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.

Wind Turbines Offshore Foundations and Connections to Grid

“…Basically, this consists of a concrete pile set up with prefabricated concrete segments. Its installation is done through drilling along the inside of the pile, which is driven into the ground while drilling moves down forward [67]; see Figure 8. Below, an example of this kind of structure installed in the German Baltic sea for a 5 MW wind turbine at around 30 m depth is presented [68,69]…”

Circular and Faceted Monopile Installation Fatigue Damage

“…The work presented in this paper was part of a larger project, the goal of which was to establish the feasibility of utilising a novel faceted monopile design. General summary of the results of that study was published by the authors [4]. The feasibility of the faceted monopile design was considered based on the structural performance comparison with a conventional circular monopile design.…”