MULTI-MODE ENERGY CAPTURE
Triton is a highly efficient multi-mode point absorber that consists of a catenary moored surface float connected to an optimally-shaped, vertically asymmetric heave plate by three taut, flexible tethers. Unlike most conventional WECs, Triton’s surface float is excited by ocean waves in multiple modes – heave, pitch, surge and roll – allowing for increased energy capture across a wide range of ocean conditions enabling a substantially lower levelized cost of electricity.
Triton’s projected performance is based on extensive numerical modeling validated by tank testing at 1:50 scale. Testing of a 1:20 scale model is planned for Q3 2016.
HIGH EFFICIENCY ENERGY CAPTURE & CONVERSION
Triton’s drivetrain uses a variable linear hydraulic gearbox to amplify and transfer loads from the tethers to the generators. The gearbox is a high reliability hydrostatic system similar to that used in hydraulic presses. It delivers the benefits of a conventional rotary gearbox without complex moving parts. Specifically, it also allows for optimum matching of the wave-generated forces to the generator input forces, so that the generators operate at maximum efficiency while allowing the appropriate system compliance for coupling with the input wave.
Every WEC has an optimal force/displacement profile for maximum mechanical energy capture and efficiency in each wave condition. Triton’s linear gearbox design allows the load amplification factor to be adjusted to optimal levels during operation based on the wave state, enabling generator displacements to be maintained at an optimum level that is largely independent of the surface float’s displacement, maximizing power transfer over a wider range of sea states than other WECs.
The linear gearbox thus makes a significant contribution to the wide power bandwidth, increased reliability, and reduced cost. It also enables various non-continuous control strategies such as latching and declutching without imposing excess loadings on the generator or marine system, which may enable the use of advanced active control algorithms to boost power in lower sea states. Optimization of the linear drivetrain, including the linear gearbox, is being funded by Wave Energy Scotland.