Ocean Energy Extraction for Sensor Applications

Remote ocean instrumentation often relies on floating buoys with sensors to acquire time series measurements such as ambient noise, acoustic tracking or communications. The operating lifetime of small remote buoys is limited by batteries (often to 12 - 24 hrs), and recharging is so inconvenient or impractical that many small sonobuoys are designed to scuttle themselves after about a day. The associated cost, as well as the environmental impact of sending large amounts of battery and electronic hardware to the bottom of the ocean is a strong driver for developing renewable ocean power. Trex Enterprises Corp, of Kahului, Maui, proposes to develop and demonstrate a simple, low-cost buoy size platform capable of generating power by scavenging energy from ocean waves. The phase 1 prototype was able to deliver over 50 Watts of power from moderate (sea state 3) waves, while anchored near shore. The phase 2 prototype (and ultimate product) will be capable of developing 100 – 200 W of power, and be deployed in the open ocean. The basic power generation scheme relies on a buoyant surface float that moves with the wave motion tethered to a submerged sea anchor that does not move with the waves.