Limiting Biofouling of Tidal Turbines through Surface Engineering

In 2016 the share of the UK's electricity generated using renewable sources was 28%, exceeding those of coal and nuclear energy [1]. It is likely that tidal power will play a key role in the continued growth of the UK's renewable energy capability. Tidal power generation most commonly uses horizontal axis turbines, consisting of a concrete base and a pylon supporting the turbine blades. Tidal turbines face the problem of biofouling by mussels. Colonisation starts on the static components of the turbine structure, and eventually spreads to the moving blades, which significantly limits efficiency.
Colonisation by marine life follows a sequence where the surface is occupied by progressively larger organisms [2]. A literature review will examine the nature of such colonisation sequences, dependencies on other organisms, and surface conditions favouring attachment. It will then be possible to identify novel, non-toxic surface treatments for limiting mussel biofouling. Approaches to selection will take two forms: surfaces which limit (i) mussel colonisation, or (ii) colonisation by precursor organisms, whilst not limiting turbine efficiency.
The project's laboratory-based activities will involve evaluation of a variety of surfaces identified as being potentially suitable. Treatments will be applied to steel and concrete surfaces and characterised in terms of contact angle, surface area, microstructure and coefficient of friction. Durability will be evaluated through exposure to simulated seawater. Projection of longer-tem performance will be conducted through modelling. Where suitable surfaces are identified, refinement of formulations and application techniques will be attempted to enhance performance.
Viable surface treatments will then be evaluated in the field. Steel and concrete specimens will be treated with surface treatments and deployed in marine environments alongside untreated controls. Mussel establishment typically takes around 12 months, after which specimens will be retrieved and evaluated in terms of coverage.