RÉMI GRUET

Rémi Gruet joined the European trade body for ocean energy in 2013. After six years in the private sector, he has spent the last 15 years influencing the European political agenda, working both inside and outside EU institutions – notably the European Parliament and European Wind Energy Association.
He is a leading authority on renewable energies and climate and environmental policy, and has authored and co-authored numerous reports, such as the recent Ocean Energy Forum Roadmap, the SI Ocean Market Deployment Strategy and the Wind energy and Climate policy report . [1]
He is a visiting lecturer on EU energy policy at the University for Political Science in Lille, France.

 

Europe needs ocean energy

Source:  ©Wello

In 2050, Europe’s energy landscape will look very different from today’s. Moving towards an electrified, carbon-neutral system means a significant increase in the uptake of renewable energy, with 80-100 % of future electricity supply set to come from renewable energy sources.

'Europe is sitting on a rich resource of clean, predictable ocean energy – and it will be needed, as the energy transition accelerates'

Tidal energy is fully predictable – even years into the future. Wave energy devices capture the energy transferred from the wind to the sea, with swells continuing to provide power even after the wind has disappeared.

Europe is sitting on a rich resource of clean, predictable ocean energy – and it will be needed, as the energy transition accelerates. It is estimated that 100 GW [1] of wave and tidal energy capacity can be deployed in Europe by 2050, which would meet around 10 % of current electricity consumption.

To achieve these ambitious goals, ocean energy research and innovation (R&I) needs to improve the reliability and survivability of ocean energy devices, reduce the perceived risk of these new technologies and lower their costs. The European Technology and Innovation Platform for Ocean Energy (ETIP Ocean) has laid out a list of priority areas for ocean energy R&I in its Strategic Research Agenda.

The three highest technological priorities for ocean energy are the deployment of demonstration devices, the improvement of power take-off performances and the development of effective control systems.

Deploying prototypes and demonstration projects

Single devices and arrays need to be deployed in real sea conditions. Through accumulation of operating hours, performance can be determined and optimised. This will allow for technology certification as well as the creation and validation of high definition models necessary for designing the next generation of ocean energy projects.

To enable commercial investment in future ocean energy projects, data is needed from full-scale demonstrations in real sea conditions. As with the development of other technologies, several projects may be necessary – from full-scale prototype to pre-commercial farms – before commercial investors will feel sufficiently confident.

However, building and testing a full-scale prototype is costly. As such, it is imperative that data from demonstration devices is available and widely shared within the industry to accelerate technology development. Various EU-funded projects such as MaRINET2, Bluegift, FORESEA and Ocean DEMO are already addressing this challenge by supporting access to European, world-leading ocean energy test centres.

Increasing yield with improved Power Take-Off

The power take-off (PTO) for ocean energy devices is the mechanism which extracts energy from the resource. The PTO is not a component in itself, but a system composed of several components. There is a multitude of PTO designs for use in different resources.

The PTO system needs to be reliable, as any failure directly impacts power production. PTO performance, survivability and reliability are crucial to the economics of any ocean energy project.

Many PTOs developed for tidal energy have been demonstrated in real sea conditions and had their design successfully validated. Simplifying those designs by reducing the number of moving parts will increase reliability and bring down costs.

A number of different designs exists, though further convergence is likely. Multiple angles and variables affect the interactions of waves with devices. This makes understanding the resource and optimising PTO design particularly important. Next steps for improving the reliability and performance of wave PTOs include short-term power storage solutions, array layout modelling and peak power management systems.

Increasing reliability and survivability with control systems

Ocean energy devices face extreme weather conditions. They need to be designed to resist occasional heavy loads over short periods of time. The cumulative effects of stresses, tensions, cyclic and extreme loadings, corrosion and biofouling increase material fatigue on the devices’ components.

Control systems allow components to react and adapt when faced with specific conditions. They can be used to mitigate fatigue and damage created by waves or currents, but also to improve performance. For instance, a control system may ‘pitch’ tidal turbine blades – rotate them on their axis – to maximise energy capture, or adjust the mooring lines of a floating device to match sea level.

Real time monitoring and forecasting of the resource is necessary to determine the control strategies that will increase performance and operability of ocean energy projects. This requires accurate resource measurement and forecasting as well as real-time transmission and specific analysis tools.

Horizon 2020 and other EU schemes have done much to enable the industry to focus on those priorities. More RD&I will be needed in the coming years to bring these nascent technologies to industrial development.

©Sustainable Marine Energy