Structural design implications of combining a point absorber with a wind turbine monopile for the east and west coast of Ireland

Abstract

The integration of offshore wind and wave or tidal energy devices could be an important step towards realizing the economic competitiveness of less advanced renewable energy technologies. The foundations of such integrated solutions require a major share of investment in these technologies. Monopile foundations are currently the market-leader for offshore wind farms. This paper reviews normative design methodologies and presents a simplified concept to assess the structural steel design implications of incorporating a point absorber wave energy device to a monopile for selected sites off the East and West coasts of Ireland. The consequent increase in steel tonnage were computed for both locations. The design analysis was validated against existing studies estimating the increase in wall thickness of monopiles due to the combination of wind and wave devices for several design scenarios. The financial implications of the combination were assessed considering the impact of each scenario on the Levelized Cost of Energy (LCOE). The work provides a review-driven methodology as a tool to obtain an initial design-based estimate of LCOE comparisons for similar devices and allows making robust decisions on development or choice of devices for a particular location. This approach will be attractive to both researchers and practitioners alike in marine renewable energy, providing relevant, connected and comparable information from first principles to economic impact.