A Toolbox of Hardware and Digital Solutions for Increased Flexibility

2020 ◽  
Author(s):  
Nicolas Demougeot ◽  
Alexander Steinbrenner ◽  
Alfredo Cires ◽  
Marc Paskin
Keyword(s):  
Power Generation ◽  
Combined Cycle ◽  
Operational Flexibility ◽  
Load Range ◽  
Power Sources ◽  
Renewable Power ◽  
Start Up ◽  
Operating Load ◽  
Technical Issues ◽  
Cavity Cooling

Abstract The power generation market has been changing rapidly with the injection of an ever increasing usage of renewable power sources. The cyclic and highly unpredictable nature of power generation output from renewable sources is forcing Gas Turbine (GT) operators to significantly increase the operational flexibility of their engines. While the industry has been, for many years, developing and fielding solutions providing increased output at the high end of the operating range, the focus has shifted recently to solutions allowing for a safe decrease of the engines’ minimum operating load. The AutoTune (AT) system was introduced at last year’s Turbo Expo conference [5], and the challenges of developing a safe Extended Turndown add-on are detailed herein. Other digital and hardware solutions presented include Part Load Performance, decreased start-up time for both simple and combined cycle units, disc cavity cooling modulation and Exhaust Bleed. Increased ramp rate is addressed with the associated significant difficulty of maintaining the mechanical integrity of the rotors and casings. PSM has been working on a toolbox of both hardware and digital solutions to increase on GT operability both on the high and low ends of the load range and the technical issues faced are described in this paper.

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

scholarly journals Modelling energy systems of Vietnam with integration of renewable power sources

2019 ◽  
Author(s):  
A.V. Edelev ◽  
D.N. Karamov ◽  
I.A. Sidorov ◽  
D.V. Binh ◽  
N.H. Nam ◽  
...  
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Markov Decision Process ◽  
Decision Process ◽  
Large Scale ◽  
Energy Systems ◽  
Stochastic Search ◽  
Power Sources ◽  
Renewable Power ◽  
Markov Decision

The paper addresses the research of the large-scale penetration of renewable energy into the power system of Vietnam. The proposed approach presents the optimization of operational decisions in different power generation technologies as a Markov decision process. It uses a stochastic base model that optimizes a deterministic lookahead model. The first model applies the stochastic search to optimize the operation of power sources. The second model captures hourly variations of renewable energy over a year. The approach helps to find the optimal generation configuration under different market conditions.

scholarly journals The Simulation Study of a Restructured Residential Low-Voltage Distribution System Microgrid

2016 ◽  
Vol 13 (2) ◽  
pp. 103
Author(s):  
L. Ramesh ◽  
Umamageswari Umamageswari
Keyword(s):  
Power Generation ◽  
Distribution System ◽  
Tamil Nadu ◽  
Low Voltage ◽  
Voltage Distribution ◽  
Distributed Energy ◽  
Power Sources ◽  
Electricity Grid ◽  
Renewable Power ◽  
Near Future

A primary and necessary focus in creating a greener environment is the conversion of existing power-generation sources to renewable power sources in the near future. Another important focus is to develop sustainable household power generation to a low-voltage electricity grid with a power purchase and selling facility. To help with achieving the above vision, the objective of this work is to critically analyze the existing low-voltage distribution system and make suggestions for restructuring it to the low-voltage interconnected microgrid (MG). The test was carried out in the Tamil Nadu Electricity Board (TNEB) 100kVA transformer feeder which was connected to supply around 100 houses with electricity. The performance analysis of the proposed system was examined through different case studies, represented as a normal operating condition of the existing distribution system and a reconstructed and interconnected MG to the TNEB grid. The project was designed and analyzed using PSCAD software. The results discussed in the project are helpful in examining the effects of multiple distributed energy resources on distributed generation. In future, knowledge of these effects may be helpful for rural area electrification. 

An Expanded Cost of Electricity Model for Highly Flexible Power Plants

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
S. Can Gülen ◽  
Indrajit Mazumder
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Plant Performance ◽  
Cost Of Electricity ◽  
Renewable Power ◽  
Effective Performance ◽  
The Impact

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.

Flexible Combined Cycle Gas Turbine Power Plant Utilising Organic Rankine Cycle Technology

2016 ◽  
Author(s):  
Michael Welch ◽  
Nicola Rossetti
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Operational Flexibility

Historically gas turbine power plants have become more efficient and reduced the installed cost/MW by developing larger gas turbines and installing them in combined cycle configuration with a steam turbine. These large gas turbines have been designed to maintain high exhaust gas temperatures to maximise the power generation from the steam turbine and achieve the highest overall electrical efficiencies possible. However, in today’s electricity market, with more emphasis on decentralised power generation, especially in emerging nations, and increasing penetration of intermittent renewable power generation, this solution may not be flexible enough to meet operator demands. An alternative solution to using one or two large gas turbines in a large central combined cycle power plant is to design and install multiple smaller decentralised power plant, based on multiple gas turbines with individual outputs below 100MW, to provide the operational flexibility required and enable this smaller power plant to maintain a high efficiency and low emissions profile over a wide load range. This option helps maintain security of power supplies, as well as providing enhanced operational flexibility through the ability to turn turbines on and off as necessary to match the load demand. The smaller gas turbines though tend not to have been optimised for combined cycle operation, and their exhaust gas temperatures may not be sufficiently high, especially under part load conditions, to generate steam at the conditions needed to achieve a high overall electrical efficiency. ORC technology, thanks to the use of specific organic working fluids, permits efficient exploitation of low temperatures exhaust gas streams, as could be the case for smaller gas turbines, especially when working on poor quality fuels. This paper looks at how a decentralised power plant could be designed using Organic Rankine Cycle (ORC) in place of the conventional steam Rankine Cycle to maximise power generation efficiency and flexibility, while still offering a highly competitive installed cost. Combined cycle power generation utilising ORC technology offers a solution that also has environmental benefits in a water-constrained World. The paper also investigates the differences in plant performance for ORC designs utilising direct heating of the ORC working fluid compared to those using an intermediate thermal oil heating loop, and looks at the challenges involved in connecting multiple gas turbines to a single ORC turbo-generator to keep installed costs to a minimum.

Low-Emissions Renewable Power Generation Using Liquid Fuels

2011 ◽  
Author(s):  
Leo D. Eskin ◽  
Michael S. Klassen ◽  
Richard J. Roby ◽  
Richard G. Joklik ◽  
Maclain M. Holton
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Liquid Fuel ◽  
Heat Rate ◽  
Combined Cycle ◽  
Liquid Fuels ◽  
Gas Turbine Combustor ◽  
Renewable Power ◽  
Combustion Technology

A Lean, Premixed, Prevaporized (LPP) combustion technology has been developed that converts liquid biofuels, such as biodiesel or ethanol, into a substitute for natural gas. This fuel can then be burned with low emissions in virtually any combustion device in place of natural gas, providing users substantial fuel flexibility. A gas turbine utilizing the LPP combustion technology to burn biofuels creates a “dispatchable” (on-demand) renewable power generator with low criteria pollutant emissions and no net carbon emissions. Natural gas, petroleum based fuel oil #1 and #2, biodiesel and ethanol were tested in an atmospheric pressure test rig using actual gas turbine combustor hardware (designed for natural gas) and achieved natural gas level emissions. Both biodiesel and ethanol achieved natural gas level emissions for NOx, CO, SOx and particulate matter (PM). Extended lean operation was observed for all liquid fuels tested due to the wider lean flammability range for these fuels compared to natural gas. Autoignition of the fuels was controlled by the level of diluent (inerting) gas used in the vaporization process. This technology has successfully demonstrated the clean generation of green, dispatchable, renewable power on a 30kW Capstone C30 microturbine. Emissions on the vaporized derived from bio-ethanol are 3 ppm NO(x) and 18 ppm CO, improving on the baseline natural gas emissions of 3 ppm NO(x), 30 ppm CO. Performance calculations have shown that for a typical combined cycle power plant, one can expect to achieve a two percent (2%) improvement in the overall net plant heat rate when burning liquid fuel as LPP Gas™ as compared to burning the same liquid fuel in traditional spray-flame diffusion combustors. This level of heat rate improvement is quite substantial, and represents an annual fuel savings of over five million dollars for base load operation of a GE Frame 7EA combined cycle plant (126 MW). This technology provides a clean and reliable form of renewable energy using liquid biofuels that can be a primary source for power generation or be a back-up source for non-dispatchable renewable energy sources such as wind and solar. The LPP technology allows for the clean use of biofuels in combustion devices without water injection or the use of post-combustion pollution control equipment and can easily be incorporated into both new and existing gas turbine power plants. No changes are required to the DLE gas turbine combustor hardware.

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.

scholarly journals Frequency Domain Stability Assessment of Photovoltaic Power Generation Systems with Quasi-Z-Source Inverters

2021 ◽  
Vol 19 ◽  
pp. 160-165
Author(s):  
Luis Sainz ◽  
◽  
Ll Monjo ◽  
Keyword(s):  
Power Generation ◽  
Frequency Domain ◽  
Stability Assessment ◽  
Power Sources ◽  
Renewable Power ◽  
Photovoltaic Power ◽  
Space Matrix ◽  
The Stability ◽  
Power Generation Systems ◽  
Averaged Model

Photovoltaic power generation systems are one of the main renewable power sources, and quasi-Z-source inverters are becoming powerful devices to integrate these systems in AC grids. However, stability issues due to the damping behaviour of converters must be considered. There are several studies in this direction but instability concerns are not completely solved yet. This paper contributes with a procedure for the stability assessment of photovoltaic power generation systems with quasiZ-source inverters in the frequency domain. The study is based on the small-signal averaged model of the system expressed in the s-domain and the stability criterion derived from the frequency characteristics of the state-space matrix. The influence of the photovoltaic power generation system operating point on stability is studied by the proposed procedure. Eigenvalue analysis and PSCAD/EMTDC simulations are also performed to validate the obtained results.

Distributed Integrated Solar Combined Cycle Power Plants: Despatchable, Reliable, Affordable, Low Carbon Electricity

2018 ◽  
Author(s):  
Michael Welch ◽  
Heidi Anttila
Keyword(s):  
Power Generation ◽  
Electricity Generation ◽  
Power Plants ◽  
Fossil Fuel ◽  
Combined Cycle ◽  
Low Carbon ◽  
Generation System ◽  
Renewable Power ◽  
Renewable Power Generation ◽  
Power Generation System

Renewable energy has a significant role to play in helping the world achieve the greenhouse gas emission reduction necessary to achieve the pathway to a 2°C increase in global temperature. Electricity generation from wind and solar resources can contribute immensely to the decarbonization of power generation, but these resources are intermittent. High penetration of intermittent renewable power generation can cause grid stability and control issues for network operators, with fast response fossil fuel power plant necessary to provide security of supply and maintain grid stability. Increasingly natural gas-fueled distributed power generation is being installed to provide the necessary grid support. However, hybrid power plants comprised of a fossil fuel power generating system, a renewable power generation system and energy storage can provide both the low CO2 electricity required to meet environmental constraints, and the despatchability and stability required by grid operators. Integrated Solar Combined Cycle Power Plants (ISCCs), comprising a Concentrated Solar Power plant and a natural gas fired combined cycle plant, have the potential to simultaneously reduce fossil fuel consumption, provide secure, highly predictable electricity generation, and reduce the cost of integrating renewable energy into a power system. While a number of ISCCs have been built at a larger scale (above 150MW power output), the concept has rarely been adopted for smaller scale distributed power applications. In addition, the traditional ISCC concept uses a steam bottoming cycle, which consumes water, and often locations where distributed ISCC could be utilized suffer from a scarcity of fresh water. This paper evaluates whether replacing the steam bottoming cycle with an Organic Rankine Cycle (ORC) alternative can provide a simpler, lower cost distributed ISCC solution that can be utilized on smaller and island grid systems, or mini- and micro-grids, to provide an affordable, water-free, low carbon power generation system.

An Expanded Cost of Electricity Model for Highly Flexible Power Plants

2012 ◽  
Author(s):  
S. Can Gülen ◽  
Indrajit Mazumder
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Plant Performance ◽  
Cost Of Electricity ◽  
Renewable Power ◽  
Effective Performance ◽  
The Impact

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 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 baseloaded 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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