Power Generation Facilities Research Articles

Solving Renewables-Integrated Economic Load Dispatch Problem by Variant of Metaheuristic Bat-Inspired Algorithm

One of the most important concerns in the planning and operation of an electric power generation system is the effective scheduling of all power generation facilities to meet growing power demand. Economic load dispatch (ELD) is a phenomenon where an optimal combination of power generating units is selected in such a way as to minimize the total fuel cost while satisfying the load demand, subject to operational constraints. Different numerical and metaheuristic optimization techniques have gained prominent importance and are widely used to solve the nonlinear problem. Although metaheuristic techniques have a good convergence rate than numerical techniques, however, their implementation seems difficult in the presence of nonlinear and dynamic parameters. This work is devoted to solving the ELD problem with the integration of variable energy resources using a modified directional bat algorithm (dBA). Then the proposed technique is validated via different realistic test cases consisting of thermal and renewable energy sources (RESs). From simulation results, it is observed that dBA reduces the operational cost with less computational time and has better convergence characteristics than that of standard BA and other popular techniques like particle swarm optimization (PSO) and genetic algorithm (GA).

Real-Time Pricing Scheme in Smart Grid Considering Time Preference: Game Theoretic Approach

Unbalanced power demand across time slots causes overload in a specific time zone. Various studies have proved that this can be mitigated through smart grid and price policy, but research on time preference is insufficient. This study proposed a real-time pricing model on a smart grid through a two-stage Stackelberg game model based on a utility function that reflects the user’s time preference. In the first step, the suppliers determine the profit-maximizing price, and then, the users decide the electricity usage schedule according to the given price. Nash equilibrium and comparative analysis of the proposed game explain the relationship between time preference, price, and usage. Additionally, a Monte Carlo simulation demonstrated the effect of the change in time preference distribution. The experimental results confirmed that the proposed real-time pricing method lowers peak-to-average ratio (PAR) and increases overall social welfare. This study is meaningful in that it presents a pricing method that considers both users’ and suppliers’ strategies with time preference. It is expected that the proposed method would contribute to a reduction in the need for additional power generation facilities through efficient operation of the smart grid.

Biomass Renewable Energy Environmental Protection Low Carbon City Power Generation and Heating Device

Biomass energy is a kind of renewable energy. The development and utilization of biomass energy can alleviate the pressure of energy shortage, reduce environmental pollution, and improve the future energy structure. This article aims to achieve eco-friendly, low-carbon, intelligent, modern, smoke-free, energy-cyclable and renewable energy through the research on biomass renewable energy and environmental protection low-carbon city power generation and heating devices. This paper proposes a modern utility model biomass renewable energy environmental protection low-carbon city power generation and heating device, and the feasibility of the device has been verified through experiments. It is concluded that the change in raw material consumption has little effect on the gas components and calorific value in biogas. The power generation and heating device has good adaptability to the amount of raw materials, and its comprehensive pollutant emissions are compared with traditional coal and petroleum. Power generation and heating facilities are reduced by 99%. The research in this paper helps to alleviate the shortage of energy supply in my country, develop a circular economy, and promote the sustainable development of social economy.

Assessment of the global climate change impact on Fuel and Energy Complex infrastructure and adaptation opportunities in the Russian Arctic

The paper considers the problems and features of the functioning of the energy complex in the regions of the Russian Arctic under the influence of global climate change. Particular attention is paid to new ideas and developments intended for practical use in developing measures to adapt to the adverse effects of climate change. The issues of optimising the composition and structure of the energy economy of the Arctic territories in the areas of permanent residence, reducing the burden on natural ecosystems, and risks in the field of sustainable economic and social development of the Arctic region are discussed. The ways are proposed for developing new approaches to the formation of a strategy for the development of the region’s energy infrastructure under the influence of climatic and environmental factors on the natural environment. The mechanisms of the impact of changes in the climatic characteristics of the region on the operating conditions and the efficiency of energy facilities of the fuel and energy complex are determined. The degree of this dependence was studied for different types of infrastructure facilities of the fuel and energy complex. The data on the assessment of the impact of global climate change on the infrastructure of the fuel and energy complex and the possibilities for its adaptation, which include: the implications for power generation facilities; impact on energy transportation; problems of thawing permafrost and solifluction; climate impact on energy consumption and socio-economic effects; the role of distributed energy and renewable energy in adaptation to climate change. It is shown that for the territories of the Russian Arctic with isolated energy supply, the development of energy-efficient systems and renewable energy will reduce climate risks for sustainable growth. Not only of this power sector but the whole economic complex of the region due to both their better adaptation to the effects of climate change and the reduction of technogenic greenhouse gas emissions, which are one of the main factors of these changes.

Development and performance assessment power generating systems using clean hydrogen

In this study, three possible reactions of aluminum - water are considered for clean hydrogen production. The utilization of this clean hydrogen through the two concepts of power generation is investigated thermodynamically. The evaluated first power generation facility based on Al - water reaction has an open cycle gas turbine, steam turbine, boiler, reactor and grinder. The second power generation facility has a fuel cell, a reactor and a grinder. The hydrogen generation resulting from the reactions then the conversion of this hydrogen into energy using turbines or fuel cell and the total exergy destruction are examined comparatively. A thermodynamic analysis is performed with the help of EES (Engineering Equation Solver) software based on the equilibrium reactions in steady state regime. The amount of water required for the hydrogen production is investigated and it is found that the energy efficiencies for the three methods are directly proportional to the amount of water. The energy efficiency for the method 1 based on Bayerite reaction is 38%, the energy efficiency for the method 2 based on boehmite reaction is 56% and the method 3 based on aluminum oxide reaction is 73%. The exergy efficiencies for all methods are calculated at around 41%. When two different power generation concepts are examined, it is observed that combustion-based energy production is more efficient in terms of both energy efficiency and exergy efficiencies.

Permanent magnet synchronous generator stator current AM-FM model and joint signature analysis for planetary gearbox fault diagnosis

Wind energy is renewable and wind power generation facilities have been growing rapidly around the world. Permanent magnet synchronous generators (PMSGs) and planetary gearboxes are commonly used in wind turbines (WTs). For planetary gearbox fault diagnosis, PMSG stator current signal analysis provides a potential alternative approach because stator current signals contain fault signatures with easier accessibility comparing to conventional vibration signals. Planetary gearbox faults result in PMSG input torque oscillations, leading to both amplitude modulation and frequency modulation (AM-FM) effects on stator current signals. To better reveal gear fault features in PMSG stator current signals, this paper proposes to diagnose planetary gearbox faults from three complementary analysis results of the PMSG stator current, i.e., Fourier spectrum, amplitude demodulated spectrum and frequency demodulated spectrum. For this purpose, an AM-FM current signal model is derived through mechanical-magnetic-electric interaction analysis. Explicit equation of Fourier spectrum is derived with its sideband characteristics investigated. Both amplitude and frequency demodulation analyses are proposed to compensate for or mitigate the difficulty in the intricate sideband analysis of Fourier spectrum. Due to its capability in signal mono-component decomposition for accurate estimation of instantaneous frequency, adaptive local iterative filtering is utilized in frequency demodulation analysis. Explicit equations of corresponding demodulated spectra are derived, and gear fault signatures in PMSG stator current signals are revealed. The theoretical derivations and proposed methods are validated through lab experiments by diagnosing localized faults on the sun, planet and ring gears.

Проблемы обеспечения сейсмостойкости объектов электросетевого хозяйства при землетрясениях

The electric grid system is the basis for functioning of the Unified electric power system of Russia and technologically isolated electric power systems. One of the most serious problems in the electric power industry is the aging of the fixed assets of already built and operating power grid facilities. The second problem is to clarify the seismic hazard of the territories of the Russian Federation in the direction of its growth. As a result, the number of power grid facilities fall into the zones of increased seismic hazard. In the zone of 7 points or more, approximately 30 % of the entire length of electric networks and transformer capacities are located. Information is provided about the characteristics of seismic load and how the objects respond to an earthquake. The experience of earthquakes testifies to the high vulnerability of the overhead power lines, cable power lines, substations, power transformers, relay protection equipment and automation under intense seismic loads. Information is provided about massive damage to the power grid during earthquakes in the territory of Russia, Armenia, and other countries of the world. Frequently occurring short circuits during earthquakes in electrical networks, at transformer substations, in electrical equipment elements of power grid facilities lead to fires. It is determined that power grid facilities have less seismic resistance than electric power generation facilities, than buildings and structures where electrical equipment is located. The problem of insufficiency of the current regulatory framework for ensuring seismic resistance of electric power facilities was also identified. Possible measures to prevent accident rate and increase the resistance, reliability, and seismic stability of power grid facilities in case of earthquakes are considered. The development of normative regulation will allow to take measures to ensure the seismic stability of power grid facilities in operation, and to ensure that control and supervision activities are carried out at a higher level.

Physical properties of wood pellets exposed to liquid water

Wood pellets have become a renewable substitute for coal in heat and power generation facilities. However, the hygroscopic nature of wood pellets is a long-standing problem in handling this product. Pellets may become wet during loading and unloading if a rain incident happens. In this research, three types of commercial wood pellets were exposed to liquid water. The durability, density, and porosity of pellets before and after wetting were measured. The commercial pellets were residential hardwood, residential softwood, and industrial softwood pellets. Predetermined volumes of water were added to increase the moisture contents of pellets to several levels ranging from 1.5 to 30% wet mass basis (wb). Exposure to liquid water caused localized swelling of pellets which dislodged particles from the surface of pellets. The data showed when moisture content (m.c.) increased to 10% wb, the pellet durability dropped from 99.5% to 97.5%. A slight increase in bulk density from an initial 690 kg/m3 was observed for pellets at 6–7% m.c (wb). The bulk density decreased to 500 kg/m3 when the adsorbed moisture was at 15% wb.

An Analysis of the Current Status of Woody Biomass Gasification Power Generation in Japan

Forests cover two-thirds of Japan’s land area, and woody biomass is attracting attention as one of the most promising renewable energy sources in the country. The Feed-in Tariff (FIT) Act came into effect in 2012, and since then, woody biomass power generation has spread rapidly. Gasification power generation, which can generate electricity on a relatively small scale, has attracted a lot of attention. However, the technical issues of this technology remain poorly defined. This paper aims to clarify the problems of woody biomass gasification power generation in Japan, specifically on the challenges of improving energy utilization rate, the problem of controlling the moisture content, and the different performance of power generation facilities that uses different tree species. We also describe the technological development of a 2 MW updraft reactor for gasification and bio-oil coproduction to improve the energy utilization rate. The lower heating value of bio-oil, which was obtained in the experiment, was found to be about 70% of A-fuel oil. Among the results, the importance of controlling the moisture content of wood chips is identified from the measurement evaluation of a 0.36 MW-scale downdraft gasifier’s actual operation. We discuss the effects of tree species variation and ash on gasification power generation based on the results of pyrolysis analysis, industry analysis for each tree species. These results indicate the necessity of building a system specifically suited to Japan’s climate and forestry industry to allow woody biomass gasification power generation to become widespread in Japan.

Biochemical methane potential assessment of municipal solid waste generated in Asian cities: A case study of Karachi, Pakistan

Municipal solid waste (MSW) generation rate in Asian cities is exponentially increasing with rise in urbanization and commercial activities. Beside this, the cities in developing Asia are deficient in adequate waste management and facing energy shortage as well. The ineffectual waste management practice is one of the main causative factors behind the negative repercussions on public health and environment. This paper provides an estimation of power generation potential along with economic and environmental benefits of biochemical methane production from MSW. The biochemical methane potential (BMP) test of the MSW generated in Karachi, Pakistan was conducted by using the fresh synthetic waste sample. Through the analysis of the results obtained in this study and available data of the MSW generation (quantity, organic fraction and moisture content) in Karachi it is estimated that, every year about 5600 tons of methane are being wasted to atmosphere adding enormous share in global climate change. This study estimated that, about 63 MWe electric power can be generated by establishing biowaste digestion plants with power generation facilities in the city. The generated power can contribute 2.1% share in daily power supply and 21% power shortage can be reduced as well. Additionally, about 401.3 million-PKRs (2.6 million-US$) revenue can be earned every year by selling the power generated by utilizing the MSW in waste to energy plants. Moreover, 0.13 Mt CO2-eq/annum greenhouse effect caused by methane emissions from open disposal of MSW can be eliminated.

Mathematic Modeling and Performance Analysis of Vanadium Redox Flow Battery

With a rapid charge/discharge feature, vanadium redox flow batteries (VRBs) are green, large-scale energy storage devices useful for power smoothing in unstable renewable power generation facilities, such as those involving solar and wind energy. This study developed a VRB model to establish a relationship between electrolyte concentration, equilibrium potential, and state of charge (SOC), to simulate the dynamic responses in charge/discharge cycles of the electrolyte concentration, terminal voltage, and SOC, and to evaluate the internal loss and battery efficiency. The proposed model not only serves as the basis of a dynamic analysis tool for future studies for designing a large-scale VRB but also reveals the time-varying electrolyte status for a long-term VRB operation.

풍하중을 고려한 100 kW급 태양광 발전 설비 지지구조물의 응력해석

The photovoltaic power generation facility is usually installed outdoors and is extensively impacted by snow and wind power as well as external contact friction caused by snow and rain. In particular, since there is a markedly high possibility of damage from devastating wind power such as a typhoon, an overall safety evaluation is essential. However, most studies are conducted using cell-level stress analysis rather than cluster-wide stress analysis. Thus, in this study, a finite element analysis was performed on the entire support structure of the photovoltaic power generation facility, wherein the wind load was applied, and the portion wherein extensive stress was generated was identified. The results of the analysis showed that the stress in the rear side was relatively higher than in the front side of the support structure for the horizontal wind. Additionally, it was confirmed that a relatively high stress occurs in the lower side than the upper side of the support structure.

50MW급 프란시스 수차발전기 운영시 발생되는 진동 특성에 관한 연구

Vibration characteristics of the rotating machinery has been usually managed to facilitate the deterioration of the equipment and to prevent accident in advance. In a hydropower turbine, pressure pulsation characteristics to induce vibration is investigated during the model testing with a small scale model turbine for various operating conditions, and a prototype turbine is constructed to operate stably on the site. However, the model test has limitation that can’t be considered together with the vibration characteristics of a generator itself and of civil engineering structures for the building that support a turbine and a generator. Therefore, field tests of vibration for a hydroelectric power plant are carried out periodically, thereby maintaining reliability for safe operation of power generation facilities. In the study, the vibration of a Francis type hydroelectric power plant operated over 30 years and overhauled a year and a half ago was measured and its characteristics has been investigated. Displacement and velocity sensors were installed at appropriate positions to measure the vibration of the rotating shaft and bearing support of a turbine and a generator, and the vibration characteristics of a typical hydroelectric power plant have confirmed by analyzing the measurement results. The vibration characteristics of rotating shaft and non-rotating parts of the hydroelectric turbine have been analyzed to confirm the degree of aging of the plant. Vibration in the power plant building depending on the operating conditions was also measured to be large enough to sense, and its frequency characteristics were analyzed.

Regional and seasonal water stress analysis of United States thermoelectricity

Most thermoelectric power plants in the United States (U.S.) rely on fresh water for cooling, resulting in significant water consumption. An understanding of the regional and seasonal water stress impact of such water consumption is needed. In this study, we used a U.S. county-level water stress index, Available Water Remaining for the United States (AWARE-US), with facility-level thermoelectric power generation water consumption data, to quantify the regional and seasonal water stress impact of U.S. thermoelectric power plants. Water stress impact was evaluated as water-scarcity footprint (WSF) using monthly AWARE-US data. Results show that most thermoelectric power plants in the United States that use fresh water are in water-abundant regions. Our findings also show that a small fraction of the U.S. thermoelectric generation facilities (13% by power) located in water stressed regions contribute the most water stress impact (88% of the total WSF) caused by thermoelectric power generation in the U.S. Even if fresh water is abundant on an annual basis, many power plants are in counties with seasonal water shortages. Of the 401 counties with thermoelectric power plants using fresh water for cooling, 80 counties in February and 160 counties in August had fresh water withdrawal requirements that exceeded the sustainable fresh water available (availability minus demand or AMD) in that region. This means that 27% and 46% of power generation facilities have difficulty securing sustainable fresh water in February and August, respectively. This study is intended to support water consumption management in existing power plants and guide the deployment of future power plants to mitigate water stress impact.

Optimizing hybrid power systems with compressed air energy storage

Concern for the environment necessitates the reduction in use of fossil fuels. A solution is to use more renewable power generation facilities. However, the intermittency of renewable energy makes operational scheduling challenging. An optimization model is developed here to determine the performance of a hydro-thermal-wind-solar hybrid power system with the possibility of integrating a compressed air energy storage system. The hybrid power system is implemented in the IEEE-30 bus system. Real-time operational constraints such as varying renewable power availability and disruptions are considered. The model was solved using the meta-heuristic approaches of differential evolution and modified bacteria foraging algorithm. Results indicate that the modified bacteria foraging algorithm arrived at better solutions, making it possible to achieve lower power loss, higher annual savings and reduced variability in voltage security. The best performance is obtained using a hybrid power system which incorporates the compressed air energy storage. Results indicate that higher renewable energy penetration with proper scheduling strategy can result in improvements in system performance.

Landfill gas condensate treatment options to eliminate odor issues and to use water for dust control

Abstract A large landfill-gas-to-power facility retained the authors to provide process evaluation and development support for a conceptual design of a landfill gas condensate (LFGC) treatment system to eliminate odor issues and reduce organic loads to the sewer or use the water for dust control. Based on the operational observations and water quality data, the source of the LFGC is moisture from gas generated by the decay of waste in the landfill that is transmitted to the power generation facilities by way of the landfill gas (LFG) collection system. As part of this project, the authors reviewed the data, and this presentation includes recommendations for long-term treatment solutions so that a permanent system can be designed, bid, procured, and installed. The purpose of the abstract is to present the findings of this analysis of LFGC treatment system alternatives to identify practical, commercially available solutions with the primary goal to reduce odor issues related to LFGC both on-site and in the sewer system, and to reduce water usage at the site for dust control. The method to evaluate the various treatment options was based on treatment efficiency, and capital and life-cycle costs. The conclusion was to continue with pilot testing of the most suitable options, which was anaerobic treatment followed by polishing with a moving bed bioreactor (MBBR) to reuse the product water in cooling towers or for dust control.

Energy Analysis for the Connection of the Nuclear Reactor DEMO to the European Electrical Grid

Towards the middle of the current century, the DEMOnstration power plant, DEMO, will start operating as the first nuclear fusion reactor capable of supplying its own loads and of providing electrical power to the European electrical grid. The presence of such a unique and peculiar facility in the European transmission system involves many issues that have to be faced in the project phase. This work represents the first study linking the operation of the nuclear fusion power plant DEMO to the actual requirements for its correct functioning as a facility connected to the power systems. In order to build this link, the present work reports the analysis of the requirements that this unconventional power-generating facility should fulfill for the proper connection and operation in the European electrical grid. Through this analysis, the study reaches its main objectives, which are the definition of the limitations of the current design choices in terms of power-generating capability and the preliminary evaluation of advantages and disadvantages that the possible configurations for the connection of the facility to the European electrical grid can have. In reference to the second objective, the work makes possible a first attempt at defining the features of the point of connection to the European grid, whose knowledge will be useful in the future, for the choice of the real construction site.

Multi-site measurement for energy application of small distributed wind farm in complex mountainous areas

As a clean and highly valuable renewable energy, wind energy has gradually become an important branch of energy technology. By means of measurement methods, the wind characteristics, energy applications for distributed wind energy source (DWES) in six sites in Henduan Mountains and economic evaluation are investigated. According to the results, the wind characteristics including wind speed and wind direction in mountainous regions are affected significant by topography. Wind speed is season-dependent, while the mean wind direction is not. The maximum wind speed occurs in spring, the minimum wind speed occurs in summer. As for extreme value distribution, the wind data in mountainous areas are more in line with Frechet distribution type. By using Weibull distribution function, Weibull parameters are calculated and energy potential are estimated with five methods. Estimation methods suitable for coastal areas can also be used for energy assessment in mountain environments. The maximum wind power density is over 200 W∕m2, occurred in Zanli site, while the minimum value is less than 10 W∕m2 in Yimen-A. Similar to mean wind characteristics, wind power density shows strong seasonality, with the maximum value in spring and the lowest value in summer. In addition, power generation facilities should be built in valleys or on the top of the mountain, and should not be built in the flat land surrounded by mountains. And the total cost of 1kWh wind-generated electricity is 0.305 CNY/kWh and 0.406 CNY/kWh with different type of wind turbine.

Hybrid power systems with emission minimization: Multi-objective optimal operation

The demand of electrical power and energy is exponentially increased with the advancement of science and technology in past decades. To fulfil this increasing demand of energy, the burden on conventional fossil fuel based units has continuously been raised, which in turn has severe consequences on the environment. A clean pollution free and healthy environment necessitates the reduction in the use of conventional fossil fuel based units. In this context, integration of non-conventional and renewable power generation facilities with conventional power generators, for instance, hybrid power system is gaining attention. However, the intermittent posed by renewable power generation facilities may make the scheduling of generators and power system operation extremely challenging. These issues and its possible solution have been addressed in this proposed study. An attempt has been made in the evaluation of an optimum generation scheduling and coordination among different hybrid power system configurations in the form of wind-thermal, hydro-thermal-wind and hydro-thermal-wind-solar systems. This stochastic optimal power flow problem of the proposed system has been formulated in a multi-objective optimization framework while incorporating real-time operational constraints. A mathematical model, operational analysis and comparative evaluation between the optimum operational paradigms obtained with a modified bacteria foraging algorithm for wind-thermal, hydro-thermal-wind and hydro-thermal-wind-solar systems have been implemented. The effectiveness and promising solutions of hydro-thermal-wind-solar in response to fulfill the operational objectives like cost effective operation, minimization of transmission loss, emission and voltage variation over other hybrid configurations in multi-objective stochastic optimal power flow environment as implemented in IEEE30 bus power system has been demonstrated.

발전용 가스터빈 대상 유연운전 실증사례 연구 (가스터빈과 스팀터빈 부하연계 부분)

Based on global environmental awareness and international agreements (Paris, and Tokyo), individual countries have set CO₂ reduction plans and are pursuing policies to increase the proportion of renewable energy. Ultimately, there is a technical need for a flexible operation in the field of power generation aiming at the carbon free energy consumption stage. In particular, gas turbines among existing power generation facilities have been attracting much attention for flexible operation due to load fluctuation rate and quick starting characteristics. In terms of flexible operation, the issue of limiting the power output in response to a sudden changed load in a gas turbine has been examined. In case of gas turbine, it is necessary to operate in conjunction with steam turbines having different dynamic characteristics in order to improve the efficiency. In the case of IP steam, some are used for cooling the gas turbine combustor, so there are many aspects to be considered in terms of control for system protection. To solve this problem, IP(Intermediate Pressure) steam control valve malfunction was prevented by parameter change for IP steam pressure control, and demonstration with this parameter was completed. In addition, a TIT(Turbine Inlet Temperature) prediction scheme was also considered to control the cooling flow to the combustor for IP steam pressure control in case of greater load fluctuations due to system requirements.