scholarly journals Comparative Assessment of Thermal Power Systems Performance Under Uncertainty

2018 ◽  
Vol 3 (7) ◽  
pp. 50
Author(s):  
Anthony Kpegele Le-ol ◽  
Sidum Adumene ◽  
Kenneth Israel

This work presents a comparative analysis of the thermo-economic performance of a simple, retrofitted and built-in combined cycle power plants within the Delta. The data were obtained from a 25MW gas turbine plant-based engine, retrofitted and MATLAB software was used to model the thermodynamic performance of the plants. The economic prediction of the plants was done using a developed net present value(NPV), internal rate of return (IRR), cost of investment (COR) and payback period (PBP).  The economic concept for plants performance was analysed under uncertainty constraints of energy need, operating conditions, energy cost and energy supply variability. Three plants configuration; simple gas turbine (SGT), retrofitted combined cycle (RCC) and Built-in combined cycle (BCC) was analysed based on these economic performance indicators. The three configurations show a positive NPV, PBP and IRR, with the BCC showing the optimum return on investment. Although the RCC show minimum initial cost on investment compare to BCC, the BCC demonstrates greater overall return with an NPV of $30,755,454.18, IRR of 17.1% and PBP of 6.3years for the period of 20years. The analysis shows cash flow of 34.1% and 52.6% for the RCC and BCC respectively. The result also showed that the plant performs better at a lower ambient temperature and higher relative humidity with a higher return on investment. This research provides great insight into the thermo-economic analysis, and benefits of combined cycle power plant and will aid energy system investors on the choice of the power plant for power generation in the Niger Delta.

Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa ◽  
Luiz Augusto Horta Nogueira ◽  
Electo E. Silva Lora

The operational rules for the electricity markets in Latin America are changing at the same time that the electricity power plants are being subjected to stronger environmental restrictions, fierce competition and free market rules. This is forcing the conventional power plants owners to evaluate the operation of their power plants. Those thermal power plants were built between the 1960’s and the 1990’s. They are old and inefficient, therefore generating expensive electricity and polluting the environment. This study presents the repowering of thermal power plants based on the analysis of three basic concepts: the thermal configuration of the different technological solutions, the costs of the generated electricity and the environmental impact produced by the decrease of the pollutants generated during the electricity production. The case study for the present paper is an Ecuadorian 73 MWe power output steam power plant erected at the end of the 1970’s and has been operating continuously for over 30 years. Six repowering options are studied, focusing the increase of the installed capacity and thermal efficiency on the baseline case. Numerical simulations the seven thermal power plants are evaluated as follows: A. Modified Rankine cycle (73 MWe) with superheating and regeneration, one conventional boiler burning fuel oil and one old steam turbine. B. Fully-fired combined cycle (240 MWe) with two gas turbines burning natural gas, one recuperative boiler and one old steam turbine. C. Fully-fired combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. D. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. The gas turbine has water injection in the combustion chamber. E. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners and one old steam turbine. The gas turbine has steam injection in the combustion chamber. F. Hybrid combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners, one old steam boiler burning natural gas and one old steam turbine. G. Hybrid combined cycle (235 MWe) with one gas turbine burning diesel fuel, one recuperative boiler with supplementary burners, one old steam boiler burning fuel oil and one old steam turbine. All the repowering models show higher efficiency when compared with the Rankine cycle [2, 5]. The thermal cycle efficiency is improved from 28% to 50%. The generated electricity costs are reduced to about 50% when the old power plant is converted to a combined cycle one. When a Rankine cycle power plant burning fuel oil is modified to combined cycle burning natural gas, the CO2 specific emissions by kWh are reduced by about 40%. It is concluded that upgrading older thermal power plants is often a cost-effective method for increasing the power output, improving efficiency and reducing emissions [2, 7].


Author(s):  
T. Mita ◽  
N. Ando ◽  
A. Kawauchi ◽  
K. Morikawa

A fully-fired combined cycle power plant (FFCCPP) combines a steam thermal power plant with a gas turbine. Hot exhaust gases fed from the gas turbine are used as combustion air for the boiler, thus increasing total plant output and efficiency. An unusually hot spell in Japan in the summer of 1990 brought about such a rapid surge in power demand for air conditioning so that all electric power companies registered record highs in consumption. This promoted Chubu Electric Power Co. to decide to add a 154-MW gas turbine to each of its six existing steam thermal power plants (four 700-MW and two 375-MW units), thus repowering their system into an FFCCPP. Construction work began in 1992. In September, 1994, two 700-MW steam thermal power plants (Chita Thermal Power Plant’s No. 6 unit and Chita Second Thermal Power Plant’s No. 1 unit) were modified into FFCCPPs, which then began operating in a trouble-free manner. This paper reports the characteristics and test-run results of the above two plants, which have been operating in good condition as the largest-capacity FFCCPPs in the world.


Author(s):  
R. Tuccillo ◽  
G. Fontana ◽  
E. Jannelli

In this paper, a general analysis of combined gas-steam cycles for power plants firing with both hydrocarbons and coal derived gas is reported. The purpose of this paper is to study the influence on power plants performance of different kind of fuels and to evaluate the most significant parameters of both gas and combined cycle. Results are presented for plant overall efficiency and net specific work, steam to gas mass flow ratio, dimensionless gas turbine specific speed and diameter, CO2 emissions etc., as functions of gas cycle pressure ratio and of the combustion temperature. Furthermore, for an existing power plant with a 120 MW gas turbine, the authors try to establish in which measure the combined cycle characteristic parameters, the gas turbine operating conditions, and the heat recovery steam generator efficiency, are modified by using synthetic fuels of different composition and calorific value. The influence is also analyzed either of bottoming steam cycle saturation pressure or — in a dual pressure steam cycle — of dimensionless fraction of steam mass flow in high pressure stream. The acquired results seem to constitute useful information on the criteria for the optimal design of a new integrated coal gasification combined cycle (IGCC) power plant.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5848
Author(s):  
Guzel Mingaleeva ◽  
Olga Afanaseva ◽  
Duc Toan Nguen ◽  
Dang Nayt Pham ◽  
Pietro Zunino

The article describes a method of integrating small distributed generation components in the power system of the Republic of Vietnam. The features of the energy system of Vietnam and the technologies used for mini thermal power plants are considered. The classification of small distributed generation components is presented with implantation of the most used resources of Vietnam—fossil and renewable. A generalized methodology for selection and calculation of technological schemes for mini thermal power plants is considered. The schemes of steam-turbine mini thermal power plants operating with coal and gas-turbine mini thermal power plants with solar air heaters are selected. Based on the calculation of the selected mini thermal power plant schemes, their distribution in the territory of the Republic of Vietnam has been obtained. The thermoeconomic efficiency has been chosen as the criterion for the best option for placing mini thermal power plants; its value for the proposed option is of 6.77%.


Author(s):  
Alcides Codeceira Neto ◽  
Pericles Pilidis ◽  
Anestis I. Kalfas

The Performance assessment of power plants involves a large number of equations with many variables taking part in the whole calculation. The assessment method described here takes into account a process for optimising a conventional gas turbine combined cycle power plant from the point of view of power plant performance calculations and economic analysis. The process requires optimisation of the whole thermal power plant based on cost considerations. The performance assessment of power plants uses the exergy method and considers the overall plant exergetic efficiency and the exergy destruction in the various components of the plant. The exergy method highlights irreversibility within plant components, and it is of particular interest in this investigation. Generally, the optimisation procedure to determine an optimal solution for a problem considers constraints imposed to some variables and requires the use of an optimisation technique. This paper is precisely concerned with the use of Genetic Algorithms (GAs) as a recommended tool for applying the optimisation process of the whole power plant based on minimising costs of products. Genetic Algorithms (GAs) are adaptive methods which may be used to solve search and optimisation problems. They are based on the genetic processes of biological organisms and do not require complicated mathematical calculations like the evaluation of derivatives necessary to be considered in conventional optimisation techniques.


Author(s):  
Toru Takahashi ◽  
Eiichi Koda ◽  
Yoshinobu Nakao

Recently, it is more necessary to maintain or improve the thermal efficiency of actual thermal power plants to reduce CO2 emission and energy consumption in the world, and it is also important to reduce the maintenance cost of commercial thermal power plants. Thus, it is crucial to investigate power plant performance deterioration factors and solve problems related to these factors promptly when the thermal efficiency decreases. However, it is difficult to understand the internal state of power plants sufficiently and to determine power plant performance deterioration factors only from operation data because actual thermal plants are composed of many components and are very complex systems. In particular, it is more difficult to understand performance deterioration in gas turbine combined cycle (GTCC) power plants than in steam power plants because the performance changes markedly in GTCC power plants depending on atmospheric conditions (temperature, pressure, humidity). In other words, when thermal efficiency changes, it is difficult to determine whether the cause is the change in external factors or that in the performance of the component. Therefore, we develop a method based on heat balance analysis to calculate the immeasurable quantity of state and the efficiency of each component in GTCC power plants, and to correct the performance of each component in a plant to a standard state using the performance function obtained from long-term operation data. Through the method, the analysis of the effects of deterioration factors on thermal efficiency becomes possible, and the performance of a plant can be simulated when the operation conditions are changed. Thus, we can determine the main factor that affects thermal efficiency using our method.


Author(s):  
A. Z. Abass ◽  
D. A. Pavlyuchenko ◽  
A. M. Balabanov ◽  
V. M. Less

At high ambient temperatures, the performance of gas turbine power plants drops significantly. Technical solutions of compensation for losses associated with the constant injection of water into the air intake of a gas turbine. This approach is not acceptable in regions with limited fresh water reserves. Radical solutions are required to reduce the cost of generated energy. Integrated Combined Solar Cycle (ISCCS) technology has proven itself on many projects. The addition of a combined cycle gas cycle with solar energy can significantly increase the overall efficiency of the power plant. Despite the increase in costs during the construction of its solar part, the total cost of operating solar collectors is several times less than a turbine installation. Given the global trend to fight carbon emissions, switching to a hybrid scheme is economically attractive. Trading in carbon credits for CO2 emissions will significantly reduce the payback period for the construction of gas turbine modernization under the ISCCS scheme. This paper presents an option to modernize a gas turbine power plant in the city of Basra (Iraq), using the advantages of solar radiation and recycling of combustion products from gas turbines. It is proposed to equip the existing 200 MW gas turbine plant with two steam turbine units with a capacity of 75 and 65 MW, working in conjunction with solar collectors producing low pressure water vapor. Due to modernization, the efficiency of the power plant should increase from 38% to 55%. The revision of the schematic and technical solutions of Iraq power plants will allow producing sufficient energy for the region.


Author(s):  
Alberto Vannoni ◽  
Andrea Giugno ◽  
Alessandro Sorce

Abstract Renewable energy penetration is growing, due to the target of greenhouse-gas-emission reduction, even though fossil fuel-based technologies are still necessary in the current energy market scenario to provide reliable back-up power to stabilize the grid. Nevertheless, currently, an investment in such a kind of power plant might not be profitable enough, since some energy policies have led to a general decrease of both the average price of electricity and its variability; moreover, in several countries negative prices are reached on some sunny or windy days. Within this context, Combined Heat and Power systems appear not just as a fuel-efficient way to fulfill local thermal demand, but also as a sustainable way to maintain installed capacity able to support electricity grid reliability. Innovative solutions to increase both the efficiency and flexibility of those power plants, as well as careful evaluations of the economic context, are essential to ensure the sustainability of the economic investment in a fast-paced changing energy field. This study aims to evaluate the economic viability and environmental impact of an integrated solution of a cogenerative combined cycle gas turbine power plant with a flue gas condensing heat pump. Considering capital expenditure, heat demand, electricity price and its fluctuations during the whole system life, the sustainability of the investment is evaluated taking into account the uncertainties of economic scenarios and benchmarked against the integration of a cogenerative combined cycle gas turbine power plant with a Heat-Only Boiler.


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