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Showing records 101 to 125 of 1602. [First] Page: 1 2 3 4 5 6 7 8 9 Last
A Market-Based Analysis on the Main Characteristics of Gearboxes Used in Onshore Wind Turbines
Cristina Vázquez-Hernández, Javier Serrano-González, Gabriel Centeno
December 10, 2019 (v1)
Keywords: drive train, gearboxes, Renewable and Sustainable Energy, wind turbines
Even though wind energy is one of the most mature renewable technologies, it is in continuous development not only because of the trend towards larger wind turbines but also because of the development of new technological solutions. The gearbox is one of the components of the drive train in which the industry is concentrating more effort on research and development. Larger rotor blades lead to more demanding requirements for this component as a consequence of a higher mechanical torque and multiplication ratio (due to lower rotational speed of blades while the rotational speed on the generator side remains at similar values). In addition, operating conditions become increasingly demanding in terms of reliability, performance, and compactness. This paper analyses the different gearbox arrangements that are implemented by manufacturers of onshore wind turbines, as well as their market penetration (including different aspects that affect the design of the gearbox, such as drive train conf... [more]
A New Platform for Automatic Bottom-Up Electric Load Aggregation
Alfredo Bartolozzi, Salvatore Favuzza, Mariano Giuseppe Ippolito, Diego La Cascia, Eleonora Riva Sanseverino, Gaetano Zizzo
December 10, 2019 (v1)
Keywords: active demand (AD), energy market, loads aggregation, loads clustering
In this paper, a new virtual framework for load aggregation in the context of the liberalized energy market is proposed. Since aggregation is managed automatically through a dedicated platform, the purchase of energy can be carried out without intermediation as it happens in peer-to-peer energy transaction models. Differently from what was done before, in this new framework, individual customers can join a load aggregation program through the proposed aggregation platform. Through the platform, their features are evaluated and they are clustered according to their reliability and to the width of range of regulation allowed. The simulations show the deployment of an effective clustering and the possibility to meet the target power demand at a given hour according to each customer’s availability.
How Wood Fuels’ Quality Relates to the Standards: A Class-Modelling Approach
Michela Zanetti, Corrado Costa, Rosa Greco, Stefano Grigolato, Giovanna Ottaviani Aalmo, Raffaele Cavalli
December 10, 2019 (v1)
Keywords: certification, multivariate modelling, quality, standard, wood biomass, wood chips
The quality requirements of wood biofuels are regulated by a series of harmonized international standards. These standards define the technical parameter limits that influence the quality of solid biomass as a fuel. In 2014 the European reference standard for solid biofuel was replaced by the International ISO standard. In the case of wood chips, the main difference between the European and International standards is the definition of particle size distribution classes. In this context, this study analyses the quality of wood chips and its variation over the years according to the “former” (EN 14691-4) and “in force” (ISO 17225-4) standards. A Soft Independent Modelling of Class Analogy (SIMCA) model was built to predict the best quality of wood chips and to clarify the relationship between quality and standard parameters, time and changes in the standard regulations. The results show that, compared to the EN standards, classification with the ISO standards increases the samples belong... [more]
Acquisition System Verification for Energy Efficiency Analysis of Building Materials
Natalia Cid, Ana Ogando, M. A. Gómez
December 10, 2019 (v1)
Keywords: acquisition system, concrete, cubicles, phase change material (PCM)
Climate change and fossil fuel depletion foster interest in improving energy efficiency in buildings. There are different methods to achieve improved efficiency; one of them is the use of additives, such as phase change materials (PCMs). To prove this method’s effectiveness, a building’s behaviour should be monitored and analysed. This paper describes an acquisition system developed for monitoring buildings based on Supervisory Control and Data Acquisition (SCADA) and with a 1-wire bus network as the communication system. The system is empirically tested to prove that it works properly. With this purpose, two experimental cubicles are made of self-compacting concrete panels, one of which has a PCM as an additive to improve its energy storage properties. Both cubicles have the same dimensions and orientation, and they are separated by six feet to avoid shadows. The behaviour of the PCM was observed with the acquisition system, achieving results that illustrate the differences between th... [more]
Exploring Marine Energy Potential in the UK Using a Whole Systems Modelling Approach
Anna Stegman, Adrian de Andres, Henry Jeffrey, Lars Johanning, Stuart Bradley
December 10, 2019 (v1)
Subject: Energy Policy
Keywords: economics, tidal stream energy, Wave Energy, whole systems modelling
The key market drivers for marine energy are to reduce carbon emissions, and improve the security and sustainability of supply. There are other technologies that also meet these requirements, and therefore the marine energy market is dependent on the technology being cost effective, and competitive. The potential UK wave and tidal stream energy market is assessed using ETI’s energy systems modelling environment (ESME) which uses a multi-vector approach including energy generation, demand, heat, transport, and infrastructure. This is used to identify scenarios where wave and tidal energy form part of the least-cost energy system for the UK by 2050, and will assess what Levelised Cost of Energy (LCOE) reductions are required to improve the commercialization rate. The results indicate that an installed capacity of 4.9 GW of wave and 2.5 GW of tidal stream could be deployed by 2050 if the LCOE is within 4.5 and 7 p/kWh for each respective technology. If there is a step reduction to the LCO... [more]
Frequency Regulation Strategies in Grid Integrated Offshore Wind Turbines via VSC-HVDC Technology: A Review
Jafar Jallad, Saad Mekhilef, Hazlie Mokhlis
December 10, 2019 (v1)
Keywords: frequency regulation, high voltage direct current transmission control, inertia emulation, voltage source converter, wind turbine-permanent magnet synchronous generators (WT-PMSG)
The inclusion of wind energy in a power system network is currently seeing a significant increase. However, this inclusion has resulted in degradation of the inertia response, which in turn seriously affects the stability of the power system’s frequency. This problem can be solved by using an active power reserve to stabilize the frequency within an allowable limit in the event of a sudden load increment or the loss of generators. Active power reserves can be utilized via three approaches: (1) de-loading method (pitching or over-speeding) by a variable speed wind turbine (VSWT); (2) stored energy in the capacitors of voltage source converter-high voltage direct current (VSC-HVDC) transmission; and (3) coordination of frequency regulation between the offshore wind farms and the VSC-HVDC transmission. This paper reviews the solutions that can be used to overcome problems related to the frequency stability of grid- integrated offshore wind turbines. It also details the permanent magnet sy... [more]
Integrated Bioethanol Fermentation/Anaerobic Digestion for Valorization of Sugar Beet Pulp
Joanna Berlowska, Katarzyna Pielech-Przybylska, Maria Balcerek, Weronika Cieciura, Sebastian Borowski, Dorota Kregiel
December 10, 2019 (v1)
Subject: Biosystems
Keywords: bioethanol, Hydrogen, hydrolysis, methane, stillage, sugar beet pulp
Large amounts of waste biomass are generated in sugar factories from the processing of sugar beets. After diffusion with hot water to draw the sugar from the beet pieces, a wet material remains called pulp. In this study, waste sugar beet pulp biomass was enzymatically depolymerized, and the obtained hydrolyzates were subjected to fermentation processes. Bioethanol, biomethane, and biohydrogen were produced directly from the substrate or in combined mode. Stillage, a distillery by-product, was used as a feedstock for anaerobic digestion. During biosynthesis of ethanol, most of the carbohydrates released from the sugar beet pulp were utilized by a co-culture of Saccharomyces cerevisiae Ethanol Red, and Scheffersomyces stipitis LOCK0047 giving 12.6 g/L of ethanol. Stillage containing unfermented sugars (mainly arabinose, galactose and raffinose) was found to be a good substrate for methane production (444 dm³ CH₄/kg volatile solids (VS)). Better results were achieved with this medium tha... [more]
Numerical Simulation and Optimization of the Melting Process of Phase Change Material inside Horizontal Annulus
Saiwei Li, Yu Chen, Zhiqiang Sun
December 10, 2019 (v1)
Keywords: Latent Heat Storage, melting, parametric study, phase change material, shell and tube
Latent heat storage (LHS) technologies adopting phase change materials (PCMs) are increasingly being used to bridge the spatiotemporal mismatch between energy production and demand, especially in industries like solar power, where strong cyclic fluctuations exist. The shell-and-tube configuration is among the most prevalent ones in LHS and thus draws special attention from researchers. This paper presents numerical investigations on the melting of PCM, a paraffin blend RT27, inside a horizontal annulus. The volume of fluid model was adopted to permit density changes with the solidification/melting model wherein natural convection was taken into account. The eccentricity and diameter of the inner tube, sub-cooling degree of the PCM, and the heating-surface temperature were considered as variables for study. Through the evaluation of the melting time and exergy efficiency, the optimal parameters of the horizontal annulus were obtained. The results showed that the higher the heating bound... [more]
Multivalued Coefficient Prestorage and Block Parallel Method for Real-Time Simulation of Microgrid on FRTDS
Bingda Zhang, Dan Zhao, Zhao Jin, Yanjie Wu
December 10, 2019 (v1)
Keywords: field programmable gate array-based real-time digital simulation (FRTDS), local iterative calculation, microgrid, multiport hybrid equivalent, multivalued coefficient prestorage, network partitioning, real-time simulation
The microgrid containing a large amount of high frequency power switches and nonlinear components has put forward high requirements for power system real-time simulation technology. Multivalued coefficient prestorage can reduce the calculation steps in real-time simulation. In order to reduce the storage pressure of the multivalued coefficients, the whole network is divided into multiple subnetworks that can be simulated in parallel, and only the parameters for computing input variables and internal variables are prestored. The multiport hybrid equivalent is performed to reduce the number of simultaneous network equations. The input variables are tied to state variables of the circuit so that the iterative calculation is limited to the local network. The devised methodology is validated through simulation of a low-voltage microgrid on a field programmable gate array (FPGA)-based real-time digital simulation (FRTDS) platform at a 5 μs time step. Comparison with a power systems computer... [more]
The Importance of Government Effectiveness for Transitions toward Greater Electrification in Developing Countries
Rohan Best, Paul J. Burke
December 10, 2019 (v1)
Subject: Energy Policy
Keywords: developing countries, electricity transitions, government effectiveness
Electricity is a vital factor underlying modern living standards, but there are many developing countries with low levels of electricity access and use. We seek to systematically identify the crucial elements underlying transitions toward greater electrification in developing countries. We use a cross-sectional regression approach with national-level data up to 2012 for 135 low- and middle-income countries. The paper finds that the effectiveness of governments is the most important governance attribute for encouraging the transition to increased electrification in developing countries, on average. The results add to the growing evidence on the importance of governance for development outcomes. Donors seeking to make more successful contributions to electrification may wish to target countries with more effective governments.
Effects of Loading Rate on Gas Seepage and Temperature in Coal and Its Potential for Coal-Gas Disaster Early-Warning
Chong Zhang, Xiaofei Liu, Guang Xu, Xiaoran Wang
December 10, 2019 (v1)
Subject: Other
Keywords: coal containing gas, critical slowing down, loading rate, seepage velocity, temperature
The seepage velocity and temperature externally manifest the changing structure, gas desorption and energy release that occurs in coal containing gas failure under loading. By using the system of coal containing gas failure under loading, this paper studies the law of seepage velocity and temperature under different loading rates and at 1.0 MPa confining pressure and 0.5 MPa gas pressure, and combined the on-site results of gas pressure and temperature. The results show that the stress directly affects the seepage velocity and temperature of coal containing gas, and the pressure and content of gas have the most sensitivity to mining stress. Although the temperature is not sensitive to mining stress, it has great correlation with mining stress. Seepage velocity has the characteristic of critically slowing down under loading. This is demonstrated by the variance increasing before the main failure of the samples. Therefore, the variance of seepage velocity with time and temperature can pr... [more]
Parametric Investigation Using Computational Fluid Dynamics of the HVAC Air Distribution in a Railway Vehicle for Representative Weather and Operating Conditions
Christian Suárez, Alfredo Iranzo, José Antonio Salva, Elvira Tapia, Gonzalo Barea, José Guerra
December 10, 2019 (v1)
Keywords: Computational Fluid Dynamics, heat transfer, heating, ventilation, air conditioning, railway vehicle, thermal comfort, tram
A computational fluid dynamics (CFD) analysis of air distribution in a representative railway vehicle equipped with a heating, ventilation, air conditioning (HVAC) system is presented in this paper. Air distribution in the passenger’s compartment is a very important factor to regulate temperature and air velocity in order to achieve thermal comfort. A complete CFD model, including the car’s geometry in detail, the passengers, the luminaires, and other the important features related to the HVAC system (air supply inlets, exhaust outlets, convectors, etc.) are developed to investigate eight different typical scenarios for Northern Europe climate conditions. The results, analyzed and discussed in terms of temperature and velocity fields in different sections of the tram, and also in terms of volumetric parameters representative of the whole tram volume, show an adequate behavior from the passengers’ comfort point of view, especially for summer climate conditions.
A Smart Forecasting Approach to District Energy Management
Baris Yuce, Monjur Mourshed, Yacine Rezgui
December 10, 2019 (v1)
Keywords: ANN, demand forecasting, district energy management, MRA, PCA, smart cities, smart grid
This study presents a model for district-level electricity demand forecasting using a set of Artificial Neural Networks (ANNs) (parallel ANNs) based on current energy loads and social parameters such as occupancy. A comprehensive sensitivity analysis is conducted to select the inputs of the ANN by considering external weather conditions, occupancy type, main income providers’ employment status and related variables for the fuel poverty index. Moreover, a detailed parameter tuning is conducted using various configurations for each individual ANN. The study also demonstrates the strength of the parallel ANN models in different seasons of the years. In the proposed district level energy forecasting model, the training and testing stages of parallel ANNs utilise dataset of a group of six buildings. The aim of each individual ANN is to predict electricity consumption and the aggregated demand in sub-hourly time-steps. The inputs of each ANN are determined using Principal Component Analysis... [more]
A Polar Fuzzy Control Scheme for Hybrid Power System Using Vehicle-To-Grid Technique
Mohammed Elsayed Lotfy, Tomonobu Senjyu, Mohammed Abdel-Fattah Farahat, Amal Farouq Abdel-Gawad, Hidehito Matayoshi
December 10, 2019 (v1)
Keywords: frequency control, hybrid power system, minimal-order observer, polar fuzzy, supply balance, V2G
A novel polar fuzzy (PF) control approach for a hybrid power system is proposed in this research. The proposed control scheme remedies the issues of system frequency and the continuity of demand supply caused by renewable sources’ uncertainties. The hybrid power system consists of a wind turbine generator (WTG), solar photovoltaics (PV), a solar thermal power generator (STPG), a diesel engine generator (DEG), an aqua-electrolyzer (AE), an ultra-capacitor (UC), a fuel-cell (FC), and a flywheel (FW). Furthermore, due to the high cost of the battery energy storage system (BESS), a new idea of vehicle-to-grid (V2G) control is applied to use the battery of the electric vehicle (EV) as equivalent to large-scale energy storage units instead of small batteries to improve the frequency stability of the system. In addition, EV customers’ convenience is taken into account. A minimal-order observer is used to estimate the supply error. Then, the area control error (ACE) signal is calculated in ter... [more]
Simulation versus Optimisation: Theoretical Positions in Energy System Modelling
Henrik Lund, Finn Arler, Poul Alberg Østergaard, Frede Hvelplund, David Connolly, Brian Vad Mathiesen, Peter Karnøe
December 10, 2019 (v1)
Subject: Optimization
Keywords: energy system analysis, investment optimisation models, modelling theory, Renewable and Sustainable Energy, simulations models
In recent years, several tools and models have been developed and used for the design and analysis of future national energy systems. Many of these models focus on the integration of various renewable energy resources and the transformation of existing fossil-based energy systems into future sustainable energy systems. The models are diverse and often end up with different results and recommendations. This paper analyses this diversity of models and their implicit or explicit theoretical backgrounds. In particular, two archetypes are defined and compared. On the one hand, the prescriptive investment optimisation or optimal solutions approach. On the other hand the analytical simulation or alternatives assessment approach. Awareness of the dissimilar theoretical assumption behind the models clarifies differences between the models, explains dissimilarities in results, and provides a theoretical and methodological foundation for understanding and interpreting results from the two archety... [more]
Technical Assessment of Different Operating Conditions of an On-Board Autothermal Reformer for Fuel Cell Vehicles
Laura Tribioli, Raffaello Cozzolino, Daniele Chiappini
December 10, 2019 (v1)
Keywords: fuel cell vehicle, high temperature proton exchange membrane (PEM) fuel cell, hydrocarbons autothermal reforming, on-board hydrogen production
This paper evaluates the performance of a fuel cell/battery vehicle with an on-board autothermal reformer, fed by different liquid and gaseous hydrocarbon fuels. A sensitivity analysis is performed to investigate the system behavior under the variation of the steam to carbon and oxygen to carbon ratios. This is done in order to identify the most suitable operating conditions for a direct on-board production of hydrogen to be used in a high temperature polymer electrolyte membrane fuel cell. The same system should be able to process different fuels, to allow the end-user to freely decide which one to use to refuel the vehicle. Hence, the obtained operating conditions result in a trade-off between system flexibility as the feeding fuel changes, CO poisoning effect on the fuel cell and overall efficiency. The system is thus coupled to a high temperature fuel cell, modeled by means of a self-made tool, able to reproduce the polarization curve as the input syngas composition varies, and the... [more]
Preliminary Study on Integration of Fiber Optic Bragg Grating Sensors in Li-Ion Batteries and In Situ Strain and Temperature Monitoring of Battery Cells
Aleksandra Fortier, Max Tsao, Nick D. Williard, Yinjiao Xing, Michael G. Pecht
December 10, 2019 (v1)
Keywords: fiber Bragg grating (FBG) sensors, in situ sensing, Li-ion batteries, safe batteries, strain, temperature, thermal runway
Current commercial battery management systems (BMSs) do not provide adequate information in real time to mitigate issues of battery cells such as thermal runway. This paper explores and evaluates the integration of fiber optic Bragg grating (FBG) sensors inside lithium-ion battery (LiB) coin cells. Strain and internal and external temperatures were recorded using FBG sensors, and the battery cells were evaluated at a cycling C/20 rate. The preliminary results present scanning electron microscope (SEM) images of electrode degradation upon sensor integration and the systematic process of sensor integration to eliminate degradation in electrodes during cell charge/discharge cycles. Recommendation for successful FBG sensor integration is given, and the strain and temperature data is presented. The FBG sensor was placed on the inside of the coin cell between the electrodes and the separator layers towards the most electrochemically active area. On the outside, the temperature of the coin ce... [more]
Highly Efficient 3rd Generation Multi-Junction Solar Cells Using Silicon Heterojunction and Perovskite Tandem: Prospective Life Cycle Environmental Impacts
René Itten, Matthias Stucki
December 10, 2019 (v1)
Subject: Materials
Keywords: carbon footprint, electricity, greenhouse gas, life cycle assessment (LCA), multi-junction, perovskite, photovoltaics, silicon heterojunction, tandem
In this study, the environmental impacts of monolithic silicon heterojunction organometallic perovskite tandem cells (SHJ-PSC) and single junction organometallic perovskite solar cells (PSC) are compared with the impacts of crystalline silicon based solar cells using a prospective life cycle assessment with a time horizon of 2025. This approach provides a result range depending on key parameters like efficiency, wafer thickness, kerf loss, lifetime, and degradation, which are appropriate for the comparison of these different solar cell types with different maturity levels. The life cycle environmental impacts of SHJ-PSC and PSC solar cells are similar or lower compared to conventional crystalline silicon solar cells, given comparable lifetimes, with the exception of mineral and fossil resource depletion. A PSC single-junction cell with 20% efficiency has to exceed a lifetime of 24 years with less than 3% degradation per year in order to be competitive with the crystalline silicon singl... [more]
Economic Optimization of Component Sizing for Residential Battery Storage Systems
Holger C. Hesse, Rodrigo Martins, Petr Musilek, Maik Naumann, Cong Nam Truong, Andreas Jossen
December 10, 2019 (v1)
Subject: Optimization
Keywords: battery aging, battery energy storage system, cost analysis, economic analysis, linear programming, Lithium-Ion battery, photovoltaic panel, residential battery, size optimization
Battery energy storage systems (BESS) coupled with rooftop-mounted residential photovoltaic (PV) generation, designated as PV-BESS, draw increasing attention and market penetration as more and more such systems become available. The manifold BESS deployed to date rely on a variety of different battery technologies, show a great variation of battery size, and power electronics dimensioning. However, given today’s high investment costs of BESS, a well-matched design and adequate sizing of the storage systems are prerequisites to allow profitability for the end-user. The economic viability of a PV-BESS depends also on the battery operation, storage technology, and aging of the system. In this paper, a general method for comprehensive PV-BESS techno-economic analysis and optimization is presented and applied to the state-of-art PV-BESS to determine its optimal parameters. Using a linear optimization method, a cost-optimal sizing of the battery and power electronics is derived based on sola... [more]
Hybrid Photovoltaic Systems with Accumulation—Support for Electric Vehicle Charging
Petr Mastny, Jan Moravek, Martin Vojtek, Jiri Drapela
December 10, 2019 (v1)
Keywords: accumulation, electric vehicle, fast charging stations, hybrid energy system, Matlab
The paper presents the concept of a hybrid power system with additional energy storage to support electric vehicles (EVs) charging stations. The aim is to verify the possibilities of mutual cooperation of individual elements of the system from the point of view of energy balances and to show possibilities of utilization of accumulation for these purposes using mathematical modeling. The description of the technical solution of the concept is described by a mathematical model in the Matlab Simulink programming environment. Individual elements of the assembled model are described in detail, together with the algorithm of the control logic of charging the supporting storage system. The resulting model was validated via an actual small-scale hybrid system (HS). Within the outputs of the mathematical model, two simulation scenarios are presented, with the aid of which the benefits of the concept presented were verified.
A Computational Tool for Comparative Energy Cost Analysis of Multiple-Crop Production Systems
Efthymios Rodias, Remigio Berruto, Dionysis Bochtis, Patrizia Busato, Alessandro Sopegno
December 10, 2019 (v1)
Keywords: agriculture, efficiency of energy, energy balance, energy cost
Various crops can be considered as potential bioenergy and biofuel production feedstocks. The selection of the crops to be cultivated for that purpose is based on several factors. For an objective comparison between different crops, a common framework is required to assess their economic or energetic performance. In this paper, a computational tool for the energy cost evaluation of multiple-crop production systems is presented. All the in-field and transport operations are considered, providing a detailed analysis of the energy requirements of the components that contribute to the overall energy consumption. A demonstration scenario is also described. The scenario is based on three selected energy crops, namely Miscanthus, Arundo donax and Switchgrass. The tool can be used as a decision support system for the evaluation of different agronomical practices (such as fertilization and agrochemicals application), machinery systems, and management practices that can be applied in each one of... [more]
Effect of Fuel Injection Strategy on the Carbonaceous Structure Formation and Nanoparticle Emission in a DISI Engine Fuelled with Butanol
Simona Silvia Merola, Adrian Irimescu, Silvana Di Iorio, Bianca Maria Vaglieco
December 10, 2019 (v1)
Keywords: Butanol, direct injection, Gasoline, nanoparticle emissions, optical investigations, spark ignition engine
Within the context of ever wider expansion of direct injection in spark ignition engines, this investigation was aimed at improved understanding of the correlation between fuel injection strategy and emission of nanoparticles. Measurements performed on a wall guided engine allowed identifying the mechanisms involved in the formation of carbonaceous structures during combustion and their evolution in the exhaust line. In-cylinder pressure was recorded in combination with cycle-resolved flame imaging, gaseous emissions and particle size distribution. This complete characterization was performed at three injection phasing settings, with butanol and commercial gasoline. Optical accessibility from below the combustion chamber allowed visualization of diffusive flames induced by fuel deposits; these localized phenomena were correlated to observed changes in engine performance and pollutant species. With gasoline fueling, minor modifications were observed with respect to combustion parameters... [more]
Development of a Diesel Engine Thermal Overload Monitoring System with Applications and Test Results
Sangram Kishore Nanda, Boru Jia, Andrew Smallbone, Anthony Paul Roskilly
December 10, 2019 (v1)
Keywords: diesel engine, lambda, monitoring system, thermal overload, thermocouple, wear rate
In this research, the development of a diesel engine thermal overload monitoring system is presented with applications and test results. The designed diesel engine thermal overload monitoring system consists of two set of sensors, i.e., a lambda sensor to measure the oxygen concentration and a fast response thermocouple to measure the temperature of the gas leaving the cylinder. A medium speed Ruston diesel engine is instrumented to measure the required engine process parameters, measurements are taken at constant load and variable fuel delivery i.e., normal and excessive injection. It is indicated that with excessive injection, the test engine is of high risk to be operated at thermal overload condition. Further tests were carried out on a Sulzer 7RTA84T engine to explore the influence of engine operating at thermal overload condition on exhaust gas temperature and oxygen concentration in the blow down gas. It is established that a lower oxygen concentration in the blow down gas corre... [more]
Break-Even Points of Battery Energy Storage Systems for Peak Shaving Applications
Claudia Rahmann, Benjamin Mac-Clure, Vijay Vittal, Felipe Valencia
December 10, 2019 (v1)
Keywords: distributed power generation, energy storage systems, peak shaving
In the last few years, several investigations have been carried out in the field of optimal sizing of energy storage systems (ESSs) at both the transmission and distribution levels. Nevertheless, most of these works make important assumptions about key factors affecting ESS profitability such as efficiency and life cycles and especially about the specific costs of the ESS, without considering the uncertainty involved. In this context, this work aims to answer the question: what should be the costs of different ESS technologies in order to make a profit when considering peak shaving applications? The paper presents a comprehensive sensitivity analysis of the interaction between the profitability of an ESS project and some key parameters influencing the project performance. The proposed approach determines the break-even points for different ESSs considering a wide range of life cycles, efficiencies, energy prices, and power prices. To do this, an optimization algorithm for the sizing of... [more]
Data Analysis and Neuro-Fuzzy Technique for EOR Screening: Application in Angolan Oilfields
Geraldo A. R. Ramos, Lateef Akanji
December 10, 2019 (v1)
Keywords: artificial intelligence (AI), enhanced oil recovery (EOR), neural network (NN), neuro-fuzzy (NF), reservoir screening
In this work, a neuro-fuzzy (NF) simulation study was conducted in order to screen candidate reservoirs for enhanced oil recovery (EOR) projects in Angolan oilfields. First, a knowledge pattern is extracted by combining both the searching potential of fuzzy-logic (FL) and the learning capability of neural network (NN) to make a priori decisions. The extracted knowledge pattern is validated against rock and fluid data trained from successful EOR projects around the world. Then, data from Block K offshore Angolan oilfields are then mined and analysed using box-plot technique for the investigation of the degree of suitability for EOR projects. The trained and validated model is then tested on the Angolan field data (Block K) where EOR application is yet to be fully established. The results from the NF simulation technique applied in this investigation show that polymer, hydrocarbon gas, and combustion are the suitable EOR techniques.
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