What is the best tower for me?

Tower Height

Our standard towers are 6, 9, 12, 13, 15, 18 and 23m metres high. In general, the higher the tower, the higher the average wind speed that the turbine will experience, and it is normally the case in UK conditions, that a taller tower will generate sufficient extra energy to justify it's additional cost, especially if there are local obstacles to be avoided.
 

The chart to the right shows how the annual energy will vary depending upon the tower height at a location with clear open ground all around the turbine. This example is based on the Iskra AT5-1 turbine at a site with an indicated AMWS of 5m/s and clear open ground. This shows that, compared to a 12m tower, a 15m tower may increase the annual energy by 15% and a 9m tower may reduce it by 15%. If however there are local obstructions, then the impact of changes in the tower height could be larger.

Our initial site survey will give you estimates of the expected energy output from the turbines at various tower heights, and allow you to make an informed decision.

For sites where there are obstructions near the turbine, a tall tower may be needed to get the turbine above the turbulence created by nearby trees or buildings, as illustrated by the diagram to the left.

The taller the tower, the more the cost of the tower, the foundations and the installation, so you should not simply ask for the tallest tower that is available, but if the turbine is to be located near (< 200m) to surrounding obstacles, then a taller tower may be the best option.

Many people will say that one of the answers to the height problem is to mount the turbine on a roof to gain extra height, but this is not a simple solution, as our Building Mounted FAQ explains.

Other factors, such as planning, may dictate the maximum height of tower you are able to install and some areas of England, especially in Areas of Outstanding Natural Beauty, may stipulate a maximum tower height of 9m. Great care however needs to be taken to ensure that a tower this low is sited well away from obstructions such as buildings and trees, otherwise the energy generation may be significantly reduced.

Tower Type

Depending upon the type of the turbine, Segen can offer either a free-standing tower, or a guyed tower.

Guyed towers will tend to be used in rural locations, and have four guy wires going from the middle of the tower to concrete ground pads. They use slightly less steel than a free standing tower, but would not be considered suitable where people would be around the turbine a lot, as you don't want to risk damage to the guy wires.

A free-standing tower or "monopole" has no guy wires, but stands on a single concrete foundation with no other supporting structure.

In many cases the choice is really down to personal preference, as to which one you prefer to look at.

The Iskra AT5-1 can be supplied with a range of 9m, 12m or 15m free standing, or 12m guyed, the Westwind 20 is supplied on either a 15m or an 18m free standing tower, the Westwind 10 on a 15m free standing and the Skystream 3.7 is supplied on a 10m or 14m free standing or 13m guyed tower. The Kestrel 1000 is available on a 12m scissor style tower and the Kestrel 600 is available on 6m scissor tower which is user installable. Segen also offers a Vestas V17, 75kW, turbine on a 23m free standing tower for commercial and community applications.

Segen only supplies turbines on these standard towers, and I'm afraid you won't be able to use any existing tower or structure you may have, for safety reasons.