A New Concept for Power Grid Stabilization Using a Motor-Assisted Variable Speed Gas Turbine System

2014 ◽  
Author(s):  
Naohiro Kusumi ◽  
Noriaki Hino ◽  
Aung Ko Thet
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Rotational Energy ◽  
Thermal Power Plants ◽  
Variable Speed

As the penetration ratio of renewable energy sources becomes larger, the fluctuations of grid load also become larger and larger because of the intermittent generation of wind power and photovoltaic power. These fluctuations cause instability of voltage and frequency in the power grid. Recently, there has been considerable research into solving these challenges, leading to development such as batteries, flywheels, and improved flexibility of thermal power plants. The batteries and the flywheels are confronted with the challenge of high initial cost for the Mega-Watt class. Improving flexibility for the thermal power plants is effective, but this improvement has several limitations such as load-follow operation capability under mechanical constraints and frequency regulation within governor-free regulating capacity. To overcome these problems, we propose a new gas turbine system named Motor-assisted Gas Turbine (MAGT). MAGT is composed of a two-shaft gas turbine: one free turbine shaft is connected to a synchronous generator rotating at a constant speed, and the other compressor shaft is coupled to an inverter-fed motor controlled at variable speed. The motor and inverter capacity is appropriate: about 5–10 % that of the gas turbine. MAGT improved the reaction rate corresponding to the load fluctuation by changing the speed of the compressor. Since the motor’s shaft, which has a compressor and a high pressure turbine, rotates at high speed and those masses are considerable, it has rotational energy of about several kWh. This energy could be charged and discharged through the converter that controls the motor speed, the same as for flywheels. This response could be much faster than conventional gas turbines, which contain huge amounts of working gas. MAGT controls its rotational energy in seconds and controls gas turbine power in minutes; thereby it improves response totally. Moreover, by assisting the compressor by using motor power, MAGT can increase gas turbine power output. Since the density of air decreases with as temperature increase, the mass of working gas is reduced. Thus, the fuel input must accordingly be reduced to suppress the combustion temperature without damaging turbine blades. As a result, power output is reduced. In such cases, a motor-assisted compressor can increase working gas. That allows more fuel input. The proposed system was evaluated using numerical simulations. The results showed that frequency variations were within ±0.1Hz and the output power was recovered under high ambient temperature.

Experimental Study on Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Mass Flow ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Combined Cycle ◽  
Range Extension ◽  
Nox Emissions ◽  
Low Load

Volatile renewable energy sources induce power supply fluctuations. These need to be compensated by flexible conventional power plants. Gas turbines in combined cycle power plants adjust the power output quickly but their turn-down ratio is limited by the slow reaction kinetics, which leads to CO and unburned hydrocarbon emissions. To extend the turn-down ratio, part of the fuel can be converted to syngas, which exhibits a higher reactivity. By an increasing fraction of syngas in the fuel, the reactivity of the mixture is increased and total fuel mass flow and the power output can be reduced. An autothermal on-board syngas generator in combination with two different burner concepts for natural gas (NG)/syngas mixtures was presented in a previous study (Baumgärtner, M. H., and Sattelmayer, T., 2017, “Low Load Operation Range Extension by Autothermal On-Board Syngas Generation,” ASME J. Eng. Gas Turbines Power, 140(4), p. 041505). The study at hand shows a mass-flow variation of the reforming process with mass flows, which allow for pure syngas combustion and further improvements of the two burner concepts which result in a more application-oriented operation. The first of the two burner concepts comprises a generic swirl stage with a central lance for syngas injection. Syngas is injected with swirl to avoid a negative impact on the total swirl intensity and nonswirled. The second concept includes a central swirl stage with an outer ring of jets. For this burner, syngas is injected in both stages to avoid NOx emissions from the swirl stage. Increased NOx emissions produced by NG combustion of the swirl pilot were reported in last year's paper. For both burners, combustion performance is analyzed by OH*-chemiluminescence and gaseous emissions. The lowest possible adiabatic flame temperature without a significant increase of CO emissions was 170–210 K lower for the syngas compared to low load pure NG combustion. This corresponds to a decrease of 15–20% in terms of thermal power.

Power Cycles of Generation III and III+ Nuclear Power Plants

2014 ◽  
Author(s):  
Alexey Dragunov ◽  
Eugene Saltanov ◽  
Igor Pioro ◽  
Pavel Kirillov ◽  
Romney Duffey
Keyword(s):  
Renewable Energy ◽  
Natural Gas ◽  
Thermal Efficiency ◽  
Nuclear Power ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Electrical Energy ◽  
Energy Sources ◽  
Thermal Power Plants

It is well known that the electrical-power generation is the key factor for advances in any other industries, agriculture and level of living. In general, electrical energy can be generated by: 1) non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and 2) renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are: 1) thermal - primary coal and secondary natural gas; 2) “large” hydro and 3) nuclear. The rest of the energy sources might have visible impact just in some countries. Modern advanced thermal power plants have reached very high thermal efficiencies (55–62%). In spite of that they are still the largest emitters of carbon dioxide into atmosphere. Due to that, reliable non-fossil-fuel energy generation, such as nuclear power, becomes more and more attractive. However, current Nuclear Power Plants (NPPs) are way behind by thermal efficiency (30–42%) compared to that of advanced thermal power plants. Therefore, it is important to consider various ways to enhance thermal efficiency of NPPs. The paper presents comparison of thermodynamic cycles and layouts of modern NPPs and discusses ways to improve their thermal efficiencies.

Dynamic Behavior of a Solar Hybrid Gas Turbine System

2015 ◽  
Author(s):  
Christian Felsmann ◽  
Uwe Gampe ◽  
Manfred Freimark
Keyword(s):  
System Dynamics ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Commercial Application ◽  
Worst Case ◽  
Electric Generator ◽  
New Findings ◽  
Component Development

Solar hybrid gas turbine technology has the potential to increase the efficiency of future solar thermal power plants by utilizing solar heat at a much higher temperature level than state of the art plants based on steam turbine cycles. In a previous paper the authors pointed out, that further development steps are required for example in the field of component development and in the investigation of the system dynamics to realize a mature technology for commercial application [1]. In this paper new findings on system dynamics are presented based on the simulation model of a solar hybrid gas turbine with parallel arrangement of the combustion chamber and solar receivers. The operational behavior of the system is described by means of two different scenarios. The System operation in a stand-alone electrical supply network is investigated in the first scenario. Here it is shown that fast load changes in the network lead to a higher shaft speed deviation of the electric generator compared to pure fossil fired systems. In the second scenario a generator load rejection, as a worst case, is analyzed. The results make clear that additional relief concepts like blow-off valves are necessary as the standard gas turbine protection does not meet the specific requirements of the solar hybrid operation. In general the results show, that the solar hybrid operational modes are much more challenging for the gas turbines control and safety system compared to pure fossil fired plants due to the increased volumetric storage capacity of the system.

Greenhouse Gas Emissions Calculation Methodology in Thermal Power Plants: Case Study of Iran and Comparison With Canada

2008 ◽  
Author(s):  
Farshid Zabihian ◽  
Alan S. Fung
Keyword(s):  
Climate Change ◽  
Greenhouse Gas ◽  
Global Climate Change ◽  
Gas Turbines ◽  
Electricity Generation ◽  
Power Plants ◽  
Global Climate ◽  
Thermal Power ◽  
Ghg Emissions ◽  
Thermal Power Plants

Nowadays, the global climate change has been a worldwide concern and the greenhouse gases (GHG) emissions are considered as the primary cause of that. The United Nations Conference on Environment and Development (UNCED) divided countries into two groups: Annex I Parties and Non-Annex I Parties. Since Iran and all other countries in the Middle East are among Non-Annex I Parties, they are not required to submit annual GHG inventory report. However, the global climate change is a worldwide phenomenon so Middle Eastern countries should be involved and it is necessary to prepare such a report at least unofficially. In this paper the terminology and the methods to calculate GHG emissions will first be explained and then GHG emissions estimates for the Iranian power plants will be presented. Finally the results will be compared with GHG emissions from the Canadian electricity generation sector. The results for the Iranian power plants show that in 2005 greenhouse gas intensity for steam power plants, gas turbines and combined cycle power plants were 617, 773, and 462 g CO2eq/kWh, respectively with the overall intensity of 610 g CO2eq/kWh for all thermal power plants. This GHG intensity is directly depend on efficiency of power plants. Whereas, in 2004 GHG intensity for electricity generation sector in Canada for different fuels were as follows: Coal 1010, refined petroleum products 640, and natural gas 523 g CO2eq/kWh, which are comparable with same data for Iran. For average GHG intensity in the whole electricity generation sector the difference is much higher: Canada 222 vs. Iran 610g CO2eq/kWh. The reason is that in Canada a considerable portion of electricity is generated by hydro-electric and nuclear power plants in which they do not emit significant amount of GHG emissions. The average GHG intensity in electricity generation sector in Iran between 1995 and 2005 experienced 13% reduction. While in Canada at the same period of time there was 21% increase. However, the results demonstrate that still there are great potentials for GHG emissions reduction in Iran’s electricity generation sector.

Parameterization of High Solar Share Gas Turbine Systems

2012 ◽  
Author(s):  
Stephan Heide ◽  
Christian Felsmann ◽  
Uwe Gampe ◽  
Sven Boje ◽  
Bernd Gericke ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Planning Process ◽  
Pressure Ratio ◽  
Thermal Power ◽  
Combined Cycle ◽  
Process Models ◽  
Solar Thermal ◽  
Thermal Power Plants ◽  
Solar Thermal Power

Existing solar thermal power plants are based on steam turbine cycles. While their process temperature is limited, solar gas turbine (GT) systems provide the opportunity to utilize solar heat at a much higher temperature. Therefore there is potential to improve the efficiency of future solar thermal power plants. Solar based heat input to substitute fuel requires specific GT features. Currently the portfolio of available GTs with these features is restricted. Only small capacity research plants are in service or in planning. Process layout and technology studies for high solar share GT systems have been carried out and have already been reported by the authors. While these investigations are based on a commercial 10MW class GT, this paper addresses the parameterization of high solar share GT systems and is not restricted to any type of commercial GT. Three configurations of solar hybrid GT cycles are analyzed. Besides recuperated and simple GT with bottoming Organic Rankine Cycle (ORC), a conventional combined cycle is considered. The study addresses the GT parameterization. Therefore parametric process models are used for simulation. Maximum electrical efficiency and associated optimum compressor pressure ratio πC are derived at design conditions. The pressure losses of the additional solar components of solar hybrid GTs have a different adversely effect on the investigated systems. Further aspects like high ambient temperature, availability of water and influence of compressor pressure level on component design are discussed as well. The present study is part of the R&D project Hybrid High Solar Share Gas Turbine Systems (HYGATE) which is funded by the German Ministry for the Environment, Nature and Nuclear Safety and the Ministry of Economics and Technology.

scholarly journals Assessment of efficiency and prospects for the use of hybrid thermal low-capacity power plants in the Republic of Vietnam

2019 ◽  
Vol 124 ◽  
pp. 01040 ◽  
Author(s):  
D. T. Nguen ◽  
D. N. Pham ◽  
G. R. Mingaleeva ◽  
O. V. Afanaseva ◽  
P. Zunino
Keyword(s):  
Power Plants ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Climatic Conditions ◽  
Energy Sources ◽  
Thermal Power Plants ◽  
Basic Design ◽  
Air Heating ◽  
The Republic

The growing demand for energy and fossil fuels creates increased number of difficulties, while renewable energy sources are still rarely used worldwide, particularly in Vietnam. In this article hybrid thermal power plants based on gas turbine plants are discussed, the increased efficiency of which is achieved by air heating after the compressor in solar air heaters. The basic design equations and the results of evaluating the efficiency and fuel consumption are presented for two thermal power plants of 4.6 MW and 11.8 MW. The dependence of the results on the intensity of solar extraction for the climatic conditions of the Ninh Thuan province of the Republic of Vietnam is discussed.

scholarly journals Small Gas Turbine With Large Parabolic Dish Collectors

1981 ◽  
Author(s):  
K. Bammert ◽  
A. Sutsch ◽  
M. Simon ◽  
A. Mobarak
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Parabolic Dish ◽  
Efficiency Comparison

An alternative solution for solar energy conversion to the heliostat-tower and solar farm (parabolic trough) concept is presented in the form of large parabolic dish collectors using small high temperature gas turbines for producing electricity from solar thermal energy. A cost and efficiency comparison for the different solar thermal power plants has shown that the large parabolic dish with gas turbine set is a superior system design especially in the net power range of 50 to 2000 kW. The important advantages of the large parabolic dish concept are discussed. For the important components such as the gas turbo converter, the receiver and the parabolic dish collector, design proposals for economic solutions are presented. An advanced layout for a 250-kW gas turbo converter with recuperator is presented in detail.

scholarly journals Prospects for the development of traditional and unconventional energy in the Chechen Republic

2021 ◽  
Vol 23 (4) ◽  
pp. 134-144
Author(s):  
R. B. Sardalov ◽  
A. A. Elmurzaev ◽  
M. V. Debiev ◽  
A. V. Khabatov
Keyword(s):  
Renewable Energy ◽  
Gas Turbine ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Regional Energy ◽  
Foreign Countries ◽  
The Republic ◽  
Electrical Loads ◽  
Effective Development

THE PURPOSE. To carry out an analysis of increasing the efficiency of energy development in the Chechen Republic. On the basis of the current structure of the power supply system of the Chechen Republic, provide indicators of the deficit of consumed electric power, as well as the generation of electricity in the republic. Consider the state of renewable energy sources in the republic and the prospects for the development of energy related to their implementation. METHODS. The analysis of the development of traditional energy, which is given close attention, is carried out, based on the experience of other subjects of Russia and foreign countries. The question of the application of the methodology for the effective development of regional energy is considered.RESULTS. A direction for the development of the energy sector of the Chechen Republic is proposed, which should inevitably be associated with thermal power plants using the most modern and efficient cycle today - steam-gas plants (CCGT), which is based on a gas turbine unit running on natural gas, being the only power plant that in the condensing mode of operation, it can supply electricity with an efficiency of more than 58%. The analysis of industrial power consumption of the largest operating and promising energy-intensive enterprises and facilities of the republic is carried out. CONCLUSION. The introduction of gas turbine plants in the centers of thermal and electrical loads helps to increase the economic efficiency of power plants. It is proposed to carry out fundamental and applied research in the field of renewable energy.

Repowering: An Option for Refurbishment of Old Thermal Power Plants in Latin-American Countries

2010 ◽  
Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa ◽  
Luiz Augusto Horta Nogueira ◽  
Electo E. Silva Lora
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Fuel Oil ◽  
Thermal Power Plants

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].

Application of Supercritical Pressures in Power Engineering

2017 ◽  
pp. 404-457
Author(s):  
Igor Pioro ◽  
Mohammed Mahdi ◽  
Roman Popov
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
High Temperature ◽  
Gas Turbine ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Thermal Power Plants ◽  
Power Cycles

SuperCritical Fluids (SCFs) have unique thermophyscial properties and heat-transfer characteristics, which make them very attractive for use in power industry. In this chapter, specifics of thermophysical properties and heat transfer of SCFs such as water, carbon dioxide and helium are considered and discussed. Also, particularities of heat transfer at SuperCritical Pressures (SCPs) are presented, and the most accurate heat-transfer correlations are listed. SuperCritical Water (SCW) is widely used as the working fluid in the SCP Rankine “steam”-turbine cycle in fossil-fuel thermal power plants. This increase in thermal efficiency is possible by application of high-temperature reactors and power cycles. Currently, six concepts of Generation-IV reactors are being developed, with coolant outlet temperatures of 500°C~1000°C. SCFs will be used as coolants (helium in GFRs and VHTRs; and SCW in SCWRs) and/or working fluids in power cycles (helium; mixture of nitrogen (80%) and helium [20%]; nitrogen, and carbon dioxide in Brayton gas-turbine cycles; and SCW “steam” in Rankine cycle).

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