scholarly journals On the relationship between battery power capacity sizing and solar variability scenarios for industrial off-grid power plants

2021 ◽  
Vol 302 ◽  
pp. 117553
Author(s):  
Louis Polleux ◽  
Thierry Schuhler ◽  
Gilles Guerassimoff ◽  
Jean-Paul Marmorat ◽  
John Sandoval-Moreno ◽  
...  
2021 ◽  
Vol 2 (2) ◽  
pp. 44-53
Author(s):  
GENNADY S. MYTSYK ◽  
◽  
ZAW HTET HEIN ◽  

The recent interest of developers of new technology in studying a structural and algorithmic synthesis (SAS) of voltage source inverters (VSI) for solar power plants (SPP) is stemming from a growing need to solve problems in connection with the revealed new possibilities of converting energy flow (from DC to AC) with better energy efficiency by reducing the depth of its pulse modulation. This problem is solved by using more rational structural and algorithmic solutions. It is shown that for SPPs for a capacity of about 1 MW and more, it is more expedient to construct inverters based on the energy flow multichannel conversion principle. Given a limited power capacity of the transistor components, the application of this principle allows the problem to be solved in fact without using an output filter. The output voltage waveform is shaped using the energy flow pulse-amplitude modulation (PAM), and its M parts are summed in the output circuit by out using M winding transfilters (M-TF). The proposed method for carrying out combined SAS of single-phase voltage source inverters with multichannel conversion is considered, which consists in using an N-level single-phase VSI (N-SPVSI) in each of the M channels with the voltage levels optimized in terms of the minimum total harmonic distortion (THD). The resulting voltage of this class of single-phase inverters, designated as MxN-SPVSI, is formed by the corresponding phase shift of the channel voltages followed by summing the channel currents by M-TF. It is shown that the resulting output voltage levels are also close to their values optimized with respect to the minimum of the THD indicator. The results from a comparative analysis of two options — a single-channel 8-level inverter and a four-channel 8-level inverter are given. For the second option, only one intermediate voltage tap in the solar battery is required (instead of seven taps in the first option) along with modern transistor components that are available for practical implementation. In both options, the THD value less than 5% is obtained with almost no need of using an output filter. The presented results provide a certain information and methodological support for system designing of single-phase voltage source inverters as applied to the specific features of solar power plants. Three-phase inverters can be built on the basis of three single-phase inverters with galvanic isolation of the power sources for each phase.


Author(s):  
Obumneme Oken

Nigeria has some surface phenomena that indicate the presence of viable geothermal energy. None of these locations have been explored extensively to determine the feasibility of sustainable geothermal energy development for electricity generation or direct heating. In this context, the present study aims to provide insight into the energy potential of such development based on the enthalpy estimation of geothermal reservoirs. This particular project was conducted to determine the amount of energy that can be gotten from a geothermal reservoir for electricity generation and direct heating based on the estimated enthalpy of the geothermal fluid. The process route chosen for this project is the single-flash geothermal power plant because of the temperature (180℃) and unique property of the geothermal fluid (a mixture of hot water and steam that exists as a liquid under high pressure). The Ikogosi warm spring in Ekiti State, Nigeria was chosen as the site location for this power plant. To support food security efforts in Africa, this project proposes the cascading of a hot water stream from the flash tank to serve direct heat purposes in agriculture for food preservation, before re-injection to the reservoir. The flowrate of the geothermal fluid to the flash separator was chosen as 3125 tonnes/hr. The power output from a single well using a single flash geothermal plant was evaluated to be 11.3 MW*. This result was obtained by applying basic thermodynamic principles, including material balance, energy balance, and enthalpy calculations. This particular project is a prelude to a robust model that will accurately determine the power capacity of geothermal power plants based on the enthalpy of fluid and different plant designs.


1980 ◽  
Vol 7 (10) ◽  
pp. 829-832 ◽  
Author(s):  
James B. Pollack ◽  
Kathy Rages ◽  
Owen B. Toon ◽  
Yuk L. Yung

Author(s):  
Dengji Zhou ◽  
Tingting Wei ◽  
Shixi Ma ◽  
Huisheng Zhang ◽  
Di Huang ◽  
...  

Digital power plant is the theory and method to improve the operating quality of power plant by quantifying, analyzing, controlling and deciding the physical and working objects of power plants in the whole life cycle. Signals and management information of power plants will be digitized, so as to realize information exchange reliably and accurately and large-scale distributed resource sharing based on the network technology. Then optimization decisions and scientific guidance for plant operation will be proposed by intelligent expert system based on the digital resources. Therefore, the foundation of digital power plant is system modeling and performance analysis. However, there are some problems in the process of the modeling performance analysis of digital power plant. For instance, each unit of the system model has different dimensions and different type of mathematical description, and the data or information used for modeling are defined differently and belong to different enterprises, who do not want to share their information. Metamodeling is potential to solve these problems. It defines the specification to describe a unit and the relationship between different elements. Compared with traditional modeling methodologies for thermal systems, metamodeling makes the model more standardized, and the relationship of the model elements is more explicit and better understood by the co-simulation partners. In this paper, the collaborative modeling and simulation platform for digital power plant has been established based on the metamodeling method and the performance of the target plant has been analyzed from different aspects via field data. The metamodeling method consists of three parts: syntax definition, model development and algorithm definition. The result shows that the collaborate modeling and simulation platform can be used to reduce costs, decrease equipment failure rate, and improve plant output, so as to guarantee the safety and increase economics.


2017 ◽  
Vol 4 ◽  
pp. 141-154
Author(s):  
Marcus Vitlin ◽  
Miroshan Naicker ◽  
Augustine Frederick Gardner

Generation III+ reactors are the latest generation of Nuclear Power Plants to enter the market. The key evolution in these reactors is the introduction of stringent safety standards. This is done through thorough incident scenario analysis and preparation, resulting in the addition of novel active and passive auxiliary safety systems, affecting the power consumption in the balance of plant. This paper analyses the parameters of PWR power plants of similar design, to determine the parameters for optimal efficiency, regarding gross and net electrical output, determining the impact the balance of plant has on this efficiency. While two of the three main factors affecting the Rankine cycle – boiler pressure and steam temperature – behaved as theoretically expected, there was a notable point of departure with the third parameter – condenser pressure. The relationship between steam temperature and gross electrical efficiency was linear across all reactors but the relation between the steam temperature and the net electrical efficiency ceased to be linear for secondary loop steam temperatures above 290°C. The relationship between boiler pressure and both gross and net electrical efficiency was linear, proving the Rankine cycle. A relationship was not observed between the condenser pressure and either the gross or net electrical efficiency


Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4249
Author(s):  
Xuan Yao ◽  
Man Zhang ◽  
Hao Kong ◽  
Junfu Lyu ◽  
Hairui Yang

After the implementation of the ultra-low emissions regulation on the coal-fired power plants in China, the problem of the excessive ammonia-slipping from selective catalytic reduction (SCR) seems to be more severe. This paper analyzes the operating statistics of the coal-fired plants including 300 MW/600 MW/1000-MW units. Statistics data show that the phenomenon of the excessive ammonia-slipping is widespread. The average excessive rate is over 110%, while in the small units the value is even higher. A field test data of nine power plants showed that excessive ammonia-slipping at the outlet of SCR decreased following the flue-gas process. After most ammonia reduced by the dust collector and the wet flue-gas desulfurization (FGD), the ammonia emission at the stack was extremely low. At same time, a method based on probability distribution is proposed in this paper to describe the relationship between the NH3/NOX distribution deviation and the De–NOX efficiency/ammonia-slipping. This paper also did some original work to solve the ammonia-slipping problem. A real-time self-feedback ammonia injection technology using neural network algorithm to predict and moderate the ammonia distribution is proposed to decrease the NH3/NOX deviation and excessive ammonia-slipping. The technology is demonstrated in a 600-MW unit and works successfully. The excessive ammonia-slipping problem is well controlled after the implementation of the technology.


2011 ◽  
Vol 696 ◽  
pp. 302-307
Author(s):  
Yuuzou Kawahara ◽  
Yoichi Matsubara

High durability, quality control and prediction of deterioration are key issues for the thermal spray coatings applied to fossil fuel and waste burning boilers. Small electrical resistance inspection (SERI) has been developed and applied for boilers to quantitatively evaluate the relationship between the deterioration mechanisms and the coating defects as well as life-times of coatings. Changes in the electrical resistance (ER) of coatings showed a good correlation with the deterioration causes and also with the bonding strength of the coatings. On the other hand, new processes such as thermal spraying and automatic fusing (SFU) process by high frequency induction heating have been developed to manufacture highly durable coatings. These SFU coatings, which are 0.5~3 mm in thickness and contain chemically bonded and dense NiCrSiB alloy layers have been found to have excellent durability which is almost equal to that of 625 weld overlays used in many WTE plants. Applications of these technologies are in progress to realize coatings with high cost performance, high efficiency and easy maintenance.


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