Prof Markus Mueller, Head of the Institute for Energy Systems, is awarded £2.5m by Wave Energy Scotland (WES) to demonstrate a novel direct drive generator technology for wave energy applications.
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. 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 reliabile 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.