Investigation, Design and Approval of Foundations for the Cathedral Rocks Wind Farm in South Australia

Tom Bowling and Sam Ditchfield

The Cathedral Rocks Wind Farm is located on the south west coast of the Eyre Peninsula in South Australia, about 30 km from Port Lincoln (Figure 1). At this location the coast consists of cliffs up to 120 m high with the cliff top plateau gently falling away on the landward (NE) side to open grazing and farming country towards Port Lincoln.

The Wind Farm consists of 33 Vestas V80 2 MW wind turbines which have a tower height of 60 m and a three blade rotor 80 m in diameter (Figure 2). The adopted footing for each turbine tower is a buried reinforced concrete pad 14.5 m square weighing approximately 640 t. The wind turbines are spread over a distance of about 9 km along the cliff top plateau. Associated infrastructure includes access and service roads, buried power and control cables, a control centre, a transformer and switchyard and a 132 kV transmission line connecting to the South Australian grid.

The wind farm has been developed as a joint venture between Roaring 40s Renewable Energy and the Spanish company EHN (the hydroelectric corporation of Navarra) which has now been taken over by the Spanish based public infrastructure and renewable energy company, Acciona. Foundation design was carried out by the Hydro Electric Corporation of Tasmania (Hydro Tasmania).