Development and Design Verification of a Floating Tidal Power Unit

Abstract

This paper presents how the design verification process for a tidal current power plant was carried out, and points out the challenges needed to be addressed in the technical assessment phase of the concept. The rules and regulations found suitable for the design process are presented. The paper focus mainly on what analysis is required to validate the capacity of the structure. The structure is exposed to a harsh offshore environment. The relative importance of the different loads and load effects is shown and discussed. The need for hydroelastic coupled analysis is demonstrated. The work shows that interactions between the main components are of large importance. There are interaction effects between moorings and structure as well as between turbine blades and structure. In fact the fully integrated system needed to be analysed as an integrated system, hence the need for coupled analysis. Although the structure was designed to derive energy from tidal currents, wave induced forces showed as important as currents for the structural integrity of the unit. The analysis demonstrated the versatility of the used FE analysis program AquaSim. This program is developed specifically to carry coupled analysis with hydroelastic interactions between structure and fluid. The FE program is in wide use within the Aquaculture industry. It is also in wide use in the offshore industry including moored systems and towed seismic equipment.

A review of the tidal current energy resource in Norway

“…So far, an exploratory survey on possible environmental impact at the site has been published [22]. Furthermore, the strucural mechanics of the floating system and the importance of wave induced loads have been discussed in [86]. Other projects to be noted in [76] are a Darrieus turbine developed by Water Power Industries AS 10 and a horizontal axis turbine developed by TideTec AS.…”