The Multi-float WaveSub Wave Energy Converter

Marine Power Systems (MPS) WaveSub Wave Energy Converter (WEC) addresses the energy trilemma by providing sustainable, cost effective, low carbon renewable energy by capturing the sub-surface orbital energy nature of waves. The patented device is tuneable to all sea states through a unique single / multi float power take-off system. Securing over £3M in grants and £2M in private investment, MPS has completed extensive testing of the single float WaveSub WEC at 1:30 scale, validating the computational simulations of power generation. MPS is currently embarking on the fabrication of a 1:4 scale WaveSub, with testing at FaBTest in 2016 / 2017. Initial techno-economic modelling using Carbon Trust Levelised Cost of Energy (LCOE) methodology shows WaveSub delivering a LCOE lower than existing WEC devices and competitive with conventional generation, with transition from single float (1.5MW) to multi-float (Multi-MW) device.

This 12 month project with MPS and University of Bath (UoB) delivers the modelling, design, manufacture, test & validation of a 1:30 scale multi-float WaveSub device, with outputs informing the LCOE model that will unlock WaveSub's true commercial potential. Within the project, UoB will design and build the Power Take Off system for the multi-float device. Building on previous experience from a 1:30th scale single float device, the PTO for the multi-float concept will consist of multiple independently controlled electro-mechanical units designed in conjunction with other WaveSub systems (e.g. winching) for proper integration. The independent control of the units will provide the greatest flexibility for exploring
different operational regimes. The unit will be controlled in real time and will allow motion, power capture and loading measurements. A range of control schemes will be implemented in order to validate numerical models and to evaluate whole system performance in all conditions. This could include linear damping, adaptive damping, and advanced nonlinear
schemes such as latching and declutching control.

National perspective:
The project objectives directly address all three aspects of the energy trilemma:
1) Reducing emissions - The project resides within the Renewable Energy technology challenge area, contributing to the 2020 and 2050 UK emissions targets.

2) Improving security of supply - Wave-energy is a reliable, predictable renewable source with high energy density. The World Energy Council estimates that wave generated power could deliver 2,000 TWh/year, but this will not happen until the technology achieves large reductions in £/W. With 15% of the 2020 estimated 85GW UK requirement to be delivered by renewable sources, this project directly tackles the security of supply issue.

3) Reducing cost - Initial techno-economic modelling using Carbon Trust Levelised Cost of Energy (LCOE) methodology shows WaveSub delivering a LCOE lower than existing WEC devices as a single-float and competitive with conventional generation as a multi-float device.

International perspective:
MPS expects to be 1 of 5 successful global Wave Energy Converter companies, with sales exported internationally from the UK.

Economic:
Multi-float project provides crucial LCOE evidence to unlock investment for next-stage full scale Demonstrator (c2018) and secures pathway to commercialisation (c2020). On full commercialisation, UK PLC and international export sales are £500m+ after 5 years.

Social:
WaveSub manufacturing supply chains will create c1000 UK jobs after 5 years of commercialisation, with up-skilling and high value jobs created in coastal areas subject to traditional maritime industries recline, thus creating wealth and sustaining communities. WaveSub devices can be transported over large distances at sea from a single coastal manufacturing base. In addition, the project supports and promotes renewables research at UoB and future undergraduate and PhD research across the UK.

Environmental:
WaveSub helps to unlock the UK's abundant wave energy resource (best in EU), with emissions reduced through displacement of high carbon energy generation. Using DECC's Impact Assessment, annual CO2e savings to UK from WaveSub sales are 250,000t with after 5 years of commercialisation with 215MW installed.

Commercial Private Sector:
The research will result in more efficient designs and reduced development time. It will accelerate the large scale deployment of wave energy devices and the expansion of the emerging wave energy sector, providing employment and associated economic benefits.