- Tidal Energy Resource Assessment in the East River Tidal Strait, New York
Sandia recently worked together with Verdant Power, Inc., and Oak Ridge National Laboratory to conduct two-months of high-resolution velocity and turbulence measurements using acoustic Doppler velocimeters (ADVs) at the Roosevelt Island Tidal Energy (RITE) site. Verdant Power was recently given permission by Federal Energy Regulatory Commission to deploy up to 30 axial-flow turbines at this site. This study’s main goal was to examine the temporal variation of
- current speeds,
- current directions,
- turbulence intensities, and
- power densities.
(a) The RITE study site, (b) current speed time series, and (c) the joint probability distribution of the current speeds and the current directions.
Due to its relatively straight and uniform channel geometry, the tidal current at the site is highly regular, which is desirable because it allows accurate electricity supply forecasting. The mean ebb and mean flood flow directions are nearly bidirectional.
The turbulence level and unsteady loads at the site are shown to increase with the mean current speed. The study also found that insufficient temporal resolution measurements can cause low pass filtering, leading to underestimations of the tidal energy resource and the device loads.
- High-Fidelity Hydrostructural Analysis of Ocean Renewable Power Company’s (ORPC’s) TidGen® Turbine
Sandia is performing a high-fidelity hydrostructural analysis of the Ocean Renewable Power Company’s (ORPC’s) TidGen® turbine using the computational fluids dynamics (CFD) tool Star CCM+® and the structural-dynamics modeling capability in the Abaqus finite-element analysis (FEA) software.
Hydrodynamic loadings from the CFD simulation will provide inputs to the Abaqus FEA model through fluid–structure coupling. The mesh for the CFD model is shown in the figure. This project’s goal is to elucidate the turbine components’ structural dynamic response during ORPC’s open-water demonstration in Cobscook Bay, Maine, which took place between September 2012 and July 2013; with a specific focus on the joint connections.
Mesh for the Star CCM+® model of the TidGen® device.
The results of this study will provide critical guidance to improve the structural design of the TidGen® turbine.
- Sandia–Atmocean Inc.’s New Mexico Small Business Assistance Project
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.
- Evaluating Hydrokinetic Turbine Operation within Roza Canal, Yakima, Washington
Instream Energy Systems turbine deployment at the Roza Canal site in Yakima, Washington.
The DOE Water Power Program has recently identified the need to better understand the potential for hydrokinetic (HK) energy development within existing canal systems. HK turbine operation alters water surface elevations and modifies its flow in canals. Primary canal-water uses—for irrigation, in flood management, and/or for conventional hydropower plant—will not tolerate significant alterations or hydrodynamic energy losses. Sandia is collaborating with U.S. Bureau of Reclamation and Instream Energy Systems, who has been deploying a vertical-axis turbine at the site, to characterize the effect of HK turbine operation in the Roza Canal using field measurements and numerical modeling (SNL-EFDC and HEC-RAS modeling and simulation packages).
The adopted approach is to conduct field measurements and then use them to derive important modeling parameters, such as velocity, water level, discharge, and turbine thrust for a single turbine. Then, propagate these parameters to model the impact of arrays of HK turbines in the canal. Three field measurement campaigns are planned for spring and summer 2014, to provide better insight on the HK turbine operation for different flow conditions.
- WEC-Sim Code Development Updates and Meeting
Comparison of WEC-Sim implementation for the RM3 two-body point absorber (a) using the new physical-system formulation and (b) using the old equation-of-motion formulation.
Sandia and NREL are involved in a three-year project to develop and verify WEC-Sim, an open-source numerical modeling tool to analyze and optimize wave-energy converters (WECs). The code, written in Matlab/Simulink/SimMechanics, was recently restructured significantly after its internal alpha release.
The new programming format allows users to construct the physical system based on a library of rigid bodies and joint connections, rather than requiring that the user formulate the governing WEC equations of motion. The user now has a library of WEC-Sim blocks corresponding to different body types and joints, which they use to construct their WEC as it looks physically. The figure shows the Reference Model 3 (RM3) as modeled previously (b, equation of motion) and as modeled in the new format (a, physical system).
On January 20–22, Sandia hosted NREL’s Michael Lawson and Yi-Hsiang Yu for a WEC-Sim meeting held in Albuquerque, NM. During the meeting, the team focused on
- finalizing the code’s transition to its new programming structure,
- making the code more user friendly, and
- creating a WEC-Sim library.
The team also successfully worked with MathWorks to overcome limitations the WEC-Sim team found when modeling WECs in the Matlab/Simulink/SimMechanics framework. The team plans to continue WEC-Sim code development using the Matlab/Simulink/SimMechanics for the code’s external beta release, which is scheduled for summer 2014.
- Current Energy Converter Array Optimization Framework
Cobscook Bay regional and local (inset) model domains including schematic of ORPC TidGen™ unit (bottom left).
In FY13, Sandia developed a framework to identify optimal placement locations—leading to marine hydrokinetic (MHK) current energy converter (CEC) device array configurations that will maximize energy production and minimize environmental effects. The CEC array optimization framework was applied to Cobscook Bay, Maine, the first deployment site of the Ocean Renewable Power Company’s (ORPC) TidGen™ CEC device.
The framework used a hydrodynamic modeling platform, known as SNL-EFDC, to investigate flow patterns before and after MHK array placements. In addition to maximizing device performance, the optimization framework also considered potential environmental effects to avoid conditions that may alter fish behavior and sediment-transport trends. Although the optimization framework’s usefulness was demonstrated in 2013, several questions remained regarding the hydrodynamic model’s sensitivity to setup and forcing conditions.
Three 5-CEC arrays investigated during FY13; unoptimized preliminary layout (left panel), an environmentally constrained optimized array (center panel), and a power optimized array without environmental constraints (right panel). The color contour shows percent change in velocity vs. baseline (no CEC devices). The placement footprint is outlined by a white rectangle. Cells with depths less than 23 m are blacked out as they are potentially too shallow for placement.
Currently, Sandia is testing the effects the model’s grid resolution has on device-performance and flow-pattern predictions. Original modeling efforts vertically resolved the water column with five layers. The coarse layering scheme was chosen to reduce computational demands for initial optimization framework development, where over 50 simulations were conducted. Sandia is now testing the hydrodynamic models sensitivity to vertical resolution by comparing model results between simulations with 3, 5, 15, and 25 vertical layers. We recently conducted the simulations and are now analyzing the results.
We are also investigating the model grid’s horizontal orientation to determine if any bias in grid/flow direction exists. The initial studies used a grid aligned with the net flow direction determined from one acoustic Doppler current profiler dataset. To the best of our knowledge, this dataset represents conditions within the site; however, we must still investigate grid-orientation bias. We are investigating the hydrodynamic model sensitivity by comparing simulations with grids orientated at +10°, +5°, –5°, and –10° with respect to the original orientation.
- DOE-Sponsored Reference Model Project Results Released
The Sandia-led Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), is a partnered effort to develop marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between DOE; four national laboratories—Sandia National Laboratories (SNL), the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL); two consulting firms—Re Vision Consulting, LLC, and Cardinal Engineering; the University of Washington; and Pennsylvania State University.
The RMP was initiated to:
- Develop a well-documented methodology for marine energy conversion (MEC) technology design and economic analysis to harness tidal, river, and ocean energy and advance the technology and knowledge base toward commercial viability;
- Develop four MEC reference resource sites modeled after actual tidal, river, ocean current energy and wave energy sites that industry and the R&D community can use to develop their MEC technologies and levelized cost of energy (LCOE) estimates to compare to the LCOE baselines in this report; and
- Demonstrate the methodology’s application by designing four reference MEC device/array archetypes for the modeled MEC reference resource sites identifying cost drivers and estimating baseline LCOE for each MEC device/array archetype.
The RMP download page contains links to an overarching report that provides project details, supplementary documents, including supporting design and analysis reports, and Excel spreadsheet files that provide detailed cost breakdown structure and LCOE for each RM. We encourage MHK developers with similar MEC technology archetypes to apply our methodology, with the appropriate reference resource sites, to design and estimate LCOEs for their technologies.
- Advanced Controls of Wave Energy Converters May Increase Power Capture Up to 330%
Although ocean waves represent an enormous energy resource, most existing WEC designs efficiently produce power only within a narrow wave frequency range. Advanced control of the power-conversion chain can alter this paradigm. Models have shown absorbed-power increases ranging from 100% to 330%. To move from idealized, theoretical paper studies to deployable WEC hardware, requires rigorous research.
The Department of Energy has recognized this work’s importance in two substantial ways. First, three recent federally funded industry awards were related to advanced-controls topics. Second, Sandia was selected to lead an effort to realize these potential gains in controlled experiments.
Sandia will leverage strong capabilities in WEC design, modeling, and testing combined with our world-renowned control-system expertise to develop a device-independent, publicly releasable, validated power-conversion-chain control platform.
A heaving two-body point absorber modeled in WEC-Sim.
- Sandia Releases Open-Source Hydrokinetic Turbine Design Model, CACTUS
CACTUS geometry for Sandia turbine.
In an effort to support marine hydrokinetic (MHK) developers and companies as they advance their technologies, Sandia recently released an open-source version of CACTUS (Code for Axial and Cross-flow TUrbine Simulation) and an accompanying user’s manual authored by Jon Murray and Matt Barone (both in Sandia’s Aerosciences Dept.).
Sandia developed CACTUS to design hydrokinetic turbines and to analyze hydrodynamic performance. Based on a vortex wake method, simulations can be completed in minutes, allowing users to efficiently explore many design iterations.
A comparison of power coefficient between experiment and CACTUS simulation.
CACTUS can also be coupled with Sandia’s optimization code, DAKOTA, allowing users to semi-automatically optimize the hydrodynamic performance of hydrokinetic turbine designs. It simulates arbitrary geometries, including cross- and axial-flow rotors.
- Joint Sandia-DOE-HMRC Testing of a Floating Oscillating Water Column Wave Energy Converter Device
From September 8th–20th, Diana Bull (in Sandia’s Water Power Technologies Dept.) worked with the team from Ireland’s Hydraulics and Maritime Research Centre (HMRC) to complete testing of Reference Model 6, a backward-bent duct buoy (BBDB) oscillating water column wave energy converter design.
Testing was completed in both the flume as well as Ireland’s Hydraulics and Maritime Research Centre (HMRC) basin. A backward-bent duct buoy (BBDB) floating oscillating water column (OWC) wave energy converter (WEC) device in HMRC ‘s wave basin.
The team from HMRC included Tom Walsh, Brian Holmes, Florent Thiebaut, Neil O’Sullivan, Tony Lewis, Ray Alcorn, and Brendan Cahill. The team from the U.S. included Alison LaBonte and Jeff Rieks (DOE) and Daniel Laird, Diana Bull, and Vince Neary (all in Sandia’s Water Power Technologies Dept.).
This testing was completed under a memorandum of understanding between Ireland and the U.S. Discussions began approximately one year ago and planning began approximately four months before this test. Testing was completed in both the flume as well as the basin at HMRC. Data capable of verifying the Sandia-developed BBDB performance model was collected and is currently being analyzed.
- Post-Processing and Analysis of Wake Measurements Around a Scaled Turbine
Photo of test set-up showing skiff and array of catamaran-mounted acoustic Doppler current profilers.
Sandia and the Univ. of Washington recently (jointly) reprocessed data from a UW wake-measurement campaign to include power-performance (Cp-TSR) and thrust (Ct-TSR) data for comparable velocity conditions obtained in the September 2012 field campaign. Their reanalysis shows that normalized wake-recovery metrics (i.e., velocity deficit vs turbine diameters downstream) suggest that wake recovery is independent of inflow velocity (in the range of 1–2 m/s) and largely independent of the turbine’s operating state (i.e., position on the Cp-TSR curve relative to peak performance). In comparison with wake studies behind turbines in flume facilities, the wake generated during the tow test generally recovered more quickly. However, additional analysis will reveal the nature of the recovery and the best ways to compare test results. Additionally, this data set is being evaluated for use as a Sandia-EFDC validation test case.
In September 2012, the UW collected wake data behind a scaled, vertical-axis cross-flow turbine using an array of catamaran-mounted acoustic Doppler current profilers. The test turbine was attached to a small skiff and towed by a larger boat in a lazy figure-eight pattern on Seattle’s Lake Washington. However, this test involved an incomplete characterization of associated turbine performance and turbine thrust.
- Sandia-NREL Wave Energy Converter (WEC)-Sim Development Meeting
Kelley Ruehl and Sam Kanner (both in Sandia’s Water Power Technologies Dept.) hosted a three-day meeting onsite at Sandia that was attended by Yi-Hsiang Yu, Michael Lawson, and Adam Nelessen of the National Renewable Energy Laboratory to further develop WEC-Sim, a multiple-year, DOE-funded, joint NREL/Sandia project to develop an open-source WEC modeling tool.
A heaving two-body point absorber modeled in WEC-Sim.
This meeting’s accomplishments included restructuring the code into a more user-friendly form and integrating the following subsystems
- time-domain simulation modules,
- hydrodynamic force calculation block,
- power take-off module,
- the six degree of freedom multiple-body solver, and the
- mooring module
into the new WEC-Sim model structure. A simple heaving two-body point absorber was then simulated using the new framework.
The WEC-Sim team feels confident that the new WEC-Sim model structure will allow for a more user-friendly interface and relatively seamless avenue to model a vast array of WEC designs, ones that operate in different degrees of freedom, with different power-conversion trains, mooring configurations, etc.
- New Mexico Small Business Assistance (NMSBA) Program Collaborations Recognized
Phil Kithil, left, CEO of Atmocean Inc. of Santa Fe, and Phillip Fullam, chief engineer of Reytek Corp. of Albuquerque, worked with Sandia National Laboratories modeling specialist Rick Givler to assess the feasibility of their pump system that turns wave power into electricity. Givler’s findings helped Atmocean attract a six-figure investment for continued product testing and component manufacturing. (Photo by Norman Johnson)
Ten NMSBA projects that achieved outstanding innovations last year were honored at the program’s annual Innovation Celebration Awards event. “NMSBA has been bringing small businesses together with scientists and engineers from Sandia and Los Alamos for more than 12 years. We are grateful to the principal investigators who work with New Mexico’s small businesses,” said Jackie Kerby Moore, manager of Technology and Economic Development at Sandia. “Together they are implementing innovative ideas and stimulating our state’s economy.”
Phil Kithil (Atmocean Inc.) partnered with Phillip Fullam (chief engineer of Reytek Corp.) to produce a pump system that converts wave power into electricity. Kithil and Fullam worked with Sandia’s Rick Givler (a specialist in modeling physical systems in Sandia’s Fluid Sciences and Engineering Dept.) to assess the feasibility of their waves-to-electricity concept. Givler proved that, using typical waves and a set number of seawater pumps, considerable pressurized water would reach the onshore array of Pelton water impulse turbines.
Givler’s findings helped Atmocean attract a six-figure investment to continue product testing, add staff, and boost component manufacturing at Reytek. “Rick’s work was absolutely essential to our moving forward with the business model,” Kithil said. “We think our system is very viable and we’ll do more testing this summer.” This collaboration received the first Honorable Speaker Ben Lujan Award for Small Business Excellence as the honoree that demonstrated the most economic impact.
Since its inception, the NMSBA program has provided 2,036 small businesses with more than $34M worth of research hours and materials. The program has helped create and retain 2,874 New Mexico jobs, increase small companies’ revenues by $145M and decrease their operating costs by $72.6M. These companies have invested $43M in other New Mexico goods and services and received $52M in new funding and financing.
- Sandia–Univ. of Minnesota (UMN) Floating Offshore Wind Collaboration
From August 27th–September 27th Sandian Kelley Ruehl hosted Toni Calderer, a Ph.D. student from UMN. UMN and Sandia are currently collaborating on a 3-year DOE-sponsored offshore wind Funding Opportunity Announcement on high-resolution offshore wind turbine/farm modeling. UMN’s contribution is experimentation and wind turbine numerical modeling; Sandia’s contribution is floating-platform modeling. The month-long collaborative effort between UMN and Sandia was to couple the wind-wave models.
As a result of the collaboration, UMN and Sandia made significant progress toward an integrated, high-resolution wind-wave model. A wave boundary condition was successfully implemented in UMN’s code and simulations were run in the combined wind-wave model of a simple floating platform when subject to regular waves of various wave periods. These results were then compared to Sandia’s results for the same platform using boundary element methods. Initial results are promising, but refinement of the combined wind-wave model is necessary before moving onto more complicated geometries, like a semisubmersible platform.
Experimental testing of the floating platform is planned to begin at UMN’s St. Anthony Falls Laboratory flume this winter.
- Bernadette Hernandez-Sanchez
Bernadette A. Hernandez-Sanchez is the project lead for the Advanced Materials Program and DOE’s Marine and Hydrokinetic Technology Database (MHTDB). The Advanced Materials Program focuses on understanding the properties and performance of materials and coatings being investigated for potential marine hydrokinetic (MHK) and ocean thermal energy conversion (OTEC) technologies as well as developing novel anti-biofouling and anti-corrosion coatings. Sandia also supports the update and maintenance DOE’s MHTDB that provides up-to-date information on marine and hydrokinetic renewable energy, both in the U.S. and around the world. Bernadette earned her B.S. in Chemistry from New Mexico Tech and her Ph.D. in Solid State Inorganic Chemistry from Colorado State University. She joined Sandia as a student intern and returned in 2004 as a postdoctoral researcher. In 2008, she became a member of technical staff in Sandia’s Ceramic Processing & Inorganic Materials Department.
- Sandia Adds Water Power to Clean Energy Research Portfolio
[singlepic id=637 w=320 h=240 float=right]ALBUQUERQUE, N.M. – Sandia National Laboratories will receive more than $9 million over three years from a Department of Energy competitive laboratory solicitation for the development of advanced water power technologies.
Sandia, through a partnership with several national laboratories and academic institutions, will lead two of the four topic areas awarded under the grant and will provide technical support in a third topic area. The topic areas are Supporting Research and Testing for Marine and Hydrokinetic Energy, Environmental Assessment and Mitigation Methods for Marine and Hydrokinetics Energy, Supporting Research and Testing for Hydropower, and Environmental Assessment and Mitigation Methods for Hydropower.
“We will perform fundamental research to develop and assess technology breakthroughs and help promote a vibrant industry that is currently in its beginnings,” said Jose Zayas, manager of Sandia’s Wind and Water Power Technologies group.
“Water power technologies contribute to the diversification of our nation’s energy mix,” Zayas said, “by providing clean energy in areas near high population centers as well as enhancing our nation’s energy security. Water power technologies could leverage an indigenous resource in parts of the country where other technologies may not be viable.”
Zayas will add the water power research to the department’s wind energy portfolio. He will oversee a multidisciplinary team drawn from many areas of lab expertise, including materials and manufacturing research, environmental monitoring and stewardship, performance modeling, and testing. The department will pursue a diverse research agenda in marine hydrokinetics (MHK) systems and will collaborate with Argonne and Oak Ridge national laboratories on conventional hydropower.
Rich Jepsen, a specialist in water resources engineering, will lead the project to examine the cost-effectiveness and reliability of technology for MHK technologies, which include wave, current/tide and thermal energy conversion. Jepsen’s water power research will also evaluate the use of Sandia’s lake facility, used for large-scale wave testing.
In partnership with Oak Ridge National Laboratory (ORNL), Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy Laboratory (NREL), activities will evaluate new device designs and conduct basic research in materials, coatings, adhesives, hydrodynamics, and manufacturing to assist industry in bringing efficient technologies to market.
The research will focus on developing and advancing the science and tools needed to bring new water power technologies to market and evaluating methods designed to improve the performance of existing hydropower facilities.
Sandia will also work with NREL, the other lead in the technology area, in the direct design and testing of new technologies.
Jesse Roberts, a specialist in sediment transport and hydrology, will lead Sandia’s research to describe and quantify environmental impacts caused by new and existing marine and hydrokinetic technologies. The team will evaluate environmental factors including rates of sediment transport, water flow, water quality and acoustic changes. The results will help quantify the types and magnitude of environmental impacts for various new and existing technologies. Researchers will collaborate with industry to develop criteria for selecting locations for projects and select technology to monitor and mitigate such impacts. Sandia will partner with ORNL, PNNL and ANL in this work.
In both areas, Zayas said, Sandia will work with universities to leverage its existing world-class facilities for research to provide students and faculty the opportunity to work on water power problems and technologies.
“Sandia will work to bridge the gap between research institutions and industry by helping to develop technologies that deliver cost-effective and reliable energy while also committing to the importance of environmental stewardship,” he said.
Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.