Étude on Gas Turbine Combined Cycle Power Plant—Next 20 Years

Author(s):  
S. Can Gülen

In 1992, United States Department of Energy's (DOE) Advanced Turbine Systems (ATS) program established a target of 60% efficiency for utility scale gas turbine (GT) power plants to be achieved by the year 2000. Although the program led to numerous technology breakthroughs, it took another decade for an actual combined cycle (CC) power plant with an H class GT to reach (and surpass) the target efficiency. Today, another target benchmark, 65% efficiency, circulates frequently in trade publications and engineering journals with scant support from existing technology, its development path as well as material limits, and almost no regard to theoretical (e.g., underlying physics) and practical (e.g., cost, complexity, reliability, and constructability) concerns. This paper attempts to put such claims to test and establish the room left for gas turbine combined cycle (GTCC) growth in the next two decades. The analysis and conclusions are firmly based on fundamental thermodynamic principles with carefully and precisely laid out assumptions and supported by rigorous calculations. The goal is to arm the practicing engineer with a consistent, coherent, and self-standing reference to critically evaluate claims, predictions, and other futuristic information pertaining to GTCC technology.

Author(s):  
S. Can Gülen

In 1992, United States Department of Energy’s Advanced Turbine Systems program established a target of 60% efficiency for utility scale gas turbine power plants to be achieved by the year 2000. Although the program led to numerous technology breakthroughs, it took another decade for an actual combined cycle power plant with an H class gas turbine to reach (and surpass) the target efficiency. Today, another target benchmark, 65% efficiency, circulates frequently in trade publications and engineering journals with scant support from existing technology, its development path as well as material limits, and almost no regard to theoretical (e.g., underlying physics) and practical (e.g., cost, complexity, reliability and constructability) concerns. This paper attempts to put such claims to test and establish the room left for gas turbine combined cycle (GTCC) growth in the next two decades. The analysis and conclusions are firmly based on fundamental thermodynamic principles with carefully and precisely laid out assumptions and supported by rigorous calculations. The goal is to arm the practicing engineer with a consistent, coherent and self-standing reference to critically evaluate claims, predictions and other futuristic information pertaining to GTCC technology.


Author(s):  
Axel W. von Rappard ◽  
Salvatore Della Villa

The contribution of the gas turbine in simple and combined cycle systems to power production in the United States has been steadily rising over the past 25 years. In 1998 their contribution to power production was approximately 15% and it increased over the past 5 years by 1.5 to 2%, annually. In parallel, the United States Department of Energy (DOE) has financially supported Advanced Technology development with good formulated goals for overall performance of plants including reliability, availability and maintainability (RAM). In this paper the authors evaluate RAM performance data from power plants over the past five years. This evaluation can be used as baseline or benchmark for further improvements. It takes into account the mode of operation being base load, cycling or peaking application and analyses the power plant on a year-by-year evaluation. All RAM-data came from the same source and are collected and analyzed according to standardized procedures. Availability will be reviewed for machines of different sizes and technologies. Maintainability will be analyzed as function of the size of units, energy production, and the mode of operation. Gas turbine simple and combined cycle power plants have been operated in peaking, cycling, base and continuous load operation. The flexibility is shown in different “Service Hours per Successful Start” and a correlation with the RAM parameters. To analyze and explain these differences will be the main result of this evaluation. The contribution shall help to evaluate the best solution for individual sites because efficiency and availability cannot always be increased in parallel.


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.


2010 ◽  
Vol 132 (12) ◽  
pp. 57-57
Author(s):  
Lee S. Langston

This article presents an overview of gas turbine combined cycle (CCGT) power plants. Modern CCGT power plants are producing electric power as high as half a gigawatt with thermal efficiencies approaching the 60% mark. In a CCGT power plant, the gas turbine is the key player, driving an electrical generator. Heat from the hot gas turbine exhaust is recovered in a heat recovery steam generator, to generate steam, which drives a steam turbine to generate more electrical power. Thus, it is a combined power plant burning one unit of fuel to supply two sources of electrical power. Most of these CCGT plants burn natural gas, which has the lowest carbon content of any other hydrocarbon fuel. Their near 60% thermal efficiencies lower fuel costs by almost half compared to other gas-fired power plants. Their installed capital cost is the lowest in the electric power industry. Moreover, environmental permits, necessary for new plant construction, are much easier to obtain for CCGT power plants.


Author(s):  
Gerhard Bohrenkämper ◽  
Herbert Bals ◽  
Ursel Wrede ◽  
René Umlauft

Gas turbine and combined cycle power plants are typically designed for a service life of over 30 years. If operated at base load in continuous duty, the gas turbine hot-gas-path components for example in a combined-cycle power plant need repair and replacement according to the maintenance program several times during plant life. Most of the hot components would reach the end of their service life, e.g. 100,000 equivalent operating hours (EOH), after 10 to 12 years. As this is well before the end of the overall plant service life defined in the power plant concept, such plant applications therefore necessitate life extension measures enabling to continuing operation beyond 100,000 EOH. This paper presents strategic options for hot-gas-path component life entension.


2020 ◽  
Vol 5 (12) ◽  
pp. 39-45
Author(s):  
Basharat Salim ◽  
Jamal Orfi ◽  
Shaker Saeed Alaqel

The proper utilization of all the available forms of energy resources has become imminent to meet the power requirement and energy demand in both the developed and developing countries of the world. Even though the emphasis is given to the renewable resources in most parts of the world, but fossil fuels will still remain the main resources of energy as these can meet both normal and peak demands. Saudi Arab has number of power plant based on natural gas and fuel that are spread in all its regions. These power plants have aeroderivative gas turbine units supplied by General Electric Company as main power producing units. These units work on dual fuel systems. These units work as simple gas turbine units to meat peak demands and as part of combined cycle otherwise. The subject matter of this study is the performance of one of the units of a power plant situated near Riyadh city of Saudi Arab. This unit also works both as simple gas turbine unit and as a part of combined cycle power plant unit. A parametric based performance evaluation of the unit has been carried out to study both energetic and exergetic performance of the unit for both simple and combined cycle operation. Effect of compressor inlet temperature, turbine inlet temperature, pressure ratio of the compressor, the stage from which bleed off air have been taken and percentage of bleed off air from the compressor on the energetic and exergetic performance of the unit have been studied. The study reveals that all these parameters effect the performance of the unit in both modes of operation.


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].


2000 ◽  
Author(s):  
Duck-Jin Kim ◽  
Hyun-Soo Lee ◽  
Ho-Young Kwak ◽  
Jae-Ho Hong

Abstract Exegetic and thermoeconomic analysis were performed for a 500-MW combined cycle plant and a 137-MW steam power plant without decomposition of exergy into thermal and mechanical exergy. A unit cost was assigned to a specific exergy stream of matter, regardless of its condition or state in this analysis. The calculated costs of electricity were almost same within 0.5% as those obtained by the thermoeconomic analysis with decomposition of the exergy stream for the combined cycle plant, which produces the same kind of product. Such outcome indicated that the level at which the cost balances are formulated does not affect the result of thermoeconomic analysis, that is somewhat contradictory to that concluded previously. However this is true for the gas-turbine cogeneration plant which produces different kinds of products, electricity and steam whose unit costs are dominantly affected by the mechanical and thermal exergy respectively.


2021 ◽  
Vol 143 (4) ◽  
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 single national price of electricity (PUN) and its variability; moreover, in several countries, negative prices are reached on some sunny or windy days. Within this context, combined heat and power (CHP) 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 (HOB).


Author(s):  
S. Can Gülen ◽  
Indrajit Mazumder

Cost of electricity (COE) is the most widely used metric to quantify the cost-performance trade-off involved in comparative analysis of competing electric power generation technologies. Unfortunately, the currently accepted formulation of COE is only applicable to comparisons of power plant options with the same annual electric generation (kilowatt-hours) and the same technology as defined by reliability, availability, and operability. Such a formulation does not introduce a big error into the COE analysis when the objective is simply to compare two or more base-loaded power plants of the same technology (e.g., natural gas fired gas turbine simple or combined cycle, coal fired conventional boiler steam turbine, etc.) and the same (or nearly the same) capacity. However, comparing even the same technology class power plants, especially highly flexible advanced gas turbine combined cycle units with cyclic duties, comprising a high number of daily starts and stops in addition to emissions-compliant low-load operation to accommodate the intermittent and uncertain load regimes of renewable power generation (mainly wind and solar) requires a significant overhaul of the basic COE formula. This paper develops an expanded COE formulation by incorporating crucial power plant operability and maintainability characteristics such as reliability, unrecoverable degradation, and maintenance factors as well as emissions into the mix. The core impact of duty cycle on the plant performance is handled via effective output and efficiency utilizing basic performance correction curves. The impact of plant start and load ramps on the effective performance parameters is included. Differences in reliability and total annual energy generation are handled via energy and capacity replacement terms. The resulting expanded formula, while rigorous in development and content, is still simple enough for most feasibility study type of applications. Sample calculations clearly reveal that inclusion (or omission) of one or more of these factors in the COE evaluation, however, can dramatically swing the answer from one extreme to the other in some cases.


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