The wind turbine is usually mounted on a tower to lift them into the free-ﬂowing air. When considering Installing Wind Turbines options, you need to find what you want to achieve:
what to take in considerations to Installing Wind Turbines?
– You need to get your wind turbine into clear, fast ﬂowing air. The higher your turbine is, the more energy you will collect from it.
– You will need to be able to access your wind turbine from time to time to carry out routine checks and maintenance.
– Wind turbines are heavy. Add the force of the wind, and your loading gets very high, very quickly. You must use a suitable tower for your choice of the wind turbine.
-Wind turbines cannot run in extreme Winds. Larger wind turbines with adjustable rotor blades will adjust the rotor blades so that the turbine comes to a halt. A mechanical brake then locks the rotor into position until the wind levels subside. With a smaller wind turbine, the turbine needs to be furled in extreme wind conditions to ensure it does not get damaged. Furling can either be automatic or manual and involves either turning the turbine side on to the wind so that the rotors cannot turn, or tipping the turbine up on its end to achieve the same effect. This furling may be part of the wind turbine design, but in other cases is a function of the tower.
– Your wind tower needs to be adequately grounded (earthed) to protect your equipment in case of a lightning strike.
how to get the best potential of your wind turbine?
you need to get it as high as possible to reduce turbulence and get into the strong, free-ﬂowing laminar winds. From a production point of view, you want your tower to be as tall as possible. However, taller towers are more expensive to install and can make maintenance and servicing more complicated. Inevitably, there is a trade-off between the height of the tower and the practicalities of your system.
As discussed earlier, there is a minimum height that you need to adhere to: you want the bottom tip of your rotor blade to be a minimum of 10 meters (32 feet) higher than any obstacles within a 160 meter (500 feet) radius.
When discussing your turbine requirements with suppliers, ask them what towers they recommend for each of their turbines. Most turbine manufacturers either supply or recommend suitable towers for their products and suppliers will have a good knowledge of the different turbines and how they work with different turbines and in different locations.
Breaking the Height Rule to Installing Wind Turbines
There are a few instances where you may wish to break the 10 meters rule and install a wind turbine at a lower level. Small wind turbines, rated below 400 watts, are often installed as low as 3 meters (10 feet).
Smaller wind turbines have smaller alternators and lower internal frictions, which means that they require less wind. Consequently, they can operate and generate some power even if they are mounted at lower levels. I would never go as low as three meters, but at five meters (16 feet) you can start producing small but useful amounts of power.
The performance of your wind turbine will be reduced: you will get around one ﬁfth of the power production at five meters compared to ten, but for some requirements, where you only require a minimal amount of electricity for a speciﬁc application, this trade-off may be perfectly acceptable.
what is the Tower Types to use for Installing Wind Turbines?
There are four basic types of tower to consider: guyed pole, tilt-up, lattice, and monopole.
There are some different variations on all of these themes. For example, there are guyed, and tilt-up lattice towers and many guyed poles incorporate tilt-up into their designs.
Guyed Pole towers
Guyed pole towers are the cheapest and simplest towers for your wind turbine. Ranging from a home-made tower using a 10-15 meter (33-49 foot) scaffolding pole suitable for turbines of up to 5oow to 50 meters (165 foot) professionally designed towers for 5okW turbines, guyed pole towers are usually the cheapest and easiest type of tower to install.
The tower itself is either bolted into a solid concrete foundation or is concreted into the foundation. The guy wires, a tensioned steel cable, tether the pole to the ground through ground hooks that have been concreted into the ground. These cables need to be adjustable using tensioning ratchets. Four separate guy wires are used to keep the tower tensioned correctly. On taller towers, the second set of guy wires are used. As a general rule of thumb, you use one set of guy wires for every 5 meters [16 feet) of the pole.
– Cheapest and simplest towers available
– Easy to install
– Some designs can incorporate a tilt-up mechanism for ease of maintenance and to lower turbine in stormy weather.
– Suitable for all sizes of wind turbine
– Big ground footprint
– Guy wires can create additional wind noise and in some cases can amplify the noise from the turbine itself
A tilt-up tower can be based on a guyed pole, a lattice or a monopole structure. The reason I have listed them as a separate tower type is that they have the signﬁcant advantage of being able to be dropped down to ground level. Various designs and mechanisms for the tilt are available, from a simple lever to a hydraulic or motor-powered system for larger towers.
The benefits of tilt-up towers are that the turbine can be installed at ground level and then hoisted into position once the installation is complete. Once the system is in use, the tower can be lowered for routine maintenance and servicing.
Tilt-up towers are only commonly available for turbines up to 5okW in power, with heights of up to 30 meters [96 feet) although larger tilt-up towers are available, though often costly.
– Easy to install
– Ease of maintenance
– The turbine can be lowered in stormy weather
– Some options can be costly -particularly the motor-powered versions
– Not suitable for larger wind turbines
Lattice towers have a larger footprint than monopoles but a smaller footprint than a guyed tower. Fifty to one hundred years ago, these towers became a popular way of mounting the water pumping wind turbines in the United States. The designs have stood the test of time and can be scaled from micro-power systems to utility-scale turbines.
Lattice towers are usually delivered in component form and assembled on-site, making them easy to transport and simpler to build. Because of their space frame structure, they are comparatively lightweight, compared to a monopole as they typically require only half as much material to build. They are usually built at ground level and then hoisted upright into position. Towers up to 30 meters tall (100ft) can generally be constructed on-site without requiring a crane or heavy machinery, thereby keeping installation costs down.
Traditional lattice towers have some drawbacks, however. Firstly, they can be noisy with the wind whistling through the structure. Secondly, birds like them and use them for nesting, increasing the number of bird strikes. Finally, many people do not like the aesthetics of a lattice tower.
All of these concerns can be mitigated, however, by enclosing the lattice tower in a UV- resistant PVC fabric. This resolves these drawbacks, resulting in a design that looks similar to a monopole.
Lattice towers have become less common over the past ﬁteen years. However, as wind turbines become larger and more powerful, lattice towers may be about to make a comeback for utility-scale energy production as they are capable of being built far taller than monopoles and at a much lower cost.
– Easier to install than monopoles for large installations
– Use 50% less material than a similar-sized monopole
– Can have wind noise blowing through the structure
– Increase in bird strikes with birds nesting in the lattice structure
– Some people dislike the aesthetics
Monopoles, also known as freestanding tubular towers, range from a simple scaffold pole in the ground for a tiny wind turbine to a huge tower, delivered in 12 meter [40 foot) sections on the back of a ﬂeet of heavy-goods trucks and assembled on-site with huge cranes and soaring 120 meters -400 feet — or more into the sky.
Monopoles have the beneﬁt of a small footprint. They are often also the cheapest tower option and have the cleanest aesthetics.
Utility-scale wind turbines that use monopoles incorporate service lifts and a servicing platform at the turbine itself. With smaller wind turbines, servicing requires access to a crane with work platform.
– Often the cheapest tower option
– Requires access to a crane with the work platform for servicing