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Gas turbine has been used widely for electrical power generation based on simple cycle system. However, the relatively low thermal efficiency engages the researchers in investigating possible methods to enhance gas turbine performance. In the current study, three different types of fuels were used (crude oil, light oil, and natural gas) to operate the gas power plant in Qayyara, Mosul, Iraq and to evaluate the plant's performance, environmental impact and economic cost. The Aspen Husys package was used for simulation based on data recorded by the control department. Results showed that the software applied was highly valid. The external environmental temperature influenced the performance and efficiency of the station significantly with maximum values obtained for winter by 114MW and thermal efficiency of 32.02 % for natural. The emissions of CO2, SO2, and NOX gases are decreased, whereas CO emission is increased when the temperature of the external environment is raised with fewer emissions obtained for natural gas. The cost of three fuels in (summer) is the highest among the four months, with the higher cost for light fuel by 68.2 Iraqi diners/kiloWatt.hour. Therefore, light fuel cannot be used for the permanent operation of gas turbines, and natural gas fuel gives better performance and lower emissions than the other two types of fuels.

Renewable energy sources have immense potential for enhancing environmental sustainability; however, addressing their intermittency and irregularity is vital for optimizing economic benefits within microgrids. Integrating renewable energy systems with energy storage presents a promising solution. This study introduces an innovative energy management system designed for hybrid renewable power stations, incorporating battery energy storage systems and diesel generators. By accounting for battery degradation costs associated with charge depth and lifespan, the study transforms long-term battery expenses into real-time operational costs. The optimization problem is formulated as a mixed integer linear programming framework with the objectives of minimizing operating costs, battery degradation costs, and pollutant gas emissions. Through diverse case studies reflecting various market profiles. The proposed approach demonstrates reductions in overall system costs.

Numerous studies have investigated ionospheric waves, also known as ionospheric disturbances. These disturbances exhibit complex wave patterns similar to those produced by solar, geomagnetic, and meteorological disturbances and human activities within the Earth's atmosphere. The radio wave phase imager described herein measures the power of the ionospheric waves using their phase shift seen in phase images produced by the Long Wavelength Array (LWA) at the New Mexico Observatory, a high-resolution radio camera. Software-defined radio (SDR) was used for processing the data to produce an amplitude image and phase image. The phase image revealed the ionospheric waves, whereas the amplitude image could not see them. From the phase image produced from the carrier wave received at the LWA, the properties of the ionospheric waves have been previously characterized in terms of their energy and wave vector. In this study, their power was measured directly from the phase shift of the strongest set of ionospheric waves. The power of these waves, which originated at Albuquerque, the local major power consumer, was 15.3 W, producing a power density of 0.018 W/m2. The calculated power density that should be generated from the local power generating stations around Albuquerque was also 0.018 W/m2, in agreement with the experimentally measured value. This correspondence shows that the power generated by power stations and being consumed is not lost but captured by the ionosphere. [ABSTRACT FROM AUTHOR]

The electrical power transmission system serves as the vital artery that supplies energy consumption centers, as it represents the link between production and distribution stations. This system consists of a set of stations and lines with varying electrical loads in Basra Province. High loads are concentrated in its eastern side due to the high population momentum compared to the mostly uninhabited western side, which consists of desert regions. The transmission process faces a range of problems, including load instability from energy supply sources, high line losses, as well as congestion in some stations and lines. To improve energy transmission efficiency, it is necessary to rehabilitate and update the lines and stations by developing and upgrading their physical components, or by utilizing solar and wind energy as ideal solutions to the energy system's problems. It has been shown that the use of these energy sources reduces the burden on transmission networks by 18.3%, 43.4%, 23.64% for the spring, summer, autumn, and winter seasons, respectively. [ABSTRACT FROM AUTHOR]

With the increasing need for flexibility in the electricity grid, combined with longer periods of low electricity prices due to an oversupply of renewable electricity, alternative solutions which include the production of carbon-free fuels in combination with the use of combined cycle power plants, are identified as a possible solution. These so-called power-to-gas-to-power solutions (P2G2P), with hydrogen and ammonia as fuel, require further research to determine their feasibility. Within this scope, the European collaborative project FLEXnCONFU aims at providing an answer toward this feasibility. The specific project idea is to recover excess grid power to produce hydrogen through proton exchange membrane (PEM) water electrolysis. Then, this hydrogen could be stored directly, or it could be fed in an ammonia synthesis process. Finally, the decarbonized fuels (ammonia and/or hydrogen) are burned in the gas turbine to produce electricity with no greenhouse gases (GHG) emission. The aim of this paper is to evaluate the impact of P2G2P system integration in a power plant. Different concepts have been applied to an existing ENGIE plant, based in Belgium, with the idea of installing all the technologies (electrolyzers, compressors, and storage, as well as ammonia fabrication units) on the power plant site. Simulations show that a considerable production time is needed to operate the plant for several hours using these e-fuels. Moreover, hydrogen storage requires an extremely huge footprint, hence it looks more reasonable to operate ammonia synthesis to store large quantities of decarbonized fuel, given the site space constraints. Additionally, Aspen plus models have been realized to evaluate the global efficiency of the P2G2P systems as well as the specific cooling requirements of the added technologies. The global efficiency for the P2H2P (with hydrogen) system is 32%. For the P2A2P (with pure ammonia) and power-to-amonia-to-hydrogen-to power (part of the produced ammonia is cracked to recover hydrogen, feeding the combustion chamber of the combined cycle gas turbine (CCGT) with a blend of 70% NH3 and 30% H2) systems, this global efficiency is reduced, respectively, to 24% and 19%. From these results, it is thus apparent that there remain still several challenges that need to be overcome to make P2G2P an efficient way to decarbonize electricity production. These main challenges are: Increase the efficiency of the transformation processes to limit the energy losses; Enhance hydrogen storage technologies to limit the footprint or develop an efficient hydrogen distribution; Reduce the cost of P2G technologies and especially of PEM electrolyzers; Progress on decarbonized fuels combustion and specifically limit NOx emission for the NH3 firing configuration. [ABSTRACT FROM AUTHOR]

Numerous studies have investigated ionospheric waves, also known as ionospheric disturbances. These disturbances exhibit complex wave patterns similar to those produced by solar, geomagnetic, and meteorological disturbances and human activities within the Earth’s atmosphere. The radio wave phase imager described herein measures the power of the ionospheric waves using their phase shift seen in phase images produced by the Long Wavelength Array (LWA) at the New Mexico Observatory, a high-resolution radio camera. Software-defined radio (SDR) was used for processing the data to produce an amplitude image and phase image. The phase image revealed the ionospheric waves, whereas the amplitude image could not see them. From the phase image produced from the carrier wave received at the LWA, the properties of the ionospheric waves have been previously characterized in terms of their energy and wave vector. In this study, their power was measured directly from the phase shift of the strongest set of ionospheric waves. The power of these waves, which originated at Albuquerque, the local major power consumer, was 15.3 W, producing a power density of 0.018 W/m2. The calculated power density that should be generated from the local power generating stations around Albuquerque was also 0.018 W/m2, in agreement with the experimentally measured value. This correspondence shows that the power generated by power stations and being consumed is not lost but captured by the ionosphere.

In aspiring to investigate diverse industrial and technological collections the Congruence Engine project highlights the fragmentation and loss of knowledge that often occurs when an industry or an individual workplace closes, or when a technology becomes obsolescent or redundant. Until relatively recently (often due to narrow institutional responsibilities and collecting policies) the heritage sector has had little ability to secure a holistic understanding of workplaces and the inter-connectedness of people, places, technology, objects and their associated records. The Historic England Archive, which is essentially a place-based collection, may be unfamiliar to many in the museum sector and academia. This paper introduces its archive collections that relate to industry and technology, describes their evolution through past recording and collecting policies and discusses how they might be used to further a deeper contextualisation of museum objects. A case study of recent work at the Science Museum to secure the historical legacy of post-war power stations follows. It describes the processes and challenges involved in collecting large industrial heritage objects and illustrates how closer working relationships between heritage institutions might ensure that a more rounded response is made to the loss of obsolescent industries, plant and technologies.

In aspiring to investigate diverse industrial and technological collections the Congruence Engine project highlights the fragmentation and loss of knowledge that often occurs when an industry or an individual workplace closes, or when a technology becomes obsolescent or redundant. Until relatively recently (often due to narrow institutional responsibilities and collecting policies) the heritage sector has had little ability to secure a holistic understanding of workplaces and the interconnectedness of people, places, technology, objects and their associated records. The Historic England Archive, [1] which is essentially a place-based collection, may be unfamiliar to many in the museum sector and academia. This paper introduces its archive collections that relate to industry and technology, describes their evolution through past recording and collecting policies and discusses how they might be used to further a deeper contextualisation of museum objects. A case study of recent work at the Science Museum to secure the historical legacy of post-war power stations follows. It describes the processes and challenges involved in collecting large industrial heritage objects and illustrates how closer working relationships between heritage institutions might ensure that a more rounded response is made to the loss of obsolescent industries, plant and technologies. [ABSTRACT FROM AUTHOR]

The coal waste from power stations in the north and south of the Kuznetsk Basin are compared in terms of their suitability for concrete production and as a source of valuable components. The mean aggregate content of rare and rare-earth metals in ash and slag waste in the Kemerovo region is 0.02–0.04%; the content of matrix elements is up to 65%. Such waste is promising for the extraction of matrix, rare, and rare-earth metals. [ABSTRACT FROM AUTHOR]

Dioxin‐like polychlorinated biphenyls (dl‐PCBs) are ubiquitous chemicals which mediate toxicity in a way similar to polychlorinated dibenzo‐p‐dioxins and polychlorinated dibenzofurans. In silico modeling was used to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of eight dioxin‐like PCBs in soil samples of 12 power stations in Lagos, Nigeria. Concentrations of Σdl‐PCB8 in soil samples ranged from 490 to 61,000 pg g−1, with mean concentrations of 17,000 pg g−1. The corresponding toxic equivalent (TEQ) concentrations of Ʃdl‐PCB8 ranged from 0.01 to 450 pg TEQ g−1, with a mean value of 42 pg TEQ g−1. Mean TEQ concentrations for Ʃdl‐PCB8 in soil samples from all but one of the sites exceeded the Canadian guideline value of 4 pg TEQ g−1 and the US and German guideline values of 5–10 pg TEQ g−1. However, the TEQ concentrations obtained were all below the US action level of 1000 pg TEQ g−1. The ADMET predictions revealed that all studied dl‐PCBs are inhibitors of three major isoforms (1A2, 2C9, and 2C19) of cytochrome P450 enzyme. Acute oral toxicity (median lethal dose) predictions revealed that all target dl‐PCBs were class III compounds. Hepatotoxicity and carcinogenicity were positive, signifying that the studied compounds all have a tendency to elicit these effects. Occupational daily TEQ exposure via soil ingestion was estimated for an average adult worker weighing 70 kg. The maximum exposure obtained was 0.14 pg TEQ kg−1 body weight day−1, which is half of the European Food Safety Authority (EFSA) tolerable daily intake (TDI) for dioxin‐like compounds. This raises concern over the possible exceedance of the EFSA TDI for these workers if other dietary and nondietary exposure pathways and dioxin‐like compounds are considered. Environ Toxicol Chem 2022;41:800–809. © 2021 SETAC [ABSTRACT FROM AUTHOR]

This article analyses four of the thirteen housing developments for workers that were designed in northern Spain for the Electra de Viesgo electricity company by Ignacio Álvarez Castelao between 1948 and 1965, namely those constructed in Puente de San Miguel in Santander, Aguilar de Campoo in Palencia, Soto de Ribera in Oviedo, and Santa María de Garoña in Burgos. We analyse the theoretical foundations Castelao developed in the mid-1950s to construct these four residential complexes, which were based on modulation, prefabrication and the systematisation of constructive elements in order to streamline their construction in the rural environment. Also systematically analysed in this paper are the public spaces, the housing, the furniture, and the transitions Castelao introduced between the various scales, from the geographical urban planning scale to architecture and furniture. In essence, we study the elements of architecture Castelao designed to create orderly housing developments with comfortable habitability conditions for the workers both inside and outside their homes.

The main objective of this study is to evaluate the emissions of volatile organic compounds (VOCs) from coal-fired power stations. A quantitative understanding of the chemistry controlling the formation and destruction of these intermediate species is a prerequisite for the realistic modelling of pollutant formation in flames. Therefore, well investigated skeletal reaction mechanism has been built and introduced into perfectly stirred reactor model in order to accomplish prediction of some of these hazardous important intermediate species. This can be great help in considering lack of experimental VOCs data from fossil fuel fired power stations. Predicted results have been validated against ICSTM Furnace data where possible. The performance of the model against the large laboratory scale experimental data has resulted in considerable confidence in the use of this model for a full-scale boiler configuration. But, more confidence will be forthcoming from an increase in the amount of validation data, which is unluckily lacking at the moment. Furthermore, the model can be used in order to provide deeper insight into the formation processes of VOC species emitted from coal-fired power stations. However, this can be accomplished far better by including more elementary reactions into the skeletal reaction mechanism.

Under new scenarios with high shares of renewable electricity, combined cycle gas turbines (CCGTs) are required to improve their flexibility to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. An inlet conditioning unit (ICU) offers the benefit of power augmentation and "minimum environmental load" (MEL) reduction by controlling the gas turbine (GT) inlet temperature using cold thermal energy storage (TES) and a heat pump (HP). Consequently, an evaluation of a CCGT integrated with this unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the ICU, a mixed-integer linear programing (MILP) optimization was formulated, aiming to maximize the operational profit of the plant within a 24 h horizon. To assess the impact of the unit operating under this dispatch strategy, historical data have been used to perform annual simulations of a reference power plant located in Turin, Italy. Results indicate that the power plant's operational profit increases by achieving a wider operational range during peak and off-peak periods. For the specific case study, it is estimated that the net present value (NPV) of the CCGT integrated with the ICU is 0.5% higher than the CCGT without it. Results also show that the unit reduces the MEL by approximately 1.34% and can increase the net power output by 0.17% annually. [ABSTRACT FROM AUTHOR]

In this article analysis of the energy system of the Republic of Yemen, its composition and characteristics of the transmission lines, power stations and substations, it also considers the prospects for the development of the power system in the country.

Conventional physics-based or experimental-based approaches for gas turbine combustion tuning are time consuming and cost intensive. Recent advances in data analytics provide an alternative method. In this paper, we present a cross-disciplinary study on the combustion tuning of an F-class gas turbine that combines machine learning with physics understanding. An artificial-neural-network-based (ANN) model is developed to predict the combustion performance (outputs), including NOx emissions, combustion dynamics, combustor vibrational acceleration, and turbine exhaust temperature. The inputs of the ANN model are identified by analyzing the key operating variables that impact the combustion performance, such as the pilot and the premixed fuel flow, and the inlet guide vane angle. The ANN model is trained by field data from an F-class gas turbine power plant. The trained model is able to describe the combustion performance at an acceptable accuracy in a wide range of operating conditions. In combination with the genetic algorithm, the model is applied to optimize the combustion performance of the gas turbine. Results demonstrate that the data-driven method offers a promising alternative for combustion tuning at a low cost and fast turn-around. [ABSTRACT FROM AUTHOR]

Renewable energy sources have immense potential for enhancing environmental sustainability; however, addressing their intermittency and irregularity is vital for optimizing economic benefits within microgrids. Integrating renewable energy systems with energy storage presents a promising solution. This study introduces an innovative energy management system designed for hybrid renewable power stations, incorporating battery energy storage systems and diesel generators. By accounting for battery degradation costs associated with charge depth and lifespan, the study transforms long-term battery expenses into real-time operational costs. The optimization problem is formulated as a mixed integer linear programming framework with the objectives of minimizing operating costs, battery degradation costs, and pollutant gas emissions. Through diverse case studies reflecting various market profiles. The proposed approach demonstrates reductions in overall system costs., Competing Interests: The authors declare that they have no conflicts of interest regarding the research presented in this manuscript. Specifically, there are no financial interests or arrangements with any individuals, organizations, or entities that could be perceived as having influenced the research conducted or the content of this paper. 10.13039/100014337Furthermore, the authors declare that they have not received any financial support, funding, or grants from any sources that might have a vested interest in the outcomes or conclusions of this research. This research has been conducted with integrity and objectivity, and the results and interpretations presented herein are solely based on the data and analysis.The authors are committed to upholding the highest standards of transparency and ethics in their research endeavors., (© 2024 The Authors.)

Purpose of the study. During the period of the fall of technical and technological stability of the Russian electric power industry, the issues related to the study of the historical experience of the origin, construction and development of such large industrial complexes are actualized. The present study aims to analyze the history of the development of the Russian electric power industry after the October Revolution of 1917, to reveal the influence of the revolution on the electric power industry, to investigate the postwar period of the formation of the Unified Energy System and to assess the current state of the electric power industry in the absence of large-scale projects and programs for updating and modernizing production facilities, propose mechanisms to improve technical and technological stability of electricity of the Russian Federation.Materials and methods. In 1920, after the October Revolution of 1917, the first plan related to the development of economic activities of the national economy was adopted, which was called the State Plan for the Electrification of Russia. This document contained the main mechanisms and requirements for the formation and establishment of a new branch for the economy. Based on the use of data from the Government of the Russian Federation, Federal State Statistics Service of the Russian Federation, the Ministry of Energy of the Russian Federation, Joint-stock company “United Energy System of Russia”, as well as electric power companies, the post-revolutionary period of the electric power industry development, the current state and the existing potential of the Russian electric power industry are analyzed. Using the economic-statistical, comparative and logical methods, the main results of the study were presented.Results. Analyzed indices of the electric power industry in the period 1920–1935 indicate a breakthrough in the development of the Russian energy sector, this period was marked by the implementation of the plans ahead of schedule. In the post-war period, from 1950–1985, there was an increase in the construction of production capacities, The development of the electric power industry after the October Revolution of 1917: origins, prospects and problems at the same time, both heat and hydro and nuclear power plants were built, thereby increasing the installed capacity by more than 10 times in thirty years. After the collapse of the Soviet Union, there has been a halt in the pace of development of the Russian electric power industry, and now the deprecation of the fixed assets increase, the degradation of energy equipment, the aging of power generation technologies, the fall in investment attractiveness and the efficiency of management of generating capacities, which can lead to mass failure equipment and emergency consequences.The conclusion. Based on the results of the study, we have the following conclusions in the need to search for new mechanisms to improve the sustainability of the electricity industry in the absence of financial resources. In the author's opinion, it is advisable to implement them on three interrelated mechanisms: revising production capacities, eliminating potentially worn-out fixed assets; the formation of common programs for the development of the electric power industry within the framework of the General Electricity Market of the Eurasian Economic Union; the construction of power plants in the border areas, due to which several national states will provide electric power.

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The behavior of poorly heat-conducting coatings of low porosity on metal substrates is simulated. Analysis of the thermoelasticity reveals the influence of the unit heat flux and the thermal compressive and tensile stress on the limiting state of the coating–substrate system. [ABSTRACT FROM AUTHOR]

The reliability of electricity supply was at the forefront of political debate in postwar New South Wales. Government-mandated power restrictions, load-shedding, and the resulting blackouts were increasingly frequent and widespread. Sound technical recommendations to resolve the effects of a fragmented industry had floundered on a lack of a political catalyst to establish central ownership and operational control of the industry. By 1950, an ineffective energy policy, ageing equipment that was unable to supply the increasing demand, inadequate maintenance, and wartime restrictions on the availability of new plant, contributed to a 30 per cent shortfall in electricity supply. Combined with a looming state election, these factors provided the political catalyst for the government to implement an energy policy to centralise the industry in May 1950 and resolve the crisis by late 1953. Resolution of the New South Wales (NSW) postwar energy crisis and the south-east Australian energy impasse of the twenty-first century were, and are, reliant on an appropriate political response and the appropriate management of technology. In the 1940s, the central problem was the lack of generation capacity; in the twenty-first century, the transition from fossil fuels to renewable sources is the core issue. [ABSTRACT FROM AUTHOR]

The main objective of this study is to evaluate the emissions of volatile organic compounds (VOCs) from coal-fired power stations. A quantitative understanding of the chemistry controlling the formation and destruction of these intermediate species is a prerequisite for the realistic modelling of pollutant formation in flames. Therefore, well investigated skeletal reaction mechanism has been built and introduced into perfectly stirred reactor model in order to accomplish prediction of some of these hazardous important intermediate species. This can be great help in considering lack of experimental VOCs data from fossil fuel fired power stations. Predicted results have been validated against ICSTM Furnace data where possible. The performance of the model against the large laboratory scale experimental data has resulted in considerable confidence in the use of this model for a full-scale boiler configuration. But, more confidence will be forthcoming from an increase in the amount of validation data, which is unluckily lacking at the moment. Furthermore, the model can be used in order to provide deeper insight into the formation processes of VOC species emitted from coalfired power stations. However, this can be accomplished far better by including more elementary reactions into the skeletal reaction mechanism. [ABSTRACT FROM AUTHOR]

It is a deeply entrenched belief that emissions of sulphur dioxide into the atmosphere are harmful to the environment, and that sulphur compounds should be removed from the gaseous wastes before discharge. The difficulties with this view are summarised. Extensive work in both North America and Europe has failed to demonstrate any of the early claims for impacts such as forest death. The claims for health effects seem unduly conservative and not supported by reliable data. There are even negative impacts from reducing sulphur emissions. Claims for high external costs associated with coal-fired power generation in South Africa are the result of arithmetic errors. The installation of flue-gas desulphurisation on the latest Eskom power station, Kusile, is shown to be completely unsustainable in the light of the minimal benefits that the considerable costs will bring.

Previous work by the authors has shown that broader analyses than those typically found in literature (in terms of operating pressures allowed) can yield interesting conclusions with respect to the best candidate cycles for certain applications. This has been tested for the thermodynamic performance (first and second laws) but it can also be applied from an economic standpoint. This second approach is introduced in this work where typical operating conditions for concentrated solar power (CSP) applications (current and future generations of solar tower plants) are considered (750°C and 30MPa). For these, the techno-economic performance of each cycle is assessed in order to identify the most cost-effective layout when it comes to the overnight capital cost (OCC). This analysis accounts for the different contributions to the total cost of the plant, including all the major equipment that is usually found in a CSP power plant such as the solar field and thermal energy storage (TES) system. The work is, thus, aimed at providing guidelines to professionals in the area of basic engineering and prefeasibility study of CSP plants who find themselves in the process of selecting a particular power cycle for a new project (set of specifications and boundary conditions). [ABSTRACT FROM AUTHOR]

The effects of collector roughness shape on the performance of solar chimney power plant were investigated in this study. The roughness shapes of triangular, curved, and square grooves were chosen and were compared to smooth case. The performance parameters of solar radiation, updraft velocity, temperature distribution, static pressure, power, and Nusselt number were varied. The effects of number, position, height, and width of the grooves on the performance were investigated. The results of this investigation show that the updraft velocity with the triangular groove increases by 1.5 times compared to the smooth case at solar radiation of 1000 W/m². At solar radiation of 1000 W/m², the power increases by 169%, 96%, and 19% for triangular, curved, and square grooves, respectively, compared to the smooth case. Moreover, the Nusselt number values with triangular groove and curved groove enhance by 42% and 26%, respectively, compared to the smooth case. The power increases by 1.98% for three grooves instead of using one groove at higher solar radiation. Increasing the groove height by 1.7 times, the power increases by 1.03 times at higher solar radiation. The power enhancement shows less sensitivity to the change of groove width at higher solar radiation. [ABSTRACT FROM AUTHOR]

In this paper, the effect of water, air, and their combined injection from two different injection points is studied in order to reduce vorticity effects in a draft tube of prototype turbine working at three operating points. The flow from spiral case to the end of draft tube is simulated using the shear stress transport k-ω turbulence and two-phase models. Using an appropriate validation method, acceptable results were obtained under the noninjection condition. To determine suitable number of points and inlet flow rate for air injection as well as the appropriate nozzle diameter for air and water injection, a new method which considers the ratio of total loss to the pressure recovery factor is used, in addition to using the traditional method which calculates the total loss in the draft tube. Comparing results of the three types of injections shows air injection in the operating range greater than 70% of turbine design flow rate, is much more effective than water injection or the combination of air and water injection. However, in the operating range below 70%, either water or air injections are not suitable, but combination of these two fluids can improve system performance. [ABSTRACT FROM AUTHOR]

The rapid growth of renewable generation and its intermittent nature has modified the role of combined cycle power stations in the energy industry, and the key feature for the operational excellence is now flexibility. Especially, the capability to start an installation quickly and efficiently after a shutdown period leads to lower operational cost and a higher capacity factor. However, most of existing thermal power stations worldwide are designed for continuous operation, with no special focus on an efficient start-up process. In most current start-up procedures, the gas turbine controls ensure maximum heat flow to the heat recovery steam generator, without feedback from the steam cycle. The steam cycle start-up controls work independently with as main control parameter the limitation of the thermal stresses in the steam turbine rotor. In this paper, a novel start-up procedure of an existing combined cycle power station is presented, and it uses a feedback loop between the steam turbine, the boiler and the gas turbine start-up controls. This feedback loop ensures that the steam turbine can be started up with a significant reduction in stresses. To devise and assess this start-up methodology, a flexible and accurate dynamic model was implemented in the Simulink environment. It contains >100 component blocks (heat exchangers, valves, meters and sensors, turbines, controls, etc.), and the mathematical component submodels are based on physical models and experimental correlations. This makes the model generally applicable to other power plant installations. The model was validated against process data related to the three start-up types (cold start, warm start, hot start). On this basis, the optimization model is implemented with feedback loops that control, for example, the exit temperature of the gas turbine based on the actual steam turbine housing temperature, resulting in a smoother heating up of the steam turbine. The optimization model was used to define the optimal inlet guide vanes position and gas turbine power output curves for the three types of start-up. These curves were used during real power station start-ups, leading to, for cold and warm starts, reductions in the start-up time of, respectively, 32.5% and 31.8%, and reductions in the fuel consumption of, respectively, 47.0% and 32.4%. A reduction of the thermal stress in the steam turbines is also achieved, thanks to the new start-up strategy. [ABSTRACT FROM AUTHOR]

Requirements for the start-up operations of gas turbine combined cycle (GTCC) power plants have become more diverse and now include such items as reduced start-up time, life consumption, and fuel gas consumption. In this paper, an optimization method is developed to solve these multi-objective problems. The method obtains optimized start-up curves by iterating the search for the optimal combination of the start-up parameter values and the evaluation of multiple objective functions. The start-up curves generated by this method were found to converge near the Pareto-front representing the best trade-off between the fuel gas consumption of the gas turbine (GT) and thermal stress in the steam turbine (ST) rotor which are defined as the objective functions. To demonstrate the effectiveness of the developed method, field tests were performed in a commercial power plant. As a result, the fuel gas consumption of HOT start-up was reduced by 22.8% compared with the past operation data. From this result, the developed method was shown to be capable of optimizing the start-up process for GTCC power plants. [ABSTRACT FROM AUTHOR]

In satellite photography, individuals on Earth are too small to be visible, yet our impact through technology is plain to see. American artist Jenny Odell tells Guest‐ Editor Liam Young how she has been scouring satellite imagery for industrial landscapes that serve as portraits by proxy, underlining our reliance on the machines we have created. [ABSTRACT FROM AUTHOR]

In this work, the exergy analysis of two configurations of hybrid solar-sugarcane cogeneration power plant is proposed in order to evaluate the overall efficiency enhancement of the cycle. Solar thermal energy was coupled to a sugarcane cogeneration power plant localized on the tropical region of Brazil, in order to preheat the feeding water supplied to the steam generators and to reduce the fuel consumption during the sugarcane-harvesting season in order to stock the unused fuel for its use during the off-season. The exergy analysis of the cycle was proposed based on a thermodynamic model, which considered real operational states, and allowed to quantify the main parameters of performance, such as the solar-to-electricity (STE) efficiency, the power generation increasing, the percentage of fuel saved, and the exergy destruction rates of the equipment. The results showed that, under design conditions, almost 10% of fuel was saved, and the overall exergy destruction decreased 11% approximately. Additionally, as a result of the hourly analysis of the annual operation, it was found that the power plant operated 331 extra hours, 8.50 GWh of electricity were generated, and due to this fact, it has attained economic benefits for the operation of the sugarcane cogeneration power plant. [ABSTRACT FROM AUTHOR]

Satellite retrievals have highlighted the South African Highveld as a region with one of the highest nitrogen oxide (NOx) emission densities in the world. There are numerous sources of NOx on the Highveld, including coal-fired power stations, petrochemical and other industries, motor vehicles and lightning, but surface measurements of NOx have not indicated that there is any cause for concern. A number of research initiatives are being undertaken in an attempt to resolve the discrepancy between surface measurements and satellite retrievals of NOx. An assessment of ground-level concentrations in various environments, including industrial and urban regions, has shown that NOx levels recorded in the low-income urban area are significantly higher than those recorded downwind of industries or power stations. NO2 column densities have been remotely sensed over the Highveld using an airborne imaging Differential Optical Absorption Spectrometer (iDOAS), in order to validate the satellite retrievals and investigate individual sources of NOx. Results from the first campaign show high NO2 integrated column densities in the immediate vicinity of sources. Well defined plumes can be observed downwind of prominent sources.

Integrated gasification humid air turbine (IGHAT) cycle is an advanced power generation system, combining gasification technology and humid air turbine (HAT) cycle. It draws great attention in the energy field considering its high specific power, high efficiency, and low emission. There are only a few HAT cycle plants and IGHAT cycle is still on the theory research stage. Therefore, the study on control strategies of IGHAT cycle has great significance in the future development of this system. A design method of control strategy is proposed for the unknown gas turbine systems. The control strategy design is summarized after IGHAT control strategy and logic is designed based on the dynamic simulation results and the operation experience of gas turbine power station preliminarily. Then, control logic is configured and a virtual control system of IGHAT cycle is established on the Ovation distribution control platform. The model-in-loop control platform is eventually set up based on the interaction between the simulation model and the control system. A case study is implemented on this model-in-loop control platform to demonstrate its feasibility in the practical industry control system. The simulation of the fuel switching control mode and the power control mode is analyzed. The power in IGHAT cycle is increased by 24.12% and 32.47%, respectively, compared to the ones in the simple cycle and the regenerative cycle. And the efficiency of IGHAT cycle is 1.699% higher than that of the regenerative cycle. Low component efficiency caused by off-design performance and low humidity caused by high pressure are the main limits for system performance. The results of case study show the feasibility of the control strategy design method proposed in this paper. [ABSTRACT FROM AUTHOR]

A detailed look at the gas turbine (GT) technology over the last three decades clearly shows that an asymptotic limit is reached in thermal efficiency in combined cycle (CC) configuration. There is little reason to expect a technology leap anytime soon to change this appreciably as long as the industry sticks to the classic Brayton cycle configuration and the brute force approach of ever higher turbine inlet temperatures (TITs). The changing landscape of electric power generation, especially integration of fossil fuel fired technologies with renewable generation and wide variation in natural gas prices, suggests that it is time to look at the direction of future development efforts differently. This paper looks at the need of a paradigm shift in GT CC technology using thermodynamic and economic arguments. [ABSTRACT FROM AUTHOR]

Future wireless communication systems will consist of multiple networks with various capabilities. Wireless networks may encounter severe distortions due to the presence of interfering signals generated at some power stations dedicated to smart grid applications. In fact, severe environmental effects of high voltage substations must be considered, particularly impulsive noise needs to be taken into account. Firstly, to cope with this kind of hostile environment, an efficient channel coding scheme in a mono‐user system is proposed, when one source user transmits data directly to one terminal user. Performance analysis shows that the proposed coding schemes based on rank metric codes are very efficient to eliminate impulsive noise in mono‐user mode. Furthermore, this approach are expanded in order to show the efficiency of rank codes in Wireless Sensors Networks (WSNs), when considering the problem of collecting data in WSNs in the presence of impulsive noise errors together with AWGN channel. To increase the reliability of the system, an advanced Network Coding technique (NC) is applied based on LRPC (Low Rank Parity Check) codes which exhibits noteworthy performances. [ABSTRACT FROM AUTHOR]

The issue of reflector soiling becomes more important as concentrating solar thermal power plants (CSP) are being implemented at sites subject to high dust loads. In an operational power plant, a trade-off between reducing cleaning costs and cleaning related collector availability on the one hand and keeping the solar field cleanliness (ξfield) high to minimize soiling induced losses on the other hand must be found. The common yield analysis software packages system advisor model (SAM) and greenius only allow the input of a constant mean ξfield and constant cleaning costs. This oversimplifies real conditions because soiling is a highly time-dependent parameter and operators might adjust cleaning activities depending on factors such as soiling rate and irradiance. In this study, time-dependent soiling and cleaning data are used for modeling the yield of two parabolic trough plant configurations at two sites in Spain and Morocco. We apply a one-year soiling rate dataset in daily resolution measured with the tracking cleanliness sensor (TraCS). We use this as a basis to model the daily evolution of the cleanliness of each collector of a solar field resulting from the application of various cleaning strategies (CS). The thus obtained daily average ξfield is used to modify the inputs to the yield analysis software greenius. The cleaning costs for each CS are subtracted from the project's financial output parameters to accurately predict the yield of a CSP project over its lifetime. The profits obtained with different CSs are compared in a parameter variation analysis for two sites and the economically best CS is identified. The profit can be increased by more than 2.6% by the application of the best strategy relative to a reference strategy that uses a constant cleaning frequency. The error in profit calculated with constant soiling and cleaning parameters compared to the simulation with variable soiling and cleaning can be as high as 9.4%. With the presented method, temporally variable soiling rates and CS can be fully integrated to CSP yield analysis software, significantly increasing its accuracy. It can be used to determine optimum cleaning parameters. [ABSTRACT FROM AUTHOR]

Flow-induced vibration analysis of the San Onofre Nuclear Generating Station (SONGS) replacement steam generators (RSG) is made using nonproprietary public data for these steam generators on the Nuclear Regulatory Commission public web site (www.NRC.gov). The analysis uses the methodology of Appendix N Section III of the ASME Boiler and Pressure Vessel Code, Subarticle N-1300 Flow-Induced Vibration of Tubes and Tube Banks. First, the tube geometry is assembled, and overall flow and performance parameters are developed at 100% design flow; then, the analysis is made to determine the flow velocity in the gap between tubes and tube natural frequencies and mode shapes. Finally, the mass damping and reduced velocity for tubes on the U bend are assembled and plotted on the ASME code Figure N-11331-4 fluid elastic stability diagram. [ABSTRACT FROM AUTHOR]

Postcombustion CO2 capture from natural gas combined cycle (NGCC) power plants is challenging due to the large flow of flue gas with low CO2 content (∼3-4 vol %) that needs to be processed in the capture stage. A number of alternatives have been proposed to solve this issue and reduce the costs of the associated CO2 capture plant. This work focuses on the selective exhaust gas recirculation (S-EGR) configuration, which uses a membrane to selectively recirculate CO2 back to the inlet of the compressor of the turbine, thereby greatly increasing the CO2 content of the flue gas sent to the capture system. For this purpose, a parallel S-EGR NGCC system (53% S-EGR ratio) coupled to an amine capture plant (ACP) using monoethanolamine (MEA) 30 wt % was simulated using gCCS (gPROMS). It was benchmarked against an unabated NGCC system, a conventional NGCC coupled with an ACP (NGCC + carbon capture and storage (CCS)), and an EGR NGCC power plant (39% EGR ratio) using amine scrubbing as the downstream capture technology. The results obtained indicate that the net power efficiency of the parallel S-EGR system can be up to 49.3% depending on the specific consumption of the auxiliary S-EGR systems, compared to the 49.0% and 49.8% values obtained for the NGCC + CCS and EGR systems, respectively. A preliminary economic study was also carried out to quantify the potential of the parallel S-EGR configuration. This high-level analysis shows that the cost of electricity (COE) for the parallel S-EGR system varies from 82.1 to 90.0 $/MWhe for the scenarios considered, with the cost of CO2 avoided (COA) being in the range of 79.7-105.1 $/ton CO2. The results obtained indicate that there are potential advantages of the parallel S-EGR system in comparison to the NGCC + CCS configuration in some scenarios. However, further benefits with respect to the EGR configuration will depend on future advancements and cost reductions achieved on membrane-based systems. [ABSTRACT FROM AUTHOR]

The techno-eсosystem concept in the hydrosphere is considered. Certain features of a technoeсosystem, such as peculiar biotopic structure, presence of high-gradient conditions, low predictability of its behavior and development are described. The concept of ecosystem-biogeocenosis gradient is introduced. The place of techno-eсosystems in the Biosphere is considered

Water is a scarce natural resource fundamental for human life. Power plant architects, engineers, and power utilities owners must do everything within their hands and technical capabilities to decrease the usage of water in power plants. This paper illustrates the research carried out by Pöyry Switzerland to reduce the water consumption on power and desalination combined cycle power plants, on which there are gas turbine evaporative cooling systems in operation. The present study analyzed the potential re-utilization and integration of the heat recovery steam generator (HRSG) blowdown into the evaporative cooling system. Relatively clean demineralized water, coming from the HRSG blowdown, is routed to a large water tank, where it is blended with distillate water to achieve the required water quality, before being used on the gas turbine evaporative cooling system. To prove the feasibility of the HRSG blowdown recycling concept, the Ras Al Khair Power and Desalination Plant owned and operated by the Saline Water Conversion Corporation (SWCC), located in the Eastern Province of the Kingdom of Saudi Arabia, was used as case study. Nevertheless, it is important to mention that the principles and methodology presented on this paper are applicable to every power and desalination combined cycle power plant making use of evaporative cooling. Sea water desalination is the primary source for potable water production on Saudi Arabia, with secondary sources being surface water and groundwater extracted from deep wells and aquifers. Saving water is of utmost importance for power plants located in locations where water is scarce, and as such, this paper aims to demonstrate that it is possible to decrease the water consumption of power and desalination combined cycle plants, on which evaporative cooling is used as gas turbine power booster, without having to curtail power production. The outcome of the study indicates that during the summer season, recycling the HRSG water blowdown into the gas turbine evaporative cooling systems would result on the internal water consumption for the gas turbine evaporative coolers decreasing by 545 ton/day, or 23.79%, compared with the original plant design which does not contemplate blowdown re-use. Using evaporative cooling results on an overall gain of 186 MW, or 10.27%, on gross power output, while CO2 emissions decrease by 46.8 ton CO2/h, which represents a 13.8% reduction compared with the case on which the evaporative cooling system is not in operation. A brief cost analysis demonstrated that implementation of the changes would result in a negligible increase of the operational expenses (OPEX) of the plant, i.e., implementation of the suggested modification has an unnoticeable impact on the cost of electricity (CoE). The payback of the project, due to limited operating hours on evaporative cooling every year, is of 12 years for a 30 year plant lifetime, while 2.22 M USD of extra-revenue on potable water sales are generated as a result of implementing the proposed solution. Although in principle this value is modest, the effect of government subsidies on water tariffs as well as political and strategic cost of water is not included on the calculations. In conclusion, the study results indicate that water recycling, and reduction of plant's water footprint for power and desalination combined cycle plants using evaporative cooling, is not only technically possible but commercially feasible. [ABSTRACT FROM AUTHOR]

A new anidolic parametric trough solar collector (PmTC) having 8.12 m net width aperture has been recently proposed for a commercial evacuated receiver tube with an absorber diameter of 70 mm. Since the collector was designed ignoring transmission, absorption, and reflection optical losses, calculations of the optical efficiency and the incidence angle modifier (IAM) by means of Monte Carlo spectral raytracing simulations using real slope errors distributions and taking into account Fresnel reflection losses were done. Comparison with an Eurotrough parabolic trough collector (PTC) shows an optical penalization of 5.1% due to the reflectivity and additional soiling of the secondary mirror, to an increase in the end losses and to the Fresnel reflection losses. The National Renewable Energy Laboratory (NREL) system advisor model (SAM) was used to perform annual simulations of two commercial 50 MWe oil power plants without thermal energy storage located in Seville. A PTC solar field consisting of 90 loops, each one having four Eurotrough solar collector assemblies (SCA) with 150 m length was first modeled resulting in a gross production of 386 kWh/(m² yr). A PmTC solar field with the same module length and similar SCA net aperture area was also simulated. A final configuration of 94 loops and four SCAs with 100 m length per loop yields a gross production of 379 kWh/(m² yr) showing no improvement compared to the reference PTC plant. The present study allows to advance in the understanding of the potential of the anidolic optic to produce optical geometries able to effectively improve the PTC technology in the short-term projecting results at a commercial plant level. [ABSTRACT FROM AUTHOR]

In this paper, a theoretical model of solar chimney power plants (SCPPs) is presented based on compressible ideal gas law assumptions. The theoretical optimal turbine pressure drop factors (TPDFs) for constant and nonconstant densities (CD and NCD) are studied, and the effects of flow area parameters examined. Results show that the theoretical optimal TPDF for CD is equal to 2/3 and is independent of the flow area parameters. Results also show that the theoretical optimal TPDF for NCD is close to 1 and is affected by the flow area parameters. However, the theoretical maximum fluid power (MFP) obtained for NCD is never attained in real life. For the actual states, the theoretical optimal TPDF for NCD is still effectively high enough. The TPDF and the fluid power for NCD increase with the reduction of the collector inlet area, and more precisely with the reduction of the chimney inlet area. The TPDF and the fluid power definitely increase with larger chimney flow area. The increase in the fluid power due to shape optimization of the SCPP is limited compared to that due to higher input heat flux of collector. Divergent-top and upward slanting roof shapes are recommended for the solar chimney and the solar collector, respectively, for better SCPP performance. Additionally, locations exposed to strong solar radiation are preferred for SCPPs. [ABSTRACT FROM AUTHOR]

In this paper, a general methodology for designing carbon-neutral residential communities is presented. Both energy efficiency measures and renewable energy technologies are considered in the design approach. First, energy end-uses for the buildings within the community are optimized based on a set of cost-effective energy efficiency measures that are selected based on a life-cycle cost analysis. Then, renewable energy technologies are considered to meet the energy needs for the residential community and ensure carbon-neutrality on an annual basis. The methodology is applied to design optimal and carbon-neutral hybrid electrical generation systems for three Kuwaiti residential communities with different sizes and energy efficiency designs. For Kuwait, it is found that wind turbines can cost-effectively generate significant electricity to meet most of the energy needs for the residential communities and thus reducing the country's reliance on fuel-based power plants. Specifically, it is found that wind turbines can generate electricity at a cost of $0.068/kWh well below the current grid power production costs of $0.103/kWh. Moreover, the analysis indicates that concentrated solar power (CSP) can be utilized to achieve carbon-neutral residential communities but at a levelized energy cost of $0.13/kWh slightly lower than the current grid power generation and distribution costs of $0.133/kWh. [ABSTRACT FROM AUTHOR]