Faceted Monopile Design Suitable for Mass Production and Upscaling

Abstract

There is a growing need for cheaper, more sustainable energy sources and this calls for optimisation of energy harnessing systems. Offshore wind energy has been highlighted as one of the more promising energy sources and in this application, the foundation structure for a typical installation contributes significantly to the overall levelised cost of energy. With this in mind, a faceted monopile foundation design and the review of its critical evaluation is presented. This type of design lends itself well to mass production and upscaling, both factors seen to reduce the overall cost of gathered energy. The evaluation of the design is performed through comparison with a conventional, circular monopile design. The comparison is undertaken using conventional design criteria as outlined by the DNV standards body. A finite element model was used to evaluate the structural performance of the designs. It is shown that the faceted design has a higher fatigue resilience than the conventional round design. Also, the fatigue damage caused to the monopile during pile driving installation is estimated from the conducted scaled down test where a series of strain gauge signals were collected to allow for stress measurement at specific points of interest. The feasibility of the proposed faceted monopile design is supported based on this critical evaluation.