’s non-linear relationships. This article examines a new flexible, close-to-real-time concept of harmonic state estimation using synchronized measurements processed in a neural network. A physics-aware approach enhances a data-driven model, taking into account the structure of the electrical network. An OpenDSS simulation generates data for model training and validation. Different load profiles for both training and testing were utilized to increase the variance in the data. The results of the presented concept demonstrate high accuracy compared to other methods for harmonic orders 1 to 20.

Photocarrier Dynamics of Two-Dimensional Aza-Fused Covalent Organic Frameworks as Bifunctional Photocatalysts toward Overall Water Splitting.

Designing high-efficiency bifunctional photocatalysts toward photoinduced overall water splitting is one of the most promising and challenging research directions for clean energy generation. By employing static electronic structure calculation and nonadiabatic molecular dynamics (NAMD) simulation, we herein established a recently synthesized two-dimensional (2D) aza-fused covalent organic framework (aza-COF) as a potential bifunctional photocatalyst toward overall water splitting reactions. Our calculated results reveal that the overpotentials for hydrogen evolution reaction and oxygen evolution reaction are only 0.06 and 0.31 V, respectively, at pH = 4. The dynamics of photoexcited charge carriers studied through NAMD simulation predicts the electron-hole recombination time (25.15 ns), and this confirms that the photogenerated electron and hole carriers migrate to the active sites for the occurrence of reaction before they recombine. Therefore, our results suggest that the 2D aza-COFs exhibit great potential as metal-free and single-material photocatalysts toward overall water splitting under visible light.

Разработка методики расчета составляющих резерва тепловой экономичности парогазовых установок

The components of the thermal efficiency reserve of thermal power plant equipment are the overexpenditure or savings of fuel due to the deviation of the actual values of the equipment performance from their nominal values. They are determined in tons of reference fuel for a certain period. The components of the thermal efficiency reserve are the most essential element of the technical record-keeping and reporting systems of power plants. They allow us to quantitatively assess the technical condition of the equipment and, on this basis, effectively plan repair programs. The methods to calculate the components of the thermal efficiency reserve of steam power plants are well developed and regulated according to the regulatory documents. Regulatory requirements for combined-cycle plants in this area contain inaccuracies and do not cover a full list of the components of the thermal efficiency reserve. Thus, it is necessary to develop a method that allows us to calculate the components of the thermal efficiency reserve of combined-cycle plants. When developing the methodology for combined-cycle plants, the authors have applied the approaches to calculate the components of the thermal efficiency reserve that are used for steam power plants. In addition, available methods for assessing the thermal efficiency of thermal power plant equipment have been used. The developed methods have been tested based on actual data on the operation of combined-cycle plant PGU-116. A methodology to calculate the components of the thermal efficiency reserve of combined-cycle plants with waste-heat boilers without fuel afterburning has been developed. The methodology has been tested in assessing the thermal efficiency indicators of combined-cycle plant in operation. Shortcomings in regulatory documents of the energy industry in terms of calculating the components of the thermal efficiency reserve of combined-cycle equipment have been identified. The developed methodology can be recommended for use in the systems of technical record-keeping and reporting of power plants when monitoring the indicators of thermal efficiency of combined-cycle plants. To ensure the objectivity of the results of the analysis of the efficiency of operated combined-cycle power units in Russia, it is necessary to adjust industry regulatory documents. They should contain uniform scientifically substantiated methods for calculating the components of the reserve of thermal efficiency of combined-cycle equipment.

Elephant Grass Cultivar BRS Capiaçu as Sustainable Biomass for Energy Generation in the Amazon Biome of the Mato Grosso State

Sustainable biomasses are vital to ensure preservation of the Amazon biome within the Mato Grosso State whilst enabling energy generation for the region and its population. Here, the potential of the elephant grass cultivar BRS Capiaçu as an alternative to replace native forest wood as biomass for energy generation is investigated, considering the whole process from plant cultivation to biomass characterisation in terms of productivity of green and dry mass per hectare; density, moisture, ash, volatile and fixed carbon content, as well as higher heating value (HHV). MANOVA indicates that the effects of plant parts and age on density and proximate analysis parameters are influenced by the plant parts and age interaction, whereas HHV can be considered similar between them. The cultivar BRS Capiaçu showed suitable energetic values (17,922 < HHV < 18,918 kJ.kg−1) compared to that of native Amazon wood. Energetic results combined with cultivation outputs of high productivity (dry mass production of 44.1 tonnes.ha−1 at 180 days) with a short cutting interval (3 months), adaptation to the region’s climate and soil, and the possibility of cultivation in areas currently consolidated for agriculture demonstrate the potential of BRS Capiaçu as biomass to reduce native wood usage and deforestation rates.

Generación renovable eólica y fotovoltaica en Ecuador: Una revisión sistemática de literatura

INTRODUCTION. Photovoltaic and wind renewable generation has grown exponentially in recent years worldwide, in Ecuador this technology has not been the exception, as several photovoltaic and wind power plants have been installed, increasing the generation of renewable energy. OBJECTIVE. This article presents a systematic review of the literature on operational photovoltaic and wind power plants in Ecuador, offering a perspective on the renewable sources connected to the national energy system. METHOD. Through a bibliographic search in the Scopus database, 8 publications were obtained that met the eligibility criteria, in addition to reports issued by government entities, to ensure that the information and technical aspects are accurate. RESULTS. The documentary analysis allows us to know the current status of photovoltaic and wind power plants, identifying their installed capacity, technology used, and operational characteristics. DISCUSSION AND CONCLUSIONS. The information collected provides a solid basis for understanding the current status and development prospects of photovoltaic and wind power generation in Ecuador. Despite certain limitations related to the availability of data in open sources, it was possible to obtain significant information on the main renewable plants in the country. These results serve as a basis for future research aimed at the expansion and optimization of renewable energies in the national context..

Investigating Physicochemical Methods to Recover Rare-Earth Elements from Appalachian Coals

The demand for rare-earth elements is expected to grow due to their use in critical technologies, including those used for clean energy generation. There is growing interest in developing unconventional rare-earth element resources, such as coal and coal byproducts, to help secure domestic supplies of these elements. Within the U.S., Appalachian Basin coals are particularly enriched in rare-earth elements, but recovery of the elements is often impeded by a resistant aluminosilicate matrix. This study explores the use of calcination and sodium carbonate roasting pre-treatments combined with dilute acid leaching to recover rare-earth elements from Appalachian Basin coals and underclay. The results suggest that rare-earth element recovery after calcination is dependent on the original mineralogy of samples and that light rare-earth minerals may be more easily decomposed than heavy rare-earth minerals. Sodium carbonate roasting can enhance the recovery of both light and heavy rare-earth elements. Maximum recovery in this study, ranging from 70% to 84% of total rare-earth elements, was achieved using a combination of calcination and sodium carbonate roasting, followed by 0.25 M citric acid leaching.

Management of Hybrid Hydropower and Floating Solar Systems at Num Ngum 1 in Lao PDR

The integration of a hybrid hydro-floating solar power (HPP-FPV) system is covered in this study with the goal of improving energy management and producing more electricity. The production capacity of the hybrid system is almost twice as high as that of the original HPP system, demonstrating its potential for higher energy generation. Because it forecasts weather and modifies electricity generation accordingly. The analysis highlights how crucial it is to make sure that the hybrid system's electricity generation doesn’t go beyond the current power grid's maximum transmission capacity. This is essential to preserving the consistency and caliber of the power that is provided. The research's overall goal of increasing the output of renewable energy through creative system integration and practical management techniques is captured in the abstract.

Deposition of Imidazole into Mesoporous Zirconium Metal-Organic Framework for Iodine Capture.

Efficient capture of radioiodine is essential for the protection of the ecological environment and the sustainable development of nuclear energy generation. Metal-organic frameworks (MOFs) and their derivatives provide alternative potential for overcoming the limitations of traditional iodine adsorbents. Herein this work, imidazole (Im) is dispersed into a robust mesoporous zirconium MOF PCN-222 by the heat deposition method, forming a high-uniformity composite Im@PCN-222. The large pore size and marked chemical resistance skeleton of PCN-222 allow the incorporation of Im to reach 43 wt % while surviving the chemical corrosion of activated Im. The nearly saturated loading of Im significantly benefits the sorption capability toward iodine and gives rise to an exceptional adsorption capacity of 10.04 g g-1 and excellent recyclability. This value is higher than that of most of the MOFs and their derivatives. Further, Im was also successfully deposited onto the PCN-222 functionalized porous Al2O3 ceramic filtration membrane, which endowed the hybrid membrane with efficient iodine sorption and separation properties. This work highlights a new strategy for the fabrication of the MOF-based radioiodine adsorption composite as well as MOF composite-based filters.

Environmental regulations’ impact on clean energy consumption: Under the assistance of governance measures

The drastic change in climate augments the importance of clean energy consumption. Therefore, this paper examines how environmental regulations influence the utilization of clean energy under the moderation of governance measures. The 2-Steps System GMM is applied to 26 OECD countries’ data from 1996 to 2019 to analyze the relationship. Our analysis depicts that environmental regulations and GDP significantly enhance clean energy usage in OECD countries. Moreover, economic globalization insignificantly impacts clean energy consumption. On the contrary, financial development in OECD countries significantly leads to a decrease in the consumption of clean energy because renewable energy projects are long-term and more expensive than non-renewable energy generation projects. This paper further discovers that the majority of the governance measures significantly and positively moderate the connection of environmental regulations with clean energy consumption. Consequently, constructive governance measures facilitate the effective implementation of environmental regulations in OECD countries eventually increasing the consumption of clean energy instead of non-renewable energy. To reduce GHG emissions in the environment, the government should encourage the usage of clean energy in their respective countries. Therefore, policymakers promote the practice of clean energy consumption through stringent environmental regulations and effective governance measures.

Constructing a novel double Z-type junction BaTiO3/ZnIn2S4/ZnTiO3 by a new chemical reaction for antibiotics degradation, H2 production, and CO2 reduction

At present, only single charge transfer channel is available in the study of BaTiO3/ZnIn2S4 heterojunction. In order to overcome this bottleneck, this paper adopts a novel chemical reaction to promote the transformation of ZnIn2S4 into ZnTiO3, thereby creating a novel triphase junction BaTiO3/ZnIn2S4/ZnTiO3 and a new transfer channel. This result leads to the photodegradation efficiencies of the levofloxacin and the lomefloxacin attaining 89 % and 92 % for the light irradiation of 30 minutes. Moreover, the removal efficiencies of the total organic carbon and the chemical oxygen demand reach 65 % and 84 % in the levofloxacin degradation, while these are 63 % and 81 % in the lomefloxacin degradation. Further, the H2 production rate attains 2.47 mmol/g/h, while the CO2 reduction rate to CO also reach 27.43 μmol/g/h. The accurate rate achieves 97.05 % for the prediction of the photocatalytic efficiency based on the Back Propagation neural network. The development toxicity indexes of the intermediate products reduce gradually to indicate the final solution is environmentally friendly. Therefore, the BaTiO3/ZnIn2S4/ZnTiO3 has a potential application in the sewage purification and the clean energy generation.

Exploring the potential of biohydrogen as a sustainable energy solution for Pakistan: A review of production processes and policy challenges

Due to growing carbon dioxide emissions and the depletion of fossil-based energy sources, international studies have been focusing more intensely on developing hydrogen as a source of renewable energy. Biohydrogen is an exciting and green alternative energy source with various different benefits. Unlike traditional energy sources, biohydrogen production does not emit pollutants, making it a more environmentally friendly option. Biohydrogen generation, particularly from microalgae and other low-cost biomass feedstocks, so offers the dual benefit of delivering clean electricity while absorbing Carbon Dioxide. This research investigates the possibility of biohydrogen as a sustainable energy solution for Pakistan's climate issue. We examine the current state of biohydrogen generation technologies, such as dark fermentation, photo fermentation, bio photolysis, with a focus on their potential application in Pakistan. The study investigates global advances in biohydrogen research and their significance in Pakistan, demonstrating biohydrogen's potential contribution to Pakistan's energy independence and environmental targets, as well as the practical and policy-related challenges that must be addressed to advance biohydrogen energy generation and wider adoption.

A two-stage bi-level electricity-carbon coordinated optimization model for China's coal-fired power system considering variable renewable energy bidding

With China's grid-connected large-scale variable renewable energy, coal-fired power system is progressively changing from being the main supplier of electric energy to providing flexibility services. The coal-fired power system must increase operating efficiency during this transition process by considering the technical characteristics of various coal-fired power units. Additionally, the trading strategies of coal-fired power units in the electricity-carbon market are impacted differently depending on the extent of VRE penetration. This paper innovatively considers these two factors and proposes a two-stage bi-level clearing model in electricity-carbon joint market to coordinate the synergistic development of variable renewable energy and coal-fired power. The upper level of the model aims to maximize the total profits of the coal-fired power system and variable renewable energy units, while the lower level of the model minimizes the total purchasing costs. Coal-fired power units and variable renewable energy units compete to sell electric energy, with the latter buying peaking regulation from the former. The research results indicate that the proposed model can significantly reduce 66.79 % carbon emissions, increase 33.96 % non-fossil variable renewable energy integration and optimize the generation structure of coal-fired power system.

FISH PRODUCTION AND THE POTENTIAL OF TILAPIA PRODUCTION IN BRAZIL AND IN THE WORLD: A SYSTEMATIC REVIEW OF ITS USE AS ENERGY AND FOOD

The need for new sources of renewable energy is something that is widely studied today. In several countries, the search for new sources of raw materials for biodiesel production is being evaluated and used. Among these sources is the use of animal fat waste. In this context, the use of fish waste is being evaluated and applied as an intensive source in the production of biodiesel. However, the development of technologies that can make the extraction of these fats viable is still a determining factor in the full use of these wastes. This study presents a review of the production of Nile Tilapia, farmed in captivity, as well as its use in the production of and application in the biodiesel production chain. This work, because it is a review of the potential for the use of waste, used a systematic assessment of the collection of studies, market assessments, and government agencies, which made it possible to obtain data on production and waste generation. For this purpose, searches were carried out on journal platforms and websites that involve the fish production chain. Thus, the verification of this new source of biomass in energy generation becomes viable for the development of new technologies that can add value to waste and reduce the environmental impacts caused by fish farming. The study indicates that there is a significant opportunity in the use of fish waste for the production of renewable fuels, specifically those that have a high lipid content, and their use for the production of biodiesel is possible.

Solar Dryers: Technical Insights and Bibliometric Trends in Energy Technologies

This review article provides a comprehensive analysis of the technical advancements and research trends in solar drying technologies for agricultural products. The study encompasses various innovations in energy storage systems, including phase change materials (PCMs) and the use of computational fluid dynamics (CFD) for optimizing the drying process. Through a bibliometric analysis of 126 scientific papers published between 1984 and 2024, five major research clusters were identified: energy generation, heat transfer, thermal storage, simulation modeling, and the integration of hybrid systems. The results demonstrate a marked increase in scientific output over the past decade, emphasizing a growing interest in the sustainable use of solar energy for drying applications. Key findings highlight that while PCM-based storage solutions significantly enhance the thermal stability of dryers, the high implementation costs and technical complexities limit their adoption, especially in small-scale operations. Similarly, CFD models have proven effective in optimizing air and temperature distribution within dryers; however, their performance is hindered by real-world fluctuations in solar radiation and humidity levels. To address these limitations, future research should focus on the development of cost-effective PCM materials and the improvement of CFD models for dynamic environmental conditions. The review concludes by emphasizing the importance of interdisciplinary collaboration in the design and application of these technologies, recommending the inclusion of real-world case studies to better illustrate the practical implications and economic benefits of solar drying technologies for agricultural production.

Projected Changes of the Warm Arctic‐Cold North American Pattern

AbstractThe Warm Arctic‐Cold North American (WACNA) pattern features opposing surface temperature anomalies, with centers over the Chukchi‐Bering Seas (CBS) and the North American Great Plains. The pattern is mainly driven by meridional heat transport and damped by the generation of available potential energy through diabatic heating. The Canadian Earth System Model CanESM5, part of the Coupled Model Intercomparison Project Phase 6 (CMIP6), reasonably reproduces this pattern and its formation mechanisms. Future projections under the Shared Socioeconomic Pathway 8.5 (SSP5‐8.5) suggest a significant weakening of WACNA with global warming. Notable changes in pattern intensity and spatial structure are anticipated, particularly a decrease in intensity over the CBS. WACNA changes are also found in 31 CMIP6 multi‐model ensemble simulations. These changes are attributed to Arctic amplification associated with global warming, which diminishes the equator‐to‐pole temperature gradient and consequently reduces meridional heat transport, particularly over the CBS region.

Evaluation of the potential power generation resources in SAARC region for sustainable energy trade

AbstractThis article presents a comprehensive review on the contemporary condition of electrical energy in the SAARC countries with particular focus on conventional as well as renewable resources. The region lies at the center of the Asia with a dense population where demand and supply gap has always been a challenging factor for the governments. In addition, the region has observed enormous industrial growth during past two and half decades whose sustainability is totally dependent upon the continuous supply of energy. A bulk of valuable literature has been published in recent years that addresses the challenges, infrastructure improvements margins and several schemes to mitigate the energy deficiency in the region but most of it focuses upon either generation or transmission. This article covers this gap and presents to‐the‐point data that can be used for future forecasting, cross‐border trade possibilities and indigenous energy generation for remote and islanded regions within and across the SAARC mainland. A detailed review on electrical power generation potential by exploiting the renewable energy resources (RERs), generation capacity, installed capacity, energy short fall and transmission and distribution (T&D) losses is presented for each SAARC country and the results are presented in forms of tables and graphs. It can be inferred from the data presented in this paper that the energy crisis of the SAARC region can be overcome by mutual trade among the land‐connected countries by transporting the electrical energy, generated through RERs, across the borders. The paper concludes that the region has enormous potential for renewable energy available in form of hydal, solar, wind and biomass that, if maturely harnessed, can only not fulfil the local demands of the region but also be exported to establish the framework of cross‐border energy trade in future for sustainability of industrial and domestic utilization.

Prediction of power conversion efficiency parameter of inverted organic solar cells using artificial intelligence techniques

Organic photovoltaic (OPV) cells are at the forefront of sustainable energy generation due to their lightness, flexibility, and low production costs. These characteristics make OPVs a promising solution for achieving sustainable development goals. However, predicting their lifetime remains challenging task due to complex interactions between internal factors such as material degradation, interface stability, and morphological changes, and external factors like environmental conditions, mechanical stress, and encapsulation quality. In this study, we propose a machine learning-based technique to predict the degradation over time of OPVs. Specifically, we employ multi-layer perceptron (MLP) and long short-term memory (LSTM) neural networks to predict the power conversion efficiency (PCE) of inverted organic solar cells (iOSCs) made from the blend PTB7-Th:PC70BM, with PFN as the electron transport layer (ETL), fabricated under an N2 environment. We evaluate the performance of the proposed technique using several statistical metrics, including mean squared error (MSE), root mean squared error (rMSE), relative squared error (RSE), relative absolute error (RAE), and the correlation coefficient (R). The results demonstrate the high accuracy of our proposed technique, evidenced by the minimal error between predicted and experimentally measured PCE values: 0.0325 for RSE, 0.0729 for RAE, 0.2223 for rMSE, and 0.0541 for MSE using the LSTM model. These findings highlight the potential of proposed models in accurately predicting the performance of OPVs, thus contributing to the advancement of sustainable energy technologies.

MIWO based MPPT of PV system for induction motor driven water pumping system

Renewable energy source-based Water Pumping Systems (WPSs) have gained popularity for drinking, agricultural, and industrial purposes. Locally situated standalone Photovoltaic (PV) powered WPS can provide a viable water supply solution, especially with induction motors (IM) due to their advantages over other motor types. However, solar PV energy output is greatly influenced by weather conditions, necessitating energy storage systems like batteries, which increase costs and require maintenance. This research proposes an efficient energy management system for a PV-powered IM-driven WPS that does not rely on batteries. The system handles Partial Shading Conditions (PSC) effectively, thanks to a sensorless speed controller combining a Modified Invasive Weed Optimization (MIWO) mechanism with the Perturb and Observe (P&O) method. This controller uses the inverter as an MPPT circuit, eliminating the need for a distinct converter to follow the MPP. The hybrid P&O-MIWO method's outcomes are compared with those of P&O hybridization with GA, PSO, and GWO to assess efficiency under various PSCs. TS-Fuzzy controllers are employed for voltage control at the DC-link and motor speed. The proposed system is analyzed across different scenarios and validated using a Simulink model in MATLAB. Results indicate that the hybrid P&O-MIWO mechanism enhances energy generation from the PV unit without relying on energy storage devices, providing a cost-effective solution for PV-based WPS implementation.

Evaluation of Modified Conventional Still Distiller Using Coupled External Passive Condenser: An Experimental Study

Solar radiation plays an important part in the desalination of saline water owing to its abundance in areas with potable water shortage and it also occupies a paramount place in green energy generation due to its simplicity of application. Still distiller is viewed by researchers as a suitable source of potable water because of low cost of fabrication, easy operation and zero emission technology. Studies by researchers are geared towards exploring new models to improve the productivity of solar stills and enhance its production rate is ongoing. The main aspiration of this work is to experiment the consequence of introducing a passive condenser to a modified conventional solar still to enhance its productivity yield. It was observed that the modified passive still distiller coupled with the external condenser gave about 11.85% higher production yield in comparison with the modified conventional still distiller. Daily and accumulated distillate yield for the still distillers have been studied and analyzed. The result of the findings revealed that sawdust padding around the still distillers is recommended to maximize productivity leading to efficient water distillation in regions where that require still distiller usage. This recommendation has been seen to produce the desired result in accessing to potable water within areas where water scarcity prevails. This is suggested to contribute effectively bearing the cost ineffective water desalination technique.