DOE offers prize challenge for wave energy conversion ideas
In April, the U.S. Department of Energy announced its launch of the Wave Energy Prize competition “as a means to use a prize challenge to help dramatically improve the performance of wave energy conversion devices, providing a pathway to game-changing reductions in the cost of wave energy.”
The competition is a multi-tiered, open entry program meant to spur development of marine hydrokinetic (MHK) technology for use in the U.S.
According to the agency, the Wave Energy Prize aims to attract next-generation ideas by offering a prize purse and providing an opportunity for testing at the Naval Surface Warfare Center Carderock’s Maneuvering and Seakeeping (MASK) Basin in Maryland.
During the year-and-a-half design-build-test competition, teams must reach a number of milestones that include a technical submission, numerical modeling, and small-scale testing.
Beginning in August 2016, developers of selected projects from the initial milestone phases will be invited to participate in further testing at the MASK basin. Winners from among the projects tested at the MASK basin will be announced in November 2016.
For more information on the competition, log onto WaveEnergyPrize.org.
Hybrid B-SAUV successfully tested
Makai Ocean Engineering Inc. and the University of Hawaii (UH) have jointly developed the bottom-skimming autonomous underwater vehicle (B-SAUV), which can deploy seafloor-sensing equipment by combining features of a free-swimming AUV and those of a bottom-crawling vehicle.
This type of AUV might be used in conjunction with marine hydrokinetic devices by measuring optimal locations in which the greatest amounts of marine energy can be harnessed.
According to information from Makai, the B-SAUV is unique in that it autonomously adjusts its wet weight (by dynamically controlling its buoyancy) in order to control how it interacts with the ocean floor.
The B-SAUV moves through the ocean using its thrusters and operating in three buoyancy modes:
Low Buoyancy: pressing on the seafloor with its full wet weight;
Medium Buoyancy: lightly skimming along the bottom at a desired wet weight (to adjust for existing bottom conditions); and
High Buoyancy: transiting temporarily above the bottom in the water column in order to overcome obstacles.
Published data indicates the B-SAUV is controlled by a computer hardware and software system that, in addition to autonomously controlling buoyancy, enables it to navigate autonomously to a predefined location and install (and log data from) oceanographic sensors in the seafloor.
“These sensors are carried as a payload within the body of the B-SAUV and can be used for environmental monitoring or remote sensing,” according to Makai.
Makai and UH have worked on the prototype B-SAUV since 2011.
Modeling advances tidal power towards commercialization
According to Sandia National Laboratories’ 2014 Annual Report, marine hydrokinetic (MHK) energy researchers and developers used a computing system to further the mission of advancing the commercialization of tidal energy converters by the U.S. Department of Energy’s Wind and Water Power Technology Office.
The system was employed to analyze the RivGen prototype generation unit, a cross-flow turbine, “which exhibits more complex flow physics than the more common axial-flow turbine,” the report said.
Glory, the system used, is a DOE National Nuclear Security Administration (NNSA) computing platform deployed in 2009. The system is part of DOE’s Tri-Labs TLCC–1 supercomputer.
“Numerical experiments, simulated on Glory, were conducted to investigate and quantify parasitic drag effects on turbine performance and how these effects could be mitigated to improve performance,” the report said. “The results of this investigation provided a clear path for modifications to be made in the next design iteration of the RivGen turbine.”
The collaboration sought to find improved power performance for tidal turbines and reduce costs associated with MHK energy. Operating costs near a price point at which MHK turbines, completely unsubsidized, could compete with other renewable sources that generate energy would likely spur industry growth.
This study demonstrated the value of high-fidelity modeling when resolving the complex three-dimensional flow effects on performance that are sometimes encountered with complex turbine architectures.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for DOE’s NNSA.
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