The use of UV for biofilm suppression in a direct drive generator for wave energy converters

Wave Energy is a potential renewable electricity generation source which can be deployed in oceans worldwide. There is no one emerging technology and many alternative wave energy converter concepts have been proposed. The success of many concepts requires the development of specific technology to convert low speed motion into electricity. In fact, required speeds are uniquely low compared to all other forms of electricity generation. Wave energy converters place other unique requirements on the electrical machine design, such as the need for biofouling suppression and corrosion protection. In a submerged and flooded generator, these requirements must be accommodated in the magnetic gap of the electrical machine. Conventional biofouling control systems, such as marine coatings, require a certain application thickness which might not be suitable to the magnetic gap of an electrical generator. This paper discusses how these challenges are being overcome by describing the progress of a research project looking specifically at biofouling suppression in an electrical generator developed for wave energy. Laboratory results are shown as well as initial findings from at sea trials of using UVC light projected on the inside surface of a linear generator. If successful, this concept would remove a key barrier to the development of a simple and robust power take off suitable for multiple wave energy converters.