Conventional Power Plants Research Articles

RANCANG BANGUN ALAT PERAGA ENERGI TEBARUKAN BERBASIS ENERGI SURYA

Electrical energy is a very important requirement both now and in the future. The electrical energy that we use today still comes from conventional power plant. Conventional power plant will create many threats such as increasing pollution and decreasing fossil fuels. Problems like this will have a bad impact on the future. Utilization of alternative energy is one way to solve these problems. Around us there is a lot of energy that will have the potential for us to develop it into a source of electricity for our daily needs. This energy includes solar energy. The purpose of this research is to create and design a solar powered renewable energy teaching aid. The method used in this process is to collect data, then the design process of the props is carried out. Making props is an important factor in this research so that during the testing process the props do not experience significant obstacles. The design of this power plant aims to make teaching aids as a learning medium and to obtain maximum and more efficient energy quantity results. The props consist of several components, namely solar panels, controllers, inverters, volt ampere meters, batteries (accumulator), cables, lights and mini houses. These props are to show that solar energy can be used to generate electricity that can be used for home lighting purposes.

Systematic optimisation framework for a sustainable multi-owner palm oil-based complex

In Malaysia, palm oil mill (POM) retrofit towards pollution control is vital to receive mandatory certification. Resource, waste, energy and water integrations could be performed between POM, palm oil refinery (POR) and conventional heat and power plant (CHP) under different owners to form a sustainable integrated palm oil-based complex (POBC). A cooperative game context is applied where multi-owner POM, POR and CHP act as multiple “players” in the POBC “game”. This study presents a systematic optimisation framework to design a sustainable multi-owner POBC. Firstly, five objectives related to economic, environmental and energy potentials are balanced using fuzzy optimisation approach to yield multi-objective optimal POBCs under four facility construction scenarios. Subsequently, profit-cost allocation within the multi-owner POBC is performed via an integrated cooperative game-based approach. The four fuzzy optimal POME-eliminated POBCs achieved economic potentials at 39.71 × 106- 40.84 × 106 USD/y with maximum λ (0.652). The profit-cost allocation results show economic potential improvements at 0.12 × 106- 0.46 × 106 USD/y for the multi-owner POBC facilities. POM is the major GP receiver whereas CHP benefits the most from POBC collaboration. The optimal multi-owner POBCs are economically feasible upon decision-makers' interest and robust against investment cost variations. The increment in Feed-in Tariff and biomass-based steam price reduces the economic stability of multi-owner POBC.

Integration and conversion of supercritical carbon dioxide coal-fired power cycle and high-efficiency energy storage cycle: Feasibility analysis based on a three-step strategy

The emission peak/carbon neutrality calls for significantly improved coal-fired power plants. Sustainability of the power plants is critical to meeting the net zero targets in 2050/2060. In this context, it is necessary to investigate the integration and conversion of the supercritical carbon dioxide coal-fired power cycle and the supercritical carbon dioxide energy storage cycle. In this work, the thermodynamic model and performance criteria are firstly presented. After comparison of the two cycles, a three-step strategy for the development of the power cycle is proposed and assessed. First step: when coal still plays an important role as a main energy resource, the integrated tri-compression coal-fired supercritical compressed carbon dioxide energy storage cycle has the highest round-trip efficiency of 56.37%. Second step: with the challenge in utilization of coal energy, a trade-off among the performance criteria must be struck in the integrated cycle with various heat sources. Third step: the adiabatic supercritical compressed carbon dioxide energy storage cycle is proposed, and a high round-trip efficiency of 72.34% is achieved in the split expansion cycle. The present research provides not only a new prospect of the conventional power plants but also design guidance for the supercritical carbon dioxide energy storage cycle.

Technical and Economic Evaluation and Development Policy Suggestions of LNG Power Plants

The return on investment (RIO) of a Liquefied natural gas (LNG) power plant is lower than that of conventional power plants with high pollution due to the “take or pay” supply mode of natural gas and the two-shift peak shaving operation mode in the LNG power plants. . In this paper, firstly, based on the characteristics of the gas turbine combined cycle (GTCC) unit for peak shaving and standby application, it is proposed to calculate the generation cost of LNG power plants according to the depreciation of operation life. Secondly, through the sensitivity analysis of power generation cost, it is found that fuel price and average efficiency are the first influencing factors. Next, to reflect the environmental protection characteristics of LNG power plants, the on-grid price included in the environmental value is put forward innovatively based on the calculation of the environmental cost and environmental value of natural gas power generation.

Development of two-dimensional hydrogen distribution model in small-scale spaces under severe accidents

Hydrogen distribution and combustion are important problems in nuclear reactor safety analysis under severe accident conditions.IPWR (Integrated pressurized water reactor) are very different from conventional nuclear power plants in design, structure and operating power. In particular, the nuclear power plant containment has a large space volume, and there are multiple compartments inside, while the small reactor containment has a small volume and a simple and compact internal layout. This makes the hydrogen in the containment behave differently in a severe accident. Thus, the hydrogen flow distribution characteristics of IPWR under severe accidents need further study.In this paper, a two-dimensional continuum model of hydrogen distribution in small-scale under severe accident conditions is established by using finite volume method and staggered grid scheme based on hydrodynamics calculation method. SIMPER (Semi-Implicit Method for Pressure Linked Equations Revised) algorithm is used to construct the pressure correction equation, alternate direction implicit algorithm is used to solve the algebraic equations, and block correction algorithm is used to accelerate the iterative convergence. Compared with the experimental study of hydrogen flow distribution characteristics in local compartments, the model can predict the change of hydrogen volume fraction distribution well with time in the experiment. After that, the flow distribution characteristics of hydrogen in the RPV (Reactorpressurevessel) and containment under the low-pressure core melt accident were analyzed with IPWR-IP200 as the research object. The results show that the coolant level in the lower head of the RPV is still about 0.8 m during hydrogen generation, so there is no hydrogen in the lower head area. The highest hydrogen volume fraction in the RPV is at the outlet of the core, which is about 23 %. The highest volume fraction of hydrogen in the containment is the outlet above the pressurizer relief valve, which is up to 17 %. Because of the high volume fraction of water vapor in the RPV, there is no risk of hydrogen combustion in the RPV. During hydrogen generation, there is a risk of hydrogen combustion within the containment, and the risk area is located in the upper space of the containment. After hydrogen production ceases, as water vapor continues to enter the containment, the hydrogen volume fraction gradually decreases, and the risk of hydrogen combustion will also decrease.The two-dimensional continuum model established in this paper can predict the hydrogen distribution under severe accidents, which can provide a reference for the hydrogen mitigation strategy of IPWR.

Benefit analysis of 15 MW biomass direct-fired power cogeneration project

Biomass direct-fired power generation technology has many advantages in realizing large-scale harmless utilization of biomass resources. It is an effective way to achieve the goal of carbon peak and carbon neutrality. Taking the 15MW direct-fired biomass power generation project of typical unit configuration as an example, this paper constructs a CHP system with biomass as fuel to replace the traditional coal-fired boiler for power generation, analyzes its economic, environmental and energy-saving benefits. As shown by results, compared with the conventional coal-fired power plant, the system cannot only save more than 700000 tons of coal, but also reduce more than 1610.41 tons of carbon dioxide emission, more than 26.41 tons of sulfur dioxide emission and more than 3000 tons of smoke and dust every year. The adoption of a new boiler and straw thermal power technology can competently deal with the three major problems of energy use, environmental protection and farmer’s income increment, which is of great significance to realize the effective cycle of “resource product renewable resource” economy.

Greenhouse gases emission reduction for electric power generation sector by efficient dispatching of thermal plants integrated with renewable systems

This research aims to contribute in developing a mathematical model for the composite probabilistic energy emissions dispatch (CPEED) with renewable energy systems, and it proposes a novel framework, based on an existing astute black widow optimization (ABWO) algorithm. Renewable energy power generation technology has contributed to pollution reduction and sustainable development. Therefore, this research aims to explore the CPEED problem in the context of renewable energy generation systems to enhance the energy and climate benefits of the power systems. Five benchmark test systems, combined with conventional thermal power plants and renewable energy sources such as wind and solar, are considered herein to obtain the optimum solution for cost and pollutant emission by using the ABWO approach. The ascendancy is not limited to environmental impacts, but it also provides the diversification of energy supply and reduction of reliance on imported fuels. As a result, the research findings contribute in lowering the cost of fuel and pollutant emissions, correlated with electricity generation systems, while increasing the renewable energy usage and penetration. Finally, the performance and efficacy of the designed scheme have been fully validated by comprehensive experimental results and statistical analyses.

Dynamic Stability Analysis of Isolated Power System

The islanded mode of operation of an electric power system (EPS) that has generation capabilities provided by conventional thermal power plants, by a pumped-storage power station, or from an interlink with a neighboring electric power system through an HVDC BtB converter is addressed in this paper. The risk for electrical power systems to fall into an islanded mode has recently grown, as it is caused not just by technical reasons but by a geopolitical situation as well. The current strains demand the close consideration of problems related to EPS operation in an islanded mode. This paper considers several. The research covers the following issues. The response of the islanded system to a sudden and spasmodic load change is analyzed in cases when the system deals with the disturbance with internal resources alone and with the help of an HVDC BtB converter’s frequency control functionality. Analysis of the impact of the settings of the HVDC BtB converter on the system’s response to disturbances is presented and the optimal set of parameters found. The impact of the system’s extended inertia on the system’s response is evaluated by using an additional unit of the pumped-storage power station in synchronous condenser mode. Transients in the system when switching a unit operating in synchronous condenser mode on and off are analyzed. The capability of the system to withstand major disturbances, such as disconnection of the pumped-storage power station’s unit operating in a pump mode and disconnection of the HVDC BtB converter in emergency modes, if a situation demands, is researched. The research is carried out by numerical simulations using PSS Sincal Electricity Basic software. Updated operating parameters of the isolated power system and the LCC HVDC BtB converter, as well as frequency control automation provided by ABB, were used in the simulations.

Integration and Flexibilization of Steam Power Plants with Growing Renewable Energy Systems

Increasing the flexibility of conventional power plants is one key challenge for the massive integration of highly volatile renewable energy resources into the Indian power system. Flexible power plants ensure the security of supply by compensating fluctuations in the electrical grid caused by intermittent renewable energy production from wind and sun. In this paper, the future development of the Indian electricity market is predicted and evaluated in terms of the future flexibility demand of coal and Lignite-fired power plants. As the flexibility measures for coal-fired power plants generally use inherent capabilities of the existing power plant systems, they are usually restricted by limiting factors. Here, the limiting factors for reducing the minimum load and increasing load change rates are discussed and potential measures to mitigate their influence are presented. An alternative way to increase the flexibility lies in properly integrating thermal energy storages. Integrating this storage concept the electrical minimum load can be reduced while simultaneously increasing the load change rate.

Risk-Based Operation and Maintenance Planning of Steam Turbine with the Long In-Service Time

In order to ensure the safety of power generation in Poland and to maintain energy production from coal-fired units with the long in-service time, it is required to develop a strategy for the further operation of the conventional power plants in conditions of increased flexibility. The presented research focuses on the critical component of the steam turbine, which is the high-pressure rotor. The methodology of the forecasting of crack propagation and growth of life-consumption processes was described, and the probability of a failure in subsequent years was estimated. The development of the identified phenomena depends mainly on the stress increases during start-ups; therefore, these increases were determined to ensure the safety of the turbine’s operation during the assumed period of operation (13 years). The permissible stress for rotor central bore (threatened with crack propagation) was 220 MPa for start-ups which were not carried out “on demand”, and for heat grooves (threatened with life-consumption processes) it was 420 MPa or 210 MPa, depending on the initial wear level of the material. An algorithm for online stress monitoring was presented, taking into account the variability of the heat transfer coefficients. The compiled method can be transformed into a real-time stress level control system. As a result, it is possible to obtain the desired increase in stress during start-up. For a longer service life (20 years), a method of selecting the optimal time interval to carry out preventive actions based on a risk analysis was additionally delineated. The optimal year to perform repair was between the 14th and 15th year of operation. The developed research allows presenting a strategy for further operation and maintenance (O&M) of the turbine, which can be adapted to a real unit.

Experimental and numerical investigations of mixed convection in turbine cavities for more flexible operations

Since the renewable sources, which have gained great attention due to the low-carbon policies, are inherently intermittent, the conventional power generation systems will be in use to meet the power demand. These systems, however, must be capable of operating along with renewables, which will lead to a need for more operational flexibility with frequent system ramps. Therefore, understanding and control of thermal stresses and clearances are essential for improving flexibility of conventional power plants. Computational fluid dynamics tools are of great importance in predicting the turbomachinery flows design since the direct measurements of detailed and spatial flow and temperature distribution are often not trivial in the real engines. During shut-down regimes of steam turbines, natural convection takes place along with relatively weak forced convection which is not strong enough to prevent a rising thermal plume leading to a non-uniform cooling in the turbine cavities. Although natural and forced convection have been studied separately in the literature, mixed type of flows in turbine cavities have not been investigated extensively. This paper provides unique experimental data set for validation and development of the predictive tools, which is generated from the detailed flow field measurements in a test facility designed for mixed type of flows in the turbine casing cavities with engine representative conditions. Additionally, large eddy simulations have been performed and validated against the generated experimental data, to gain deeper insight into the flow field. Thus, this paper offers a great insight in these complex flow interactions and unique experimental data for enabling the flexible operations and the development of advanced turbulence modelling.

Transient Modeling and Optimization of a PEM Electrolyzer for Solar Photovoltaic Power Smoothing

While renewable energy fuel has always had no cost, in the past the cost of the energy conversion technology was prohibitive. Today, due to improved efficiency in the technology and substantial increases in manufacturing volume the cost to generate electricity from the renewables and the cost to store this electricity in lithium-ion batteries for four hours has made these technologies more than competitive with traditional sources. As higher renewable energy penetrations occur the variability and intermittent nature of solar photovoltaic (PV) electricity can cause steep ramping of conventional power plants, so longer term energy storage (days, weeks, instead of hours) will be needed to increase the reliability of grid operation. In Florida cloud cover of a PV field can cause rapid fluctuations of PV output requiring a fast response to smooth out the PV electric power output. A polymer electrolyte membrane (PEM) electrolyzer can serve as a utility controllable load that can be available at all times and the produced hydrogen can be sold or converted back into electricity directly through a PEM fuel cell. To study the integration of renewable solar with hydrogen for increasing grid reliability, a multi-software power control method and a transient thermal electrochemical PEM electrolyzer model has been developed.One-dimensional ("through-plane") and two-dimensional ("through-plane" and "in-plane") un-steady state models using gPROMS 2.1.1. were developed. The model considers mass, energy, momentum and current balance equations. The thermal energy balance considers the heat transfer through the backing layer, the flowfield plates and the gas and liquid flows. Kinetic parameters used in the model were determined using parameter estimation of single cell steady state polarization curves [1]. The single cell unsteady state models were extended to a stack model by adding cells in series and parallel. Real-time PV data taken from a 8.9 MWAC solar farm from Orlando Utilities Commission’s Stanton Energy Center was scaled up to 75 MWAC to design the electrolyzer that would be sized with the typical utility PV installation in Florida. The 75 MW PV data was smoothed using a power control strategy developed in MATLAB. The developed multi-software power control method and the electrochemical dynamic stack model shows the effectiveness of an electrolyzer in smoothing the PV signal to increase the grid stability and flexibility. Results are presented of different size electrolyzers to minimize short term cloud cover spikes in power while maximizing hydrogen production and the effectiveness of the electrolyzer.[1] Vincenzo Liso, Giorgio Savoia, Samuel Simon Araya, Giovanni Cinti and Søren Knudsen Kær, “Modelling and Experimental Analysis of a Polymer Electrolyte Membrane Water Electrolysis Cell at Different Operating Temperatures”, Energies, 11 (2018) 3272. doi:10.3390/en11123273

Research on the prospects of applying socio-demographic data for the analysis of demand management potential

Today, the most developed countries are rapidly increasing the volume of electricity generation based on renewable energy sources, which primarily includes an increase in the share of generation at solar and wind power plants. The increase in the share of their generation leads to problems with maintaining the balance of generation and load. The reason for this is the stochastic nature of the generation of solar and wind power plants. There are a significant number of possibilities to compensate for this problem: maintaining the balance at the expense of existing conventional power plants with a high rate of power change, installation of energy storage at generation sites, shutting down some generation capacity at renewable energy sources, selling or buying energy in neighbouring countries, and demand management. This article focuses on demand management, specifically on the use of the concept of prosumers for this purpose. As process participants in electric power systems, solicitors are also capable of functioning in today's conventional electric systems, provided they gain additional market operations capabilities, but the benefits of the Smart Grid greatly enhance their effectiveness. We considered the potential of attracting Smart Grid players to align load schedules and maintain the balance of active power in the power system. For this purpose, we considered methods and tools for analysing the modes of operation of conventional consumers and solenoid meters. However, to obtain real consumption schedules of a residential area or even an individual house is a difficult task, which requires a significant amount of coordination and at the same time provides information only about individual facilities. That is why the analysis of the modes of operation of requestors is based on the study of load schedules of ordinary consumers based on the software for generating load schedules, taking into account the socio-demographic characteristics of households and international experience in demand management.

Economic-emission load dispatch for power system operation using enhanced sunflower optimization

Conventional thermal power plant uses limited sources of gas, fuel or coal which contributes to the rise of air pollution. Thus, it is crucial to efficiently use the natural sources and minimize the emissions of greenhouse gases and other pollutants. This paper presents an optimal economic dispatch considering three factors which are cost of generation, loss of power transmission and amount of emission for an efficient operation of power generation. Enhanced sunflower optimization (ESFO) algorithm is applied to determine the solution for three different cases: economic load dispatch, emission load dispatch and economic-emission load dispatch. The optimal solution based on the minimum generation cost and emission is obtained for the IEEE 6-unit test system using MATLAB software

Optimization of Microgrid Operation under the Diffusion of Solar and Wind Plant with Special Attention on Environment

This paper introduces a priority based Fuzzy Goal Programming (FGP) method for modelling and solving of microgrids using Genetic Algorithm (GA). The microgrid consider in this article consists of conventional and nonconventional power plants, such as wind and solar power plants. To incorporate the fluctuating outputs of solar and wind plants, the objectives of the problem are fuzzily described. In this article, optimal generation cost, total losses, and environmental ill-effect of power generation under the penetration of renewable energy resources (RES) are considered. In model formulation, the membership functions associated with fuzzy goals are transformed into membership goals and introducing under- and over-deviational variables to each of them. A GA scheme is used within the structure of FGP model to achieve the aspired levels of goals based on priorities in the decision environment. Then, a sensitivity analysis with variations of priority structure is performed and then the notion of Euclidean distance function is used to identify optimal power generation decision. To prove the usefulness of the intended method, three versions of a modified IEEE 30-bus and 6-generator system with renewable power generations are counted as the test systems. The model solution is also evaluated with the solutions obtained by using other approaches.

Coordination of DERs and Flexible Loads to Support Transmission Voltages in Emergency Conditions

The large-scale integration of renewable generation and the gradual decommissioning of conventional power plants has led to decreased availability of resources for providing services and support to the bulk transmission grid. This paper presents a novel methodology for providing support to the bulk transmission system through the control of thousands of small distributed energy resources (DERs), located in distribution systems. This control scheme is expected to serve jointly with other classical countermeasures against instability conditions. The proposed method is model-free, scalable, and does not rely on extensive communication infrastructure. It integrates an online method (New LIVES) to monitor the voltage stability status of the transmission system, a rule-based decentralized decision algorithm, and the local DER mechanisms implementing the control actions. The proposed approach is implemented on a combined transmission and distribution test system with over 4200 low-voltage buses and the dynamic simulation results illustrate its flexibility, practicality, and tractability.

Techno-Economic Analysis and Optimal Operation of a Hydrogen Refueling Station Providing Frequency Ancillary Services

Following the urgency of climate change issues, investments in renewable energy sources and electrification of the transportation sector have enormously increased to facilitate the transition to a more sustainable future. However, as renewable resources like wind parks are replacing conventional power plants, new balancing solutions are required to strengthen grid stability. As responsive loads with quick dynamics, electrolyzers operating in hydrogen refueling stations (HRSs) can offer flexible balancing services to the power grid. To gain this benefit, this article examines the techno-economic features of providing different frequency grid services by an HRS, considering the possibility of hydrogen injection into the industrial and natural gas pipelines. The ratings of the subcomponents and dispatch plans are optimized to enhance the performance of the plant. A probabilistic mixed-integer linear programming problem is solved over one year with a time resolution of 1 h and using real-world historical data based on the European electricity market. The simulation results indicate that the economic profits can be increased significantly as a result of participating in the ancillary service markets and meeting its operation specifications while the stable performance of the HRS is guaranteed.

Fast Var Margin Evaluation of High Wind Penetration Power Systems: An Objective-Oriented Dimensionality Reduction Approximation Approach

A high proportion of wind power systems with correct as set weak network connections may suffer from cascading trip faults due to the lack of conventional power plants and voltage/var support, which brings about great challenges to secure wind farm operations. To accurately and efficiently evaluate the dynamic var margin for an online field application within large-scale integrated wind areas, the transient dynamic voltage processes of hundreds or thousands of wind turbines must all be considered due to the dramatic interior voltage fluctuation effect of wind units, which brings a heavy computational burden for solving the TSCOPF problem. Therefore, to address these large-scale challenges, this paper proposes an objective-oriented approximation dimensionality reduction equivalent (OOA-DRE) approach, which accurately transforms the high-dimensional differential system to a low-dimensional system with few differential equations and low-dimensional algebraic equations for the wind unit with the maximum electrical distance value. Meanwhile, this paper uses the Levenberg-Marquardt method to obtain the global pre-evaluation error, so that the evaluation error reaches the minimum value. Finally, an actual wind power system verifies that the calculation time is reduced by approximately 2/3 compared with the original model on the premise of ensuring accuracy for large-scale systems.

The economics of power generation and energy storage via Solid Oxide Cell and ammonia

Green hydrogen finds its vital role in bridging the intermittent supplied renewable energy and fossil fuel infrastructure in a broad energy transition context. The bottleneck still lies in hydrogen's low volumetric energy density, prohibiting long-distance, large-scale, and cost-effective transportation. As a promising hydrogen carrier, ammonia possesses mature production, storage, transportation, and distribution supply chains. These advantages of ammonia enabled the possibility of transforming the renewable hydrogen at a minimum initial cost. This paper investigates the technological and economic feasibility of green ammonia utilization in the Solid Oxide Cells for power generation and energy storage. The result shows that the cost of Ammonia induced energy (183.75 US$/MWh) is significantly higher than that of natural gas power plants (81.77 US$/MWh). The main contributor is the fuel cost. In the optimum case, with fuel costs substantially dropping, the conceptual plant can be highly feasible, and the generated energy (97.40 USS$/MWh) is comparable to the conventional power plant.

Optical and structural optimization of a large aperture solar parabolic trough collector

Concentrating solar power is well established renewable energy technology. It involves the same heat engine cycle as the conventional power plants, and the heat produced can be stored effectively. However, expensive mirrors and structural support systems required to maintain high precision in the shape of reflectors for better optical and thermal efficiencies are the challenges involved in making it competitive with other solar power technologies. In the present work, a methodology is proposed based on the finite element method and Monte-Carlo ray tracing to design and optimize a parabolic trough collector. The effect of geometric and optical parameters such as rim angle, the width of the collector, tracking errors, and slope errors are analyzed. The effect of tracking errors in the East-West direction and slope errors are substantial compared to the other non-random errors. Loss of 25% and 7.1% in optical efficiency occurs for tracking errors of 20 mrad and slope error of 3.2 mrad, respectively. Based on the structural and optical study, an optimization method and optimum configurations are proposed. Using the proposed methodology, heat flux maps at the receiver can also be obtained for the structural health monitoring of the receiver tube.