Lifetime Of Power Plant Research Articles

Water, energy and environment nexus: Quantitative assessment for integrated power plants with renewable energy

The population increase and the demand for water and energy, accompanied by the implications of environment pollution for natural and human resources, indicate the critical necessity for a coherent movement towards nexus between water, energy, and environment. Due to the fact that power generation industry is responsible for a significant proportion of water and fuel consumption and Carbon dioxide emissions within the world, in this research, the application of the hybrid renewable system in a thermal power plant has been assessed based on the approach of analyzing the link between energy, water and environment. The design of the solar system and the assessment of carbon balance during the power plant lifetime have been conducted in PVsyst application in 2022. Moreover, ReCipe environmental model has been used for assessing the effect of decrease in carbon emission on the ecosystem. The findings of the research indicate that the replacement of at least 2 % of the nominal capacity of the fossil fuel power plant with the renewable one, prevents the emission of 1431.28 tons of carbon dioxide yearly. This amount equals to 380.34 cubic meters of reserve in fossil fuel consumption and 391.73 tons of crude oil. The results also showed that in addition to preserving natural resources, the hybrid cycle design leads to significant water demand reduction which equals to 3842 cubic meters with the capacity to supply underground water sources. Due to the interests of preserving water and energy resources and decreasing carbon emission in power plant industry, within the framework of nexus approach, management of energy supply by replacing resources and using water and heat recovery technologies and application of energy demand management policies based on energy efficiency and environmental implications is recommended.

Numerical analysis of water, energy, and environment nexus in the hybrid thermal and solar multigeneration power plants

AbstractThe challenge of providing water, energy, and managing the environment is widely recognized as a significant barrier to global advancement in light of the increasing population. Based on projections, it is anticipated that the global community will encounter crises pertaining to water, energy and the environment in the foreseeable future. In this research, the application of the hybrid renewable system in a thermal power plant has been assessed based on the approach of analyzing the link between energy, water, and environment. The design of the solar system and the assessment of carbon balance during the power plant lifetime have been conducted in PVsyst application in 2022. Moreover, ReCipe environmental model has been used for assessing the effect of decrease in carbon emission on the ecosystem. The findings of the research indicate that the replacement of at least 2% of the nominal capacity of the fossil fuel power plant with the renewable one, prevents the emission of 1340.37 tons of carbon dioxide yearly. This amount equals to 371.25 m3 of reserve in fossil fuel consumption and 382.64 tons of crude oil. The results also showed that in addition to preserving natural resources, the hybrid cycle design leads to significant water demand reduction which equals to 3751 m3 with the capacity to supply underground water sources. Due to the interests of preserving water and energy resources and decreasing carbon emission in power plant industry, within the framework of nexus approach, management of energy supply by replacing resources and using water and heat recovery technologies and application of energy demand management policies based on energy efficiency and environmental implications is recommended.

Assessment of Climate Change Impacts and Water Restrictions on Solar Tower Plants

Climate projections under the high-emission representative concentration pathway “RCP-8.5” scenario are used to show the effects of global warming on the energy production of two similar concentrated solar tower power plants in Spain and Chile from 2025 to 2060. Results show a reduction of the annual energy production of almost 1.8% for Chile and an increase of almost 6% in the Spanish plant, but an increase of 10% water consumption due to both the increase in dry- and wet-bulb temperatures and changes in the direct normal irradiation caused by climate change. When the effect of water restrictions is included in the model caused by the foreseen reduction in water availability in Spain, the increase of the annual energy production is only 2%. Finally, the levelized cost of energy (LCOE) calculated during the whole power plant lifetime (35 years) with respect to the LCOE obtained at the beginning of the project is increased by 1.1% in the Chilean plant, whereas in the Spanish plant, it can be reduced more than 2.5% if there are no water restrictions, while a reduction of 0.4% is expected in a scenario with water restrictions. Results show that careful consideration of climate projections should be considered to properly estimate the economic viability of solar tower plants.

Hydraulic Transient Impact on Surrounding Rock Mass of Unlined Pressure Tunnels

The frequent pressure pulsations due to hydraulic transients in hydropower plants induce cyclic loading on the rock mass that may contribute to increased instances of block falls and increased risk of tunnel collapse over the power plant lifetime. This study focuses on understanding the effect of frequent start and stop sequences of hydropower in unlined pressure tunnels. For this purpose, data from a pore water pressure monitoring system is utilized, which was installed at the downstream end of the headrace tunnel at the 50 MW Roskrepp hydropower plant in southern Norway. The objective of this study is to analyze the recorded data and quantify the impact of the hydraulic transient on the surrounding rock mass in the unlined pressure tunnel. The monitoring of pressure data over several years clearly shows that frequent load changes could cause a considerable effect on the rock mass and constituent joint system. A delayed response of the pressure in boreholes in the rock mass compared with inside the tunnel is seen in all start and stop sequences and is considered to be the main reason for instability caused by transients. The response of pore pressure in boreholes is greatly influenced by the characteristics of joints. The results show that the start sequence and shorter shutdown duration exert a greater impact on rock mass as compared to the stop sequence and longer shutdown duration. Therefore, it is recommended to increase the shutdown duration so that the impact can be minimized to increase the tunnel lifetime. This study recommends implementing a more conservative design approach in tunnels with weak rock masses in projects that involve frequent load changes.

Temperature dependence of high-temperature corrosion on nickel-based alloy in molten carbonates for concentrated solar power applications

Concentrated solar power plants present several issues due to salt-induced corrosion, and the modelling of these mechanisms is needed for estimating power plants lifetime predictions. Moreover, a small variation of temperature can lead to microstructure changes due to allotropic transformations and thus free energy of formation of phases within the materials. Therefore, a corrosion study of molten carbonates, being high potential heat transfer fluids for CSP applications, on H230 alloy was performed at 700ºC, 750ºC and 800ºC up to 1000 h, in air atmosphere. The diffusion processes inducing the corrosion mechanism were analyzed and modelled with microstructural characterizations and thermogravimetric studies.

Multiphase Eulerian-Eulerian CFD supporting the nuclear safety demonstration

Nuclear safety demonstration is a key issue where thermal hydraulics plays a central role, whether at the design stage or for nuclear power plants lifetime extension. Combined with huge efforts dedicated to simulation software developments during the past decades, this context naturally leads to a progressive introduction of CFD (Computational Fluid Dynamics) tools to support the nuclear safety demonstration. However, this progressively increasing use of CFD also implies strong requirements related to nuclear safety issues. A declination of this methodology will show what is the current place of multiphase CFD in nuclear safety, and what are the necessary prerequisites to use it in this context. Including the development and validation of dedicated models, allowing for example, all-flow regimes transitions. An illustration of application on one of the most challenging case, involving all these flow phenomena with heat and mass transfer will be described to show where we are in terms of limit of usage for the safety demonstration purpose.

Safe Management of the Operating Lifetimes of Nuclear Power Plants

Safe Management of the Operating Lifetimes of Nuclear Power Plants

A Deep Learning-Based Approach for Generation Expansion Planning Considering Power Plants Lifetime

In Generation Expansion Planning (GEP), the power plants lifetime is one of the most important factors which to the best knowledge of the authors, has not been investigated in the literature. In this article, the power plants lifetime effect on GEP is investigated. In addition, the deep learning-based approaches are widely used for time series forecasting. Therefore, a new version of Long short-term memory (LSTM) networks known as Bi-directional LSTM (BLSTM) networks are used in this paper to forecast annual peak load of the power system. For carbon emissions, the cost of carbon is considered as the penalty of pollution in the objective function. The proposed approach is evaluated by a test network and then applied to Iran power system as a large-scale grid. The simulations by GAMS (General Algebraic Modeling System, Washington, DC, USA) software show that due to consideration of lifetime as a constraint, the total cost of the GEP problem decreases by 5.28% and 7.9% for the test system and Iran power system, respectively.

The Carbon Value of Nuclear Power Plant Lifetime Extensions in the United States

Nuclear power is currently the single largest carbon-free source of electricity in the United States. The climate mitigation cost savings of the existing U.S. nuclear fleet is denominated in hundreds of billions of dollars [net present value (NPV)] based on an integrated assessment modeling of the U.S. energy system within a globally consistent framework. Lifetime extensions of the existing nuclear fleet from 40 years to 60 and 100 years resulted in $330 billion to $500 billion (all figures are in U.S. dollars) (NPV) of mitigation cost savings for the United States under a deep decarbonization scenario consistent with limiting global temperature change to 2°C. The addition of new nuclear deployments in the United States increased the total U.S. mitigation cost savings of the 2°C climate goal by up to $750 billion (NPV). Immediate actions are required in the United States and globally to achieve net-zero carbon emissions by mid-century, and once achieving net-zero emissions, they must remain at net-zero indefinitely. Lifetime extensions of the existing nuclear fleet, in the United States and globally, support urgent near-term emissions reduction goals. Additionally, the longevity of nuclear power technologies reduces the need for new capacity additions of all carbon-free electricity sources and supports long-term actions necessary to maintain net-zero emissions.

Effects of implausible power plant lifetime assumptions on US federal energy system projected costs, greenhouse gas emissions, air pollution, and water use

Abstract Climate change motivates rapid decarbonization of the energy sector, with a particular focus on decarbonizing and expanding the electricity system. Given multiple plausible pathways toward decarbonization, scenario-based analysis of potential energy futures is a common analytical approach in the field of macro-energy systems. Scenario analysis is particularly valuable for assessing multicriteria impacts and identifying potential unintended consequences, especially when policies focus on a specific indicator, like greenhouse gas emissions. In the United States (US), the federal government produces projections for the future US energy system using the National Energy Modeling System, published in an Annual Energy Outlook (AEO) that includes multiple economic and policy scenarios to inform decision making. Although AEO scenarios are not intended as predictions, they are widely used as contextual baselines for evaluating cost, pace, and environmental impacts of the energy transition. As the official energy system scenarios of the US, a wealthy, high-emissions country, AEO scenarios serve an anchoring function that influences perceptions of the relative implications of alternative energy transition strategies. This research shows that projected cost and environmental intensity of the US electricity system are surprisingly stable across AEO scenarios. Why? We show that by not incorporating business-as-usual license expiration and generator lifespans, AEO effectively assumes that power plants can run indefinitely, which overlooks major asset replacement costs and fleet turnover opportunities that would likely accelerate decarbonization. Assuming typical lifespans and licensed operating periods, roughly 700 gigawatts (GW) of fossil and nuclear electricity generation capacity beyond the 170 GW of retirements modeled in AEO2020’s reference case would be expected to close, with an estimated unmodeled replacement cost of 2019$1.3 trillion. This cost is similar to the projected cost impact of a $35/tonne carbon dioxide price. Macro-energy systems analysis can be improved with more attention to physical and infrastructural constraints in models.

Uncertainty assessment for the displacement damage of a pressurized water reactor vessel

The neutron irradiation-induced mechanical property change is a major challenge for nuclear materials. For a Pressurized Water Reactor (PWR), neutron irradiation embrittlement of the reactor pressure vessel is one of the most important issues that determine the whole nuclear power plant lifetime. The present work focuses thus on the uncertainty assessment for the neutron irradiation displacement damage of a PWR vessel. The uncertainties of neutron flux, nuclear data, and atomic displacement models are propagated to Displacement per Atom (DPA) rates with a special emphasis on the importance of correlation matrices. In addition to the uncertainty propagated from the threshold displacement energy, the total uncertainty of damage energy rate is about 10% (at 1 σ ), whereas the uncertainty is largely underestimated if the correlations of damage cross section and neutron flux are not considered. Apart from the complete uncertainty propagation shown in this paper, combining the damage energy rate uncertainty and the displacement threshold energy uncertainty is recommended for estimating the calculated DPA rate uncertainty. Besides the uncertainty, the biases induced by the model defects are preliminarily estimated.

Co-production of electricity and hydrogen from wind: A comprehensive scenario-based techno-economic analysis

The aim of this study is to investigate the economic prospects of producing electricity and hydrogen using wind energy under different scenarios. For this, the most essential criteria to investors including Levelized Cost of Wind-generated Electricity (LCOWE), Levelized Cost of Wind-based Hydrogen (LCOWH), payback period, and rate of return are examined. Technical and environmental impacts are factored into the LCOWE formulation to obtain comprehensive insight. Owing to the uncertain nature of future, five degradation rates concerned with wind turbine performance and five likely rates as to the future value of money are investigated under the scenarios of I) utilizing wind electricity to replace fuel oil electricity, II) to replace natural gas electricity and III) without considering environmental penalties. The results indicate that LCOWE would be in the range of 0.0325–0.0755 $/kWh, while the corresponding LCOWH being in the range of 1.375–1.59 $/kg. Moreover, payback period of the related LCOWE and LCOWH would be in the range of 2.55–9.48 yr during the lifetime of wind power plant and 3.91–8.41 yr during that of hydrogen production system, respectively. The corresponding rate of return pertinent to the above-mentioned ones would be respectively in the range of 14.15–23.54% and of 9.87–21.55%.

Accelerating China’s Fossil Fuel Plant Retirement and Renewable Energy Expansion via Capacity Mechanism

The capitalization and lifetime of coal-fired power plants as well as political support for them are the largest impediments to decarbonisation, particularly in China. We introduce a market-oriented capacity remuneration mechanism to transform current coal capacity into an essential tool to support renewable electricity integration. This mechanism will not only reduce CO2 emissions but also backstop renewable electricity in the near-term to improve system reliability. Using generation and emissions data from the SWITCH-China model, this paper calculates the reserve economic value and its development pathway for the current legacy coal capacity. Our results show that more than 500 gigawatts (GW) of coal capacity can continue to serve as the reserve capacity by 2050, and this contributes 25% of the total reliable capacity required by the system. In contrast to the aggressive strategy of retiring all coal capacity, this pathway could save the China's power system at least US$100 billion in fixed-asset investment costs.

Outdoor Implied Current–Voltage Measurements of an Individual Encapsulated Cell in a Module

The performance of solar cells influences the reliability, lifetime, cost, and safety of photovoltaic power plants. The electrical performance of these cells, as well as, their degradation rates over time, can vary between individual cells within the same photovoltaic module. Current-voltage measurements can provide detailed data on cell performance, however, it cannot be performed on individual cells in encapsulated modules. In this study, we propose a contactless and nondestructive method that is based on Suns-photoluminescence measurements to extract the current-voltage characteristics of individual solar cells under operating conditions in the field. Applications of the method to identify the extent of various degradation mechanisms, such as light-induced and potential-induced degradation, are demonstrated and discussed. The main advantages of the proposed method include its low cost, and its fast and easy applicability.

Microstructure, mechanical properties and IASCC susceptibility of stainless steel baffle bolts after 30 years of operation in a PWR

Neutron irradiation in the core of a nuclear power plant can change the material properties of stainless steel significantly. In this paper cold worked AISI 316 baffle bolts retrieved from Doel 1 PWR were investigated with the aim to assess the structural degradation due to neutron irradiation by analyzing microstructure, mechanical behavior and stress corrosion susceptibility. The baffle bolts had received neutron doses ranging from 6 to 59 dpa covering a major part of a nuclear power plant's lifetime. First, microstructural investigations were carried out to reveal the defect and dislocation density and the amount of void swelling. Then mechanical properties were determined using tensile tests and fracture toughness tests. The irradiation assisted stress corrosion cracking (IASCC) susceptibility was investigated by slow strain rate testing and crack growth rate testing. Results were compared with literature values and found to be in good agreement. Main conclusions were that void swelling was small even for the highest dpa values and that the fracture toughness values saturated above 15 dpa. The material was susceptible to IASCC as shown by SSRT and crack growth rate measurements exhibiting intergranular fracture morphology.

Stochastic NPV Based vs Stochastic LCOE Based Power Portfolio Selection Under Uncertainty

This paper investigates the problem of power portfolio selection under uncertainty using two different metrics, namely the stochastic Net Present Value (NPV) and the stochastic Levelized Cost of Electricity (LCOE). In the first metric, stochastic revenues, as well as stochastic costs incurred during the whole lifetime of power plants, are taken into account. The second metric is based on stochastic costs only. This means that revenues deriving from selling electricity in power markets over long-term horizons play an important role in determining optimal portfolios under the stochastic NPV metric, but they have no impact on optimal portfolios under the stochastic LCOE metric. Uncertainty arising from unpredictable movements of electricity market prices, fossil fuels, and nuclear fuel prices is considered. Moreover, stochastic CO 2 costs are included into the analysis. The aim of this study was to examine in what circumstances efficient NPV-based portfolios differ in a significant way from efficient LCOE-based portfolios. The portfolio selection is performed using two different risk measures, namely the standard deviation and the Conditional Value at Risk Deviation (CVaR) deviation. The proposed methodology can be used as a powerful tool of analysis for planning profitable investments in new generating technologies paying attention to risk reducing strategies through power sources diversification.

Modified Cable Insulation Characteristics Using Nano Composites for the Nuclear Power Plant

Nowadays, The Nuclear Power Plant (NPP) Lifetime can be extended to around 80 Years; This Is Assist to Recommend the Modifications Some Properties of Polymeric Cross Linked Polyethylene (XLPE) Cable Insulation. This Work is A Laboratory Implementing the Nano-fillers as Silicon Dioxide (Sio2) and Clay to Enhance Cable Insulation. The Volume Resistivity, Capacitance, Dielectric Loss, Tensile Strength and Elongation Properties Were Tested and Measurement for the Nanorized Samples. Furthermore, These Measurements Have Been Carried Out for the (XLPE) with Modified XLPE/Sio2 and XLPE/Clay, at Additive Concentration of 1, 2.5, 4 and 5 Weight Percentage (Wt%). The Officially Documented Results Have Been Provided Much Better Cable Electrically Insulation and Mechanically Profile. A 205% and 189% for Volume Resistivity and Instance were improved for The XLPE/Sio2 and XLPE/Clay Respectively, and The Analytical Calculations were in Agreement with the Experimental Results.

Modification of Cable Insulation Characteristics Using Nanocomposites for the Nuclear Power Plant

Nowadays, the nuclear power plant (NPP) lifetime can be extended to 80 years. This allows recommending the modifications in some properties of cross-linked polyethylene (XLPE) cable insulation. This work is laboratory implementation of nanofillers such as silicon dioxide (SiO2) and clay to enhance cable insulation. The volume resistivity, capacitance, dielectric loss, tensile strength and elongation properties were tested and measured for the nanosized samples. Furthermore, these measurements were carried out for modified XLPE/SiO2 and XLPE/clay samples with additive concentration of 1, 2.5, 4 and 5 weight percentage (wt. %). The officially documented results showed much better cable electrical insulation and mechanical profile. 205% and 189% improvement in volume resistivity was observed for XLPE/SiO2 and XLPE/clay, respectively. The analytical calculations were in agreement with the experimental results.

Review of solid particle materials for heat transfer fluid and thermal energy storage in solar thermal power plants

AbstractCurrent concentrated solar power (CSP) plants that operate at the highest temperature use molten salts as both heat transfer fluid (HTF) and thermal energy storage (TES) medium. Molten salts can reach up to 565°C before becoming chemically unstable and highly corrosive. This is one of the higher weaknesses of the technology. Solid particles have been proposed to overcome current working temperature limits, since the particle media can be stable for temperatures close to 1000°C. This work presents a review of solid particles candidates to be used as HTF and TES in CSP plants in open receivers. In addition, the interactions between solid particles with major system components are described in this review, for example, with TES system or heat exchanger. The parameters and properties of solid particles are identified from the material science point of view explaining their nature and the relation to the power plant efficiency and lifetime durability. Finally, future development is proposed; such as material selection according to each specific design, materials characterization, or durability test.

Optimization of a 900 mm Tilting-Pad Journal Bearing in Large Steam Turbines by Advanced Modeling and Validation

Modernization of steam turbine components can extend power plant lifetime, decrease maintenance costs, increase service intervals, and improve operational flexibility. However, this can also lead to challenging demands for existing components such as bearings, e.g., due to increased rotor weights. Therefore, a careful design and evaluation process of bearings is of major importance. This paper describes the applied advanced modeling methods and performed validation for the optimization of a novel 900 mm three-pad tilting pad journal bearing that showed high temperature sensitivity to the fresh oil supply temperature. The bearing was developed to cope with increased rotor weights within the low pressure (LP) steam turbine modernization at two 1000 MW nuclear power plants. With a static load of 2.7 MN at a speed of 1500 rpm, it represents one of the highest loaded applications for tilting pad bearings in turbomachinery worldwide. After identification of the reasons for the sensitivity, advanced modeling methods were applied to optimize the bearing. For this purpose, a more comprehensive bearing model was developed considering the direct lubrication at the leading pad edge and pad deformation. The results of the entire analyses indicated modifications of bearing clearances, pad length, thickness, and pivot position. The optimized bearing was then implemented on both units and proved its excellent operational behavior at increased fresh oil supply temperatures of up to 55 °C. In conclusion, the application of advanced modeling methods proved to be the key success factor in the optimization of this bearing, which represents an optimal solution for turbomachinery.