Showing papers on "Diesel generator published in 2012"

Planned Scheduling for Economic Power Sharing in a CHP-Based Micro-Grid

Abstract: At the planning of combined heat and power (CHP)-based micro-grid, its distributed energy resources (DER) capacity is to be selected and deployed in such a way that it becomes economically self-sufficient to cater all the loads of the system without utility's participation. Economic deployment of DERs is meant to select optimal locations, optimal sizes, and optimal technologies. Optimal locations and sizes, which are independent of CHP-based DERs types, are selected, here, by loss sensitivity index (LSI) and by loss minimization using particle swarm optimization (PSO) method, respectively. In a micro-grid, both fuel costs and NOx emissions are, mainly, dependent on types of DERs used. So the main focus of the present paper is to incorporate originality in ideas to evaluate how different optimal output sets of DER-mix, operating within their respective capacity limits, could share an electrical tracking demand, economically, among micro-turbines and diesel generators of various sizes, satisfying different heat demands, on the basis of multi-objective optimization compromising between fuel cost and emission in a 4-DER 14-bus radial micro-grid. Optimization is done using differential evolution (DE) technique under real power demand equality constraint, heat balance inequality constraint, and DER capacity limits constraint. DE results are compared with PSO.

Microgrid Generation Capacity Design With Renewables and Energy Storage Addressing Power Quality and Surety

Abstract: Microgrids are receiving attention due to the increasing need to integrate distributed generations and to insure power quality and to provide energy surety to critical loads. Since renewables need to be in the mix for energy surety, a high renewable-energy penetrated microgrid is analyzed in this paper. The standard IEEE 34 bus distribution feeder is adapted and managed as a microgrid by adding distributed generation and load profiles. The 25 kV system parameters are scaled down to 12 kV and renewable sources including solar PV and wind turbines, an energy storage system, and a diesel generator for islanded mode have been added to the 34-bus system. The distribution generations (DG) and renewables are modeled in detail using PSCAD software and practical constraints of the components are considered. The monitoring of the microgrid for measuring power quality and control requirements for these DGs and storage are modeled to maintain the power quality of the system when loads are varied. Renewable sources are modeled with seasonal variation at different locations. The microgrid is monitored at number of buses and the power quality issues are measured and indexes are calculated. This paper proposes a generalized approach to design (determine the capacity requirements) and demonstrates the management of microgrids with metrics to meet the power quality indexes.

Optimal Sizing of Hybrid Wind/PV/Diesel Generation in a Stand-Alone Power System Using Markov-Based Genetic Algorithm

Abstract: Owing to the Kyoto Protocol and the growing depletion of natural resources, renewable energies have attracted much attention. This paper considers 25-kW wind-turbine generator, 5-kW PV and 30-kW diesel generator as unit sizes for generation planning in a stand-alone power system. The investment cost (installation and unit costs) and fuel cost are minimized while retaining the reliability requirement and CO emission limit. First, the fuzzy-c-means (FCM) is employed to cluster the operation states for system load, wind-turbine generations (WTG), and PV in 8760 h. Then, the Markov models for the system load, WTG, and photovoltaic (PV) are established. The Markov models are embedded into the genetic algorithm to determine the optimal sizes for WTG, PV, and the diesel generator. The simulation results reveal that computation time can be reduced greatly while optimality can be still retained, compared with the traditional method using chronological data.

Economic evaluation of hybrid renewable energy systems for rural electrification in Iran—A case study

Abstract: The Binalood region in Iran enjoys an average wind speed of 6.82 m/s at 40 m elevation and an average daily solar radiation of 4.79 kWh/m2/day. Within this perspective, a remote rural village in Binalood region, called Sheikh Abolhassan, can readily be expected to have more than enough potential for its load demand to be supplied with a stand-alone hybrid renewable energy system. Yet the local state-run electrical service provider extended the utility grid to the village in 2006 to boost the already present diesel generator. This study aims, firstly, to explore how economical it would have been to keep supplying the electricity of the village by the diesel generator and add renewable energy generators to increase the renewable fraction of the system. On a second stage, we tried to investigate how renewable energy sources (RESs) can still be added to the current utility grid power supply in Sheikh Abolhassan to achieve a more economical and environmentally friendly system. The software HOMER is used in this study to evaluate the feasibility of various hybrid diesel-RES and grid-RES energy systems. Findings indicated that the addition of renewable power generators to the system both before and after the grid extension could and still can result in a more economical power system, which is obviously cleaner and more climate-benign.

Design of controller and communication for frequency regulation of a smart microgrid

Abstract: In this study an isolated microgrid comprising both controllable and uncontrollable sources, like solar, wind, diesel generator, fuel cell, aqua-electrolyser, hydrogen storage and battery is considered. To establish an efficient resource management strategy, a central controller takes the decisions based on the status of the loads and sources. The status is obtained with the help of multi-agent concept (treating each load and source as an agent) through internet using User Datagram Protocol/Internet Protocol (UDP/IP). The decisions are transmitted to the controllable sources to regulate their power output for damping of frequency excursion following a disturbance. A control strategy is adopted to regulate the power output from the battery only during transient, resulting in a floating battery scheme in steady state. This will reduce the ampere hour rating of the battery and can improve the damping of frequency excursion following each load disturbance. In a microgrid with generation rate constraint (GRC), tuning of controller parameters and frequency bias is a nonlinear optimisation problem. Hence, this study attempts to tune the controller parameters using an evolutionary technique named bacterial foraging optimisation (BFO). The tuned gains obtained utilising BFO method give satisfactory frequency excursion following a disturbance in the microgrid.

Integrated Microgrid Laboratory System

Abstract: The paper presents an integrated microgrid laboratory system with a flexible and reliable multimicrogrid structure; it contains multiple distributed generation systems and energy storage systems and integrates with a diesel generator that serves as a back-up power source and flywheel energy storage for fast balancing to provide uninterruptible power-supply services in cooperation with the diesel generator. The microgrid system, by adopting the master-slave control strategy, can be transited flexibly between grid-connected and islanded modes and can be disconnected from the utility when a fault occurs or the power quality falls below specified standards. The developed bi-directional inverter which is applied in the system plays an important role. The small microgrids of this system are intended to operate separately or in the form of one large microgrid with a certain switch status. Furthermore, experiments on control, protection, and other technologies have been carried out. The results show that the operation conditions meet the related IEEE Standard 1547 and power quality requirements. The integrated microgrid laboratory system is able to operate stably and reliably under different conditions, including mode transition and fault events.

Estimation of carbon footprints from diesel generator emissions

Abstract: The aim of this paper is to estimate the amount of carbon footprints emitted from diesel generators in terms of carbon dioxide. A constant load demand of 1.05 kW per hour (6.3 kW/day) with six hours of operation of a diesel generator per day was selected for this analysis. The fuel consumption rate and carbon footprints in terms of carbon dioxide (CO2) were determined. It was discovered that emission of carbon footprints increased by five folds as emission factor was increased from 1 kg to 5 kgCO2/liter. Similarly, the increment of a single kW rated power diesel generator at a constant emission factor increases 1.1 to 1.2 times carbon footprint emissions. It is revealed that the efficiency of diesel generator is inversely proportional to its rated power, fuel consumption rate and CO2 emissions. Therefore, the rated power of selected diesel generator should be close to the required load demand.

Optimisation of hybrid off-grid energy systems by linear programming

Abstract: In this study, a general model of a hybrid off-grid energy system is developed, which can be adjusted to reflect real conditions in order to achieve economical and ecological optimisation of off-grid energy systems. Using linear programming methods in the General Algebraic Modeling System (GAMS) environment, the optimal configuration of the electrical power supply system following characteristic restrictions as well as hourly weather and demand data is found. From this model, the optimal mix of solar- and wind-based power generators combined with storage devices and a diesel generator set is formed. The operation of this model was tested in two real off-grid energy systems, a cluster of villages in India and Titumate in Colombia. Both optimisation processes resulted in hybrid energy systems, utilising photovoltaics (PV), lead-acid batteries and a diesel generator as a load-balancing facility. With respect to small off-grid energy systems, it was found that renewable energy in combination with electrical storage devices help to reduce the cost of energy compared to stand-alone diesel generator sets. The optimal solutions strongly depend on the particular load demand curve. As both PV and wind energy benefit from energy storage, the costs of the battery can be shared and the two technologies complement each other. Finally, although the optimised capacity of the diesel generator remains nearly constant, its contribution to the total power generation is being substituted by renewable energy sources, which serve as fuel-saving technologies.

Techno-economic analysis of a hybrid mini-grid system for Fiji islands

Abstract: The Pacific Island Countries constantly struggle with the challenges of high petroleum dependence for their electricity production and lack of adequate energy services. It is possible to alleviate the energy poverty by utilizing abundant renewable energy resources available in the region. The objective of this work is to investigate the feasibility of a wind/solar photovoltaic/diesel generator-based hybrid power system in a remote location in Fiji islands. We used the Hybrid Optimisation Model for Electric Renewables (HOMER) software to simulate the system and perform system optimisation analysis. The system characteristics were studied in terms of optimal configuration, net present cost and the cost of energy. An entirely renewable energy-based configuration is feasible if 10% annual capacity shortage is allowed, while for a scenario with no capacity shortage, addition of a diesel generator is necessary. The addition of renewable energy components results in greenhouse gas reduction which could be used for carbon trading.

An autonomous hybrid energy system of wind/tidal/microturbine/battery storage

Abstract: This paper focuses on dynamic modeling, simulation, control and energy management in an isolated integrated power generation system consisting of a 315 kW offshore wind turbine, a 175 kW tidal turbine, a 290 kW microturbine, and a 3.27 kAh lead acid battery storage. A first, due to efficient and economical utilization of the renewable energy resources, optimal sizing of the hybrid system is accomplished based on economic analysis using genetic algorithms. A model of power-consumption for a microturbine is obtained using least square estimation algorithm based on capstone™ company data and is suggested for implementing at economic analysis. For extraction of maximum energy from a variable speed wind turbine, a developed Lyapunov model reference adaptive feedback linearization method accompanied by an indirect space vector control is applied. Because of more reliability, more fuel flexibility, less environmental pollution, less noise generation and less power fluctuation in comparison with a diesel generator, a microturbine integrated with battery storage is suggested as a back up for this system. A supervisory controller is designed for energy management between the maximum energy captured from the wind turbine and consumed energies of the load, dump load, energy of the battery based on state of charge and generated energy by the microturbine. Dynamic modeling and simulation are fulfilled using MATLAB Simulink™7.2.

Simulation of Real-World Vehicle Missions Using a Stochastic Markov Model for Optimal Powertrain Sizing

Abstract: Growing concerns about petroleum supplies and air pollution have spurred increased interest and research into hybrid electric vehicles (HEVs). While standard driving cycles are commonly used for the purpose of propulsion chain optimization, the issue of how representative they actually are is questioned. This paper proposes a novel methodology for modeling real-world vehicle missions by considering the stochastic characteristics of the driving pattern and the dependence among the variables of the mission, i.e., vehicle speed, acceleration, and road gradient. The modeling procedure is based on a Markov matrix formulation, and a simulation algorithm is implemented to generate an unlimited number of stochastic mission profiles. Two kinds of mission natures have been modeled and discussed so as to stress the mission impact on the energy consumption according to the propulsion chain sizing. The approach is then validated using the architecture of a series HEV powered by a diesel generator and batteries. The results on fuel consumption are presented, and the benefit of the proposed method over conventional approaches is argued.

Innovative Remote Micro-Grid Systems

Abstract: Most small islands and remote communities around the world today are dependent on imported fossil fuels for most of their energy requirements. High fuel costs in recent time have translated into tremendous increases in the cost of energy generation in remote areas. Solar and wind power technologies are clean, affordable, readily available, and sustainable and can replace or supplement generators. Hybrid energy systems integrate these renewable energy technologies with diesel generators, inverters and batteries to provide grid quality power in remote areas not connected to a utility grid. Such an isolated grid is known as Remote Micro-Grid and is widely recognized as the remote area electrification technology for the 21 st century. It is predicted that there will be a 21% increase in capacity for the remote micro-grid market by 2017, from 349 MW to 1.1 GW with a projected total revenue of more than $10 billion. One solution to save fuel in a diesel generator is to enable the engine to operate at variable speeds in direct relation to the electrical load demand. The author has developed an innovative variable speed generator technology (patent pending) with high penetration of renewable energy. There are a number of applications where the power demand varies greatly that can benefit from the new technology which maintains constant voltage and frequency while adjusting the engine speed to power demand. This paper will present case studies on previous hybrid power system projects and the limitations of the existing technology. Case studies on applications in remote mining, holiday resort and remote mobile telecom base stations are described.

Dynamic model of diesel generator set for hybrid wind-diesel small grids applications

Abstract: In order to reduce the carbon gas emissions, wind energy conversion systems are currently more and more connected to actual diesel power plants to provide electricity to small remote communities where the power grids are not available. As for classical power systems, the stability analysis, prediction, identification, control and diagnostic of hybrid wind-diesel small grids need accurate modelling of its main components. The state space representation is known as the more suitable system representation for simulation, identification/diagnostic and stability studies purposes. In this paper a linear state modelling of a diesel generator is proposed. The global diesel generator model obtained from the superposition principle of its components is applied for stability analysis using the eigenvalues calculation. Furthermore, the effectiveness of the model is assessed through numerical simulations of large transient tests such as load rejections and the synchronous generator automatic voltage regulation action is carried out. field transients during a Field short-circuit test with the stator in open circuit is also simulated.

A techno-economic model for optimising component sizing and energy dispatch strategy for PV-diesel-battery hybrid power systems

Abstract: This paper presents the development and application of a simple spreadsheet-based simulation model for sizing, energy performance evaluation and economic analysis of PV-diesel-battery power supply systems. The model is employed to generate a set of sizing curves that define the design space for hybrid systems using dimensionless generator component size variables, for a specified supply reliability and diesel energy dispatch strategy. The component size combination with the least unit cost of energy is selected among the many possible combinations satisfying a desired loss-of-load probability. Storage battery and diesel generator lifespan, as well as generator fuel efficiency, which depend on the operational loading stress of these components, are recognised as important variables in the economics of the system. The lifespan of the battery is premised to depend on the depth and rate of discharge of the operating cycles, while both the diesel generator lifespan and fuel efficiency are dependent on the degree and frequency of partial loading. The choice of diesel generator dispatch strategy was shown to be another important factor influencing the energy performance and economics of the system. The outputs of the model reveal several important sizing, operational and economic characteristics of the systems, and enables appraisal of comparative advantage of different types of designs and operational strategies. The merits of the hybrid concept are well demonstrated by the study results.

Optimum sizing of hybrid PV/wind/battery/diesel system considering wind turbine parameters using Genetic Algorithm

Abstract: This paper proposes an optimum sizing methodology to optimize the configuration of a hybrid energy system (HES) based on Genetic Algorithm (GA). The proposed methodology considers the effect of wind turbine parameters such as rated speed and rated power on electricity cost and compares the performance of various HES. Furthermore, the relationships between renewable energy fraction and the cost of energy are also given. The proposed method was applied to the analysis of HES which supplies energy for remote village located in the northern part of Saudi Arabia. The decision variables included in the optimization process are the PV array capacity, wind turbine number, battery bank number and diesel generator rated power.

Technical and economic assessment of hybrid energy systems in South-West Nigeria

Abstract: The technical and economic assessment of using hybrid energy system for electricity generation in rural communities in the south-west of Nigeria is investigated in this study. Renewable resources (wind and solar data) in Ibadan located on the latitude of 7.43 °N and longitude 3.91 °E are used. Hybrid Optimization Model for Electric Renewable software has been employed to carry out the present study. It was found that Wind-PV-Generator-Battery hybrid system is most suitable option as stand-alone electricity generating system in Ibadan. The optimal simulation results indicate that the levelised cost of energy for this hybrid energy system varies between $0.437/kWh and $0.606/kWh depending on the diesel price. These costs are significantly lower than the cost of using diesel generator only (without battery) which varies between $0.607 and $0.940 per kWh. It was further observed that there is a significant reduction in emission produced if hybrid energy system is used instead of only generator based energy sy...

Deterministic Optimization and Cost Analysis of Hybrid PV/Wind/Battery/Diesel Power System

Abstract: This paper focuses on the development of a deterministic approach for optimum sizing of the hybrid power systems (PV/wind/battery/diesel and PV/wind/diesel) based on the DIviding RECTangles (DIRECT) algorithm, which can attain the optimum values of commercially available system devices ensuring that the system total investment cost is minimized while guaranteeing the electricity requirements of the customers and the safety of the system. The hybrid power systems are assumed to be installed at an Experimental Remote Ecological Area (EREA), France, with 5-year period of average hourly data (solar radiation, wind speed, ambient temperature and electrical power demand of the load). Finally, the optimum values obtained of the system components during a period of 20-year are obtained including the number of PV modules, the PV module surface area, the number of wind turbines, the wind turbine installation height, the battery bank number and the diesel generator operating hours with their lowest system total investment costs. Additionally, a detailed analysis of the System Total Investment Cost (STIC), structure of the hybrid PV/wind/battery/diesel power system and an impact of optimum system configuration on system performance are compared and discussed in the case studied.

Reliability evaluation of stand-alone hybrid microgrid using Sequential Monte Carlo Simulation

Abstract: Adequacy assessment of a stand-alone microgrid including diesel generator (DG), Micro Gas Turbine(MGT), Wind Turbine Generator(WTG), and Photovoltaic(PV) with different configurations is carried out using Sequential Monte Carlo Simulation(SMCS) method. To obtain the output power of WTG and PV, some atmospheric data such as wind speed, solar irradiation, and ambient temperature data are needed. Weibull distribution is used to obtain these data. To obtain the adequacy model of DG and MGT a two-state reliability model is employed. A combination of the two-state reliability model and output power can be also used to build the generation model of WTG and PV. In addition, the generation model of system compares with IEEE Reliability Test System (IEEE RTS) load model and adequacy indices are then achieved. Simulation results corroborate the flexibility of SMSC in risk evaluation of both stable and unstable resources.

Increasing wind energy penetration level using pumped hydro storage in island micro-grid system

Abstract: Ramea is a small island in southern Newfoundland. Since 2004, it has a wind-diesel hybrid power system to provide power for approximately 600 inhabitants. In this paper, wind speed data, load data, and sizing of pumped hydro system at Ramea, Newfoundland are presented. The dynamic model of wind turbine, pumped hydro system, and diesel generator are included in this paper. The dynamic model is simulated in SIMULINK/MATLAB to determine the system voltage and frequency variation and also to visualize different power outputs. Sizing of pumped hydro system indicates that a 150-kW pumped hydro storage system can be installed in Ramea to increase the renewable energy fraction to 37% which will reduce non-renewable fuel consumption on this island. Also, it is found that a pumped hydro energy storage system for Ramea is a much better choice than a hydrogen energy storage system. Such a system will have a higher overall efficiency and could be maintained using local technical expertise, therefore, a more appropriate technology for Ramea.