Alstom has signed a partnership agreement with Freyssinet with the aim of providing higher towers for wind turbines on less windy sites. Under the agreement the two companies will work together to develop a 119 m concrete tower specifically designed for Alstom’s ECO 122 wind turbine. The new tower will be made of 11 concrete sections, the lowest measuring 7.20 m in diameter, at the base of the structure.
Coupled with the MOU agreement previously signed with Max Bögl Wind AG, to develop a 139 m tower of hybrid design featuring a concrete bottom section and a steel top section, the new partnership with Freyssinet gives Alstom the ability to offer two high tower options for its ECO 122, enabling operators to harness the stronger winds found at high altitudes.
For the concrete tower, Freyssinet has developed an installation method called "Eolift" based on proven heavy lifting techniques used in civil engineering. This facilitates nacelle and tower assembly for high towers, while reducing contingencies relating to difficult conditions, such as high wind conditions during installation.
Also thanks to the installation of a temporary structure and a mobile factory close to the wind farm, each element of the Freyssinet concrete tower can be produced and assembled on site or nearby prior to full installation of the turbine, "allowing increased local content, and reduced transport costs", says Alstom.
In addition a 3 MW version of the ECO 122 is now commercially available, giving a 6% higher yield than the 2.7 MW machine. The high capacity factor deriving from higher altitude deployement combined with the turbine’s higher rated power make it "ideally suited for low to medium winds", Alstom notes.
Following measurements taken over a 2-month period on an initial 3 MW ECO 122 unit installed in Wieringermeer, Netherlands, the power curve of the new wind turbine has been measured and certified by ECN, providing tangible evidence of the machine’s efficiency.
Photo: ECO 122 wind turbine at Wieringermeer Netherlands (Source: Alstom)
