At the International Tidal Energy Summit (ITES) which took place in London recently, delegates heard a presentation on new guidance for the assessment and characterisation of turbulence in marine environments.
Designed to improve the understanding of the effect of marine turbulence on tidal arrays in Scottish waters, turbulence was measured in the challenging tidal environments of both the Sound of Islay and the Inner Sound of Pentland Firth, some of the most energetic stretches of water anywhere in the world.
Following evaluation, turbulence was mapped across differing tidal energy development sites with the guidance developed by the TiME (Turbulence in Marine Environments) project consortium - consisting of partners Partrac, Ocean Array Systems, ABPmer, and IT Power.
Within the consortium, Partrac conducted measurements, ABPmer then incorporated the data in resource characterisation, Ocean Array Systems provided turbulence characterisation and hydrodynamic analyses and IT Power contributed engineering design, device performance and tidal turbine array modelling.
Although new methods have been developed and tested to measure and characterise turbulence, more importantly data from these new methods were then used to show that designing tidal turbines and array layouts to the true turbulence existing at different points in a site could lead to significant cost reductions.
As Guy Henley, project manager of the Marine Renewables Commercialisation Fund (MRCF) Array Technology Innovation Programme at project backers the Carbon Trust, explains: “The Guidance formulated by the project team is comprehensive and provides a solid understanding of the impact of turbulence on tidal arrays, which is a critical aspect of realising commercial-scale tidal arrays.”
Dr. Tom Clark of Ocean Array Systems added: “Assessment of [turbulence] impact on engineering design considerations highlighted the importance of properly accounting for turbulence – especially in considering yield and fatigue lifetimes”.
This is of course the key to commercialisation of marine tidal technologies. It is by thoroughly understanding not just turbulence but how multiple machines interact and their influence on each other that commercial-scale projects can be achieved with the minimum of risk. And effective risk management suggests the lowest-cost route to competitive marine energy.