Gifts of Eol

A wind power plant serving a country house testifies not only to the owner’s desire for independence, but also to the fact that he is not indifferent to what kind of air his children will breathe. But in all cases, is the use of such equipment justified from an economic point of view? Let’s try to figure it out.

Wind, are you strong?

Age/East News
The prototype of a modern windmill— windmill Alas, nature has not collected all the winds in deposits, as it did with natural gas, oil and coal, and did not force them to flow along the channels, like rivers. Wind energy is truly colossal (about 53000kWh, which is 4 times more than the current energy consumption of the planet), but, alas, it is scattered in space in different cities and villages. ToIn addition, the speed and direction of the wind often change many times on the same day— it is not for nothing that in folklore and classical literature it symbolizes inconstancy. However, it is still possible to assess whether there will be any benefit from using such an installation on your site. To do this, it is necessary to know the wind potential of the territory, more precisely, its main characteristic— average annual wind speed (arithmetic mean of all wind speeds observed during the year). This can be done at the Center for Hydrometeorology and Environmental Monitoring or even at the nearest airfield (if it has its own meteorological service).

Age/East News
The best place to install a wind turbine— open field or steppe At low average annual wind speed (within 3-4m / s) electricity produced using a wind turbine costs a pretty penny for the consumer. For example, in the Moscow region, where the average annual wind speed is approximately 4m/s (3.7-4.2m / s), a modern windmill with a capacity of 1kW will produce about 120kWh / month (however, this is enough to power several energy-saving lamps, a TV, a refrigerator and a circulation pump— see table). For the year, the production of equipment will be 1440kWh, and for the entire service life, that is, approximately 20years (quality equipment should work so much),— 28800kWh. The cost of a turnkey wind turbine in a configuration that provides guaranteed power supply to the cottage, we will take equal to $7000 ($3000-10000). In this case, the cost of 1kWh will be approximately equal to $0.24, or at the rate of mid-January 2006G.— about 6.93rub. for 1kWh. For reference: electricity purchased by private individuals from the state costs 1.60 in the Moscow regionrub. for 1kWh, and when connected through a private supplier company— up to 3.5rub. for 1kWh.

Architects I.Jansone, K.Avotins
Photo by M.Stepanova From the above, it is easy to conclude that the use of a wind power plant in the Moscow region is economically justified if there is no and will not be network electricity in the house, and the cost of energy obtained using other types of autonomous sources, such as a diesel generator, exceeds 7rub. For cottages that are already connected to the network, it is pointless to install a windmill for reasons of economy, except perhaps for backup power supply. BUTif electricity has not yet been supplied to the cottage, but is it possible to supply it? Here it makes sense to think and calculate everything, taking into account the cost of connecting to the network (which in different areas of the Moscow region will cost To use wind energy «to the fullest», the mast of the windmill must be 3-4m above all obstacles within a radius of 200m$800-1200 for 1kW, and you must immediately connect at least 5kW), as well as a constant increase in prices for purchased electricity (about 10% per year). It may be more profitable to abandon the centralized supply and choose a wind turbine— as in the case of a fatal unavailability of network electricity.

ATin those regions of the country where the average annual wind speed is higher than in the Moscow region, the use of a wind power plant may well be more profitable than buying electricity. For example, in areas where the wind speed is 8m / s, it will be possible to get about 580 from a kilowatt devicekWh/month, and electricity will cost the consumer 1.43rub. for 1kWh. Most often it is cheaper than buying electricity «on the side»— at commercial, and sometimes at state prices. For example, in Kamchatka electricity costs from 2rub. for 1kWh. BIt is beneficial for Russia to install wind turbines on the coasts of the Arctic Ocean, the Gulf of Finland, the Black and Caspian Seas, as well as in Kamchatka, Sakhalin and Chukotka, in Yakutia. Many other areas are also promising, where strong winds (with an average annual speed of up to 10m / s) and the construction of a network power supply system entails bhigher costs than the creation of an autonomous independent system.

With wind speeds up to 2.5m / s, it is not worth using a wind turbine as an energy source. Bmost of the time it will be idle— the force of the wind will be insufficient even to move the wind wheel from its place.

Approximate energy consumption of electrical equipment of a country house

Basis of the system

2.5 power inverterkW. The device can be installed both horizontally and vertically. Currently, the leading manufacturers of wind turbines have focused their efforts on horizontal-axis models that can most effectively convert wind energy into electricity. The power of horizontal-axis wind turbines used for autonomous power supply of cottages,— from a few tenths of a kilowatt to 10-15kW. More powerful models are also available.— up to several megawatts. However, their purpose— generate electricity for supply to the power supply networks in order to save fuel and the resource of thermal power plants. ATFor Russia, unlike the Western countries, such assistance to the country’s energy sector is not yet welcome.

The wind generator is located at a distance of 30-40m from residential buildings, so that the light rustle of a rotating wind wheel does not bother the inhabitants of the house. The height, and therefore the cost of the mast, depends on the presence of obstacles (trees, buildings and other objects) near it. For the most efficient operation of the installation, it is proposed to build a mast of such a height that the axis of the wind wheel is at least 3-4m above obstacles located at a distance of less than 200m. The mast itself must be fixed on the foundation and additionally secured with stretch marks from a galvanized metal cable (for this, 5-6 reinforced concrete columns with a diameter of 500mm, poured to a depth of about 2m). AThouse electricity from the generator of the installation is supplied through a two-core copper wire with a cross section of up to 6-8mm²laid in a sealed underground channel.

Wind turbine or more?

Getty/FOTObank The electricity generated by the generator is used directly to power appliances that are insensitive to power quality (incandescent lamps and heaters), as well as for street lighting. Other devices, such as computers and radios, may fail prematurely from such a power supply due to sudden changes in the magnitude and frequency of the voltage. Connecting a windmill directly to the load is only permissible when supplying power to outbuildings, whose electrical appliances can be de-energized during periods of calm or weak winds without compromising the safety and comfort of people.

Interruptions in the supply of energy to a modern cottage— emergency incident. For guaranteed power supply of a country house during periods of calm or weak winds, it is necessary to equip an uninterruptible power supply system. It will allow you to store the energy extracted during strong winds for the future and provide the house with energy in the event of a long calm. Uninterruptible power supply system equipment is best located directly in the cottage— in a small, soundproof, heated room with a maximum relative humidity of 70% and at least three air changes. This room is equipped near the mast of the wind turbine.

The complex of rechargeable batteries allows you to store electricity for future use.The composition of the uninterruptible power supply system includes, first of all, a set of rechargeable batteries. If a generator with a capacity of 1kW, four lead-acid or alkaline starter batteries (190BUTh each). If a plant with a capacity of about 5kW, the number of such batteries should reach14. To recharge the batteries, you will need a charger that rectifies the incoming voltage and protects the batteries from overcharging. ATthe power grid of the cottage energy must be supplied through a special device— inverter. It converts DC from batteries into «high quality» AC 220B/50Hz, suitable for powering any household appliances. The rated power of inverters used in cottages is usually 0.5-5kW, maximum— 2 times more. Compressors, pumps, electric motors at the time of startup consume power for a short time, 2-5 times higher than the nominal one. The starting power of such equipment at a single start should not exceed the maximum power of the inverter.

Gasoline generator with a capacity of 5.5kW in a low-noise version based on a HONDA engine— it is a diesel, gasoline or bottled gas powered electric generator. You cannot do without such a device if the average annual wind speed in the region does not exceed 4-6m / s (for example, in the Moscow region). Included in the power supply system of the cottage, the generator will work as a backup power source during a period of prolonged calm. Indeed, if the wind barely blows for several days in a row, the wind power plant will not be able to deliver the rated voltage. Meanwhile, in the house, electricity will be consumed as usual; sooner or later the battery station will be depleted and the power supply will stop. ATIn this case, the generator will have to be turned on manually (if autostart is not provided) for only a few hours a day to recharge the batteries. Thus, a reliable and economical system of uninterrupted power supply of the cottage will be created.

Choose

Many models exist in the form of a prototype. As a rule, such wind turbines are offered by small design bureaus at old machine-building plants. The calculation and design parts of these developments correspond to all scientific and technical canons. There is only one drawback, but a very significant one: the developers are not interested in small-scale production, so it is impossible to buy such an installation, except perhaps for the power supply of a village of 50-100 houses. Yes, and it is not so easy to check the proposed equipment for professional suitability «behind the eyes». Therefore, investing in such projects— It’s a very risky business.

Battery charger(a). Inverter that converts the DC voltage of batteries into AC single-phase 220B/50Hz for powering household appliances(b) Another type of wind turbine on the market— models that were mass-produced during the Soviet era. Enterprises that produced such equipment existed at the expense of financing from various state programs, for example, to support the small peoples of the North, and, of course, did not survive the transition to a market economy. ATcurrently production is stopped, old stocks are being sold. Thanks to good packaging and preservation, these wind turbines have survived safely to this day and can be used for their intended purpose. The question remains only their maintainability.

ATCurrently, there are very few firms that regularly carry out single or small-scale production of wind turbines. It is logical to turn to such manufacturers, however, it is advisable to get acquainted with the quality of their equipment and work with your own eyes. To do this, it is best to communicate with the owners of cottages serviced by equipment installed by these firms. Among the Russian manufacturers of wind power plants, one can name, for example, SAPSAN-WIND ENERGY, ELECTROSPHERE, WINDEK, LMV VETROENERGETIKA COMPANY, TsNII ELEKTROPRIBOR, GMKB RADUGA. Among foreign— company J.BORNAY (Spain), RUTLAND, MARLEC (Great Britain), BERGEY, SOUTHWEST WINDPOWER, PROVEN (USA) and many others.

The editors would like to thank SAPSAN-WIND ENERGY for assistance in preparing the article and provided photographic materials.

• Source: Ideas for Your Home Magazine#94