An Overview of Wind Turbine Power Plants: Costs and Revenues, Optimal Layout, and Environmental Impacts

The growing trend of the world population has brought about an inevitable increase in energy demand, and this issue, apart from the fact that non-renewable energy sources are finite, can bring about many environmental problems. Considering the importance of environmental impacts and the development of renewable energies, the construction of wind farms to absorb wind energy as one of the renewable energies is increasing all over the world. Wind is one of the important sources of energy that is clean, cheap, available and permanent. This article reviews wind power plants from their emergence and development and the research conducted in this field. One of the important factors is the economic analysis of the construction of a wind power plant, which is done by examining the investment and annual costs and the income from the power plant. Another important point in the construction of wind farms is the optimal arrangement of the farm, including the number of turbines and their arrangement, so that maximum energy production and efficiency are achieved with the lowest cost of connection between turbines. Finally, the environmental impacts of wind power plants were addressed, including the environmental impacts of electricity generation, the effects of wind turbine noise on noise annoyance, and the impact of wind power plants on air temperature.
Introduction
One of the solutions to energy shortages and dependence on non-renewable resources is to increase the use of renewable energy sources. In this regard, new energies, including hydropower, solar, and wind energies, are of particular importance because they do not pollute the environment. Wind energy has increased its presence in electrical power systems around the world in recent decades. Wind power plants have expanded more than any other existing technology for utilizing renewable resources in the power system due to their high efficiency, institutionalization of the technology used to exploit wind energy, low cost of electricity generation, presence of windy areas most of the time, and ability to generate power on a large scale and cost-effectively. On the other hand, the increasing technological progress of wind turbine manufacturing, which includes reducing the costs of designing and operating wind turbines, has forced countries around the world to use this energy more and more. Today, wind power (the conversion of wind energy into a useful form of energy such as electrical energy using wind turbines, mechanical energy, for example in windmills or wind pumps, or the propulsion of boats and ships, for example in sailboats) in the world has an annual production capacity of 430 TWh of electrical energy, which is 2.5% of the world's electricity consumption. The annual production capacity of electricity can be increased by expanding wind farms.
Literature review
Before building a wind farm, a financial and economic assessment is essential and critical. The economic assessment should be considered from both a national perspective and a power producer perspective. In the national economic assessment, the benefits of the wind farm project are compared with the costs of an alternative thermal power plant (e.g., a gas turbine), including fuel, repair, and maintenance costs. In the power producer economic assessment, the revenues are related to the present value of the electricity sales revenue over the life of the project.
One of the most important and complex issues in the construction of wind farms is the optimal number and arrangement of turbines in relation to each other in order to maximize energy production and efficiency. The arrangement and installation of turbines in the farm, given the limitations of land and capital, requires precise calculations in order to obtain the most energy from the power plant. The speed of the wind exiting the turbine decreases after passing through it and some of its energy is reduced. This phenomenon is called wake. This reduction in wind speed is a function of various factors such as distance, turbine dimensions and wind speed entering the turbine. Of course, this effect improves with distance, which is due to the general air currents in the area. Therefore, the denser the turbines in a power plant, the less wind is able to recover and as a result, the output power decreases.
Environmental studies conducted on wind energy show that the turbine production and wind power plant construction stage is a significant factor in greenhouse gas emissions in wind power plants, accounting for about 73-90% of the cumulative greenhouse gas emissions, and the remaining stages, including operation and maintenance, power plant demolition, and transportation, account for about 10-90%. Wind power plants, as one of the new methods of producing renewable energy with the least environmental impact compared to other energy sources, are considered one of the sources of noise pollution that have long attracted the attention of many researchers. Studies have examined the potential impacts of wind farms on global and local weather and climate. Modeling studies agree that wind farms can significantly influence local meteorology. In some cases, these effects may be beneficial, such as nighttime warming in stable conditions that can protect crops from frost.
Conclusion
This article aims to examine wind power plants and review the research conducted in this field. Wind is one of the clean, cheap, permanent and available renewable energy sources in the world. Many countries, including the United States and China, have made investments in this field and are making great use of this energy. Iran also has a number of wind farms, but as a country with many windy areas, if this energy source is used, it can provide a large part of its energy needs. There are important points to consider when constructing a wind power plant. The most important point is the economic analysis of constructing a wind power plant. At this stage, the investment and annual costs of the power plant are examined, and on the other hand, the income from the power plant, which includes the sale of electricity, is predicted. If it is economically viable, the wind power plant can be constructed. Another important point is the layout of the farm, which should consider the layout and number of turbines to produce the most energy for the least cost to connect the turbines. The next important point is the environmental impacts of wind power plants, both during the construction and operation stages, which should be minimized. These factors include the environmental impacts of electricity generation, the effects of wind turbine noise on noise nuisance, and the effects of the power plant on air temperature.