Special emphasis is placed on the Northeast region because it contains the major installed wind capacity and, on the other hand, it includes economically disadvantaged and drought-prone areas in the country. Highlights for the production, operation and maintenance of wind turbines are also undertaken. Clean energy can be understood as energy sources that do not release pollutants into the environment and that have an impact on nature only at the site of installation. Among the forms of energy that meet these requirements are wind, solar, tidal, geothermal, hydraulic and biomass energies.
All these sources cause environmental impacts, even if they are minimal, but do not interfere with pollution at the global level. According to [ 10 ], renewable-power plants are the least CO 2 -emission-intensive forms for electricity supply currently available.
Wind is air in motion. Since air has a mass 1. This energy can be turned into electric power, heat or mechanical work by wind turbines [ 3 ]. Wind energy from the Latin aeolicus , belonging to or related to Aeolus, god of the winds in Greek mythology is every form of energy that comes from the wind, having been used since prehistory, when man used the wind to propel Ancient Egyptian ships. In Antiquity, around bc , the Persians used windmills to pump water for irrigation of plantations and for grinding grain [ 3 , 11 ]. With the technological advances, wind machines became able to generate a greater amount of energy, until the first wind-power plants appeared.
Today, it is possible to find modern wind turbines scattered around the world, with a nominal power capacity superior to 7 MW per unit [ 12 ]—enough to supply more than 10 homes in the Brazilian consumption standard. A wind-power plant is considered a source of clean energy generation, takes up little physical space, can produce energy in remote locations and is plentiful, because wind is available across the globe. It generates income for the landowners by renting land for the towers, allowing the owner to continue with plantations or raising animals.
Land use is not compromised, since only a small percentage of the space where the wind farm is installed is effectively occupied. However, many wind farms are located far from consumer markets and, although prices are decreasing, it is still more expensive than hydroelectricity the major Brazilian electric matrix share. Even though wind turbines are compact and stand hundreds of meters tall [ 12 ], one unit produces less electricity than a fossil-fuel plant, so a wind farm requires many turbines for the same result. Knowledge of wind and weather conditions is also needed.
The period of no wind, or irregular winds, is known as intermittency and in practice this means that, e. That means more than wind turbines each 2 MW will have to be built in order to completely replace a single MW coal-power plant [ 13 ]—a considerable industrial undertaking. However, modern wind systems can be matched or linked to other renewable source facilities to minimize and eliminate intermittency [ 10 ].
Although wind energy has a history of thousands of years, the first attempts for electricity production appeared in the late nineteenth century and only emerged as a viable alternative from the s onwards with the oil crisis, the major energy input of the world at the time, when the technology for the wind-power plant construction was driven for the first time [ 3 , 11 , 12 ]. In the s, with the wind-power concession policies adopted by many countries, the wind market developed rapidly, and wind-turbine technology undertook significant evolution over time.
Despite the original pioneering of Germany, the USA, Denmark and Spain, countries like China and Brazil have made substantial efforts in recent decades to rapidly develop the wind-energy industry and today they achieve good results. Current global wind-energy supply comes mainly from land plants. However, there is a growing interest in offshore power plants, as wind is usually stronger and more uniform in the sea [ 11 ]. Large wind turbines seem to be the best choice for offshore plants, since their main barrier is the capital cost of the wind farms at sea.
The development of growing larger turbines will enable the reduction of capital cost, as well as operating and maintenance costs per kWh. Unprecedented in Brazil, offshore wind energy began to take its first steps in by Petrobras [ 14 ], a semi-public Brazilian multinational corporation in the energy industry, with the installation of a pilot plant in the Northeast region, next to its oil platforms in shadow fields, expected to start operation in the year In , the worldwide installed capacity of wind energy was China accounted for Brazil ranked eighth Over the years, some other projects were conducted in some states of Brazil, but little progress was made to consolidate wind energy as alternative electric power generation, attributed to the lack of public policies and still prohibitive technology costs at that time.
Without doubt, the atlas was an important milestone for wind-sector development in Brazil. Over time, wind-turbine technology developed significantly by providing models of higher power and dimensions for operation at higher altitudes. The PROINFA was created in by the federal government [ 17—19 ] to increase the participation of alternative renewable sources—small hydroelectric plants, wind-power plants and biomass thermoelectric projects—in the production of electric energy, prioritizing those companies that did not have corporate ties with generation, transmission or distribution concessionaires.
PROINFA, as the first effective public policy focused on the wind sector, provided an environment with few risks for investment with a technology still little known in the country at that time. Thus, from , Brazil began the adoption of the system of auctions for the lowest price for contracting the electricity demand foreseen by the concessionaires and a reserve amount.
As of , through specific auctions for renewable sources, wind energy has been marketed in a regulated environment. Ferreira [ 20 ] explains that the contractual auctions scheme for wind generators was designed to reduce the risk of investment by the private sector. Wind energy has economic characteristics such as high initial investment, low operating cost and a seasonal and intermittent production flow, which were formulated into a contract model to consider the average production over the years and to allow readjustments and compensations according to generation history.
This change in the contracting system stimulated the development and growth of wind energy in Brazil. Due to the economic crisis experienced by Brazil in , electricity consumption was 1. As a result of the drop in the electricity consumption and economic recession, there was a reduction in the contracting of wind energy in , even with three auctions that year.
In , there was no contracting of wind energy. The auctions in Brazil are conducted by the National Electric Energy Agency, which coordinates and controls the entire process, with auctions of new and existing projects, new energy and existing energy. Existing energy auctions refer to the contracting of energy for the short term, usually for the following year, which implies that the energy comes from projects already in operation, while new energy auctions are related to the contracting of energy for the medium and long term, which implies that the energy comes from power plants in project or in construction.
For these reasons, installed wind capacity in was higher than , even though there were no auctions of new hires that year. As discussed before, and based on the graph analysis, wind power began its effective growth in with the first auction of energy commercialization turned exclusively to this source, with intensification as of Evolution of installed wind capacity in Brazil from to and a forecast up to Source: the authors, based on data from [ 15 , 22 ]. Actually, considering current technologies for wind-energy production and, mainly, the use of wind turbines of m high, Brazilian wind potential should be much higher than evaluated by the first wind atlas in Estimates point only to the Northeast region with an onshore potential of GW [ 23 ].
The Brazilian offshore wind potential is also huge and is estimated to reach 1. From the Brazilian wind atlas for wind speeds at heights of and m [ 24 ], the South and Northeast coast oceanic regions can be identified as high-wind areas for wind-power generation. Today, Brazil presents a diversified electric matrix and wind energy is highlighted by the excellent wind quality and huge investments. There was a 1. Renewable sources had the highest increase in the IES 9. Special attention is given to the increase of A total of Each installed MW corresponds to the generation of 15 jobs and a reduction of 23 Mt per year in CO 2 emissions equivalent to 16 million cars [ 22 ].
However, wind power is expected to be the second main source of the electrical matrix as early as [ 22 ]. Despite the great potential for exploration of wind power, whether for large complexes or for distributed generation initiatives, there are limits to the expansion of its participation in the Brazilian electricity matrix. Due to the intermittent nature of the winds, which is uncontrollable and varies according to climatic conditions, there is a possibility of disturbances in the network quality parameters voltage, frequency and harmonics , as well as the energy flow management itself.
Consequently, there is a growing need for automation and self-management of electricity sector networks, with the implementation of smart grids. Until October , there were wind farms installed in 12 states of Brazil Also, it can be observed that major states are located in the Northeast region, i. Brazil is expected to have another new wind farms by The estimates point out that, by , the wind-power chain could generate approximately new direct and indirect jobs [ 22 ]. Source: the authors, based on data from [ 22 , 25 , 26 ]. Significant participation of hydroelectric power and bioenergy in the Brazilian energy matrix provides emission indicators much lower than the world average 2.
In , China and the USA accounted for When looking for a good site at which to install wind turbines, many different factors must be considered. The most important factor is the wind resource, once local conditions, like hills and mountains, buildings and vegetation, influence the wind and should be considered in a more detailed calculation of how much energy wind turbines will be able to produce at the site [ 3 ]. In this sense, the Northeast region has the highest concentration of wind farms in Brazil, as seen in Table 1 , being the main focus of investors in the sector because it concentrates the South Atlantic trade winds, which are strong, stable and favourable to energy generation in the country.
This scenario of water-source preponderance in the Northeast region has changed in recent years.
In fact, the participation of thermoelectric and wind-power sources has grown significantly in the composition of electricity generation in the Northeast Subsystem, due to the occurrence of years with low rainfall and the increase in installed wind-power capacity in this region. In this context, the wind-power source is what contributes most to the generation of electric power, having a participation in of According to Bezerra [ 23 ], an auction held on April approved In the August auction, an amount of Based on these data, it can be inferred that wind-power source is today the most competitive generation alternative in Brazil.
It is also worth mentioning that, on the same day, the Northeast was an energy exporter throughout the day—a reality totally opposite to its energy-importer nature [ 22 ].
Therefore, Brazil is consistently accumulating records, both on weekends and weekdays, in both daily averages and at specific times. Since , the city of Tacaratu km 2 and around 24 inhabitants , in the semiarid area of Pernambuco, has contained the Fontes Complex—the first hybrid wind and solar production plant in Brazil; in this city, the majority of the population lives on small crops of beans, maize and cassava, and have in the rental of land an alternative source of income.
Renewable-power manufacturing technologies involve a highly skilled workforce and a modernizing of the local industry base [ 10 ]. The manufacture of wind turbines can be classified as a project production system once it includes low inventory levels, low production volume and a low level of automation, high flexibility, high labour specialization and greater difficulty in planning, scheduling and controlling production.
In general, wind turbines comprise five main components: i rotor blades; ii transmission, including pitch control, hub, mounting, main shaft, bearings and gear box; iii generator, electronic controls and cables; iv tower, including yaw; and v foundations. The rotor transfers the kinetic energy from the wind to a revolving shaft that drives a generator that produces electric power. The rotor in the generator has a magnetic field, which is created by either permanent magnets or electromagnets. When the wind turbine starts to revolve, it creates a rotating magnetic field; when this magnetic field passes the stationary coils, an electric current is induced in them and this current can be fed into the power grid [ 3 , 28 , 29 ].
The mean wind speed and the frequency distribution at the site at which the wind turbine is installed are also important parameters [ 3 ]. Nowadays, in order to bring down the cost of renewable-energy generation, more powerful and larger-scale wind turbines are needed. In the s and s, the diameter of the rotor was about 20—30 m, producing 50—75 kW. From to the present day, the rotor has been — m in diameter, with — kW of nominal power. Projections for the coming years are rotors of m in diameter and 20 kW of nominal power [ 11 , 12 , 30 , 31 ]. The increase in the nominal power of the wind turbines means a better utilization of the electrical and civil construction infrastructures with gradual and significant reductions in the cost of installed kW and consequently in the cost of the kWh generated.
Furthermore, reducing the number of rotors in motion, the visual impact of wind farms can be softened.
Wind-turbine blades can be manufactured in a variety of shapes and designs, but current horizontal-axis turbines typically have a standard three-blade configuration, using large angled propeller blades to catch the wind [ 3 , 13 , 32 , 33 ], which provides a good ratio between operating performance, structure weight and costs manufacturing, installation and operation. As a consequence, they achieve good power generation at low rotational speeds, which results in the production of less noise and a significant increase in their useful life.
However, Wizelius [ 3 ] describes that the advantage of fewer blades is that the weight of the rotor and many other turbine components decreases. Small vertical-axis turbines tend to be used in homes or buildings because they occupy less space, produce less noise and have a lower cost [ 13—29 , 34 ]. Most large grid-connected wind turbines have conical steel towers. Smaller turbines can have a lattice tower or guyed mast.
To make turbines firmly rooted in the ground, so that they will not be turned over by strong winds, they are mounted on foundations of reinforced concrete. If the bedrock is solid and stable, they can be bolted to the rock [ 3 ]. In modern wind turbines, the nacelles on most horizontal-axis turbines can be controlled to face into the wind, where they will have the greatest efficiency [ 13 ]. In stormy conditions, when winds are extremely high, the rotor can be damaged and the blades are faced perpendicular to the wind in order to keep them from spinning out of control.
Brakes can also be employed to keep the blades from spinning too fast. The basic design aspects for a wind blade are the selection of material and shape. The material should be stiff, strong and light. The shape should be aerodynamic, in which rotor blades are inclined in relation to the wind and the moving air pushes against the blades that start to move in one direction with the air moving in the other [ 30 , 31 ].
Wind blades are made of a composite material, i.
Hence, the primary materials needed for wind turbines include steel for towers, nacelles and rotors , pre-stressed concrete for towers , magnetic materials for gearboxes , aluminium and copper for nacelles and polymeric composites for rotor blades [ 13 , 29 , 35 , 36 ]. Rotor-blade manufacturing is quite complex, since the parts have large dimensions over 40 m in length and the processes are mostly manual, with a low level of automation, making standardization and quality control difficult.
Generally, an epoxy-based polymer resin is the matrix of the composite and glass fibres are the reinforcement material [ 36—41 ]. Other materials, such as polyvinyl chloride PVC or polyurethane PU foams and balsa wood, are often placed as filler elements.clublavoute.ca/pacer-dating-gay-de.php
Wind power - Wikipedia
Blades are produced by combining the fibres and resin in an open mould, which will define the final blade shape. The leading edge is the part of the blade that first contacts the air. Hiteva sussex. Hiteva, Ralitsa and Watson, Jim Governance of interactions between infrastructure sectors: the making of smart grids in the UK. Environmental Innovation and Societal Transitions. ISSN Hiteva, Ralitsa and Sovacool, Benjamin Harnessing social innovation for energy justice: a business model perspective. Energy Policy, Hiteva, Ralitsa [Review] Mary C. Neuburger : Balkan smoke. Tobacco and the making of modern Bulgaria.
Journal of Consumer Culture, 14 3. Jeffrey D. Rory Spowers. Confessions of a Greenpeace Dropout. Patrick Albert Moore. The Market Gardener.
Planning with the missing masses: innovative wind power planning in France
Jean-Martin Fortier. Playing for Time. Lucy Neal. The Solar Revolution.
Steve McKevitt. Sustainability: The Basics. Peter Jacques. Giacomo D'Alisa. Sustainable Energy - without the hot air. David J. Start Something That Matters. Blake Mycoskie. Can Life Prevail? Pentti Linkola.