For onshore wind farms, concrete is already
the established material of choice for foundations, either to form gravity
structures or pile caps. For towers, the foreseeable trend is for increasing
height, supporting higher powered, longer-bladed turbines, many of which may be
located at remote or less accessible sites. The consequence of taller towers is
the need for increased structural strength and stiffness required to cope with
challenging turbine weights and bending forces under wind action. In turn this will require larger cross-sectional
diameters, which may introduce significant transportation problems; bearing in
mind that 4.5m is the practical diameter limit for complete ring sections on
public highways.
Concrete towers can cost-effectively accommodate
these requirements as well as offering a range of other associated benefits.
Already, many leading wind power companies have realised the benefits of
concrete and offer precast or in-situ concrete tower solutions.
Whitelee wind farm,
near Glasgow, was developed by ScottishPower through
principal contractors Morrison Balfour Kilpatrick. The objective was to find a
locally sourced cementitious solution and a sustainable product with lower
embodied CO2 for a construction project focused on providing renewable energy.
The product also had to be suitable for large concrete pours required for the
foundations and bases of 215 wind turbines on the 5,300
hectare site, an area roughly the size of Aberdeen.
Base of onshore wind tower using in-situ
concrete
Buttress of onshore wind tower using in-situ
concrete