Wind farms (wind farms) - devices of a special design in which wind energy is converted into electrical energy. Every day they become more popular. Using natural, and most importantly, renewable energy sources, convenient and simple wind power plants, the so-called windmills, are an excellent alternative to traditional power plants, especially in private houses.
Using wind power
Windmills, or rather the principle of their action, were undeservedly forgotten in the twenties of the last century. However, wind power was not used even then to obtain electric energy. She powered millstones, was used as a mover for sailing ships, and later launched pumps for pumping water into tanks, that is, turned into mechanical energy.
Wind energy began to develop rapidly in the late sixties of the last, XX century. At that time, traditional energy carriers became sorely lacking, in addition, they rose sharply in price, and environmental problems associated with their use became increasingly acute.
He promoted the use of alternative sources of electricity, including wind power, and technological progress. New high-strength and fairly lightweight materials have appeared, allowing the construction of towers up to 120 m high and huge blades.
The winds blowing in many regions of the planet are able to rotate the turbines of the power plant at a sufficient speed to provide energy to private homes, small farms or schools in rural areas.
But in any barrel of honey there is at least one fly in the ointment. The wind cannot be subdued; it does not always blow, especially in the same direction and at the same speed. Technological progress does not stand still. If today wind farms for a private house, generating hundreds of kilowatts of electricity, are no longer a rarity, then tomorrow, maybe tens of megawatts will become daily routines. In any case, there are already wind farms with a capacity of 5 mW or more.
Advantages and disadvantages of wind farms
In addition to the use of free wind energy and independence from external sources of electricity, wind power stations have several significant advantages. There is no environmental problem of storage and disposal of waste, and the method of producing energy is one of the most environmentally friendly. Not to mention how a wind turbine aesthetically looks against the sky, it can be considered its advantage that the installation can be both stationary and mobile.
In addition, today it is already possible to select a wind farm of a suitable model and capacity or to use a plant combining the use of several energy sources, traditional and alternative. It can be a diesel or solar-wind power station.
Wind farms also have disadvantages. Firstly, they are so noisy that large installations have to be turned off at night. Secondly, they often interfere with air traffic or radio waves. Thirdly, they need to be placed on truly huge areas. And there is another significant drawback of the lobed structures - they must be turned off during mass seasonal bird flights.
Types of wind farms
According to the functionality of the power plant, wind farms can be divided into stationary and mobile, or mobile.Powerful stationary installations require a whole range of preparatory work, but they are able to accumulate sufficient amount of electricity for use in calm weather in rechargeable batteries.
Mobile power plants are simpler in design, unpretentious, easy to install and easy to operate. They are usually used to power electrical appliances or when traveling.
The design distinguishes between vane and rotor wind farms.
At the place of installation of the wind farm there are:
- ground. They are installed on high ground and are most common today;
- coastal. They are built in the coastal zone of the seas and oceans, where due to uneven heating of land and water, winds constantly blow;
- offshore. They are built in the sea at a distance of 10-15 km from the coast, where sea winds constantly blow;
- floating. They are also located at about the same distance from the coast as offshore, but on a floating platform.
By the scope of the power plant, wind turbines are industrial and domestic.
Winged wind farm
Vane wind farms, which are leaders in the wind energy market, have become familiar. On a high dream, a blade mechanism is installed with a horizontal axis of rotation, mainly a three-blade one, and its power depends on the size of the blades. Such an aggregate reaches its maximum rotation speed when the blades are perpendicular to the wind flow; therefore, its design provides for the device to automatically rotate the axis of rotation in the form of a stabilizer wing on small and electronic yaw control systems at more powerful stations.
Vane wind farms differ mainly by the number of blades. They can be multi-blade, two-blade, even with one blade and counterweight.
Rotary wind farms
Rotary, or rotary, wind power plants have a vertical axis of rotation and are independent of the direction of the wind. This is an important advantage when using surface yawing air currents. The disadvantage of a wind farm of this design is the use of multi-pole generators that operate at low speeds and are not widespread.
These installations are slow-moving and, as a result, do not create much noise. In addition, their advantage is the simplicity of electrical circuits, which are not violated by random sudden gusts of wind.
Experts believe that rotary wind farms are the most promising for large wind power. True, in order to promote such an installation, external energy must be applied to it. Only when it reaches certain aerodynamic performance does it itself go into generator mode from engine mode.
Combined wind-diesel system
The disadvantage of wind turbines - uneven supply of electricity - in large networks is offset by a large number of installations.
You can also compensate for this drawback using combined systems in which there are special devices that distribute the load between the wind power plant (wind turbine) and the diesel engine. Therefore, autonomous networks of low power from 0.5 to 4 MW paired with a diesel engine can operate reliably and evenly.
Modern equipment, which saves about 65% of liquid fuel per year, allows you to connect a diesel engine or turn it off in just a few seconds if necessary.
Household and industrial wind farms
Household wind power plants have power from 250 W to 15 kW, can work in conjunction with solar panels, with or without a battery.
Electricity generated by household wind farms is quite expensive, but it often happens that there are simply no other sources.
Domestic wind farms in Russia are manufactured with a direct current generator that charges batteries up to 800 Ah. All household appliances can work from such batteries in the house: a TV, an electric kettle, etc.
The process of charging batteries after disconnecting the load can be quite long, depending on the strength of the wind and the power of the generator.
There are also domestic domestic wind farms in the Russian market, they are quite expensive, but they usually give out less than half the rated power.
Industrial wind farms are distinguished by significantly greater power and are usually integrated into single networks.
Private wind farms generally have a capacity of 3 to 5, less often 10 kW. If the average annual wind speed in the region reaches 3-4 m / s, then such a wind farm can provide electricity to an average country house, service station or a small cafe.
The main characteristics of the wind farm
Rated power is the main indicator that characterizes all power plants, wind turbines are no exception. It is determined by the power generated by the generator at an average wind speed of 12 m / s, and depends on the type of station.
The next important indicator is the nominal voltage of the wind farm that the generator generates. It can be either 220 V or 12 V, and 24 V.
The electric power of the generator depends on the power of the turbine. Since the power of the turbine is higher, the larger its diameter and, therefore, the stronger the mast, this indicator is important when choosing and calculating the design of the mast.
The wind turbine has several more characteristics. Its performance is important - this is the amount of electricity that the device generates per year. When choosing a wind turbine, it is necessary to know the maximum wind speed that the turbine can withstand, and its minimum (starting) speed at which it starts to rotate. When choosing a turbine rotation frequency and the number of blades play a role.
Principle of operation and arrangement of wind farm
In a wind farm, an air stream rotates a wheel with blades, from which torque is transmitted to other mechanisms. The larger the dimensions of the wheel, the greater the airflow it captures and therefore rotates faster.
In the language of physics, the linear wind speed is converted into the angular velocity of rotation of the axis of the generator, which, in turn, converts the rotational motion into electrical energy, transmitting it through the controller to the batteries. At the exit of the device, electricity is already suitable for domestic use.
That is, a small wind farm consists of a turbine, blades, tail (rotary mechanism), a mast with extension cables, batteries, a charge controller and an inverter that converts 12 V to 220 V.
In addition to these devices, an industrial wind farm also contains tracking systems for the direction of the wind and its speed, the state of the wind generator and protection against lightning discharges. In addition, the mast does not cope with the loads of a larger scale, and it is replaced by a tower, in which all additional equipment is located.
Wind farm design
The main indicator that allows you to decide on the use of a wind farm is the average annual wind speed, which should be at least 5 m / s. True, today there are already easily dispersible wind farms designed to power private households, which begin to operate with a minimum air velocity of 3.5 m / s.
To determine this indicator, special wind charts are used.
In different climatic zones of Russia wind speed measurements were taken to determine how efficient wind farms are there. Wind turbines and stations are already operating in the Kaliningrad region, on the Commander Islands, in Murmansk, the Republic of Sakha (Yakutia), and Bashkortostan.
When deciding whether to install a wind power plant or a private wind farm, it’s worth starting with specialists to conduct research on the direction and strength of the wind using anemometers and build maps of the availability of its energy.Based on these data, a wind turbine design or a design of several plants, its technical and geometric parameters is calculated and developed.
It is impossible to build an industrial wind farm of sufficient capacity without investors, and well-executed calculations and a completed project will help determine the payback period of the project and attract additional finance.
Private wind farms
According to significantly underestimated statistics, which do not take into account detached remote buildings and structures, about 30% of private households in rural areas, where the laying of electric networks is impossible for economic reasons, do not have electricity. Not everywhere are even generators for liquid fuel. And this is in the 21st century!
Studies have shown that wind power stations of various capacities can be installed in many areas of the north and the Far North, on Sakhalin and Kamchatka, in the Lower Volga region, Siberia, Karelia and the North Caucasus.
The choice of installation is influenced by customer needs. If it is necessary to ensure the operation of agricultural machinery, a low-power wind generator will cope with this task. If you need to electrify the whole building, establish street lighting, provide heating for the house, you need to carry out the project of a wind power station.
In addition to the average monthly wind speed and its direction, it is necessary to calculate the average monthly consumption and peak load of electricity. Such calculations, if desired, are easy to perform independently.
There is another indicator that affects the cost of equipment and installation of wind turbines. This is the height of the mast. The higher the structure, the greater the wind speed and the more expensive it costs. Optimal, according to experts, is a mast height of 10 greater than the tallest tree or building within a radius of 100 m.
DIY wind farm
For the operation of an electric pump, television, lighting or other low-power electrical appliances in a summer cottage, a wind power installation can be done with one's own hand, if there is some knowledge of electrical engineering.
There are reference data and recommendations for choosing the power of the wind generator, the size and number of its blades, and quite detailed instructions on how to make a wind power plant with your own hands, from what materials and components.
Today, investments in the construction of large wind farms are growing in Europe. Mass construction reduces the cost of one kilowatt and brings it closer to the price of electricity received from traditional sources.
The design of wind farms is constantly being improved, aerodynamic and electrical indicators are improved, losses are reduced.
Home wind farms are estimated by economists to be the most cost-effective energy projects. In the future, they promise independence from negative trends in this market.
