The MegaRoller project team has completed an ''advanced custom structure interaction Wave Energy Converter (WEC) model.''

So, what wave energy technology is under development, and what have been the results so far?

In an effort to support the wave energy industry in its bid to become a mainstream energy source, the European Commission is funding the MegaRoller project via its Horizon 2020 programme. The project, launched in 2018 and planned for completion in 2021, is seeking to develop and demonstrate a 1MW Power Take Off (PTO) technology for oscillating wave surge converters (OWSC). As Michael Holm - Chief Marketing & Communications Officer at project partner K2 Management, explains, the MegaRoller project aims to reduce the levelised cost of energy (LCOE) of the system to below 150€/MWh by increasing its PTO capacity, reliability and efficiency and streamlining the PTO system with standard components.

In doing so, the project team is focusing its efforts on the developments of OWSC) technology - a type of wave power technology that generates electricity by exploiting the horizontal movement of waves in near-shore coastal areas, at water depths of 10-20m. Typically, OWSCs use bottom-hinged flaps that oscillate in pitch, following the horizontal motion of the water particles.

"The MegaRoller project specifically focuses on the development of the PTO system - that is, the core component that converts the mechanical power to electricity," says Holm.

Earlier this year, the project reached an important milestone following the completion of an advanced custom structure interaction Wave Energy Converter (WEC) model. The model was developed to enable a detailed assessment of the distributed loads affecting the MegaRoller WEC system, in an effort to support the PTO design process. It is based on the numerical simulation package WEC-Sim, and contains a number of novel features, including an advanced wave-by-wave control system implementation, the possibility of using a position dependent database of hydrodynamic inputs, and the capability to assess the influence directional spectrum in the estimated load patterns. It also includes an advanced structural dynamics module linked to WEC-Sim to enable the consideration of structural deformations of the flap surfaces as a response to the distributed loads on the WEC.

"A preliminary validation exercise was conducted, using the previous WaveRoller design iteration tested in the Queen University of Belfast in 2018," says Holm.

Once the full-scale PTO test rig is completed as part of the MegaRoller project, testing activities will focus on PTO functionality, performance and power quality, operating the test bench with representative sea states.

Moving forward, Holm reveals that, as the MegaRoller project progresses to the implementation and integration phase, a number of critical aspects are being checked to ensure that the work can progress smoothly.

"This includes the procurement process, with clear specifications, schedule and documentation being prepared to avoid issues in the delivery of the components - and communication between the different project teams to ensure that the components integrate properly with each other," he says.

"Risk levels are consistently monitored throughout the project, in line with best practice, as should be the case with an ambitious and dynamic project of this kind," he adds.

Looking ahead, Holm points out that the next steps of the initiative will involve the completion of the manufacturing drawings, a milestone the project team expects to reach by the end of 2019. Following this, components will be received for assembly of the PTO subsystems and integration of the test rig - including hardware and software.

"This will involve assembly, test commissioning and validation, including validation of the numerical models developed in our first project milestone. Dissemination activities will also be conducted as the MegaRoller project progresses, involving publication of project results and key findings. The project is currently on track to be completed within the 36-month timescale," adds Holm.

By Andrew Williams