Figure 1. Atmocean’s OHS™ with five pumping modules, with one pumping module expanded.
Sandia led a six-month project funded by the New Mexico Small Business Assistance (NMSBA) on “Subsea Modeling of an Innovative Wave Energy Array Using OrcaFlex Software,” in which we supported developing and modeling the mooring system for Atmocean Inc.’s Ocean HydroPower System (OHS™). This project involved three New Mexico small businesses
- Atmocean Inc. (wave-energy converter [WEC] developer),
- Reytek Corporation (WEC fabricator), and
- Mesa Analytics (WEC modeler).
Figure 2. WaveHub resource based on NDBC and Met Office UK data.
Sandia’s role was to model the Atmocean Inc. WEC array in OrcaFlex, in support of their upcoming wave-tank and open-ocean tests at WaveHub. This required Sandia to perform a preliminary resource assessment for the WaveHub site (wave characteristics shown in Figure 2) and approximate the site’s current using the current power law with a maximum speed of two knots
Sandia also developed an OrcaFlex model of the OHS™ system, requiring accurate modeling of the power take-off system and variable sea anchors, which only apply a resistive force when moving upward. The OrcaFlex model was then run for four regular wave cases both with and without current:
- Pacific Northwest summer waves,
- WaveHub summer waves,
- WaveHub winter waves, and
- a survival wave.
Following Sandia’s OHS™ system model development in OrcaFlex, Kelley Ruehl (Water Power Technologies Dept.) led the November 25th NMSBA technology-transfer and closeout meeting at Reytek’s Albuquerque facility.
Figure 3. Atmocean’s OHS™, as modeled in OrcaFlex, with one pumping module expanded.
Sandia presented the simulation results, which will be used to characterize the OHS™ loads and to drive mooring-system design improvements, to Phil Kithil of Atmocean Inc. and Phil Fullam of Reytek Corp. Sandia also delivered the numerical model files and led a short training course on how to set up, modify, run, and post-process the OHS™ system’s OrcaFlex model.
These efforts leveraged Sandia models already developed for the DOE Water Power Program.