Screening for Biofouling and Corrosion of Tidal Energy Device Materials: In-situ results for Admiralty Inlet, Puget Sound, Washington

Abstract

From April 2009 to February 2010, coupons of materials which could be used in the rotor, drive train, or foundation of tidal energy devices were deployed in-situ on the seabed at a prospective tidal energy site to screen for biofouling and corrosion. Materials include glass and carbon fiber composites, stainless steel, aluminum, structural steel, and common steel. Several potential rotary bearing materials were also screened. Coatings, including high copper anti-fouling, low copper anti-fouling, and inert foul-release are also evaluated for their ability to control biological fouling. For smooth surfaces, there is limited biological fouling at this particular site, which is below the photic zone. Stainless steel shows excellent corrosion resistance, while common and structural steels experience major surface oxidation after three months of exposure to the marine environment – even with sacrificial anodes. More quantitative work is required to evaluate corrosion rates and the potential strength degradation of glass and carbon fiber composites over long-term exposure to the marine environment.