Reducing pile size ‘key to cheaper offshore wind energy’

DONG Energy has entered into cooperation with an academic consortium of three leading universities to work on an R&D project aimed at reducing the cost of energy from offshore wind turbines.

The academic consortium, led by Oxford University and including Imperial College London and University College Dublin, will investigate how offshore wind turbine foundations can be designed more effectively in the future.

Project PISA (Pile Soil Analysis) is being carried out by an industry group headed by DONG Energy and involves RWE, Statoil, Statkraft, SSE, Scottish Power and Vattenfall.

PISA is being run under the framework of the Carbon Trust Offshore Wind Accelerator (OWA), a UK government supported organisation established to promote offshore wind energy and reduce the cost of energy.

‘The cost of energy from offshore wind turbines must be reduced,’ said said Bent Christensen, senior vice president in DONG Energy Wind Power. ‘We expect to find significant savings by trimming monopile sizes and finding new ways of installing the foundations, amongst others. Consequently, we believe a significant contribution can come from this area towards our efforts of reducing the price of offshore wind power by 35-40 per cent by 2020.’

According to DONG Energy, the monopile foundation for a typical offshore wind turbine weighs approximately 600 tonnes and primarily consists of steel.

For a wind farm of 100 or more turbines this represents a substantial fabrication and installation cost. The thickness of the steel used for each pile is about 100mm. If this can be reduced without compromising the load-carrying capacity and stiffness of the foundation, there will be significant savings made in developing offshore wind.

The industry group has entered into cooperation with Oxford University for 18 months, with the project commencing on 1 August 2013. The project will provide funding for a range of academic contributions including two full time post-doctoral research assistants and, in the longer term, will result in three PhD projects.

The aim of the working group is to find technological solutions to be implemented in time for the design and construction of the large Round 3 offshore wind projects in the UK. The working group will publish their final reports at the beginning of 2015.