Brief Animation of offshore 3 meter diameter prototype turbine
Detailed Animation of offshore 3 meter diameter prototype turbine
The kinetic energy of the Gulf Stream has significant potential to supply Florida with much of its needed consumer electricity, provided that technically-feasible and environmentally-friendly harvesting technology can be developed. Although harnessing the energy of the Gulf Stream has been considered for over a century, no system has been installed for more that a few hours. Therefore, no technical or environmental knowledge-base exists for in-situ operation, from which to design turbines, or make decisions for policy and permitting. Thus, FAU’s Center for Ocean Energy Technology intends to install a small-scale experimental ocean current turbine offshore south Florida.
The objective of the experiment is to develop, fabricate, and deploy a turbine to investigate and collect data about potential environmental impacts, as well as perform a technology assessment of the environment and equipment. The experiment is intended to be incremental in deployment times, beginning with an initial short term deployment (less than a day), and then progressing to deployment periods of up to, and exceeding, one month.
No turbine has been deployed offshore in the Gulf Stream for more than a few hours and thus, little, if any, knowledge exists about in-situ performance of technology. Although many laboratory tests, tow tank experiments, and numerical simulations have been performed, they are only approximations of the real operating environment. As well, these laboratory experiments cannot replicate the long term operating effects of real system deployment and operation. As a result, a strong level of confidence cannot be placed in existing analyses. Thus, this experiment is intended to assess the in-situ performance of existing technology and map out the technology areas of study.
Since no turbines have been deployed in the Gulf Stream for more than a few hours, no knowledge exists of the environmental impact. Although some statistical estimates can be made based on the species density, the actually interaction of the turbine and local biota cannot be assessed without deploying the system. Because of the macro level interaction of the biota, laboratory experiments cannot be used either. Thus, this experiment is an initial step at gather data and performing and quantifying the environmental impact which can be extrapolated to commercial scale.
The overall system consists of a main permanent mooring buoy connected to the ocean floor by a 5/8 inch diameter steel cable to a gravity anchor, a 20 kW turbine, and a twin-hull observation and control buoy.
The underwater turbine is a 20 kW open blade axial-flow horizontal turbine design, driven by a 3 m diameter 3-blade rotor. The turbine is connected to a flounder plate on the main mooring line by a synthetic rope. Using opposed buoyancy and weight modules mounted on its masts, it counters torque generated by the rotor blades. The underwater housing contains a generator, gearbox, and mechanical brake (to stop the rotor blades from turning) and is filled with bio-degradable oil. The turbine is connected to the observation and control buoy by: 1) a synthetic rope which is used to deploy and recover the turbine, 2) communications lines used to monitor and control the turbine, and 3) power cables used to transmit power to/from the turbine. Sensors on the turbine include, are but not limited to, an array of underwater cameras connected to video monitors and DVRs, vibration sensors, tachometers, temperature sensors, tilt sensors, and pressure sensors. The generator acts both as a generator and a motor (with brake redundancy via electric means).
