The SEA-TITAN project aims at making a step change in the wave energy sector by designing, building, testing and validating a crosscutting and innovative Direct Drive Power Take-Off (PTO) solution to be used with multiple types of wave energy converter. The design will be based on the existing Wedge Global W200 PTO prototype and will focus on augmenting its specific force density and efficiency to levels which can significantly increase the energy capture in many types of Wave Energy Converters. These enhancements will also solve one of the key issues with WEC PTO systems, namely achieving sufficiently high peak force to limit hitting end-stops during large waves whilst maintaining high efficiency and low cost for the average wave case.
The performance and reliability demanded by wave energy systems exceeds the normal capabilities of commercial, off the shelf components commonly used in other industries. In the few cases where they are suitable, the costs often prove prohibitive. In addition, the lack of predominant PTO technology is causing a barrier to establishing a dedicated supply chain.
Currently each original equipment manufacturer system has different requirements, and pursuing the development of bespoke components not only limits the utility of the end product but also multiplies the development costs.
The objective of SEA TITAN proposal is to break this practice and to develop an optimized crosscutting power takeoff based on the existing switched reluctance linear generator from Wedge Global with application to multiple systems through collaboration with multiple wave energy developers and an industrial partner with a strong track record on technology. In addition this proposal aims to offer the developed technology open source to promote update and accelerate innovation.
The overall objective of the SEA-TITAN project is to make a step change in the wave energy sector by designing, building, testing and validating an innovative second generation Direct Drive Linear Electric Generator Power Take-Off solution: an Azimuthal Multitranslator Linear Switched Reluctance Machine (AMSRM). This development is based on a new configuration and geometry of a first generation Multitranslator Linear Switched Reluctance Machine developed by some of the proponents some years ago. The development aims at achieving high continuous and peak force densities and also high efficiencies with application to multiple wave energy conversion technologies through collaboration with different wave energy developers and industrial partners with strong track record on technology.
A high peak force for short intervals is critical to the overall PTO functions and in particular to end-stop control, whilst higher overall force density is essential to allow WECs to take advantage of advanced control strategies and to maximize energy capture from large sea-states in a wider range of wave periods. Nevertheless high force values with poor efficiencies are useless, since most of the extra captured energy would be lost in the PTO.
A given Wave Energy Converter (WEC) has a theoretical limit of energy extraction capability, which depends on the control strategy, the wave parameters, the available force, etc. A useful indicator that will be explained later in section 1.3 is the Integrated Power Capture Ratio (IPCR), which reflects the relative energy that can be captured with a WEC including a real PTO compared to a WEC including an ideal PTO with no force limit and 100% efficiency. As it will be shown later, IPCR is very sensitive to the PTO force and will be considered as one key indicator to define the project goals. This solution will also contribute to reduce significantly the Levelized Cost-of-Energy (LCOE) of any WEC based on the proposed PTO system. Also Capital Expenditure (CapEx) can be reduced, at the time the overall system efficiency (Float-to-Wire Efficiency (FtWE)) can be augmented. The term FtWE is defined as the ratio between the mechanical energy absorbed by the WEC and the electricity fed into the grid.
