Preventing Biofouling of Oceanographic Sensors Using UV Illumination Powered by a Compact Wave Energy Converter

Electrical power is scarce at most offshore locations, so oceanographers design buoy systems to consume very little power in order to reduce the frequency of ship voyages to replace batteries. These expensive voyages can cost several tens of thousands of dollars per day. Solar and wind power can recharge batteries, but harvested power is limited and each source has shortcomings. Wave energy operates when the sun does not shine and could provide additional power, but the few commercial systems available generally cost far too much for oceanography applications. Furthermore, even when sufficient power is available, growth of unwanted organisms (biofouling) on oceanographic sensors still necessitates expensive ship voyages to replace sensors on buoys. The company has designed a compact, low-power and relatively inexpensive wave energy converter to provide power for a variety of marine applications. This device can also power ultraviolet light-emitting diodes to inhibit biofouling on sensors. The marine research institute partner operates arrays of offshore buoys. In order to function for longer periods of time between ship visits, these buoys will need both additional power and inhibition of biofouling. The company and its partner will work together to adapt the wave energy converter technology to operate on buoys in an existing array. The Company will also develop an ultraviolet source to prevent biofouling on the marine research institute partner’s sensors. Phase I work will establish feasibility, mechanical design of the new wave energy converter, and optical and electrical design of the ultraviolet source. While the two systems will be designed to work together, the wave energy converter and anti-biofouling source will each be able to operate without the other. During Phase I, the company will work with marine buoy engineering experts at the marine research institute partner to develop and optimize a model for wave energy conversion based on real-time motion data from existing buoys and prior conversion efficiency measurements made on the company’s prototype. Drawing on deep experience in light emitting diodes, including for disinfection, the company will build ultraviolet source modules and run experiments in a lab and at a dock to determine operating parameters (wavelength, optical power density and duty cycle) required to prevent biofouling in a cost- effective manner. An electrical engineering consultant with a strong background in control systems will develop a block diagram for optimal power extraction from the wave energy converter, as well as design anti-biofouling source electronics. The marine research institute partner needs to prevent biofouling on its 600 sensors that are deployed down to 200 m depth. Other oceanography buoys are expected to produce a market at least an order of magnitude larger. More generally, a small, cost-effective wave energy converter could be used in a wide range of marine applications, including aquaculture, aids to navigation, offshore wind environmental monitoring, defense and security, environmental monitoring, communications, and other areas of oceanography and meteorology. Market Watch predicts that the powered data buoy market will reach over 45,000 units globally by 2022. This wave energy converter technology can be scaled up to higher powers as well, opening further opportunities.