Development of a new parameter based design approach for offshore wind farm foundations could significantly cut costs according to claims by a major research project.
Oxford University lecturer Byron Byrne said yesterday at the British Geotechnical Association’s annual conference that the work on the Pisa – Pile Soil Analysis - project could remove conservatism from existing design models.
Pisa is an initiative being carried out by an industry working group headed by Dong Energy and involving RWE, Statoil, Statkraft, SSE, Scottish Power and Vattenfall, which is being run under the framework of the Carbon Trust Offshore Wind Accelerator. The project is supported by an academic consortium led by the University of Oxford and including Imperial College London and University College Dublin.
Byrne said that foundations on existing wind turbines are stiffer than expected suggesting that the designs are conservative and the aim of Pisa is to develop new design guidance for all types of offshore wind farm that will remove this over design in a bid to reduce costs.
According to Byrne, the parameter based method that has been developed closely matches the design output from finite element modelling and suggests that pile lengths could be reduced by up 35%. “This represents significant savings in both the steel used to manufacture these piles and also in the costs and time to install the piles on site,” he said.
Byrne cautioned that the approach is for a baseline case and consideration of cyclic loading complicates the issue but he added that the project is now moving to the field testing stage where the impacts of cyclic loading can be fully considered. “We will be testing scaled down versions of the piles and testing them under a range of load conditions, including cyclic loading,” said Byrne.
Testing is expected to get underway at sites in Cowden in the UK and Dunkirk in France towards the end of this year with a view to publishing the results in the form of new guidance next summer.