The floating oscillating water column reference model (RM6) backward bent duct buoy (BBDB) device design and dimensions and Wells turbine schematic. The width of the device (not shown) is 27 m.

The floating oscillating water column reference model (RM6) backward bent duct buoy (BBDB) device design and dimensions and Wells turbine schematic. The width of the device (not shown) is 27 m.

The DOE-supported Reference Model Project was developed to provide publicly available technical and economic benchmarks for a variety of marine energy converters. The final reference model, an oscillating water column (OWC) device, has been completed. Key aspects of the Backward Bent Duct Buoy (BBDB) have been modeled and documented for public release. This model has been used to develop a conservative estimate of the levelized cost of energy (LCOE) of this device. The comprehensive final report is now available for download. In addition, under the Reference Model 6 heading, detailed reports are also available describing the results for the following analyses:

  • Performance Model: The pneumatic power output of the BBDB in random waves is optimized through the use of a hydrodynamically coupled, linear, frequency-domain, performance model that links the oscillating structure to internal air-pressure fluctuations with a simple resistive loading control strategy.
  • Structural Design: A structural model designed to withstand a large hydrostatic submergence pressure was used to develop an understanding of the structural mass and cost of the device.
  • Mooring System: The mooring system was designed to withstand the 100-year storm at the deployment location. An OrcaFlex model based on a Morison’s Equation based response was created in order to size the mooring components.
  • Power Conversion Chain (PCC): Sandia and Penn State’s Applied Research Laboratory (ARL) developed and implemented an optimization methodology for the PCC design which is based on a Wells turbine. The pneumatic power is decremented by the Wells turbine, generator, and VFD efficiencies for each sea state. This methodology has been used to determine the PCC components for the LCOE calculations for the OWC.
  • Experimental Verification: Experimental verification of the device’s performance was carried out in collaboration with the Hydraulic and Maritime Research Center at University College Cork.
  • Environmental Considerations: Pacific Northwest National Laboratory (PNNL) completed the environmental impact analysis of the BBDB. This analysis considered the likely permitting requirements as well as the possible impacts the device may have on the environment.
  • Economic Analysis: The National Renewable Energy Laboratory (NREL) completed the economic analysis for this device. This analysis combined all of the models into an economic framework in order to determine an estimate of the LCOE of this device type.