Energies

20 pages, 1154 KiB

Open AccessArticle

Thermodynamic Performance Comparison of CCHP System Based on Organic Rankine Cycle and Two-Stage Vapor Compression Cycle

by Tailu Li, Jingyi Wang, Yao Zhang, Ruizhao Gao and Xiang Gao

Energies 2023, 16(3), 1558; https://doi.org/10.3390/en16031558 - 3 Feb 2023

Cited by 2 | Viewed by 2052

Abstract

Owing to different temperature rages of power generation and refrigeration in the cogeneration system, for the sake of selecting the working fluids that are suitable for both power generation and refrigeration simultaneously, 17 commonly used working fluids are evaluated in this paper, based [...] Read more.

Owing to different temperature rages of power generation and refrigeration in the cogeneration system, for the sake of selecting the working fluids that are suitable for both power generation and refrigeration simultaneously, 17 commonly used working fluids are evaluated in this paper, based on an organic Rankine cycle coupled with a two-stage vapor compression cycle system in different geothermal fluid temperatures. The performances of working fluids under different working conditions, and the maximum power generation as well as cooling capacity are analyzed. Additionally, the main parameters are analyzed to optimize the system performance. The results indicate that net power output has a local maximum where it corresponds to the optimal evaporation temperature. Besides, the lower the critical temperature, the greater the thermal conductance, and the pressure ratio decreases with evaporation temperature. Hydrocarbons all have higher total heat source recovery efficiency. R1234yf, propane and R1234ze, R152a have excellent maximum net power output when the geothermal fluid temperature is low and high, respectively. R134a always has better maximum net power output and cooling capacity. The net power output is used for cooling, and the COP is closed, therefore, maximum net power output results in the maximum cooling capacity. In addition, that of propane and R1234yf are excellent until the geothermal fluid temperature are 140 °C and 120 °C separately. R1234ze and R152a are good when the geothermal fluid temperatures are 140 °C and 150 °C, respectively. Full article

(This article belongs to the Special Issue Low Carbon Energy Technology for Heating and Cooling of Buildings)

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15 pages, 1217 KiB

Open AccessArticle

Characterization of the Ensemble of Lignin-Remodeling DyP-Type Peroxidases from Streptomyces coelicolor A3(2)

by Hegne Pupart, Piia Jõul, Melissa Ingela Bramanis and Tiit Lukk

Energies 2023, 16(3), 1557; https://doi.org/10.3390/en16031557 - 3 Feb 2023

Cited by 10 | Viewed by 2652

Abstract

Lignin is Nature’s major source of aromatic chemistry and is by many seen as the green entry-point alternative to the fossil-based chemical industry. Due to its chemically recalcitrant structure, the utilization of lignin is challenging, wherein enzymes might be the key to overcome [...] Read more.

Lignin is Nature’s major source of aromatic chemistry and is by many seen as the green entry-point alternative to the fossil-based chemical industry. Due to its chemically recalcitrant structure, the utilization of lignin is challenging, wherein enzymes might be the key to overcome this challenge. Here, we focus on the characterization of dye-decolorizing peroxidases from Streptomyces coelicolor A3(2) (ScDyPs) in the context of enzymatic modification of organosolv lignins from aspen and Miscanthus × giganteus. In this study, we show that the ScDyPB can remodel organosolv lignins from grassy biomass, leading to higher molecular weight species, while ScDyPAs can deconstruct hardwood lignin, leading to an overall reduction in its molecular weight. Additionally, we show that ScDyPB is effective in polymerizing low-molecular-weight phenolics, leading to their removal from the solution. Full article

(This article belongs to the Special Issue Biofuels Production from Lignocellulosic Biomass)

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17 pages, 3321 KiB

Open AccessReview

Prospect of Green Hydrogen Generation from Hybrid Renewable Energy Sources: A Review

by Asim Kumar Sarker, Abul Kalam Azad, Mohammad G. Rasul and Arun Teja Doppalapudi

Energies 2023, 16(3), 1556; https://doi.org/10.3390/en16031556 - 3 Feb 2023

Cited by 88 | Viewed by 8743

Abstract

Hydrogen is one of the prospective clean energies that could potentially address two pressing areas of global concern, namely energy crises and environmental issues. Nowadays, fossil-based technologies are widely used to produce hydrogen and release higher greenhouse gas emissions during the process. Decarbonizing [...] Read more.

Hydrogen is one of the prospective clean energies that could potentially address two pressing areas of global concern, namely energy crises and environmental issues. Nowadays, fossil-based technologies are widely used to produce hydrogen and release higher greenhouse gas emissions during the process. Decarbonizing the planet has been one of the major goals in the recent decades. To achieve this goal, it is necessary to find clean, sustainable, and reliable hydrogen production technologies with low costs and zero emissions. Therefore, this study aims to analyse the hydrogen generation from solar and wind energy sources and observe broad prospects with hybrid renewable energy sources in producing green hydrogen. The study mainly focuses on the critical assessment of solar, wind, and hybrid-powered electrolysis technologies in producing hydrogen. Furthermore, the key challenges and opportunities associated with commercial-scale deployment are addressed. Finally, the potential applications and their scopes are discussed to analyse the important barriers to the overall commercial development of solar-wind-based hydrogen production systems. The study found that the production of hydrogen appears to be the best candidate to be employed for multiple purposes, blending the roles of fuel energy carrier and energy storage modality. Further studies are recommended to find technical and sustainable solutions to overcome the current issues that are identified in this study. Full article

(This article belongs to the Section A: Sustainable Energy)

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19 pages, 4811 KiB

Open AccessArticle

Numerical Simulation Study of Huff-n-Puff Hydrocarbon Gas Injection Parameters for Enhanced Shale Oil Recovery

by Alsu Garipova, Elena Mukhina, Alexander Cheremisin, Margarita Spivakova, Anton Kasyanenko and Alexey Cheremisin

Energies 2023, 16(3), 1555; https://doi.org/10.3390/en16031555 - 3 Feb 2023

Cited by 1 | Viewed by 1960

Abstract

Gas injection has already proven to be an efficient shale oil recovery method successfully tested all around the world. However, gas-enhanced oil recovery methods have never been implemented or tested for the greatest Siberian shale oil formation yet. This article proposes numerical simulation [...] Read more.

Gas injection has already proven to be an efficient shale oil recovery method successfully tested all around the world. However, gas-enhanced oil recovery methods have never been implemented or tested for the greatest Siberian shale oil formation yet. This article proposes numerical simulation of a hydrocarbon gas injection process into a horizontal well with multiple hydraulic fractures perforating Bazhenov shale oil formation in Western Siberia characterized by ultra-low permeability. A complex field-scale numerical study of gas injection for such a formation has never been performed before and is presented for the first time in our work. The hydrodynamic compositional simulation was performed utilizing a commercial simulator. A sensitivity study for different operating parameters including cycle times, bottom-hole pressures for the production and injection period, and injected gas composition was performed after the model was history matched with the available production data. Some uncertain reservoir properties such as relative permeability curves were also sensitized upon. Two different ways of accounting for multiple hydraulic fractures in the simulation model are presented and the simulation results from both models are compared and discussed. Eventually, huff-n-puff injection of a hydrocarbon gas resulted in a 34–117% increase in oil recovery depending on the fracture model. Full article

(This article belongs to the Special Issue Advanced Technologies for Exploitation of Geo-Energy and Geo-Resources)

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14 pages, 3014 KiB

Open AccessArticle

Study of the Influence of Dynamic and Static Capillary Forces on Production in Low-Permeability Reservoirs

by Yuanzhang Zhang, Youqi Wang, Jianwen Gao, Yuehua Cui and Shuoliang Wang

Energies 2023, 16(3), 1554; https://doi.org/10.3390/en16031554 - 3 Feb 2023

Viewed by 1671

Abstract

Low-permeability reservoirs have strong heterogeneity, and the production prediction based on traditional seepage model is not accurate enough. The dynamic capillary-force seepage model can characterize the dynamic heterogeneity of seepage and more accurately describe the oil–water flow process. In this paper, the calculation [...] Read more.

Low-permeability reservoirs have strong heterogeneity, and the production prediction based on traditional seepage model is not accurate enough. The dynamic capillary-force seepage model can characterize the dynamic heterogeneity of seepage and more accurately describe the oil–water flow process. In this paper, the calculation formula of the dynamic capillary force is obtained through a real low-permeability core experiment, and the seepage model of dynamic capillary force is established. Based on the model, the authors quantitatively study the effects of formation pressure, heterogeneity and production speed on dynamic capillary force through numerical solutions. It is found that compared with the traditional static capillary-force seepage model, the dynamic capillary-force seepage model makes the predicted water cut increase and the recovery factor decrease. With the increase in development time, formation pressure and production rate will make the effect of dynamic capillary force more obvious. According to the comparison of heterogeneous reservoir models, results show that the horizontal heterogeneity will strengthen the dynamic capillary-force effect, while the vertical heterogeneity will weaken the dynamic capillary-force effect. In the range of research parameters, the recovery ratio predicted by the dynamic capillary-force seepage model can be reduced by 4.7%. A new oil–water seepage model is proposed, which can characterize the spatial difference and dynamic change of low-permeability reservoirs with time. It is of great significance for describing the remaining oil distribution of low-permeability reservoirs in detail and making decisions on efficient EOR measures. Full article

(This article belongs to the Topic Fluid Mechanics)

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19 pages, 3865 KiB

Open AccessArticle

Evolutionary Game and Simulation Analysis of Power Plant and Government Behavior Strategies in the Coupled Power Generation Industry of Agricultural and Forestry Biomass and Coal

by Dan Yu, Caihong Zhang, Siyi Wang and Lan Zhang

Energies 2023, 16(3), 1553; https://doi.org/10.3390/en16031553 - 3 Feb 2023

Cited by 6 | Viewed by 1790

Abstract

Under the background of “dual carbon”, the coupled power generation of agricultural and forestry biomass (AFB) and coal, as a new path of coal-power transformation, is key to achieving energy conservation and reducing emissions in the power sector. Timely and effective government subsidies [...] Read more.

Under the background of “dual carbon”, the coupled power generation of agricultural and forestry biomass (AFB) and coal, as a new path of coal-power transformation, is key to achieving energy conservation and reducing emissions in the power sector. Timely and effective government subsidies as well as regulation policies will play important roles in the development of the coupled power generation industry. Previous studies usually assumed government policy as singular and static, rarely considering the dynamic changes in government policies. In this study, evolutionary game theory and systematic dynamics research methods were combined. The game relationship and the dynamic evolution process of the behavioral strategies of both sides are analyzed through the construction of a mixed-strategies game model of the government and power plants. A system dynamics model is built for simulations based on the results of the dynamic game evolution, and the influence paths of key factors on the behavioral strategies of the government and power plants were further demonstrated. The results indicated the following: (1) The behavioral strategies of the government and power plants were not stable for a long period of time, but fluctuated during their mutual influence. The dynamic policies and measures formulated by the government according to changes in the behavioral strategies of power plants will promote industrial development more effectively. (2) Increasing subsidization and the strengthening of supervision caused by government policy can increase the enthusiasm of power plants to choose the coupled power generation of AFB and coal. (3) If the government improves the benefits or reduces the transformation costs caused by coupled power generation the industry will be fundamentally improved. The results clearly show the interactions as well as adjustment processes of the behavioral strategies of power plants and the government in the coupled power generation industry of AFB and coal, and the specific effects of key factors on the behavioral strategies of power plants and the government were investigated. This study can provide a theoretical basis for the government to formulate reasonable industrial policies and measures for the coupled power generation of AFB and coal, in addition to being a valuable reference for other countries to develop a coupled power generation industry. Full article

(This article belongs to the Topic Enabling Strategies and Policies toward a Sustainable Environment)

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16 pages, 907 KiB

Open AccessArticle

Estimating the Error of Fault Location on Overhead Power Lines by Emergency State Parameters Using an Analytical Technique

by Aleksandr Kulikov, Pavel Ilyushin, Konstantin Suslov and Sergey Filippov

Energies 2023, 16(3), 1552; https://doi.org/10.3390/en16031552 - 3 Feb 2023

Cited by 6 | Viewed by 1471

Abstract

Fault location on overhead power lines achieved with the highest possible accuracy can reduce the time to locate faults. This contributes to ensuring the stability of power systems, as well as the reliability of power supply to consumers. There are a number of [...] Read more.

Fault location on overhead power lines achieved with the highest possible accuracy can reduce the time to locate faults. This contributes to ensuring the stability of power systems, as well as the reliability of power supply to consumers. There are a number of known mathematical techniques based on different physical principles that are used in fault location on overhead power lines and whose errors vary. Fault location on overhead power lines uses techniques based on the estimation of emergency state parameters, which are referred to as distance-to-fault techniques and are widely used. They are employed in digital protection relay terminals and power-line fault locators. Factors that have a significant impact on the error of fault location on overhead power lines by emergency state parameters are design, manufacturing, and operation. The aim of this article is to analyze the existing techniques and to present a new analytical technique for estimating errors of fault location on overhead power lines by using emergency state parameters. The technique developed by the authors makes it possible to properly take into account a set of random factors, including various measurement errors of currents and voltages in the emergency state, which have a significant impact on the fault location on overhead power lines error. The technique allows one to determine more accurately the fault location and the size of the inspection area, which is necessary to reduce the time it takes to carry out emergency recovery operations. The proposed technique can be applied in fault locators and digital protection relay terminals that use both single-end, double- and multi-end sensing of currents and voltages in the emergency state. Full article

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28 pages, 5301 KiB

Open AccessArticle

Phase-Homogeneous LiFePO₄ Powders with Crystallites Protected by Ferric-Graphite-Graphene Composite

by Dmitry Agafonov, Aleksandr Bobyl, Aleksandr Kamzin, Alexey Nashchekin, Evgeniy Ershenko, Arseniy Ushakov, Igor Kasatkin, Vladimir Levitskii, Mikhail Trenikhin and Evgeniy Terukov

Energies 2023, 16(3), 1551; https://doi.org/10.3390/en16031551 - 3 Feb 2023

Cited by 1 | Viewed by 2395

Abstract

Phase-homogeneous LiFePO₄ powders have been synthesized. The content of impurity crystalline phases was less than 0.1%, according to synchrotron diffractometry (SXRD) data. Anisotropic crystallite sizes

{\bar{L}}_{V [h k l]}

were determined by XRD. A low resistance covering layer of mechanically [...] Read more.

Phase-homogeneous LiFePO₄ powders have been synthesized. The content of impurity crystalline phases was less than 0.1%, according to synchrotron diffractometry (SXRD) data. Anisotropic crystallite sizes

{\bar{L}}_{V [h k l]}

were determined by XRD. A low resistance covering layer of mechanically strong ferric-graphite-graphene composite with impregnated ferric (Fe³⁺) particles < 10 nm in size increases the cycleability compared to industrial cathodes. In accordance with the corrosion model, the destruction of the Fe³⁺-containing protective layer of crystallites predominates at the first stage, and at the second stage Fe escapes into the electrolyte and to the anode. The crystallite size decreases due to amorphization that starts from the surface. The rate capability, Q(t), has been studied as a function of

{\bar{L}}_{V [h k l]}

, of the correlation coefficients

r_{i k}

between crystallite sizes, of the Li diffusion coefficient, D, and of the electrical relaxation time, τ_el. For the test cathode with a thickness of 8 μm, the values of D = 0.12 nm²/s, τ_el = 8 s were obtained. To predict the dependence Q(t), it is theoretically studied in ranges closest to experimental values: D = 0.5 ÷ 0.03 nm²/s, τ_el = 8/1 s, average sizes along [010]

{\bar{L}}_{1}

= 90/30 nm, averaged

\bar{r}

= 0/1. Full article

(This article belongs to the Special Issue Nuclear and New Energy Technology)

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21 pages, 6765 KiB

Open AccessArticle

Prediction of Food Factory Energy Consumption Using MLP and SVR Algorithms

by Hyungah Lee, Dongju Kim and Jae-Hoi Gu

Energies 2023, 16(3), 1550; https://doi.org/10.3390/en16031550 - 3 Feb 2023

Cited by 10 | Viewed by 2509

Abstract

The industrial sector accounts for a significant proportion of total energy consumption. Factory Energy Management Systems (FEMSs) can be a measure to reduce energy consumption in the industrial sector. Therefore, machine learning (ML)-based electricity and liquefied natural gas (LNG) consumption prediction models were [...] Read more.

The industrial sector accounts for a significant proportion of total energy consumption. Factory Energy Management Systems (FEMSs) can be a measure to reduce energy consumption in the industrial sector. Therefore, machine learning (ML)-based electricity and liquefied natural gas (LNG) consumption prediction models were developed using data from a food factory. By applying these models to FEMSs, energy consumption can be reduced in the industrial sector. In this study, the multilayer perceptron (MLP) algorithm was used for the artificial neural network (ANN), while linear, radial basis function networks and polynomial kernels were used for support vector regression (SVR). Variables were selected through correlation analysis with electricity and LNG consumption data. The coefficient of variation of root mean square error (CvRMSE) and coefficient of determination (R²) were examined to verify the prediction performance of the implemented models and validated using the criteria of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Guideline 14. The MLP model exhibited the highest prediction accuracy for electricity consumption (CvRMSE: 17.35% and R²: 0.84) and LNG consumption (CvRMSE: 12.52% and R²: 0.88). Our findings demonstrate it is possible to attain accurate predictions of electricity and LNG consumption in food factories using relatively simple data. Full article

(This article belongs to the Section G: Energy and Buildings)

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21 pages, 4728 KiB

Open AccessArticle

Developing an Appropriate Energy Trading Algorithm and Techno-Economic Analysis between Peer-to-Peer within a Partly Independent Microgrid

by Fahim Muntasir, Anusheel Chapagain, Kishan Maharjan, Mirza Jabbar Aziz Baig, Mohsin Jamil and Ashraf Ali Khan

Energies 2023, 16(3), 1549; https://doi.org/10.3390/en16031549 - 3 Feb 2023

Cited by 3 | Viewed by 2564

Abstract

The intimidating surge in the procurement of Distributed Energy Resources (DER) has increased the number of prosumers, creating a new possibility of local energy trading across the community. This project aims to formulate the peer-to-peer energy (P2P) sharing model to encourage the DERs [...] Read more.

The intimidating surge in the procurement of Distributed Energy Resources (DER) has increased the number of prosumers, creating a new possibility of local energy trading across the community. This project aims to formulate the peer-to-peer energy (P2P) sharing model to encourage the DERs to share surplus energy among the consumers. An effective pricing method is developed based on the supply-demand ratio (SDR) with the importance of self-optimization, which allows the prosumers to maximize their energy sharing and profits. To implement this pricing method, a simplified dynamic matchmaking algorithm has been deployed to introduce the Outstanding Prosumer to interact with existing consumers to increase the efficiency and profitability of the trade network. Consumers also benefit from this model, as they can pick the most economical energy supplier instead of relying on the utility grid. The prosumer with high excess energy and the consumer with the highest energy demand will be prioritized to maintain the SDR ratio to one or greater than one. Here, all the above-stated features of the peer-to-peer energy trading have been demonstrated with some calculations to back up some tangible results. Finally, a case study is simulated among the residents of Dhaka, Bangladesh, to demonstrate how peers can profit from participating in trading at a given time. Comparing the results with and without P2P trading, there has been a 17.54% reduction in an electric bill on a typical day of July, and a 49.53% reduction in the interaction with the grid. Full article

(This article belongs to the Special Issue Energy for Sustainable Development and Circular Economy)

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27 pages, 7777 KiB

Open AccessArticle

The Use of a Regulating Transformer for Shaping Power Flow in the Power System

by Szymon Żurek and Maksymilian Przygrodzki

Energies 2023, 16(3), 1548; https://doi.org/10.3390/en16031548 - 3 Feb 2023

Cited by 2 | Viewed by 2307

Abstract

The current situation in world energy requires a new approach to the control of the power flow in power systems. On the one hand, regulations within the EU require the transition to renewable energy. On the other hand, there are no conventional sources [...] Read more.

The current situation in world energy requires a new approach to the control of the power flow in power systems. On the one hand, regulations within the EU require the transition to renewable energy. On the other hand, there are no conventional sources available. Thus, there is a need to use known control tools in non-standard applications. One such example is the use of a regulating transformer inside the power grid to use it to shape the power flow in the system. This article presents a proposal of an algorithm for determining new locations for regulating transformers from the point of view of active power control. By analyzing the parameters of the power grid, it is possible to determine which branch of the grid is the most suitable for installing a regulating transformer in it. The use of a regulating transformer inside the grid improves the transmission capabilities of the national power system. Full article

(This article belongs to the Special Issue Research on Power System Control and Optimization)

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26 pages, 7022 KiB

Open AccessArticle

Micro-Scale Lattice Boltzmann Simulation of Two-Phase CO₂–Brine Flow in a Tighter REV Extracted from a Permeable Sandstone Core: Implications for CO₂ Storage Efficiency

by Yidi Wan, Chengzao Jia, Wen Zhao, Lin Jiang and Zhuxin Chen

Energies 2023, 16(3), 1547; https://doi.org/10.3390/en16031547 - 3 Feb 2023

Cited by 1 | Viewed by 2132

Abstract

Deep saline permeable sandstones have the potential to serve as sites for CO₂ storage. However, unstable CO₂ storage in pores can be costly and harmful to the environment. In this study, we used lattice Boltzmann (LB) simulations to investigate the factors [...] Read more.

Deep saline permeable sandstones have the potential to serve as sites for CO₂ storage. However, unstable CO₂ storage in pores can be costly and harmful to the environment. In this study, we used lattice Boltzmann (LB) simulations to investigate the factors that affect steady-state CO₂–brine imbibition flow in sandstone pores, with a focus on improving CO₂ storage efficiency in deep saline permeable sandstone aquifers. We extracted three representative element volumes (REVs) from a digital rock image of a sandstone core and selected a tighter REV in the upper subdomain so that its permeability would apparently be lower than that of the other two based on single-phase LB simulation for further analysis. The results of our steady-state LB simulations of CO₂–brine imbibition processes in the tighter REV under four differential pressures showed that a threshold pressure gradient of around 0.5 MPa/m exists at a differential pressure of 200 Pa, and that higher differential pressures result in a greater and more linear pressure drop and stronger channelization after the flow are initiated. Furthermore, we conducted simulations over a range of target brine saturations in the tighter REV at the optimal differential pressure of 400 Pa. Our findings showed that the relative permeability of CO₂ is greatly reduced as the capillary number falls below a certain threshold, while the viscosity ratio has a smaller but still significant effect on relative permeability and storage efficiency through the lubrication effect. Wettability has a limited effect on the storage efficiency, but it does impact the relative permeability within the initial saturation range when the capillary number is low and the curves have not yet converged. Overall, these results provide micro-scale insights into the factors that affect CO₂ storage efficiency in sandstones. Full article

(This article belongs to the Special Issue Integrated Managements/Operations of Conventional and Unconventional Reservoirs)

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13 pages, 4226 KiB

Open AccessArticle

Improve Oil Recovery Mechanism of Multi-Layer Cyclic Alternate Injection and Production for Mature Oilfield at Extra-High Water Cut Stage Using Visual Physical Simulation Experiment

by Lun Zhao, Jincai Wang, Libing Fu, Li Chen and Zhihao Jia

Energies 2023, 16(3), 1546; https://doi.org/10.3390/en16031546 - 3 Feb 2023

Viewed by 1414

Abstract

In order to achieve sustainable development of mature oilfield, a series of adjustment measures should be implemented to improve production performance at the extra-high water cut stage. South Kumkol reservoir is a typical multi-layer low viscosity oil reservoir, which has the characteristics of [...] Read more.

In order to achieve sustainable development of mature oilfield, a series of adjustment measures should be implemented to improve production performance at the extra-high water cut stage. South Kumkol reservoir is a typical multi-layer low viscosity oil reservoir, which has the characteristics of small sandstone body, high shale volume, and strong heterogeneity. At present, the water cut of the South Kumkol reservoir is about 90%, which is on the verge of being abandoned. Multi-layer cyclic alternate injection and production (MCA-IP) is an ideal adjustment measure for multi-layer oil reservoir to improve oil recovery (IOR) at the extra-high water cut stage. In this paper, we designed the double-plate visual physical device and the MCA-IP experimental program and then calculated the sweep coefficient using image recognition method. Furthermore, the sweep coefficient was quantitatively calculated by image recognition method. The results show that the sweep area extends to both sides of the main streamline and the sweep efficiency is gradually improved after the completion of MCA-IP. In addition, the IOR mechanism of MCA-IP mainly includes reperforation, well-pattern encryption, and asynchronous injection-production. The reperforation and well-pattern encryption increased the sweep coefficient by about 19.52%, while asynchronous injection-production increased the sweep coefficient by about 1.2%, and the overall sweep coefficient increased by about 20.7%. According to the experimental data statistics, the MCA-IP method can increase oil recovery by about 11% and reduce water cut by about 6%. Full article

(This article belongs to the Collection Flow and Transport in Porous Media)

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35 pages, 6799 KiB

Open AccessArticle

Life Cycle Environmental Impacts Assessment of Post-Combustion Carbon Capture for Natural Gas Combined Cycle Power Plant in Iraq, Considering Grassroots and Retrofit Design

by Rudha Khudhair Mohammed and Hooman Farzaneh

Energies 2023, 16(3), 1545; https://doi.org/10.3390/en16031545 - 3 Feb 2023

Cited by 6 | Viewed by 3900

Abstract

In this work, the Life Cycle Assessment (LCA) methodology is used to examine the implications of CO₂ capture from a natural gas combined cycle power plant with post-combustion carbon capture (NGCC-CCS) in Iraq, taking into account two different design scenarios. In the [...] Read more.

In this work, the Life Cycle Assessment (LCA) methodology is used to examine the implications of CO₂ capture from a natural gas combined cycle power plant with post-combustion carbon capture (NGCC-CCS) in Iraq, taking into account two different design scenarios. In the first scenario (retrofit), the carbon capture unit is considered as an end pipe technology that can be linked to an existing power plant. The second scenario considers a grassroots design, in which a new power plant equipped with a carbon capture unit needs to be constructed. The LCA is carried out based on different impact assessment (LCIA) methodologies of ReCipe 2016 Midpoint (H), TRACI 2.1, and IMPACT 2002+ to investigate whether the chosen LCIA method influences the LCA scenario analysis for decision support in process development. The results of three impact categories applied to both scenarios reveal a 28% reduction in Global Warming Potentials (GWPs) and a 14% and 17% increase in the Particulate Matter Formation Potential (PMFP) and Acidification (AP) potential in the grassroots scenario, respectively. Finally, an uncertainty analysis is performed to more accurately reflect the influence of uncertain factors on the statistical significance of the environmental impact evaluation in this research, indicating that these uncertainties may significantly affect the ultimate decision. Full article

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11 pages, 3070 KiB

Open AccessArticle

Crude Oil Pyrolysis Studies: Application to In Situ Superheat Steam Enhanced Oil Recovery

by Eric N. Coker, Burl Donaldson, Brian Hughes and Nadir Yilmaz

Energies 2023, 16(3), 1544; https://doi.org/10.3390/en16031544 - 3 Feb 2023

Cited by 6 | Viewed by 1788

Abstract

This work focuses on the occurrence and composition of flammable pyrolysis gases which can be expected from stimulation of heavy oil with superheat steam. These gases can have commodity value or be used to fire a conventional boiler to generate steam vapor for [...] Read more.

This work focuses on the occurrence and composition of flammable pyrolysis gases which can be expected from stimulation of heavy oil with superheat steam. These gases can have commodity value or be used to fire a conventional boiler to generate steam vapor for superheater feed. Seven oil samples taken from different US locations were tested via thermogravimetric analysis (TGA) with off-gas analysis of light hydrocarbons via mass spectrometry (MS). The samples were heated up to 500 °C at 5 °C/min in a gas flow of moist carbon dioxide and held at 500 °C until no further mass loss was noted. Then, carbonaceous residue was exposed to air at 500 °C to determine enthalpy of combustion by differential scanning calorimetry (DSC). To demonstrate that pyrolysis was indeed occurring and not simple de-volatilization, a high-molecular-weight reagent-grade organic molecule, lactose, was first demonstrated to produce components of interest. After treatment under moist CO₂ at 500 °C, all samples were found to lose around 90% of mass, and the follow-up combustion process with air further reduced the residual mass to between 2% and 12%, which is presumed to be mineral matter and char. The light hydrocarbons methane, ethane, and propane, as well as hydrogen, were detected through MS during pyrolysis of each oil sample. Heavier hydrocarbons were not monitored but are assumed to have evolved, especially during periods where additional mass loss was occurring in the isothermal process, with minimal light hydrocarbon evolution. These results correspond to a possible concept of subsequent in situ combustion drive with or without heat scavenging following high-temperature pyrolysis from in situ superheat steam injection. Full article

(This article belongs to the Special Issue Enhanced Hydrocarbon Recovery)

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28 pages, 3169 KiB

Open AccessArticle

A New Explicit Sequentially Coupled Technique for Chemo-Thermo-Poromechanical Modelling and Simulation in Shale Formations

by Lateef T. Akanji, Adamu Ibrahim, Hossein Hamidi, Stephan Matthai and Alfred Akisanya

Energies 2023, 16(3), 1543; https://doi.org/10.3390/en16031543 - 3 Feb 2023

Cited by 1 | Viewed by 1557

Abstract

A new explicit sequentially coupled technique for chemo-thermo-poromechanical problems in shale formations is developed. Simultaneously solving the flow and geomechanics equations in a single step is computationally expensive with consequent limitations on the computations involving well or reservoir-scale geometries. The newly developed solution [...] Read more.

A new explicit sequentially coupled technique for chemo-thermo-poromechanical problems in shale formations is developed. Simultaneously solving the flow and geomechanics equations in a single step is computationally expensive with consequent limitations on the computations involving well or reservoir-scale geometries. The newly developed solution sequence involves solving the temperature field within the porous system. This is followed by the computation of the chemical activity constrained by the previously computed temperature field. The pore pressure is then computed by coupling the pore thermal and chemical effects but without consideration of the volumetric strains. The geomechanical effect of the volumetric strain, stress tensors, and associated displacement vectors on the pore fluid is subsequently computed explicitly in a single-step post-processing operation. By increasing the borehole pressure to 20 MPa, it is observed that the rock displacement and velocities concurrently increase by 50%. However, increasing the wellbore temperature and chemical activities shows only a slight effect on the rock and pore fluid. In the chemo-thermo-poroelasticity steady-state simulation, the maximum displacements recorded in the

H_{m i n}

and

H_{m a x}

are 0.00633 m and 0.0035 m, respectively, for 2D and 0.21 for the 3D simulation. In the transient simulation, the displacement values are observed to increase gradually over time with a corresponding decrease in the maximum pore-fluid velocity. A comparison of this work and the partial two-way coupling scheme in a commercial simulator for the 2D test cases was carried out. The maximum differences between the computed temperatures, displacement values, and fluid velocities are

0.33 %

,

0.7 %

, and

0 %

, respectively. The analysed results, therefore, indicate that this technique is comparatively accurate and more computationally efficient than running a full or partial two-way coupling scheme. Full article

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15 pages, 5053 KiB

Open AccessArticle

Energetic and Exergetic Analyses of an Experimental Earth–Air Heat Exchanger in the Northeast of France

by Wael Zeitoun, Jian Lin and Monica Siroux

Energies 2023, 16(3), 1542; https://doi.org/10.3390/en16031542 - 3 Feb 2023

Cited by 7 | Viewed by 1796

Abstract

Earth–air heat exchanger (EAHE) systems are used to pre-heat or pre-cool air before entering into a building using shallow geothermal energy. Assessment of EAHE systems is important to quantify the profitability of these systems. For this purpose, an EAHE system built at ICUBE [...] Read more.

Earth–air heat exchanger (EAHE) systems are used to pre-heat or pre-cool air before entering into a building using shallow geothermal energy. Assessment of EAHE systems is important to quantify the profitability of these systems. For this purpose, an EAHE system built at ICUBE at the University of Strasbourg in the northeast of France was studied using energy and exergy analyses for a typical heating period (between 25 February and 3 March). Energy analysis was used to determine the heat gained by the air in the system during the studied period and to determine the Coefficient Of Performance (COP) of the system. Additionally, exergy analysis, which considered temperature, pressure, humidity, and the variation in the control volume boundary temperature, was realized to determine inefficiencies in the system by determining the exergy destroyed in each component of the system and evaluating its exergetic efficiency. Results showed that the heat energy gained using the system was around 63 kWh and that the exergetic efficiency of the system was about 57% on average. The comparison of exergetic efficiency between the EAHE components showed that the fan has the lowest performance and should be improved to achieve better overall performance. Full article

(This article belongs to the Special Issue Building Performance Simulation, Energy Efficiency and Renewable Energy Resources for Buildings 2022)

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21 pages, 1941 KiB

Open AccessArticle

Performance Assessment of Coupled Concentrated Photovoltaic-Thermal and Vacuum Membrane Distillation (CPVT-VMD) System for Water Desalination

by Juan Pablo Santana, Carlos I. Rivera-Solorio, Jia Wei Chew, Yong Zen Tan, Miguel Gijón-Rivera and Iván Acosta-Pazmiño

Energies 2023, 16(3), 1541; https://doi.org/10.3390/en16031541 - 3 Feb 2023

Cited by 4 | Viewed by 2150

Abstract

Numerical simulations were carried out to assess the technical and economic feasibility of a solar water desalination system that has a novel hybrid Concentrating Photovoltaic Thermal (CPVT) collector coupled with a Vacuum Membrane Distillation (VMD) process. A special characteristic of this CPVT is [...] Read more.

Numerical simulations were carried out to assess the technical and economic feasibility of a solar water desalination system that has a novel hybrid Concentrating Photovoltaic Thermal (CPVT) collector coupled with a Vacuum Membrane Distillation (VMD) process. A special characteristic of this CPVT is its triangular receiver with PV cells facing the reflecting surface. This type of receiver has the advantage of generating more electricity with less PV surface area and great potential to be used to hybridize conventional parabolic thermal collectors. TRNSYS was employed to analyze the annual performance of the CPVT-VMD system evaluating parameters such as solar fraction, specific permeate production and specific energy production for different coastal cities. In the dynamic simulations, local annual weather data and specific information about the characteristics and operating conditions of a real CPVT collector and a VMD module were considered. From the parametric analysis the optimal surface area of collectors and the input temperature of the VDM module were determined. A maximum specific permeate of 218.410 m ³/m²_VMD for Acapulco, MX, and a minimum of 170.365 m ³/m²_VMD for Singapore, SG, were achieved for the proposed CPVT-VMD system of four solar collectors with an operating set temperature of 55 °C. An economic profit was found after 7 years for Acapulco city, which showed great potential to use solar energy from hybrid CPVT collectors for a VMD process to provide freshwater in coastal cities. Full article

(This article belongs to the Special Issue Water Desalination Plants Driven by Hybrid Energy Conversion Systems)

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25 pages, 3793 KiB

Open AccessArticle

A Comparative-Analysis-Based Multi-Criteria Assessment of On/Off-Grid-Connected Renewable Energy Systems: A Case Study

by Ruben Zieba Falama, Virgil Dumbrava, Abdelaziz Salah Saidi, Etienne Tchoffo Houdji, Chokri Ben Salah and Serge Yamigno Doka

Energies 2023, 16(3), 1540; https://doi.org/10.3390/en16031540 - 3 Feb 2023

Cited by 7 | Viewed by 2067

Abstract

Different configurations of on/off-grid-connected hybrid renewable energy systems (HRESs) are analyzed and compared in the present research study for optimal decision making in Sub-Saharan Africa, facing the problems of electricity deficit. A multi-criteria analysis is performed for this purpose using MATLAB software for [...] Read more.

Different configurations of on/off-grid-connected hybrid renewable energy systems (HRESs) are analyzed and compared in the present research study for optimal decision making in Sub-Saharan Africa, facing the problems of electricity deficit. A multi-criteria analysis is performed for this purpose using MATLAB software for simulation. The obtained results show that the levelized cost of energy (LCOE) corresponding to 0% power supply deficit probability (PSDP) is 0.0819 USD/kWh, 0.0925 USD/kWh, 0.3979 USD/kWh, 0.3251 USD/kWh, 0.1754 USD/kWh, 0.1641 USD/kWh, 0.5385 USD/kWh, and 1.4515 USD/kWh, respectively, for the Grid-PV/Wind/Battery, Grid-PV/Battery, Grid-Wind/Battery, Grid-Wind, PV/Wind/Battery, PV/Battery, Wind/Battery, and stand-alone Wind systems. The CO₂ emissions are 14,888.4 kgCO₂/year, 16,916.6 kgCO₂/year, 13,139.7 kgCO₂/year, 6430.4 kgCO₂/year, 11,439 kgCO₂/year, 14,892.5 kgCO₂/year, 10,252.6 kgCO₂/year, and 1621.5 kgCO₂/year, respectively, for the aforementioned systems. It is found that the Grid-connected PV/Wind/Battery is the most cost-effective system leading to a grid energy cost reduction of 30.89%. Hybridization of different renewable energy sources (RESs) could significantly improve the electricity cost and reduce the CO₂ emissions. However, this improvement and this reduction depend on the used RES and the system configuration. On-grid-connected HRESs are more cost-effective than off-grid-connected HRES. The least polluting energy system is the stand-alone Wind system, which allows a reduction in the grid CO₂ emissions by 93.66%. The sensitivity analysis has proven that the long-term investment, the decrease in the battery cost, and the decrease in the discount rate could lead to the reduction in the LCOE. Full article

(This article belongs to the Section F1: Electrical Power System)

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15 pages, 15462 KiB

Open AccessArticle

Computational Analysis of Tube Wall Temperature of Superheater in 1000 MW Ultra-Supercritical Boiler Based on the Inlet Thermal Deviation

by Pei Li, Ting Bao, Jian Guan, Zifu Shi, Zengxiao Xie, Yonggang Zhou and Wei Zhong

Energies 2023, 16(3), 1539; https://doi.org/10.3390/en16031539 - 3 Feb 2023

Cited by 4 | Viewed by 2561

Abstract

Local over-temperature is one of the main reasons for boiler tube failures (BTF). By accurately monitoring and controlling tube wall temperature, local over-temperature can be avoided. Based on the measured flue gas parameters and numerical simulation, a method of thermal deviation calculation is [...] Read more.

Local over-temperature is one of the main reasons for boiler tube failures (BTF). By accurately monitoring and controlling tube wall temperature, local over-temperature can be avoided. Based on the measured flue gas parameters and numerical simulation, a method of thermal deviation calculation is proposed in this study for the on-line calculation of the tube wall temperature of boiler superheaters. The full-size three-dimensional numerical simulation was presented on the combustion in a pulverized coal-fired boiler of 1000 MW ultra-supercritical (USC) unit. A difference in the thermal deviation of the vertical direction was innovatively introduced into a segmented discrete model, and the thermal deviation condition conforming to reality was introduced into the calculation. An on-line calculation system developed based on the current calculation method was applied in a 1000 MW USC unit. The calculated local high-temperature zone was consistent with the actual over-temperature position and conformed to the law of the allowable metal temperature of the final superheater (FSH) serpentines segment. The comparison results showed that the calculated data by this method were more reflective of tube wall temperature change with boiler loads than the measured data. According to the calculated local over-temperature zone, the immediate warning response can effectively reduce the possibility of over-temperature BTF. Full article

(This article belongs to the Special Issue Electrical Power Converter Modeling, Simulation, Control and Realization with Energy Storage and Optimization)

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27 pages, 12467 KiB

Open AccessArticle

Integration of SiC Devices and High-Frequency Transformer for High-Power Renewable Energy Applications

by Weichong Yao, Junwei Lu, Foad Taghizadeh, Feifei Bai and Andrew Seagar

Energies 2023, 16(3), 1538; https://doi.org/10.3390/en16031538 - 3 Feb 2023

Cited by 6 | Viewed by 2916

Abstract

This paper presents a novel structure of Integrated SiC MOSFETs with a high-frequency transformer (I-SiC-HFT) for various high-power isolated DC–DC converters. Several resonant converters are considered for integration in this paper, including the phase-shift full-bridge (PSFB) converter, inductor–inductor–capacitor (LLC) resonant converter, bidirectional PSFB [...] Read more.

This paper presents a novel structure of Integrated SiC MOSFETs with a high-frequency transformer (I-SiC-HFT) for various high-power isolated DC–DC converters. Several resonant converters are considered for integration in this paper, including the phase-shift full-bridge (PSFB) converter, inductor–inductor–capacitor (LLC) resonant converter, bidirectional PSFB converter, and capacitor–inductor–inductor–capacitor (CLLC) resonant converter. The applications of I-SiC-HFT are focused on V2G EV battery charging systems, energy storage in DC and AC microgrids, and renewable energy systems. SiC devices, including MOSFETs, Schottky diodes, and MOSFET modules, are used in this novel structure of I-SiC-HFT. The high-frequency magnetic structure uses distributed ferrite cores to form a large central space to accommodate SiC devices. The optimized architecture of I-SiC-HFT and heatsink structure is proposed for thermal management of SiC devices. To prove the concept, a small-scale 1.5 kW prototype I-SiC-HFT is used to demonstrate the basic structure and various performance indicators through the FEM based electromagnetic simulation and DC–DC converter experiments. Full article

(This article belongs to the Special Issue Analysis of SiC MOSFETs for Advanced Energy-Conversion Systems)

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17 pages, 2122 KiB

Open AccessArticle

Kinetics of Oxygen Reduction Reaction of Polymer-Coated MWCNT-Supported Pt-Based Electrocatalysts for High-Temperature PEM Fuel Cell

by Md Ahsanul Haque, Md Mahbubur Rahman, Faridul Islam, Abu Bakar Sulong, Loh Kee Shyuan, Ros emilia Rosli, Ashok Kumar Chakraborty and Julfikar Haider

Energies 2023, 16(3), 1537; https://doi.org/10.3390/en16031537 - 3 Feb 2023

Cited by 5 | Viewed by 2767

Abstract

Sluggish oxygen reduction reaction (ORR) of electrodes is one of the main challenges in fuel cell systems. This study explored the kinetics of the ORR reaction mechanism, which enables us to understand clearly the electrochemical activity of the electrode. In this research, electrocatalysts [...] Read more.

Sluggish oxygen reduction reaction (ORR) of electrodes is one of the main challenges in fuel cell systems. This study explored the kinetics of the ORR reaction mechanism, which enables us to understand clearly the electrochemical activity of the electrode. In this research, electrocatalysts were synthesized from platinum (Pt) catalyst with multi-walled carbon nanotubes (MWCNTs) coated by three polymers (polybenzimidazole (PBI), sulfonated tetrafluoroethylene (Nafion), and polytetrafluoroethylene (PTFE)) as the supporting materials by the polyol method while hexachloroplatinic acid (H₂PtCl₆) was used as a catalyst precursor. The oxygen reduction current of the synthesized electrocatalysts increased that endorsed by linear sweep voltammetry (LSV) curves while increasing the rotation rates of the disk electrode. Additionally, MWCNT-PBI-Pt was attributed to the maximum oxygen reduction current densities at −1.45 mA/cm² while the minimum oxygen reduction current densities of MWCNT-Pt were obtained at −0.96 mAcm². However, the ring current densities increased steadily from potential 0.6 V to 0.0 V due to their encounter with the hydrogen peroxide species generated by the oxygen reduction reactions. The kinetic limiting current densities (J_K) increased gradually with the applied potential from 1.0 V to 0.0 V. It recommends that the ORR consists of a single step that refers to the first-order reaction. In addition, modified MWCNT-supported Pt electrocatalysts exhibited high electrochemically active surface areas (ECSA) at 24.31 m²/g of MWCNT-PBI-Pt, 22.48 m²/g of MWCNT-Nafion-Pt, and 20.85 m²/g of MWCNT-PTFE-Pt, compared to pristine MWCNT-Pt (17.66 m²/g). Therefore, it can be concluded that the additional ionomer phase conducting the ionic species to oxygen reduction in the catalyst layer could be favorable for the ORR reaction. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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21 pages, 3920 KiB

Open AccessArticle

An Analysis of Energy Consumption in Small- and Medium-Sized Buildings

by Marian Kampik, Marcin Fice, Adam Pilśniak, Krzysztof Bodzek and Anna Piaskowy

Energies 2023, 16(3), 1536; https://doi.org/10.3390/en16031536 - 3 Feb 2023

Cited by 5 | Viewed by 4003

Abstract

Building energy efficiency has grown strong in a context of soaring energy prices, especially in Europe. The use of energy-saving devices strongly influences its improvement, but in many cases, it is far from sufficient., especially if the energy comes from renewable sources with [...] Read more.

Building energy efficiency has grown strong in a context of soaring energy prices, especially in Europe. The use of energy-saving devices strongly influences its improvement, but in many cases, it is far from sufficient., especially if the energy comes from renewable sources with forced production. In the case of buildings, these are usually photovoltaic (PV) sources. For this reason, energy management systems (EMS) are becoming increasingly popular as they allow the increase in self-consumption and reduce the size of energy storage. This article presents analyses of historical energy consumption profiles in selected small- and medium-sized buildings powered by renewable energy sources. The implementation limitations of this type of systems, depending on the profile of the building, were identified and guidelines were presented to assess low-cost solutions dedicated to small buildings and considering the actual conditions of existing systems. Statistical analyzes were conducted for the energy demand profiles of 15 different buildings. The analyzes consisted of the preparation of box plots for each hour of working days and the calculation of the relative standard deviation (RSD) index for annual profiles of 60 min periods. The analyzes showed that the RSD index has low values for commercial buildings (e.g., hospital 7% and bank 15%) and very high values for residential buildings—even over 100%. On this basis, it can be concluded about the usefulness of energy profiles for demand forecasting. The novelty of the proposed method is to examine the possibility of using measurement data as data to forecast energy consumption based on statistical analysis, dedicated to low-cost EMS system solutions. Full article

(This article belongs to the Special Issue Knowledge and Project Management Peculiarities in Energy Sources and Energy Consumption)

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26 pages, 3505 KiB

Open AccessReview

Noise Measurement, Characterization, and Modeling for Broadband Indoor Power Communication System: A Comprehensive Survey

by Michael Adegoke Ogunlade, Saheed Lekan Gbadamosi, Israel Esan Owolabi and Nnamdi I. Nwulu

Energies 2023, 16(3), 1535; https://doi.org/10.3390/en16031535 - 3 Feb 2023

Cited by 2 | Viewed by 2427

Abstract

A thorough study of the literature suggests that greater attention has to be paid to power line noise measurements, characterization, and modeling. Several studies show that significant differences do exist, and the findings are somewhat conflicting. This may be attributed to the diverse [...] Read more.

A thorough study of the literature suggests that greater attention has to be paid to power line noise measurements, characterization, and modeling. Several studies show that significant differences do exist, and the findings are somewhat conflicting. This may be attributed to the diverse environment under investigation, which includes volatile noise sources, differences in electrical grid structure from country to country, topology, and unknown power cable characteristics. An in-depth analysis of the approaches for measuring, characterizing, and modeling noise, as well as the descriptions of relevant components, and the environment needed to carry out the measurements, is presented. This review serves as a roadmap for academics and engineers in the deployment of power line communication systems. Full article

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26 pages, 3847 KiB

Open AccessArticle

Sustainable Production of Biodiesel from Novel Non-Edible Oil Seeds (Descurainia sophia L.) via Green Nano CeO₂ Catalyst

by Maryam Tanveer Akhtar, Mushtaq Ahmad, Mohamed Fawzy Ramadan, Trobjon Makhkamov, Akramjon Yuldashev, Oybek Mamarakhimov, Mamoona Munir, Maliha Asma, Muhammad Zafar and Salman Majeed

Energies 2023, 16(3), 1534; https://doi.org/10.3390/en16031534 - 3 Feb 2023

Cited by 20 | Viewed by 3855

Abstract

The current study focuses on the synthesis of Cerium oxide (CeO₂) nanocatalyst via Tragacanth Gum (TG) using the wet impregnation method and its application for sustainable biodiesel production from a novel, non-edible Descurainia sophia (L.) Webb ex Prantl seed oil. The [...] Read more.

The current study focuses on the synthesis of Cerium oxide (CeO₂) nanocatalyst via Tragacanth Gum (TG) using the wet impregnation method and its application for sustainable biodiesel production from a novel, non-edible Descurainia sophia (L.) Webb ex Prantl seed oil. The D. sophia seed oil has higher oil content (36 wt%) and free fatty acid (FFA) value (0.6 mg KOH/g). Innovative analytical methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy, were used to characterize the newly synthesized, environmentally friendly, and recyclable CeO₂-TG phytonanocatalyst (FT-IR). The results show that the CeO₂-TG phytonanocatalyst was 22 nm in diameter with a spherical shape outer morphology, while the inner structure was hexagonal. Due to low FFA content, the D. sophia seed oil was pretreated and transesterified via a single step. Using varying parameters, the optimized process variables were determined via Response Surface Methodology (RSM). The optimum process values were 8:1 methanol to oil molar ratio, 0.3 wt% catalyst concentration, 90 °C temperature, and reaction time of 210 min with 98% biodiesel yield. The recently created phytonanocatalyst was reliable and effective, with three times reusability in the transesterification reaction. Thin layer chromatography (TLC), FT-IR, gas chromatography–mass spectroscopy (GCMS), and Nuclear magnetic resonance (NMR) analyses were used to characterize the synthesized biodiesel. Physico-chemical properties of D. sophia biodiesel, i.e., Kinematic viscosity (4.23 mm²/s), density (0.800 kg/m³), pour point (−7 °C), cloud point (−12 °C), and flash point (73.5 °C) agree well with international biodiesel standards (ASTM-6751, 951), (EU-14214), and China (GB/T 20828) standards. The results show that the synthesized nanocatalyst demonstrated remarkable stability, indicating a bright future for industrial biodiesel production from low-cost feedstock. Full article

(This article belongs to the Special Issue Biomass Resources and Bio-Energy Potential)

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14 pages, 1825 KiB

Open AccessArticle

Six Days Ahead Forecasting of Energy Production of Small Behind-the-Meter Solar Sites

by Hugo Bezerra Menezes Leite and Hamidreza Zareipour

Energies 2023, 16(3), 1533; https://doi.org/10.3390/en16031533 - 3 Feb 2023

Cited by 5 | Viewed by 1797

Abstract

Due to the growing penetration of behind-the-meter (BTM) photovoltaic (PV) installations, accurate solar energy forecasts are required for a reliable economic energy system operation. A new hybrid methodology is proposed in this paper with a sequence of one-step ahead models to accumulate 144 [...] Read more.

Due to the growing penetration of behind-the-meter (BTM) photovoltaic (PV) installations, accurate solar energy forecasts are required for a reliable economic energy system operation. A new hybrid methodology is proposed in this paper with a sequence of one-step ahead models to accumulate 144 h for a small-scale BTM PV site. Three groups of models with different inputs are developed to cover 6 days of forecasting horizon, with each group trained for each hour of the above zero irradiance. In addition, a novel dataset preselection is proposed, and neighboring solar farms’ power predictions are used as a feature to boost the accuracy of the model. Two techniques are selected: XGBoost and CatBoost. An extensive assessment for 1 year is conducted to evaluate the proposed method. Numerical results highlight that training the models with the previous, current, and 1 month ahead from the previous year referenced by the target month can improve the model’s accuracy. Finally, when solar energy predictions from neighboring solar farms are incorporated, this further increases the overall forecast accuracy. The proposed method is compared with the complete-history persistence ensemble (CH-PeEn) model as a benchmark. Full article

(This article belongs to the Special Issue Intelligent Forecasting and Optimization in Electrical Power Systems)

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37 pages, 1597 KiB

Open AccessArticle

Energy Consumption Analysis of the Selected Navigation Algorithms for Wheeled Mobile Robots

by Adam Rapalski and Sebastian Dudzik

Energies 2023, 16(3), 1532; https://doi.org/10.3390/en16031532 - 3 Feb 2023

Cited by 9 | Viewed by 2654

Abstract

The article presents the research on navigation algorithms of a wheeled mobile robot with the use of a vision mapping system and the analysis of energy consumption of selected navigation algorithms, such as RRT and A-star. Obstacle maps were made with the use [...] Read more.

The article presents the research on navigation algorithms of a wheeled mobile robot with the use of a vision mapping system and the analysis of energy consumption of selected navigation algorithms, such as RRT and A-star. Obstacle maps were made with the use of an RGBW camera, and binary occupation maps were also made, which were used to determine the traffic path. To recreate the routes in hardware, a programmed Pure Pursuit controller was used. The results of navigation were compared on the basis of the forward kinematics model and odometry measurements. Quantities such as current, except (x, y, phi), and linear and angular velocities were measured in real time. As a result of the conducted research, it was found that the RRT star algorithm consumes the least energy to reach the designated target in the designated environment. Full article

(This article belongs to the Special Issue Improvements of the Electricity Power System II)

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14 pages, 1252 KiB

Open AccessReview

A Review on Techno-Economic Study for Supporting Building with PV-Grid-Connected Systems under Saudi Regulations

by Sultan J. Alharbi and Abdulaziz S. Alaboodi

Energies 2023, 16(3), 1531; https://doi.org/10.3390/en16031531 - 3 Feb 2023

Cited by 15 | Viewed by 3302

Abstract

As the demand for electricity continues to grow in Saudi Arabia, finding ways to increase power generation becomes increasingly important. However, conventional power generation methods such as burning fossil fuels contribute significantly to environmental pollution and harm human health through the emissions of [...] Read more.

As the demand for electricity continues to grow in Saudi Arabia, finding ways to increase power generation becomes increasingly important. However, conventional power generation methods such as burning fossil fuels contribute significantly to environmental pollution and harm human health through the emissions of greenhouse gases. One potential solution to this problem is the use of solar energy, which has the advantage of being abundant in Saudi Arabia due to its location in the sun belt. When compared to conventional power generation methods, solar energy is a viable alternative, particularly when the indirect costs of fossil fuels, such as harm to the environment and human health, are considered. Using photovoltaic cells to convert sunlight into electrical energy is a key method for producing clean energy. Despite the initial cost of investing in solar energy infrastructure, it is ultimately less expensive than electricity derived from fossil fuels. In recognition of the potential of solar energy, the Saudi government has outlined an ambitious plan to install 41 GW of solar capacity and invest USD 108.9 billion by 2032. Additionally, financing and significant tax benefits have been provided to promote the development of the solar industry. This research article reviews the techno-economic analysis of PV power plants and examines previous policy papers and the existing research on the topic. Full article

(This article belongs to the Collection Review Papers in Solar Energy and Photovoltaic Systems)

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25 pages, 2743 KiB

Open AccessReview

Artificial Intelligence and Machine Learning in Grid Connected Wind Turbine Control Systems: A Comprehensive Review

by Nathan Oaks Farrar, Mohd Hasan Ali and Dipankar Dasgupta

Energies 2023, 16(3), 1530; https://doi.org/10.3390/en16031530 - 3 Feb 2023

Cited by 18 | Viewed by 6250

Abstract

As grid-connected wind farms become more common in the modern power system, the question of how to maximize wind power generation while limiting downtime has been a common issue for researchers around the world. Due to the complexity of wind turbine systems and [...] Read more.

As grid-connected wind farms become more common in the modern power system, the question of how to maximize wind power generation while limiting downtime has been a common issue for researchers around the world. Due to the complexity of wind turbine systems and the difficulty to predict varying wind speeds, artificial intelligence (AI) and machine learning (ML) algorithms have become key components when developing controllers and control schemes. Although, in recent years, several review papers on these topics have been published, there are no comprehensive review papers that pertain to both AI and ML in wind turbine control systems available in the literature, especially with respect to the most recently published control techniques. To overcome the drawbacks of the existing literature, an in-depth overview of ML and AI in wind turbine systems is presented in this paper. This paper analyzes the following reviews: (i) why optimizing wind farm power generation is important; (ii) the challenges associated with designing an efficient control scheme for wind farms; (iii) a breakdown of the different types of AI and ML algorithms used in wind farm controllers and control schemes; (iv) AI and ML for wind speed prediction; (v) AI and ML for wind power prediction; (vi) AI and ML for mechanical component monitoring and fault detection; and (vii) AI and ML for electrical fault prevention and detection. This paper will offer researchers and engineers in the wind energy generation field a comprehensive review of the application of AI and ML in the control methodology of offshore and onshore wind farms so that more efficient and robust control schemes can be designed for future wind turbine controllers. Full article

(This article belongs to the Special Issue Renewable Energy System Technologies)

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11 pages, 2054 KiB

Open AccessArticle

Investigating the Influence of Pore Shape on Shale Gas Recovery with CO₂ Injection Using Molecular Simulation

by Juan Zhou, Shiwang Gao, Lianbo Liu, Tieya Jing, Qian Mao, Mingyu Zhu, Wentao Zhao, Bingxiao Du, Xu Zhang and Yuling Shen

Energies 2023, 16(3), 1529; https://doi.org/10.3390/en16031529 - 3 Feb 2023

Cited by 1 | Viewed by 1557

Abstract

Carbon-dioxide-enhanced shale gas recovery technology has significant potential for large-scale emissions reduction and can help achieve carbon neutrality targets. Previous theoretical studies mainly focused on gas adsorption in one-dimensional pores without considering the influence from the pore geometry. This study evaluates the effects [...] Read more.

Carbon-dioxide-enhanced shale gas recovery technology has significant potential for large-scale emissions reduction and can help achieve carbon neutrality targets. Previous theoretical studies mainly focused on gas adsorption in one-dimensional pores without considering the influence from the pore geometry. This study evaluates the effects of pore shape on shale gas adsorption. The pure and competitive gas adsorption processes of CO₂ and CH₄ in nanopores were investigated using molecular simulations to improve the prediction of shale gas recovery efficiency. Meanwhile, quantitative analysis was conducted on the effects of the pore shape on the CO₂-EGR efficiency. The results indicate that the density of the adsorption layer in pores is equally distributed in the axial direction when the cone angle is zero; however, when the cone angle is greater than zero, the density of the adsorption layer decreases. Smaller cone-angle pores have stronger gas adsorption affinities, making it challenging to recover the adsorbed CH₄ during the pressure drawdown process. Concurrently, this makes the CO₂ injection method, based on competitive adsorption, efficient. For pores with larger cone angles, the volume occupied by the free gas is larger; thus, the pressure drawdown method displays relatively high recovery efficiency. Full article

(This article belongs to the Special Issue Research on Thermo-Chemical Conversion Processes)

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