Power Plant Availability Research Articles

Analysing the impact of diverse factors on electricity generation cost: Insights from Sri Lanka

The primary responsibility of a power system utility is to provide continuous, high-quality electricity at a fair and competitive price. To maintain low generation costs while utilising diverse energy sources, optimisation methodologies are crucial. Water value and generation costs exhibit significant variability on seasonal, daily and timely basis and reflect dynamic interactions between electricity demand and power plant availability. Currently, power system planners often overlook these seasonal and time-of day dependent variations in water value and generation costs. This research paper addresses this gap by analysing how fluctuations in electricity demand and power plant availability affect generation costs in the Sri Lankan power system. It introduces a novel economic dispatch model and presents three methods for estimating water value to calculate seasonal and time-of-day electricity costs. The discussion highlights how these findings can utilise policymaking, particularly in the context of electricity pricing debates and water management for agriculture versus electricity generation, as well as in calculating the water value for each reservoir.

Managing the heat: In-Vessel Components.

The Spherical Tokamak for Energy Production (STEP) programme aims to deliver a first-of-a-kind fusion prototype powerplant (SPP). The SPP plasma places extreme heat, particle and structural loads onto the plasma-facing components (PFCs) of the divertor, limiters and inboard and outboard sections of the first wall. The PFCs must manage the heat and particle loads and wider powerplant requirements relating to safety, net power generation, tritium breeding and plant availability. To enable STEP PFC concepts to be identified that satisfy these wide-ranging requirements, an iterative design ('Decide & Iterate') methodology has been used to synchronize a prioritized set of decisions, within the fast-paced, iterative, whole plant concept design schedule. This paper details the 'Decide and Iterate' methodology and explains how it has enabled the identification of the SPP PFC concepts. These include innovative PFC solutions such as a helium-cooled discrete and panel limiter design to increase tritium breeding while providing sufficient coverage and enabling individual limiter replacement; the integration of the outboard first wall with the breeding zone to enhance fuel self-sufficiency and power generation; and the use of heavy water (D2O) within the inboard first wall and divertor PFCs to increase tritium breeding within the outboard breeding zone. This article is part of the theme issue 'Delivering Fusion Energy - The Spherical Tokamak for Energy Production (STEP)'.

Optimizing Power Plant Availability and Reliability Excellence through End-to-End Asset Healthiness Monitoring Dashboard

PT Indonesia Power Semarang PGU, a sub-company of PT PLN that Operating power plants with a total capacity of 1,409 MW, has a way to manage assets using a web-based asset management which based on ISO 55001:2014. Our asset management’s pillars such as Work, Planning, and Control (WPC), Supply Chain Management (SCM), and Reliability should be incorporated by risk management to make decision easier. The system is called the end-to-end asset healthiness dashboard. Prior to the implementation of this system, there were increases in the backlog of Work Orders (WO) due to delays in receiving materials (WMATL). From the WO backlog, there were 45.47% WMATL WO in 2018 and 78.47% in 2020. Real-time asset wellness, follow-up tasks related to asset wellness, and Asset Criticality Ranking (ACR) are displayed on the dashboard. When WPC and SCM are integrated as good as possible, ACR selects the assets’s follow-up task related to asset wellness, maintenance is completed quickly and when needed, and the SCM process is accurately linked to maintenance execution and listed in the 52-week planning. By keeping our power plants availability, this condition also makes it easier to maintain the highest priority assets first. In 2021, it successfully reduces WMATL WO by 14.65%. Ultimately, our assets are effectively managed, consistently meeting the reliable electric power needs of our consumers.

ADOPTING AND IMPLEMENTING PRACTICAL RELIABILITY TOOLS IN NIGERIA ELECTRIC POWER INDUSTRY

The dynamics of power plant operations and maintenance has changed drastically over the past decades. In the past, generation and supply of power to both the pub lic and industrial sectors was not competitive, partly because most of the businesses of power generation, transmission and distribution were owned and run by government. The event turned out to be no business as the managers of those plants were not faced with stiff competitions. And as such were not on their heels create, seek and apply new technologies in power operations and management. With the dwindling efficiencies, resulting in outages, black out, most countries developed and adopted new business models where the private sector were allowed to fully own and run the business of power generation, transmission and distribution especially with changing expectations of customers’ demands for energy; the power sector became more competitive, resulting in the exit of non-performers. Reliability and availability of power plants become a central focus. The successes recorded in global power sector serves as a business model for non performing countries to copy or modify and apply. This forms the theme of this research to show case how the Nigeria electric power industry can key in into this successful model to turn the fortune of the Nigeria electric power industry in a positive direction. This research presents reliability engineering principles that should be adopted by the Nigeria electric power industry in order to optimize plants’ operations and deliver the needed posi-watt and not nega-watt to the ever ready consumers. It is believed that if these measures are judiciously applied, the Nigeria electric power industry will make a huge jump and join the global counterparts in electric energy generation and supply of the needed power.

Real-time mode of operation data analysis to catch the thread-tip denotes the failure cause of the grid-tie PV central inverter

The inverter is considered the core of the PV power plant. The inverter’s failure leads to generation loss and decreases plant availability. So, it is required to investigate a clear Root Cause Analysis (RCA) to deduce the failure causes and implement the required corrective action in addition to the preventive action to avoid more inverter failure, hereby maintaining the plant available to a certain value. This paper discusses real-time mode operation data analysis of the PV grid-connected inverter due to real central inverter incidents in Benban solar park located in Egypt.The central inverter plays an important role in the Mega-Scale PV power plant. The main function of this inverter is to convert the DC power produced by the PV modules to AC power to be injected into the utility grid by considering specific characteristics based on the grid code. The availability of any PV power plant directly depends on the healthy inverter’s operation. The more increases for the installed inverters, the less availability loss in the case of inverter partial or catastrophic failures. So, it is required to focus on the failure causes of the central inverter by implementing a technical analysis using the available operational data. The monitored data of the central inverter in the PV power plant is classified into two types. The first type is the continuous time data stored in the memory. It represents the waveforms of inverter outputs like voltage, current, frequency, …. etc. Unfortunately, in case of a catastrophic failure, the central inverter is completely charred, and the continuous time data is lost due to storage memory damage. The second type is the operation data that is recorded by the SCADA system (per one-minute interval). Hereby, the operation data is the sole data in the case of the completely charred inverter. The representation of the operational data in curves indicates symptoms that can be used for the RCA processes. The investigation outcomes include three results. The first result is detecting the signature of the IGBT thermal stress on the voltage balance of the DC link capacitor. The second result is verifying a scenario for the cause of the IGBT failure by implementing a technical mathematical model based on the detected symptoms that denote the fault signature which is considered the thread-tip for detecting the failure cause. The third result is the simulating scenario for the interpretation of a DC link capacitors explosion due to the short circuit fault that occurred due to IGBT failure. The investigation in this paper is performed based on operation data analysis of the PV grid-connected inverter (central type) due to a real incident. The analysis methodology is based on mathematical calculation for the IGBT junction temperature using the measured heatsink temperature. The study concludes that after the IGBT failure occurred, it was a short circuit for a while and closed the terminals of the DC link capacitors. So, the DC link capacitors exploded and produced heavy sparks that led to enough fire to burn the inverter container completely.

Analysing Effective and Ineffective Impacts of Maintenance Strategies on Electric Power Plants: A Comprehensive Approach

The maintenance strategy used in an electric power plant plays a crucial role in its overall performance and operational efficiency. An effective maintenance strategy describes the approach to exploiting various forms of maintenance (corrective, preventive, predictive, proactive, etc.) in an electric power plant. In this paper, the effective and ineffective impacts of maintenance strategies on power plants were examined. Also, the distinction between corrective, preventive, and aggressive maintenance was considered. In terms of effective impacts, a well-designed and executed maintenance strategy enhances the reliability and availability of the electric power plant by minimising unplanned downtime. It extends the lifespan of critical equipment, improves safety measures, increases energy efficiency, and contributes to long-term cost savings. However, in terms of ineffective impacts, poorly planned or executed maintenance strategies can result in increased downtime, higher repair costs, safety risks, decreased efficiency, and regulatory compliance issues. Neglecting maintenance can lead to equipment failures, reduced productivity, and potential environmental incidents.

Numerical investigation of air admission influence on the precessing vortex rope in a Francis turbine

Precessing vortex rope (PVR) plays a key role in inducing hydraulic resonance in Francis turbines operating at partial load, possibly degrading power plant stability and availability. Air injection into the runner cone is a suitable mitigating alternative; however, the influence mechanism of air injection on PVR remains unclear. The principal objective of this study was to establish response relationships between the characteristic parameters and air injection by the method of computational fluid dynamics (CFD) considering the fluid components of water, water vapour and air. The findings show that cavitation flow can be completely suppressed by slight air injection; however, the helical vortex structures are persisted at 1.0% and 2.0% air volume fractions, and the static pressure recovery is improved together with a slight increase in the hydraulic loss. At 3.0% air volume fraction, the vortex structure completely disappears, leaving an umbrella-shaped structure, with no pressure vibration arising in the turbine. Moreover, the physical mechanism of reducing the pressure amplitudes is clarified. This results clarify the influence mechanism of air injection on PVR, and contribute to steadily extending the flexibility of the operating range of the turbine during the engineering application.

FMEA and FTA of coal handling system of power plant

Maintenance of the machines along with increasing their availability is a challenge in Power Plants. The effectiveness of machine maintenance can be improved by implementing RCM tools. This paper discusses the implementation of two essential tools of RCM i.e., FMEA and FTA applied to the coal handling system of the power plant. The power plant availability is crucial for electricity production. Hence, all the types of equipment of the power plant and its ancillaries should be maintained to avoid breakdown. The RCM-based techniques help to mitigate equipment failure by practically implementing the qualitative and quantitative approaches.

Modelling power prices in markets with high shares of renewable energies and storages—The Norwegian example

Though power markets evolved into high shares of renewable energies markets, typical optimisation models, designed for thermal electricity markets, lead to prices with low volatility when applied to the Norwegian market. The objective of this work is to adapt typical optimisation models, so that they can depict price structures in markets with high shares of renewables and flexibilities. Additionally, also the sensitivity of the prices to the smallest parameter variations of the influencing factors shall be highlighted. For this purpose, the key factors which are qualitatively examined in the literature are selected. These are implemented in a standard electricity market model and subsequently analysed quantitatively. It is demonstrated that adding uncertainty and storage restrictions is sufficient to adequately represent typical price structures in Norway. Furthermore, it is shown that price structures are highly dependent on the parameters. E.g., limiting the maximum availability of storage power plants to 63%–69% leads to significant price peaks, resulting in a maximum price increase of up to 160 €/MWh. This indicates that the influencing factors identified here should be taken into consideration when modelling future power systems, although great diligence is recommended during parameterisation of these factors.

Electricity Spot Price Modeling and Forecasting in European Markets

In many competitive electricity markets around the world, the dynamic behavior of hourly electricity prices is subject to significant uncertainty and volatility due to electricity demand, availability of generation sources, fuel costs, and power plant availability. This work is devoted to describing and comparing the dynamics of electricity prices for some markets in Europe, selecting the five countries representing the largest economies in Western Europe (France, Germany, Italy, Spain, and the United Kingdom). Additionally, Denmark is included in the study to assess whether the size of the country is a determinant of price behavior. The six datasets of hourly price series, which exhibits a strong daily seasonality, are modelled using the most relevant well-known statistical models for time series analysis: ARIMA models and different versions of GARCH models. The comparison of the estimated models’ parameters, the analysis of outliers’ rate of appearance and the evaluation of out-of-sample one-day-ahead forecast let us draw some insightful similarities and dissimilarities between the analyzed countries.

Long-Distance Transport of Green Power via High Voltage Direct Current Submarine Cable

This study aims to perform a technical, environmental, and economic assessment of long-distance transport (around 10000 km) of green power from Australia to Japan through High Voltage Direct Current (HVDC) submarine power cables by literature studies. A PV power plant generates green power; 8000 GWh annual production is chosen as capacity. For the HVDC value chain, according to the assessments, energy efficiency is 74%. Power loss during cable transport is the key contributor. GHG footprint of power delivered is 112 kg CO2e/MWh compared to 50 kg at the outlet of the PV plant. Capital expenditure (CAPEX) is 29058 M€. At the end of the 10th and 20th years, another 4500 M€ investment is required for battery replacement. Operating expense (OPEX) is 166 M€/y. The technical cost of power produced is 428 €/MWh. Results of sensitivity analysis show that submarine cables length, power loss and lifetime, battery storage system sizing, and power plant availability have a significant impact on the economic and environmental performance of the whole HVDC value chain.

Case studies on system availability of PVP plants in Thailand

Analysis of the system availability (SA) of commercial utility-scale PV power (PVP) plants is important for the development, planning, and the financial assessment of the long-term operation of the plants. Many previous studies were done to analyse SA but these were mainly for plants located in non-tropical climatic and environmental conditions. In this study, six utility-scale PVP plants in the central region of Thailand were selected for case studies. The case studies first aimed to evaluate failures of PVP plant operations. Root causes and solutions to these failures were then identified. Based on the five-year data collected from the case studies, an initial modelling analysis was conducted to forecast and to attain better SA values of new PVP systems. However, more mathematical analysis based more sample operating plants with longer data period needs to be done to allow the use of a mathematical model for projecting the SA of proposed PVP plants and for it to be useful too in the financial assessments of the new PVP plants.

Experience with valuation methods for the creation of real options enabling diversity of nuclear fuel supply

ABSTRACT Defense in depth is a pillar of nuclear power plant design and it also plays an important factor for the reliability of fuel supply. While most safety systems of a classical light water reactor usually remain unchanged for many years of operation the first and second fission product barrier – the fuel and the cladding – are regularly exchanged by loading fresh fuel assemblies into the reactor core. We review our experience of achieving high reliability in fuel supply by means of real options. The required activities for option creation are explained in detail. Real option valuation is known to be more difficult than financial option valuation and we review the valuation metrics which we found most useful. Due to the incompleteness and illiquidity of the considered option market and due to the barriers of realizing arbitrage, lower and upper bounds are easier to determine than exact option values. Notwithstanding these constraints using concepts based on volatility and stochastic processes in our experience is good practice to avoid naked bets on future power plant availability and avoids the pitfalls of static forecasts.

Prospects of Sustainable Biomass-Based Power Generation in a Small Island Country

Biomass resources are abundantly present in the Pacific Island Countries (PICs) but are mostly used for cooking and crop drying. Only three countries viz. Papua New Guinea, Fiji, and Samoa use biomass for power generation. This paper aims to (i) quantify the forest logging residue generated in Fiji, (ii) carry out a techno-economic and environmental assessment of a potential 10 MW biomass power plant (BPP) in Fiji and study the impact of feedstock cost (FC) on the electricity production cost (EPC) in relation to the financial viability, and (iii) discuss possible strategies to overcome challenges PICs face in developing biomass energy projects. It is found that a 10 MW BPP would require approximately 60,000 tonnes of biomass feedstock, which can be supplied by forest residue from logging in the western division of Viti Levu in Fiji. If the FC is taken as USD68.6/tonne and electricity export tariff to national grid is taken as USD0.1621/kWh, then the net present value is USD16.1 million, simple payback period is 5.6 years, and the benefit-to-cost ratio is 2.5. A sensitivity analysis reveals that electricity export tariff, availability of power plant, and feedstock costs are critical parameters affecting the NPV of the project. Various strategies such as utilising forest residues, planting short-rotation plantations in unused land, enabling policies, early stakeholder engagement, attractive electricity export tariff, and using appropriate harvesting and transportation technologies can help develop the biomass-based power sector in Fiji.

ENERGY SYSTEM DESIGN IN PACITAN REGENCY-EAST JAVA PROVINCE

Planning the construction of renewable energy plants in Pacitan district addresses the increasing electricity needs every year. Pacitan Regency is located on the coast with natural conditions in most of the mountains; there is a lot of renewable energy potentials such as water, wind and sunlight. Based on data from the central statistics agency of Pacitan district with the population increased by 0.18%/year. The energy system planning in this study allocates 70% of renewable energy generation and 30% of fossil plants by 2030.Projected availability of steam power plants with installed capacity of 2 x 315 MW, power capable of 560 MW. The distribution of renewable energy power plants is spread in the Pacitan area with hydroelectric power plants with a total target of at least 412 MW by 2025 and Pump Storage power plants with a total target of at least 1000 MW by 2025. Solar power plants have the potential of intensity radiation 4300 Wh/m2; the average air temperature is 32.5 0C and Solar Radiation 38.71%. Electricity generation waste power with a total target capacity of at least 84 MW. Wind potential with an average speed of 9 m/s. By 2030, the population of Pacitan district will reach 566,413 people, with an energy consumption of 843.85 kWh/capita; the demand required is 187,613 Mwh. By reducing the use of power plants from 100% to 30% can reduce CO^2 emissions to 125,419,390,667 Tons.

A Bayesian updating of crack distributions in steam generator tubes

The structural failure of steam generator tubes is a common problem that can a ect the availability and safety of nuclear power plants. To minimize the probability of occurrence of failure, it is needed to implement maintenance strategies such as periodic nondestructive inspections of tubes. Thus, a tube is repaired or plugged whenever it has detected a crack which a threshold size is overtaken. In general, uncertainties and errors in crack sizes are associated with the nondestructive inspections. These uncertainties and errors should be appropriately characterized to estimate the actual crack distribution. This work proposes a Bayesian approach for updating crack distributions, which in turn allows computing the failure probability of steam generator tubes at current and future times. The failure criterion is based on plastic collapse phenomenon, and the failure probability is computed by using the Monte-Carlo simulation. The failure probability at current and future times is in good agreement with the ones presented in the literature.

Remote Renewable Hubs for Carbon-Neutral Synthetic Fuel Production

This paper studies the economics of carbon-neutral synthetic fuel production from renewable electricity in remote areas where high-quality renewable resources are abundant. To this end, a graph-based optimisation modelling framework directly applicable to the strategic planning of remote renewable energy supply chains is proposed. More precisely, a hypergraph abstraction of planning problems is introduced, wherein nodes can be viewed as optimisation subproblems with their own parameters, variables, constraints and local objective. Nodes typically represent a subsystem such as a technology, a plant or a process. Hyperedges, on the other hand, express the connectivity between subsystems. The framework is leveraged to study the economics of carbon-neutral synthetic methane production from solar and wind energy in North Africa and its delivery to Northwestern European markets. The full supply chain is modelled in an integrated fashion, which makes it possible to accurately capture the interaction between various technologies on an hourly time scale. Results suggest that the cost of synthetic methane production and delivery would be slightly under 150 €/MWh (higher heating value) by 2030 for a system supplying 10 TWh annually and relying on a combination of solar photovoltaic and wind power plants, assuming a uniform weighted average cost of capital of 7%. A comprehensive sensitivity analysis is also carried out in order to assess the impact of various techno-economic parameters and assumptions on synthetic methane cost, including the availability of wind power plants, the investment costs of electrolysis, methanation and direct air capture plants, their operational flexibility, the energy consumption of direct air capture plants, and financing costs. The most expensive configuration (around 200 €/MWh) relies on solar photovoltaic power plants alone, while the cheapest configuration (around 88 €/MWh) makes use of a combination of solar PV and wind power plants and is obtained when financing costs are set to zero.

Numerical Study of Ammonia/O2-Fired Semiclosed Cycle Gas Turbine for Oxy-Fuel IGCC Power Generation With CO2 Capture

Abstract With an increase in renewable energy generation, thermal power generation has been switched to standby power in various parts of the world. Ammonia, one of the storage and transport media for H2, is produced in a highly efficient oxyfuel integrated coal gasification combined cycle (IGCC) system with CO2 capture, for the future hydrogen-using society. Using ammonia as an industrial raw material, agricultural fertilizer, and transportation fuel, energy systems can be established by combining renewable energy and thermal power generation. Therefore, it is possible to simultaneously construct a thermal power supply system suitable for backup power source owing to the fluctuation of the renewable power generation and to improve the availability of the thermal power plant and the load-leveling. This will serve as an incentive to build a future zero-emission thermal power plant. In this study, an oxy-fuel IGCC power generation coproduced with ammonia and CO2 capture is conceptually proposed. Furthermore, the features and challenges of a gas turbine that fuels CO2-free NH3 are investigated. In particular, the combustion exhaust characteristics of ammonia/oxygen-fired semiclosed cycle gas turbine combustor in comparison with those of the conventional fuels are characterized through a kinetic analysis.

Could on-site fuel storage economically reduce power plant-gas grid dependence in pipeline constrained areas like New England?

In the Northeastern United States, natural gas supply constraints have led to periods when gas shortages have caused up to a quarter of all unscheduled power plant outages. Dual fuel oil/gas generators or local gas storage might mitigate gas supply shortages. We use historical power plant operational and availability data to develop a supply curve of the costs required for generators to mitigate fuel shortage failures in New England. Based on 2012–2018 data, we find that the historical fuel shortages at approximately 2 GW worth of gas-fired capacity could be mitigated using on-site fuel storage. For comparison, New England’s average reserve margin was 1.7–2.8 GW over our sample period. Oil dual fuel plants would recoup their investment if compensated with a reliability adder of $3−7/MWh during their normal operations, while $7−16/MWh would incentivize using on-site, compressed natural gas storage. We estimate that the capital expenses associated with the fuel storage options would be less expensive than installing battery backup for resource adequacy at current battery prices.

Optimal Photovoltaic Multi-String Inverter Topology Selection Based on Reliability and Cost Analysis

Inverters are the most vulnerable parts of the photovoltaic (PV) power plants. Therefore, choosing an appropriate inverter topology to maximize the reliability and availability of the PV power plants is very important, especially in the large scale power plants. This paper proposes a novel index named Total Financial Losses (TFL) to compare different inverter topologies from reliability and energy losses points of view. Initial cost, repair cost, financial losses due to the downtime and element losses, and environmental conditions are considered in evaluating the TFL index. Using this universal index, the optimal inverter topology and its switching frequency are determined when the TFL is minimized. Considering the fact that the reliability of power electronic devices is strongly dependent on their power losses and ambient conditions, the exact failure rates of vulnerable elements such as capacitors, switches, diodes, and cooling system are calculated. The system availability and frequencies of encountering the failure states are determined using the Markov method. Finally, the optimal photovoltaic inverter of the 150 kW power range is selected out of commonly used two-level and three-level topologies.