Posters

Abstract

Onshore wind turbines generally are founded on large circular slabs of reinforced concrete, superficially anchored at a depth of about 3m. A wind turbine has to be renewed approximately every 20 years to install a new aerogenerator, this is called repowering. In its current practice in France, the repowering of wind turbines leads to the complete deconstruction of the old reinforced concrete foundation, before rebuilding a new one, at the same location or in the immediate vicinity. In an effort to reduce environmental impacts and limit greenhouse gas emissions, this practice appears to be far from optimal. A consortium of players working in the field of onshore wind turbine foundations has been formed around INSA Lyon, the academic partner, to research and develop innovative solutions to reuse all or part of the old foundations within the new foundation in order to reduce the volume of concrete required by the new footing and limit the environmental impacts. The research project, started in September 2018 for 5 years, was based on an approach combining: - In-situ measurements and tests on the foundations of new wind turbines, finely instrumented (soil, concrete foundation, anchor cage and base of the mast), - Production of digital models of the foundation on the real scale and on a scale of 1/10, - Carrying out laboratory tests on 1/10 scale models. The proposed technical solution, called “mushroom solution”, comprising: - deconstruction by sawing of the upper cylindrical part of the footing - onstruction of a new sole, relatively thin, placed and sealed on the old sole. The technical solution developed is tested and validated on a 1/10 scale model. In addition, life cycle analysis (LCA) studies have been carried out. Ultimately, the purpose of the project is to be able to design slabs that could be adapted to several successive generations of aerogenerators.