What are the benefits, disadvantages and differences between the different types of tower?

It is not a good idea to buy a tower or mast not specifically designed for your turbine of choice. Mismatching the turbine to the mast could lead to vibration, noise, failure or collapse of the installation. It is advisable to use masts designed for a specific turbine as these will be designed to cope with the loadings and harmonics created by the associated turbine.

There are a number of variations on masts for small turbines. These can be categorised into two distinct structures - guyed or freestanding - with variations on the construction of the tower. The key considerations for tower selection are cost, space and suitability with the turbine of choice. The characteristics of each type of support structure are discussed below.

Guyed Pole

• A narrow tubular pole or joined pipe sections supported by guy wires.
• Uses less material in its construction and thus reduces material costs.
• 'Tilt-up' construction with a Tirfor using a gin pole as lever arm around pivot point at the base. A Tirfor is a lifting device or which allows slow winching of a lifting cable. A gin pole is an A-frame lever point which makes it possible to winch the support from a horizontal position.
• There are usually 2 levels of guys on most towers although the number depends on height.
• The radius of the guys should never be less than half the height of the tower and can be as wide as there is space beyond that but generally a radius of 75% of the height is satisfactory.
• No climbing or elevated access is required as the pole can be lowered for maintenance and access.
• Requires less of a concrete footing than free standing tower variations.
• Not suitable for mixing with larger livestock due to risk of interference with the wires and anchors.
• Could be prone to vandalism if in an accessible area.
• Generally the least expensive type of tower.

Tubular Steel

• Single tapered pole -street light type- which is usually hot-dip galvanised steel.
• Scaled down version of typical type of tower used in wind farms.
• Requires more substantial concrete footing than a guyed pole.
• No guy wires required and thus minimal risk of structural interference from animals or people.
• Cranage may be required but as with the other types of tower raising with a gin pole, pivot and Tirfor is a preferable, more preferable option with many variations.
• Variations which cannot be tilted down require hoist hire or other elevated access for preventative maintenance and repairs.
• Material costs can be high when compared to other tower types (more steel per metre height).
• Generally the most expensive form of support for a turbine.

Lattice tower

• Similar in appearance to common 'criss-cross' towers.
• Lattice is manufactured by welding tubular, flat or angle profiles together to form a structure.
• Can use up to half the quantity of material for a similar strength free standing tubular steel tower.
• Can be guyed or free standing depending on design.
• Guyed lattice towers warrant similar consideration in relation to site, space, land use and security as guyed pole towers.
• Installation is in sections and usually requires cranage although some arrangements allow raising with a gin pole, pivot and Tirfor.
• Base would need to be made secure with fencing to prevent climbing if in accessible area.