After going through the steps of planning and evaluating whether a small home wind turbine would work at a given location, general information was obtained:
- The amount of wind available at the site.
- Zoning requirements and regulations in the region.
- The economics, payback period and incentives associated with installing a wind system.
Now is the time to look at the issues involved in installing a wind system:
- Choosing the optimal location for the system.
- Estimating annual energy production and selecting the appropriate turbine and mast size.
- Deciding how to connect the system to the electrical grid.
Installation and maintenance. The system should be installed by a professional installer. A reliable specialist can offer additional services, such as obtaining the necessary permits. Check whether the installer has electrical licenses, ask for references and verify them. You can also contact your local Better Business Bureau.
With proper installation and maintenance, a small wind turbine should last up to 20 years or more. Annual maintenance may include:
- Checking and tightening bolts and electrical connections.
- Inspecting machinery for corrosion and strain on lashings.
- Checking and possibly replacing protective tape on the edges of turbine blades.
- Replacing components such as turbine blades or bearings as needed.
The installer can offer a service and maintenance program or recommend the right person for these tasks.
Locating a small wind system.
A professional installer should help you choose the best location for your wind turbine. Important aspects to consider include:
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Wind resources. In the case of complex terrain, proper selection of the installation site is crucial. Placing a wind turbine on the top or windward side of a hill will provide better access to prevailing winds than in a valley or on the leeward side of a hill in the same area. Wind resources can vary within a single parcel of land. In addition to measuring or knowing the annual wind speeds, it is important to understand the directions of the prevailing winds in an area. In addition to geological formations, existing obstacles such as trees, buildings or sheds should be considered. It is also necessary to consider future obstacles, such as new buildings or trees that have not yet reached their full height. The turbine should be located windward of buildings and trees, at a height of at least 9 meters above any obstacles within a 90-meter radius.
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System parameters. It is recommended to choose small wind turbines that have been tested and certified according to national performance and safety standards. When locating, ensure that there is sufficient space to raise and lower the mast for maintenance. For a mast with lashings, it is necessary to include space for lashing ropes. Whether the system is stand-alone or grid-connected, the length of the cable between the turbine and the load (house, batteries, water pumps, etc.) must be considered. Significant energy losses can occur due to the resistance of the cable – the longer the cable, the greater the losses. Using a larger or longer cable will also increase the cost of installation. Losses on the wire are greater with direct current (DC) than with alternating current (AC). In the case of a long wire, it is recommended to replace DC with AC.
Selection of small wind turbines.
Small wind turbines used in homes typically range from 400 watts to 20 kilowatts, depending on electricity demand.
The average household uses about 10,649 kilowatt-hours of electricity per year (about 877 kilowatt-hours per month). Depending on the average wind speed in the area, a wind turbine of between 5 and 15 kilowatts will be needed to make a significant contribution to meeting this demand. A 1.5 kilowatt wind turbine will meet the needs of a house consuming 300 kilowatt-hours per month in an area where the average annual wind speed is 6.26 m/s.
A professional installer will help determine what size turbine will be appropriate. First, determine the energy budget. Energy efficiency is usually cheaper than energy production, so it may be more cost-effective to reduce electricity consumption at home and reduce the need for a larger wind turbine.
The height of a wind turbine’s mast also affects the amount of electricity the turbine will be able to generate. A professional installer should help you determine the appropriate mast height.
Estimating annual energy production.
Estimating a wind turbine’s annual energy production (in kilowatt-hours per year) is the best way to determine whether the turbine and mast will produce enough energy to meet your needs.
A professional installer can help estimate expected energy production. The manufacturer will use calculations based on the following factors:
- The power curve of the wind turbine in question.
- The average annual wind speed at the installation site.
- The height of the planned mast.
- The frequency distribution of the wind, that is, the estimated number of hours the wind will blow at each speed during an average year.
The installer should also adjust the calculations according to the elevation of the site.
Small wind energy systems connected to the electric grid.
Small wind energy systems can be connected to the electricity distribution grid, they are called grid-connected systems. A grid-connected wind turbine can reduce the consumption of energy supplied by the utility, used for lighting, appliances, electric heating and cooling, and vehicle charging. When the turbine is unable to supply enough energy, the power utility makes up the difference. When the wind turbine produces more energy than is needed, the excess is accounted for and can be used to cover future grid consumption.
Modern grid-connected wind turbines operate only when the grid is available. They can also operate during power outages if they are configured to work with energy storage, creating a home microgrid to provide emergency power.
Grid-connected systems can be viable if the following conditions are met:
- The area has an average annual wind speed of at least 4 meters per second.
- Electricity supplied by the power utility is expensive (about 10 cents per kilowatt hour).
- The power utility’s requirements for connecting the system to the grid are not very expensive, and the grid has enough capacity to integrate the system.
- The power utility can provide a list of requirements for connecting the system to the grid.
Wind energy in grid-isolated systems.
Wind energy can be used in grid-isolated systems, such as microgrids that are not connected to the distribution grid. In such applications, small wind turbines can be used in conjunction with other components, such as a small photovoltaic system, to form hybrid energy systems. Hybrid power systems can provide reliable off-grid power for homes, farms and even entire communities (for example, housing community projects) that are far from the nearest power lines.
An off-grid hybrid system can be viable if:
- The area has an average annual wind speed of at least 4 meters per second.
- No access to the grid or connecting to the grid would require costly expansion. The cost of running a power line to a remote location may not be cost-effective.
- There is a desire for energy independence from the power utility.
- There is a need to generate clean energy.
Information sources:
https://pl.wikipedia.org/wiki/Elektrownia_wiatrowa
https://pl.wikipedia.org/wiki/Energia_wiatru
https://en.wikipedia.org/wiki/Wind_power_in_Europe