Wave Energy Scotland Awards £7.5m for Power Take Off Projects

Wave Energy Scotland has selected 3 technologies to go forward to stage 3 of its Power Take Off (PTO) development programme.

The projects will involve demonstration and testing of scale prototypes in a representative environment and cover a range of technology options: digital hydraulics, electrical linear generation and a ball-screw generation. A total of £7.5m has been awarded for the projects which will be completed over the next 2 years and involve 15 organisations from across Scotland. The award recipients are:

  • Artemis Intelligent Power Ltd - £2,498,400
  • University of Edinburgh - £2,499,556
  • Umbra Cuscinetti SpA- £2,469,450

WES Managing Director Tim Hurst said, “After an extensive evaluation process, these technologies were assessed to be the best in the programme and worthy of further development. This represents a significant milestone for WES as projects from our first call reach an advanced stage of maturity. This takes us one step further towards finding the best solution for the PTO component of a Wave Energy Converter (WEC).”

Paul Wheelhouse, Minister for Business, Innovation and Energy said,

“I am delighted to see a strong show of Scottish talent in this latest round of funding.  The Scottish Government recognises the enormous potential for wave energy to contribute to Europe, and indeed the global energy need, and we are fully behind this technology programme.  I am pleased that our investment is now showing promising results. Supporting the development of wave energy technology in Scotland is allowing us to use home-grown skills while expanding our domestic marine energy sector.  The WES programme is strategically important to Scotland and will help the Scottish supply chain to build collaborations and to maintain its strong lead in this emerging industry.”

Notes to Editors:

Power Take Off is the name given to the method used to convert wave motion into electrical energy, which can then be collected and used either in the grid, locally or stored for future use.

The WES programme works by initially selecting several projects at stage 1 (concept design) from the call. Once these short projects have been concluded, each of them can apply for stage 2 funding. To determine which projects succeed, they are assessed with external input and the best are selected to develop their projects further. Only a percentage of the proposals proceed through the assessment process. A similar procedure occurs for projects moving from stage 2 to stage 3 where further funding is invested in the emerging technologies.

WES expects to announce a fourth innovation funding call for Control Systems in April 2017.

Wave Energy Scotland was set up as a subsidiary of Highlands and Islands Enterprise and is fully funded by the Scottish Government. The new organisation is seen as a fresh approach to tackling the issues which have proved challenging in the wave energy sector.

Project Details in no order or priority

Project Title: Quantor hybrid hydraulic PTO – Stage 3

Lead Contractor: Artemis Intelligent Power

Subcontractors: Quoceant Ltd.

Project Summary:

The power-take-off (PTO) system of an efficient wave energy converter (WEC) has three main technical functions. It provides reaction forces against wave-induced motions in such ways as to capture the most energy from the sea. It stores this energy with a time constant of at least the longest wave period. It exports energy smoothly in the form of grid-compliant electricity.

Artemis Intelligent Power and Quoceant believe that the sea-proven ‘quantised chamber-switching’ concept provides the most promising foundation for addressing these challenges. Quantised systems are very efficient and able to deal economically with very high instantaneous power levels whilst generating electricity at steady mean powers. However, by its nature, chamber-switching produces coarsely stepped load profiles that limit WEC controllability and compromise wave energy absorption.

In a previous Stage 2 project, Artemis and Quoceant demonstrated that Digital Displacement® (DD) technology can be used to complement quantised chamber-switching, smooth out the load steps and provide continuously variable control.

By offering unparalleled efficiency, controllability and power handling capability, this hybrid hydraulic ‘Quantor’ PTO can increase the productivity of a wide range of WECs. It will also offer some compelling benefits in other renewable and marine hydraulic applications where a continuously variable, four-quadrant, efficient transmission is required over rapidly varying power levels.

Artemis and Quoceant are teaming up again for the next stage of Quantor development. Their Stage 3 project will advance it to full demonstration on a purpose built test-rig that will allow realistic representation of WEC dynamics. This is vital because interactions between WEC and PTO can cause instability and performance limitations that must be understood when developing control software. The test-rig may be adaptable to other PTO systems to allow the comparative testing of alternative systems. The Stage 3 project includes development of the underlying DD technologies to enable implementation of the Quantor PTO at power levels up into the megawatt range.

Project Title: EMERGE (Electro-Mechanical Reciprocating Generator)

Lead Contractor: Umbra Cuscinetti S.p.A. (UMBRA)

Subcontractors: Hebrides Marine Services Ltd (HMS), The University of Edinburgh (UNIEDIN), Bureau Veritas UK Limited (BV), Green Marine UK Ltd (GRMAR), Doosan Babcock Ltd (DOOSAN), Seapower Scrl (SEAPOWER), Supply Design Ltd (SUPDES), JGC Engineering & Technical Services Ltd (JGC)

Project Summary:

The Electro-Mechanical Generator (EMG) is an innovative direct-drive system able to convert linear, reciprocating motion into electricity. It is based on the integration of a recirculating ballscrew and a permanent magnet generator.

In the EMERGE project, the EMG will undergo testing both in relevant and operational environments to reach a Technology Readiness Level (TRL) of 7. In particular, it will be first tested in a bench with a Hardware-In-the-Loop (HWIL) configuration while submerged in synthetic salt water. Then, it will be integrated with a point-pivoted Wave Energy Converter (WEC) and undergo sea trials in the Orkney Islands. This project will allow developing engineering solutions for survivability in the marine environment and give valuable information concerning the EMG performance in real sea conditions.

Project Title: C-GEN Direct Drive

Lead Contratcor: University of Edinburgh

Subcontractors: Forth Ports, DNVGL, Bernard Hunter Crane

Project Summary:

The UK has a significant wave energy resource, but is yet to exploit it fully for the generation of electricity.

The power take off (PTO) system converts the captured mechanical energy into electricity for delivery into the national grid. The PTO needs to be reliable, efficient, and affordable to ensure both technical and economic success. Direct drive systems involve the generator being directly coupled to the prime mover, which minimises the number of moving parts, leading to a high level of reliability, and hence availability.

The C-GEN generator is a novel direct drive linear generator which is easy to manufacture and assemble, as well as being highly efficient over a wide range of loads, typically 85-90% for wave applications from part to full load. This is greater than competing PTOs such as hydraulics, and hence annual energy yields will be greater.

A number of prototypes ranging in scale from 15 kW to 1 MW, have been demonstrated to confirm the scientific and technical rigour of the concept, including a 50 kW prototype for wave energy applications. Recent developments for wave energy (WES Stage 2) includes testing of components (electrical windings and bearings) in flooded conditions, using custom made dedicated test rigs.

A significant improvement in thermal performance was achieved, and an improved design for reliable and robust bearings for linear generators. Economic analysis of the C-GEN generator has shown that a CAPEX of less than £500k/MW, and the LCoE target of £150/MWh are achieveable depending upon the wave device and site.

All previous developments have taken place in the lab, with experiments in realistic environments. For wave energy the technology is at TRL4, and is now ready for development to TRL5-6, in which a 150 kW demonstrator will be built and tested in the sea, satisfying the requirement for operation under suitable environment and loads. The demonstrator will be modular, so that part or all of it can be integrated into a wave device in a WES Stage 4 project.