Stand-alone Power Plant Research Articles

Design and Parametric Analysis of a Stand-Alone Solar-Hydro Power Plant with Pumped Water Storage Technology

There is a global over reliance on fossil fuel for energy generation which has triggered global alarm on climate change due to greenhouse gases emitted by fossil fuel. These harmful effects of fossil fuel on the environment have tilted global effort towards harnessing renewable energy sources which is obviously the future of energy. In this paper, the design and parametric analysis of a stand-alone solar-hydro power plant using pumped water storage technology is presented. It is aimed at addressing the growing concern of bulk energy generated from renewable energy sources. The paper adopted the University of Uyo main campus as its case study site, performed a load demand profile assessment on a section of the campus, obtained the meteorological data of the site, and designed a 250 kVA solar-hydro power plant with pumped storage technology. The results of the Matrix laboratory (MATLAB) simulation revealed that when the generating head of the upper reservoir was increased from 20 m to 100 m, the required generating flow rate decreased from 1.0994 m 3 /s to 0.2199 m 3 /s. It also revealed that, an increase in the pipe diameter from 0.2 m to 1 m, decreased the equivalent head losses from 337.04 m to 0.0878 m. Keywords: Pumped storage hydropower, bulk energy storage, renewable energy, stand-alone, green battery.

Optimal configuration, design and control of a binary geothermal combined heat-and-power plant

In this paper, a two-step design optimization framework is developed for four low-temperature geothermal combined heat-and-power plant configurations. The economic comparison, including off-design performance, has not been done before. The optimization tool is applied for an existing district heating system and for geothermal and meteorological conditions which are based on the Belgian situation. It is concluded that a combined heat-and-power plant results in an economically profitable project (net present value of 3.46 MEUR), whereas the stand-alone electrical power plant does not (net present value of −3.65 MEUR). Furthermore, the design for the series set-up is optimal, and the best connections during operation are the series and parallel connections for low and high heat demands, respectively. Also, a less detailed (high-level) control optimization model is developed for this series set-up, based on the part-load operating maps which are calculated from the detailed two-step optimization model results. The calculation time is much faster (∼milliseconds) and the errors on the total revenues are smaller than 0.1%. The goal of this high-level model is to optimize the amounts of heat and electricity to produce, so that the plant can be used as a flexibility tool in energy markets driven by price signals for heat and electricity.

Transient performance improvement of a stand-alone fuel cell for residential applications

In this paper, the dynamic behavior of a solid oxide fuel cell in transient conditions is improved based on considering utilization factor concept as well as the flow rate of hydrogen fuel for distributed power system applications. Among different types of FCs, SOFC has been chosen for distributed power systems because of its ability to operate under relatively impure fuel conditions. The main drawback of the fuel cell system is its slow dynamic. Consequently, storage devices such as ultra-capacitor and battery bank with a fast dynamic response should be used in hybrid configurations. Accordingly it is rational to utilize cost-effective control strategies to enhance the dynamic response of FC systems. The proposed method enhances the dynamic response through properly controlling of DC/AC converter and utilization factor. In this regard, via controlling the power condition unit in the right way, the amplitude of utilization factor can be controlled to satisfy the limitation of fuel flow rate and protect FC system against overuse or underuse conditions. The simulation results of the solid oxide fuel cell in the stand-alone power plant structure across different active and reactive load changes along with mathematical proofs indicate the effectiveness of the proposed method.

Optimal configuration for a low-temperature geothermal CHP plant based on thermoeconomic optimization

In this paper, we propose a thermoeconomic optimization procedure for four configurations of low-temperature geothermal combined heat-and-power (CHP) plants. The series, parallel, preheat-parallel and HB4 configurations are investigated. Electricity is produced via an organic Rankine cycle (ORC) and two types of district heating (DH) systems are considered for the heat delivery: a 90/60 and a 65/40 DH system. The objective is to maximize the net present value (NPV) of the CHP plant for given DH system requirements. We conclude that, under the assumptions considered, the NPV can be increased from −2.81MEUR (unprofitable) for a stand-alone electrical power plant to 12.5, 28 and 58MEUR (economically feasible) for the optimal CHP, and for a heat demand of 5, 10 and 20 MW th, respectively. Also, the exergetic plant efficiency is higher for the CHP plants, which means that the geothermal energy source can be utilized in a better way. Furthermore, we have found that the series CHP is generally the optimal CHP configuration. Only for the 90/60 DH system and low heat demands, the HB4 is more suitable. Compared to the simple series and parallel CHPs, the HB4 configuration has a 16% and 5.5% higher NPV, for heat demands of 5 and 10 MW th, respectively.

Generation unit sizing, economic analysis of grid connected and standalone PV power plant

This paper presents a design for a grid connected PV system with the capacity of 1.5 MVA, as well as a standalone PV system with the capacity of 50 kVA in the West Bank industrial zone, Palestine. The factors affecting the design and size of the system are also presented and evaluated. To ensure adequate, reliable and economical system design, over and under sizing energy has been avoided. Furthermore, a numerical analysis will be carried out to evaluate the effects of the grid-connected system on the network, with respect to the voltage profile, power flow, and energy losses. The results have shown a good enhancement in the total energy losses and voltage profile in reference to load and generation capacity. However, the voltage profile is enhanced on buses located close to the proposed PV plant while the profile enhancements decrease when moving closer to the source buses. The maximum increase in voltage profile is 0.4% which is satisfactory in our case. Furthermore, the power losses were clearly decreased with installed of PV systems. Finally, an economic analysis for both systems will be presented. It was found that the total income of the project is expected to be around $616,923 per year. Further, the payback period is expected to be .5 years and the Net Present Value (NPV) is about $3,885,125.91. The Internal Rate of Return (IRR) for the project during a 20-year lifespan is about 26%.

Differences in the impact of harmonic distortion due to the installation of electronic load controller in self-excited induction generator and synchronous generator

In general, the application of Self-Excited Induction Generator (SEIG) or Synchronous Generator (SG) on the Stand-Alone Micro Hydel Power Plant (MHPP) is equipped with Electronic Load Controller (ELC) to control generator output during variations in consumer load. One type of ELC that is cheap and rigid developed today is the ELC, which is constructed by the uncontrolled bridge rectifier with DC Chopper. Based on the operational concept, basically this type of ELC can be implemented on both SEIG and SG, but both of these generators will have a different harmonic distortion effect on the output and its load. This paper examines the differences in the effects of harmonic distortions due to ELC installation on SEIG and SG. The initial stage of this study was to design the ELC developed. Then, the harmonic distortion response due to the installation of ELC on SEIG and SG is tested, which includes harmonic distortion in: stator current, PCC voltage, and consumer load current. THD<sub>I </sub>(Current Total Harmonic Distortion) stator current at SEIG with ELC has shown an average value smaller than the THD stator current in SG with ELC. Likewise, the THD<sub>V</sub> (Voltage Total Harmonic Distortion) value of PCC voltage and THDI value of the current consumer load on SEIG equipped with ELC has been shown to be smaller than the THD<sub>V</sub> value of PCC voltage and THD<sub>I</sub> value of the current consumer load on SG equipped with ELC. The effects of harmonic distortions due to the installation of ELCs that developed in this study on SEIG is still within the permitted limits, while on the SG, the harmonic distortion reduction is needed at the generator output.

KAJIAN KUALITAS DAYA LISTRIK PLTS SISTEM OFF-GRID DI STT-PLN

Inadequate power quality causes damage and may even cause damage to electrical equipment. Solar Power Plants Off-grid is a stand-alone power plant is not connected to the network. This system uses storage media such as batteries to maintain the availability of electricity at night or when the sun's intensity decreases. Solar power plant has a PV module that works based on the intensity of the captured sunlight and the inverter that can change the dc voltage into ac where as is known in the inverter there are non linear components which can result in poor quality of electrical power in this case the total harmonic distortion and voltage variations change. This may result in damage to electrical equipment. The electrical power quality of the STT-PLN off-grid PLTS will be analyzed and compared with the IEEE 519-1992 and SPLN 1: 1995 standards. Based on the results of the discussion that the THDi and THDv values ​​are still above the established standard limit of 5%.

Annual performance analysis and optimization of a solar tower aided coal-fired power plant

The integration of solar energy into coal-fired power plants has been proven as a potential approach in the utilization of solar energy to reduce coal consumption. Moreover, solar augmentation offers low cost and low risk alternatives to stand-alone solar thermal power plants. In this study, the annual performance of a solar tower aided coal-fired power (STACP) system is investigated, and the influence of thermal storage system capacity on the annual solar generating power and annual solar-to-electricity efficiency is explored. The thermal storage system capacity is optimized to obtain the lowest levelized cost of electricity (LCOE). At the same time, the influence and sensitivity of several important economic factors are explored and assessed. Results demonstrate that compared to a coal-fired power system, the reduction in the annual average coal consumption rate of the STACP system with high direct normal irradiance (DNI), medium DNI, and low DNI are 5.79, 4.52, and 3.22 g/kWh, respectively. At a minimum, the annual coal consumption can be reduced by 14,000 t in a 600 MWe power generation unit. Because the same solar field is considered under different DNI conditions, the LCOE in the high DNI, medium DNI, and low DNI scenarios are all fairly similar (6.37, 6.40, and 6.41 ¢/kWh, respectively). When the solar multiple is 3.0, the optimal thermal storage capacity of the STACP system, with high, medium, and low DNIs are 6.73, 4.42, and 2.21 h, respectively. The sensitivity analysis shows that the change in economic parameters exerts more influence on the STACP system with the high DNI compared with the other two scenarios.

Гибридные солнечные элементы с системой концентрации оптического излучения

Hybrid solar cells based on InGaP/Ga(In)As/Ge and Si elements integrated in a crystalline silicon heat-removing base with a system for optical-emission concentration based on linear Fresnel lenses and carbon-fiber body shell have been developed and their characteristics examined. These hybrid elements with light concentrators provide a specific electric power of 390 W/m2 (AM0, 1367 W/m2) at a specific mass of the photogenerating part reduced to 1.0 kg/m2. The improved photoelectric characteristics and the radiation hardness of the cells enable application of the hybrid elements with light concentrators in space solar cells and in stand-alone terrestrial power plants with solar light concentration.

A fuzzy logic embedded energy management software with multi-agent system for a stand-alone PV power plant

The worst scenario projected for an off-grid photovoltaic power system is the time interval that the solar irradiation amount is in short to supply the load throughout the day, and this situation is resulted in energy deficiency. Nowadays, an off-grid power generating system, which is designed to consider the worst scenario encountered only during a certain period of time, brings through big financial problems in terms of the initial installation costs. This study proposes a smart software to perform energy management considering users’ comfort and their criteria, which are taking some information from the agents communicating with the consumption units wirelessly and the battery agent. All loads and agents in this system are initially defined by the user according to the importance of the consumption loads such as critical, essential, significant, lesser, and insignificant loads. The proposed energy management software includes fuzzy logic-based decision maker to manage load suspension or put the suspended load into effect again according to the state of the sources. The total amount of consumption is kept less than the total existing energy so that the energy to be consumed by the critical loads is always provided. Considering the existing amount of energy and consumer preferences, the total amount of load units is maximized at each sampling step. The proposed system, which is attained without compromising the user comfort, enables more efficient energy consumption. Also, for supplying the critical loads in case of lack of energy is possible.

Techno-economic analysis of a stand-alone microgrid for a commercial building in eight different climate zones

Small commercial buildings in the United States consume 47% of the total primary energy of the buildings sector and, to save energy and mitigate the environmental impact of electricity consumption, distributed generation, involving renewable energy sources, might be a promising solution. In the present paper, a self-made simulation tool has been developed using Matlab/Simulink® to model a stand-alone polygeneration power plant for a strip mall. A photovoltaic panel array has been coupled to a battery and a unitized regenerative polymer electrolyte membrane fuel cell as primary storage/backup systems and a diesel generator as secondary backup system. The possibility of applying the same plant layout and control strategy to eight different climate zones in eight different States has then been assessed. Results show that even in the most favorable conditions in terms of daily radiation and average temperature, such as Miami, Las Vegas or Houston, the cost of electricity of the utility makes the implementation of these systems still inconvenient, unless a reduction in the initial investment costs of above 60% is pursued by means of incentives or a further establishment of the proposed technologies.

Improvement of Efficiency of Coal-Fired Steam Power Plant by Reducing Heat Rejection Temperature at Condenser Using Kalina Cycle

This paper proposes an approach for improving the plant efficiency by reducing the heat rejection temperature of power cycle using Kalina Cycle System 11 (KCS11) which is integrated at the steam condenser of a 500 MWe SubC (subcritical) coal-fired power plant. It is modelled by using power plant simulation software ‘Cycle Tempo’ at different plant operating conditions. Results show that the additional net electric power of 5.14 MWe from KCS11 improves the net energy and exergy efficiencies of the power plant by about 0.302 % point and 0.27 % point, respectively at full load over the stand-alone coal-fired steam power plant. Thereby, the carbon dioxide (CO2) emission is reduced by about 2.02 t/h at full load. Combined plant efficiencies decrease with decrease in evaporator outlet temperature due to decrease in vapour quality of binary mixture at turbine inlet and higher steam turbine back pressure. Levelized Cost of Electricity (LCoE) generation and payback period of the combined cycle power plant are about Rs 1.734 and 4.237 years, respectively and the cost of fuel saving is about Rs 0.685 per kg of coal which is lower than the fuel cost.

Performance Analysis of Integrated Solar Tower With a Conventional Heat and Power Co-Generation Plant

Abstract This paper presents the results of a thermo-economic analysis of integrating solar tower (ST) with heat and power cogeneration plants that is progressively being installed to produce heat and electricity to operate absorption refrigeration systems or steam for industrial processes. The annual performance of an integrated solar-tower gas-turbine-cogeneration power plant (ISTGCPP) with different sizes of gas turbine and solar collector's area have been examined and presented. Thermoflex + PEACE software's were used to thermodynamically and economically assess different integration configurations of the ISTGCPP. The optimal integrated solar field size has been identified and the pertinent reduction in CO2 emissions due to integrating the ST system is estimated. For the considered cogeneration plant (that is required to produce 81.44 kg/s of steam at 394 °C and 45.88 bars), the study revealed that (ISTGCPP) with gas turbine of electric power generation capacity less than 50 MWe capacities have more economic feasibility for integrating solar energy. The levelized electricity cost (LEC) for the (ISTGCPP) varied between $0.067 and $0.069/kWh for gas turbine of electric power generation capacity less than 50 MWe. Moreover, the study demonstrated that (ISTGCPP) has more economic feasibility than a stand-alone ST power plant; the LEC for ISTGCPP is reduced by 50–60% relative to the stand-alone ST power plant. Moreover, a conceptual procedure to identify the optimal configuration of the ISTGCPP has been developed and presented in this paper.

Performance and Simulation of a Stand-alone Parabolic Trough Solar Thermal Power Plant

In this paper, a Simulink® Thermolib Model has been established for simulation performance evaluation of Stand-alone Parabolic Trough Solar Thermal Power Plant in Universiti Teknologi PETRONAS, Malaysia. This paper proposes a design of 1.2 kW parabolic trough power plant. The model is capable to predict temperatures at any system outlet in the plant, as well as the power output produced. The conditions that are taken into account as input to the model are: local solar radiation and ambient temperatures, which have been measured during the year. Other parameters that have been input to the model are the collector’s sizes, location in terms of latitude and altitude. Lastly, the results are presented in graphical manner to describe the analysed variations of various outputs of the solar fields obtained, and help to predict the performance of the plant. The developed model allows an initial evaluation of the viability and technical feasibility of any similar solar thermal power plant.

Effect of Load Growth on PLTH Baron Techno Park Performance

The reliability of stand-alone and hybrid power plant systems was dependent on electrical loads that the system must supply. For example, on renewable energy sources (RES), Reviews of those systems needs to be calculated well before the development process. One of the most important processes in the initial calculation is the electrical load that must be supplied by the system. The electrical load has a major influence on the amount of power generating capacity. A power plant that has higher electricity production than the load to be fulfilled was considered capable of meeting the system electrical load requirements. However, in terms of the reliability, it is considered as a loss because it will affect the life of the components and the high cost of operating from the system. Therefore, this research discusses the effect of load growth on hybrid power plant system performance of Baron Techno Park. The result of the research shows that the total electricity production of Baron Techno Park hybrid power plant system is 319.695 kWh/year with Net Present Cost (NPC) is $560.077 and the cost of energy (COE) is $0.64/kWh. Total electricity consumption of the PLTH Baron Techno Park is 67.413 kWh/year with total excess electrical energy is 245,547 kWh/year. Load growth of 5%, 10%, 15%, and 20% of the total current load affect the consumption of electric energy, excess electrical energy, and COE. The higher the load growth will affect the total electricity consumption that is increasingly higher so that the total excess electrical energy is lower. This research found that the performance of the system is not influenced by load growth. The highest performance of the system is resulted by the wind turbine of 72.62%, followed by solar panels of 18.82%, and biodiesel of 8.56%.

Optimization of solar aided coal-fired power plant layouts using multi-criteria assessment

This paper presents an integration methodology for medium and high temperature solar aided coal-fired power generation systems. A set of preferred integration methods is proposed using analysis of pinch point, exergy and solar share and the application of system simulation methods. These methods can be used for hybrid (solar/fossil) systems screening, pre-assessment and decision-making. Power plant annual performance is analyzed to confirm the validity of the abovementioned methods. The presented methodology has been applied into a 100 + 1000 MWe grade solar tower aided coal-fired power generation plant (STAPG). According to the proposed methodology, the best integration scheme is found for a scenario where high-temperature solar thermal energy is used for steam reheating, while the remaining solar thermal energy is used for feedwater heating providing the maximum utilization of solar energy. The analysis reveals that as much as 214.7 MWe could be generated using solar thermal energy under the best integration scheme. This accounts for 21.3% of total electricity produced, while representing more than twice as much the power produced by an equivalent stand-alone solar tower power plant of the same solar field size. Furthermore, solar-to-electricity efficiency of the hybrid system may reach 36.8%, with power block efficiency of 43.3%, and the coal consumption rate is 203.5 g/kW h. All these parameters are representative of the best scenario amongst the seven integration schemes studied in this paper.

An integrated program of a stand-alone parabolic trough solar thermal power plant: Code description and test

Solar thermal systems produce steam after being energized by solar parabolic trough concentrators, are incorporated with a steam turbine-generator assembly to produce electricity. This study presents a code for prediction of performance, while under-taking preliminary plant-sizing for a variety of parabolic trough solar fields operating under nominal conditions. The code, named as PTPPPP (Parabolic Trough Power Plant Performance Predictor) consists of four blocks. The code allows prediction of variables including: heat loss coefficient, UL, aperture effective direct normal irradiance, I, heat gain, Qgain, and the thermal efficiency of stand-alone parabolic trough solar thermal power plant in commerce, ηp. The conceptual design of the stand-alone parabolic trough solar involves: selection and sizing of system components, power generation cycles, working fluid types, and power block sizing. The input weather parameters and the operational parameters to the code have been acquired from in-situ measurements. The prediction results of the code have been found in good agreement with literature data with mean error of 0.18% in prediction of output power. In addition, this code is able to provide a flexibility in terms of temperature, heat transfer, and pressure range.

Reducing the Costs of Paying for Consumed Electric Energy by Utilizing Solar Energy

The use of a low-power solar network and standalone power plants is the most promising for the needs of the housing and utilities sector, small industrial enterprises, social and public health facilities, recreation areas, remote objects, and agricultural industries; this will make it possible to reduce the load on the energy system at peak moments, as well as to decrease losses when transporting electric energy in its elements. It is assumed that the minimum value of the unit cost of generated electric energy is used as the criterion for configuring and selecting the parameters of solar power equipment, which will make it possible to set up an economically feasible additional power supply to the consumer, since it excludes the use of storage devices and rearrangement of the power supply system.

PHOTOVOLTAIC MODELING METHODS BASED ON MATLAB SIMULINK IMPLEMENTATION

This paper presents photovoltaic system as a stand-alone electric power plant in the renewable energy development. To maximize these stand-alone generators, it is necessary to design photovoltaic modeling to produce energy and maximum power. The problems that exist in the design of PV systems are PV configuration, battery size, and the maximum power system. Therefore, this research will be proposed modeling Matlab/Simulink based PV system. The contribution of this research can provide various characteristics of the photovoltaic system with a capacity of 100 Wp. This modeling is designed using Matlab/Simulink software. The data generated from this simulation will provide a good reference for designing the stand-alone generators in the future.

Energy-exergy-economic (E3) analysis of stand-alone solar thermal cogeneration power plant

Concentrating solar power (CSP) based solar cogeneration plants are more energy efficient compared to single purpose power plants. In this paper, energy, exergy and economic analysis have been carried out for the stand-alone solar thermal co-generation power plant (SASTCPP), which is based on Rankine cycle. Both direct and indirect steam generation is adopted for the comparative E3 analysis. To achieve high energy efficiency, back pressure steam turbine with regenerative feed water heating is incorporated in power block. Reference cogeneration power plant has a capacity of 50 MWth. levelised cost of electricity (LCOE) associated to SASTCPP is calculated with three different cost allocation approach – direct, equivalent fuel consumption, and exergy approach. The observed exergy efficiency (33–35%) is comparatively less than energy efficiency (62–70%) and the maximum exergy destruction takes place within the solar field. Minimum LCOE calculated as Indian rupees (INR) 5.46 with direct steam generation (DSG).