Impact of Operating Regime on Economic Performamnce of Combined Cycle Power Plants

2005 ◽  
Author(s):  
Mircea Fetescu
Keyword(s):  
Economic Performance ◽  
Capital Investment ◽  
Power Plants ◽  
Operating Regime ◽  
Combined Cycle ◽  
Economic Feasibility ◽  
Start Up ◽  
Wide Range ◽  
The Impact ◽  
Base Load

It is accepted that CCPP has the highest fuel conversion efficiency among fossil fuel fired generation technologies. The extensive installed base of CCPP worldwide is justified by additional advantages: low capital investment, short construction time, low environmental impact and high operating flexibility. The operating flexibility, with fast loading and deloading and short start-up and shutdown durations, allows CCPPs to fulfill a wide range of operating duties, such cycling, intermediate load to base load, grid frequency or voltage control and part load operation; mostly on a competitively generated cost basis. The traditional approach to CCPP development is to design an optimised plant, taking into consideration the technical and economic boundary conditions of a specific project. This includes assumptions for operating regime: base load, intermediate load or cycling with daily start-up and shutdown. In a deregulated environment, plants are dispatched on merit. The assumptions related to operating regime and used for optimising the configuration of a particular CCPP, often deviate significantly during commercial operation. The objective of this work is to evaluate the impact of the operating regime on CCPP economic performance. During the economic feasibility evaluation of a power project it is frequently considered that the main factors affecting the electricity generation cost, are capital cost and fuel cost. As far as the operating regime is concerned, a number for yearly operating hours is then assumed and eventually sensitivity is considered. The content of this work is an investigation on how the capital, fuel and O&M costs, components of the generation costs, are affected by the utilisation factor, by operating modes and loads, frequency and duration of start-up and shudown [s&s] of the plant. The conclusion of the paper is that both, operating regime and operating procedure have an important impact on economic performance of combined cycle plants. Annual operating hours and the number of s&s influence the factors which contribute to the profitability and competitiveness of the plant, such as EOH, availability, performance degradation, O&M costs and directly the average plant output and efficiency. Finally the economic performance of combined cycle plants can be significantly improved by re-visiting the conceptual design and the operating concept.

Gas Turbine Technology and Cycle Selection for Combined Cycle Power Plants: Decision Criteria, Economic Aspects and Risk Mitigation

2003 ◽  
Author(s):  
Mircea Fetescu
Keyword(s):  
Gas Turbine ◽  
Economic Performance ◽  
Capital Investment ◽  
Power Plants ◽  
Risk Mitigation ◽  
Risk Identification ◽  
Combined Cycle ◽  
Special Focus ◽  
Decision Criteria ◽  
Utilization Factor

Gas Turbine technology and cycle selection have a major impact on the economic performance of Combined Cycle Power Plants projects. The main objective of this paper is to investigate decision criteria and their relative importance in the selection of gas turbine technology and cycle configuration. Relevant factors influencing the choice of technology are investigated and their impacts on the economic performance of the Combined Cycle Power Plant are quantified. Sensitivities on relevant parameters are provided. Due to the fact that uncertainties and risks associated with the Combined Cycle Power Plants are major decision criteria, special focus has been placed on risk identification and quantification as well as recommendation for their mitigation. The conclusion of the investigation is that besides the overall accepted and commonly used criteria such as fuel efficiency and specific capital investment, there are other important contributors to the economic performance of a Combined Cycle Plant. The most important are operating and maintenance costs, availability factor, performance degradation and operating mode (utilization factor, load profile, start-up and shutdown frequency).

High Steam Turbine Operating Flexibility Coupled With Service Interval Optimization

2003 ◽  
Author(s):  
Artur Ulbrich ◽  
Edwin Gobrecht ◽  
Michael R. Siegel ◽  
Erich Schmid ◽  
Pamela K. Armitage
Keyword(s):  
Steam Turbine ◽  
Service Time ◽  
Power Plants ◽  
Economic Calculation ◽  
Stress Monitoring ◽  
Time Consumption ◽  
Start Up ◽  
Fast Start ◽  
The Impact ◽  
Base Load

Historically steam turbine operations were designed for a market that was typically either base load or intermediate duty load operation. The optimal steam turbine start-up profile was established using the maximum allowable component stress and therefore optimizing service time consumption. Over the last few years, the market requirements have changed significantly. The market requires plant start-up flexibility with the ability to accurately predict start-up time, and reliably meet the start-up time. Applying the historical steam turbine start-up philosophy either limits the operating flexibility of the plant or exceeds steam turbine allowable stresses increasing service time consumption. Innovative concepts are being presented on how steam turbines can achieve reduced start-up times while minimizing service time consumption thereby improving availability. These concepts allow the customer to be able to accurately predict start-up times and reliably meet the dispatch bid. Therefore, an economic calculation may be performed to determine the most effective start-up mode. This economic calculation will evaluate the impact to service life (inspection and test intervals) versus the benefits of power generation. The new concepts provide one solution for base load, intermediate duty load operation, and plants requiring fast start up capability. The new market needs for flexible operation including fast start-up times require plant operability enhancements [1]. Some of the operability enhancements that can be implemented include: • steam turbine stress controller and stress monitoring systems which allow a selection of the start-up mode determining the start-up time, thermal stress and service time consumption; • high level of plant automation; • plant systems designed to provide steam conditions necessary for selected start-up mode. The benefit of these solutions will be presented by means of examples from recently modified power plants. It is possible to achieve a significant improvement in the plant operation and start-up with low costs.

Operational Flexibility of GE’s F-Class Gas Turbines With the DLN2.6+ Combustion System

2018 ◽  
Author(s):  
William D. York ◽  
Derrick W. Simons ◽  
Yongqiang Fu
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Combustion System ◽  
Operational Flexibility ◽  
Start Up ◽  
Wide Range ◽  
Combined Cycle Plant ◽  
Base Load

F-class gas turbines comprise a major part of the heavy-duty gas turbine power generation fleet worldwide, despite increasing penetration of H/J class turbines. F-class gas turbines see a wide range of applications, including simple cycle peaking operation, base load combined cycle, demand following in simple or combined cycle, and cogeneration. Because of the different applications, local power market dynamics, and varied emissions regulations by region or jurisdiction, there is a need for operational flexibility of the gas turbine and the combustion system. In 2015, GE introduced a DLN2.6+ combustion system for new and existing 7F gas turbines. Approximately 50 are now in operation on 7F.04 and 7F.05 turbines, combining for nearly 150,000 fired hours. The system has been demonstrated to deliver 5 ppm NOx emissions @ 15% O2, and it exhibits a wide window of operation without significant thermoacoustic instabilities, owing the capability to premixed pilot flames on the main swirl fuel-air premixers, low system residence time, and air path improvements. Based on the success on the 7F, this combustion system is being applied to the 6F.03 in 2018. This paper highlights the flexibility of the 7F and 6F.03 DLN2.6+ combustion system and the enabling technology features. The advanced OpFlex* AutoTune control system tightly controls NOx emissions, adjusts fuel splits to stay clear of instabilities, and gives operators the ability to prioritize emissions or peak load output. Because of the low-NOx capability of the system, it is often being pushed to higher combustor exit temperatures, 35°C or more above the original target. The gas turbine is still meeting 9 or 15 ppm NOx emissions while delivering nearly 12% additional output in some cases. Single-can rig test and engine field test results show a relatively gentle NOx increase over the large range of combustor exit temperature because of the careful control of the premixed pilot fuel split. The four fuel legs are staged in several modes during startup and shutdown to provide robust operation with fast loading capability and low starting emissions, which are shown with engine data. The performance of a turndown-only fueling mode is highlighted with engine measurements of CO at low load. In this mode, the center premixer is not fueled, trading the NOx headroom for a CO emissions benefit that improves turndown. The combustion system has also demonstrated wide-Wobbe capability in emissions compliance. 7F.04 engine NOx and dynamics data are presented with the target heated gas fuel and also with cold fuel, producing a 24% increase in Modified Wobbe Index. The ability to run unheated fuel at base load may reduce the start-up time for a combined cycle plant. Lastly, there is a discussion of a new OpFlex* Variable Load Path digital solution in development that will allow operators to customize the start-up of a combined cycle plant.

The Effect of Alternative Turbine Cooling Schemes on the Performance of Utility Gas Turbine Powerplants

1982 ◽  
Author(s):  
Arthur Cohn ◽  
Mark Waters
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Power Plants ◽  
Heat Rate ◽  
Combined Cycle ◽  
Specific Power ◽  
Cooling Effectiveness ◽  
Turbine Cooling ◽  
The Impact ◽  
Systems Studies

It is important that the requirements and cycle penalties related to the cooling of high temperature turbines be thoroughly understood and accurately factored into cycle analyses and power plant systems studies. Various methods used for the cooling of high temperature gas turbines are considered and cooling effectiveness curves established for each. These methods include convection, film and transpiration cooling using compressor bleed and/or discharge air. In addition, the effects of chilling the compressor discharge cooling gas are considered. Performance is developed to demonstrate the impact of the turbine cooling schemes on the heat rate and specific power of Combined–Cycle power plants.

System Integration and Techno-Economy Analysis of the IGCC Plant With CO2 Capture: Results of the EU H2-IGCC Project

2015 ◽  
Author(s):  
Mohammad Mansouri Majoumerd ◽  
Mohsen Assadi ◽  
Peter Breuhaus ◽  
Øystein Arild
Keyword(s):  
Co2 Capture ◽  
Capital Investment ◽  
Power Plants ◽  
System Analysis ◽  
Combined Cycle ◽  
Economic Evaluations ◽  
Extensive Literature ◽  
Capital Costs ◽  
Cost Of Electricity ◽  
Plant Components

The overall goal of the European co-financed H2-IGCC project was to provide and demonstrate technical solutions for highly efficient and reliable gas turbine technology in the next generation of integrated gasification combined cycle (IGCC) power plants with CO2 capture suitable for combusting undiluted H2-rich syngas. This paper aims at providing an overview of the main activities performed in the system analysis working group of the H2-IGCC project. These activities included the modeling and integration of different plant components to establish a baseline IGCC configuration, adjustments and modifications of the baseline configuration to reach the selected IGCC configuration, performance analysis of the selected plant, performing techno-economic assessments and finally benchmarking with competing fossil-based power technologies. In this regard, an extensive literature survey was performed, validated models (components and sub-systems) were used, and inputs from industrial partners were incorporated into the models. Accordingly, different plant components have been integrated considering the practical operation of the plant. Moreover, realistic assumptions have been made to reach realistic techno-economic evaluations. The presented results show that the efficiency of the IGCC plant with CO2 capture is 35.7% (lower heating value basis). The results also confirm that the efficiency is reduced by 11.3 percentage points due to the deployment of CO2 capture in the IGCC plant. The specific capital costs for the IGCC plant with capture are estimated to be 2,901 €/(kW net) and the cost of electricity for such a plant is 90 €/MWh. It is also shown that the natural gas combined cycle without CO2 capture requires the lowest capital investment, while the lowest cost of electricity is related to IGCC plant without CO2 capture.

Diagnosis of the Operation of Power Plants

2007 ◽  
Author(s):  
Jose´ Miguel Gonza´lez-Santalo´ ◽  
Abigail Gonza´lez-Di´az ◽  
Carlos Alberto Marin˜o-Lo´pez
Keyword(s):  
Power Plants ◽  
Environmental Changes ◽  
Environmental Parameters ◽  
Combined Cycle ◽  
Characteristic Parameters ◽  
Operating Variables ◽  
Design Values ◽  
The Individual ◽  
The Impact

A system was developed to diagnose the operation of combined cycle power plants and to determine, when deviations are found, which components are causing the deviations and the impact of each component deviation. The system works by comparing the values of the actual operating variables with some reference values that are calculated by a model that was adjusted to the design heat balances. The model can use the actual values of the environmental parameters as well as the design values, so the effect of environmental changes can be quantified and separated. The determination of the individual equipment impacts is done by adjusting the equipment parameters in order to reproduce the values of the measured variables. The adjustment is done by varying the values of the characteristic parameters of the equipment in order to minimize the sum of the squares of the differences between the values of the measured variables and the calculated values from the model.

Risk-Based Assessment of Unplanned Outage Events and Costs for Combined-Cycle-Plants

2012 ◽  
Author(s):  
Dale Grace ◽  
Thomas Christiansen
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Cash Flow ◽  
Gas Turbines ◽  
Operational Reliability ◽  
Combined Cycle ◽  
Maintenance Costs ◽  
Wide Range ◽  
Turbine Equipment ◽  
The Impact

Unexpected outages and maintenance costs reduce plant availability and can consume significant resources to restore the unit to service. Although companies may have the means to estimate cash flow requirements for scheduled maintenance and on-going operations, estimates for unplanned maintenance and its impact on revenue are more difficult to quantify, and a large fleet is needed for accurate assessment of its variability. This paper describes a study that surveyed 388 combined-cycle plants based on 164 D/E-class and 224 F-class gas turbines, for the time period of 1995 to 2009. Strategic Power Systems, Inc. (SPS®), manager of the Operational Reliability Analysis Program (ORAP®), identified the causes and durations of forced outages and unscheduled maintenance and established overall reliability and availability profiles for each class of plant in 3 five-year time periods. This study of over 3,000 unit-years of data from 50 Hz and 60 Hz combined-cycle plants provides insight into the types of events having the largest impact on unplanned outage time and cost, as well as the risks of lost revenue and unplanned maintenance costs which affect plant profitability. Outage events were assigned to one of three subsystems: the gas turbine equipment, heat recovery steam generator (HRSG) equipment, or steam turbine equipment, according to the Electric Power Research Institute’s Equipment Breakdown Structure (EBS). Costs to restore the unit to service for each main outage cause were estimated, as were net revenues lost due to unplanned outages. A statistical approach to estimated costs and lost revenues provides a risk-based means to quantify the impact of unplanned events on plant cash flow as a function of class of gas turbine, plant subsystem, and historical timeframe. This statistical estimate of the costs of unplanned outage events provides the risk-based assessment needed to define the range of probable costs of unplanned events. Results presented in this paper demonstrate that non-fuel operation and maintenance costs are increased by roughly 8% in a typical combined-cycle power plant due to unplanned maintenance events, but that a wide range of costs can occur in any single year.

Modeless Start-Up Control for Operational Flexibility of Combined Cycle Power Plants

2020 ◽  
Vol 53 (10) ◽  
pp. 636-645
Author(s):  
Yasuhiro Yoshida ◽  
Yuya Tokuda ◽  
Takuya Yoshida ◽  
Yuki Enomoto ◽  
Nobuhiro Osaki ◽  
...  
Keyword(s):  
Power Plants ◽  
Combined Cycle ◽  
Operational Flexibility ◽  
Start Up

Coordinated Control of Gas and Steam Turbines for Efficient Fast Start-Up of Combined Cycle Power Plants

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Yasuhiro Yoshida ◽  
Kazunori Yamanaka ◽  
Atsushi Yamashita ◽  
Norihiro Iyanaga ◽  
Takuya Yoshida
Keyword(s):  
Thermal Stress ◽  
Steam Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Stresses ◽  
Control Method ◽  
Coordinated Control ◽  
Combined Cycle ◽  
Steam Turbines ◽  
Start Up

In the fast start-up for combined cycle power plants (CCPP), the thermal stresses of the steam turbine rotor are generally controlled by the steam temperatures or flow rates by using gas turbines (GTs), steam turbines, and desuperheaters to avoid exceeding the thermal stress limits. However, this thermal stress sensitivity to steam temperatures and flow rates depends on the start-up sequence due to the relatively large time constants of the heat transfer response in the plant components. In this paper, a coordinated control method of gas turbines and steam turbine is proposed for thermal stress control, which takes into account the large time constants of the heat transfer response. The start-up processes are simulated in order to assess the effect of the coordinated control method. The simulation results of the plant start-ups after several different cool-down times show that the thermal stresses are stably controlled without exceeding the limits. In addition, the steam turbine start-up times are reduced by 22–28% compared with those of the cases where only steam turbine control is applied.

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