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At least 109 records · Page 6

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DOE OSTI2014

Reference Model 4 Cost Breakdown (RM4: Ocean Current Turbine)

Contains the Reference Model 4 (RM4) spreadsheets with the cost breakdown structure (CBS) for the levelized cost of energy (LCOE) calculations for a single RM4 device and multiple unit arrays. These spreadsheets are contained within an XLSX file and a spreadsheet editor such as Microsoft Excel is needed to open the file. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 4 (RM4) is a flying-wing ocean current turbine concept intended for deployment in the Gulf Stream off the southeast coast of Florida. The RM4 device has four rotors, with a rotorless center nacelle housing the power electronics, attached on a straight wing 120 m long. The device is designed to be submerged ~50 m below the surface and is moored to the seabed. The RM4 uses buoyancy within the wing and the five nacelles to maintain its position in the water column. Each rotor has a diameter of 33 m and has a 1-MW power rating, yielding a total device rated power of 4 MW. The rotors on the left and right side of the wing rotate in opposite directions in order to balance the torque applied to the device. The rotorless center nacelle housing the power electronics serves to condition the power generated by the rotors before it is delivered to the grid.

16 TIDAL AND WAVE POWER↗

DOE OSTI2014

Reference Model 3 Cost Breakdown (RM3: Wave Point Absorber)

Contains the Reference Model 3 (RM3) spreadsheets with the cost breakdown structure (CBS) for the levelized cost of energy (LCOE) calculations for a single RM3 device and multiple unit arrays. These spreadsheets are contained within an XLSX file and a spreadsheet editor such as Microsoft Excel is needed to open the file. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 3 (RM3) is a wave point absorber, also referred to as a wave power buoy, that was designed for a reference site located off the shore of Eureka in Humboldt County, California. The design of the device consists of a surface float that translates (oscillates) with wave motion relative to a vertical column spar buoy, which connects to a subsurface reaction plate. This two-body point absorber converts wave energy into electrical power predominately from the devices heave oscillation induced by incident waves; the float is designed to oscillate up and down the vertical shaft up to 4 m. The bottom of the reaction plate is about 35 m below the water surface. The device is targeted for deployment in water depths of 40 m to 100 m. The point absorber is also connected to a mooring system to keep the floating device in position.

16 TIDAL AND WAVE POWER↗

DOE OSTI2014

Reference Model 2 Cost Breakdown (RM2: River Current Turbine)

Contains the Reference Model 2 (RM2) spreadsheets with the cost breakdown structure (CBS) for the levelized cost of energy (LCOE) calculations for a single RM2 device and multiple unit arrays. These spreadsheets are contained within an XLSX file and a spreadsheet editor such as Microsoft Excel is needed to open the file. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 2 (RM2) is a variable speed dual-rotor cross-flow river turbine that is deployed at the water?s surface. It was designed for deployment at a reference site modeled after a reach in the Mississippi River near Baton Rouge, Louisiana. The rotors are anchored to a two-pontoon vessel platform. Surface deployment of the turbine minimizes the handling requirements during deployment and recovery and reduces overall costs for all O&M activities, including allowing for easy access to the power conversion chain (PCC). The design (two rotors per platform) also reduces the environmental footprint and associated environmental compliance costs.

16 TIDAL AND WAVE POWER↗

DOE OSTI2014

Reference Model 1 Cost Breakdown (RM1: Tidal Current Turbine)

Contains the Reference Model 1 (RM1) spreadsheets with the cost breakdown structure (CBS) for the levelized cost of energy (LCOE) calculations for a single RM1 device and multiple unit arrays. These spreadsheets are contained within an XLSX file and a spreadsheet editor such as Microsoft Excel is needed to open the file. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 1 (RM1) is a dual variable-speed variable-pitch (VSVP) axial-flow tidal turbine device, designed for the Tacoma Narrows tidal current energy resource site in Puget Sound, Washington. RM1 comprises a monopile foundation and a crossarm assembly to mount the two rotors. The cross-arm assembly is nearly neutrally buoyant so the attached rotors can be recovered and redeployed with a minimal amount of lifting crane capacity; therefore, the design minimizes the handling requirements during deployment and recovery, which reduces overall cost in all O&M activities including access to the power conversion chain (PCC).

16 TIDAL AND WAVE POWER↗

DOE OSTI2014

Reference Model 5 Full Scale Geometry (RM5: Oscillating Surge Flap)

Contains the Reference Model 5 (RM5) full scale geometry files of the Oscillating Surge Flap, developed by the Reference Model Project (RMP). These full scale geometry files are saved as SolidWorks assembly, IGS, and STEP files, and require a CAD program to view. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 5 (RM5) is a type of floating, oscillating surge wave energy converter (OSWEC) that utilizes the surge motion of waves to generate electrical power. The reference wave energy resource for RM5 was measurement data from a National Data Buoy Center (NDBC) buoy near Eureka, in Humboldt County, California. The flap was designed to rotate against the supporting frame to convert wave energy into electrical power from the relative rotational motion induced by incoming waves. The RM5 design is rated at 360 kilowatts (kW), uses a flap of 25 m in width and 19 m in height (16 m in draft), and the distance from the top of the water surface piercing flap to the mean water surface (freeboard) is 1.5 m. The flap is connected to a shaft with a 3-m diameter that rotates against the supporting frame. The supporting frame is assumed to have an outer diameter of 2 m, and the total length of the device structure is 45 m. The RM5 OSWEC was designed for deep-water deployment, at depths between 50 m and 100 m, and was tension-moored to the seabed.

16 TIDAL AND WAVE POWER↗

DOE OSTI2014

Reference Model 6 Full Scale Geometry (RM6: Oscillating Water Column)

Contains the Reference Model 6 (RM6) full scale geometry files of the Oscillating Water Column, developed by the Reference Model Project (RMP). These full scale geometry files are saved as SolidWorks assembly, IGS, and STEP files, and require a CAD program to view. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 6 (RM6) is a Backward Bent Duct Buoy (BBDB), which is a type of oscillating water column wave energy converter. First proposed by Masuda, the BBDB design is a floating Oscillating Water Column (OWC) device that consists of an air chamber, an L-shaped duct, bow and stern buoyancy modules, and a power take-off (PTO) composed of a Wells air turbine and a generator. This L- shaped device opens to the ocean downstream from the wave propagation direction. Power is produced by the motion of the wave, which causes the ambient pressure in the air chamber to vary thereby forcing air to flow through the Wells turbine. The reference wave energy resource for RM6 was developed from site information collected near Eureka, in Humboldt County, California.

16 TIDAL AND WAVE POWER↗

DOE OSTI2014

Reference Model 4 Full Scale Geometry (RM4: Ocean Current Turbine)

Contains the Reference Model 4 (RM4) full scale geometry files of the Ocean Current Turbine, developed by the Reference Model Project (RMP). These full scale geometry files are saved as SolidWorks assembly, IGS, X_T, and STEP files, and require a CAD program to view. This data was generated upon completion of the project on September 30, 2014. The Reference Model Project (RMP), sponsored by the U.S. Department of Energy (DOE), was a partnered effort to develop open-source MHK point designs as reference models (RMs) to benchmark MHK technology performance and costs, and an open-source methodology for design and analysis of MHK technologies, including models for estimating their capital costs, operational costs, and levelized costs of energy. The point designs also served as open-source test articles for university researchers and commercial technology developers. The RMP project team, led by Sandia National Laboratories (SNL), included a partnership between DOE, three national laboratories, including the National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL), and Oak Ridge National Laboratory (ORNL), the Applied Research Laboratory of Penn State University, and Re Vision Consulting. Reference Model 4 (RM4) is a "flying-wing" ocean current turbine concept intended for deployment in the Gulf Stream off the southeast coast of Florida. The RM4 device has four rotors, with a rotorless center nacelle housing the power electronics, attached on a straight wing 120 m long. The device is designed to be submerged ~50 m below the surface and is moored to the seabed. The RM4 uses buoyancy within the wing and the five nacelles to maintain its position in the water column. Each rotor has a diameter of 33 m and has a 1-MW power rating, yielding a total device rated power of 4 MW. The rotors on the left and right side of the wing rotate in opposite directions in order to balance the torque applied to the device. The rotorless center nacelle housing the power electronics serves to condition the power generated by the rotors before it is delivered to the grid.

16 TIDAL AND WAVE POWER↗

DOE OSTI2017

Predicting Cavitation on Marine and Hydrokinetic Turbine Blades with AeroDyn V15.04

Cavitation is an important consideration in the design of marine and hydrokinetic (MHK) turbines. The National Renewable Energy Laboratory's AeroDyn performance code was originally developed for horizontal-axis wind turbines and did not have the capability to predict cavitation inception. Therefore, AeroDyn has been updated to include the ability to predict cavitation on MHK turbines based on user-specified vapor pressure and submerged depth. This report outlines a verification of the AeroDyn V15.04 performance code for MHK turbines through a comparison to publicly available performance data.

13 HYDRO ENERGY↗

DOE OSTI2020

Behavioral responses of fish to a current-based hydrokinetic turbine under mutliple operational conditions

There is significant international interest in developing current-based marine and hydrokinetic (MHK) technologies to capture the power of tidal energy. However, concerns have been raised regarding the ecological effects of these projects on fish, including the risk of blade collision and behavioral impacts such as the disruption of migratory behavior and food acquisition and displacement from preferred habitats. In this study, we conducted mobile hydroacoustic surveys to track fish as they approached a tidal turbine deployed in Cobscook Bay, Maine. There was a significant decline in fish numbers with decreasing distance to the turbine, beginning approximately 140 m from the turbine. Similar declines were not observed at control transects or when the turbine was not spinning. The decline in fish numbers appeared to be the result of horizontal displacement, not vertical, movements to avoid the turbine. Noise rather than visual cues or flow field disturbance seemed to be a likely explanation for the reduced number of fish near the turbine. This finding, combined with near-field blade collision studies indicating a low probability of encounter, suggests that a single turbine poses a low collision risk to pelagic fish and that a single turbine is likely to result in minimal behavioral responses by fish. However, the risk may be different with additional devices, which will become more relevant as commercial-scale MHK arrays come under consideration. Therefore, the risks associated with commercial-scale operations will ultimately have to be evaluated to fully understand the ecological impacts of MHK devices.

42 ENGINEERING↗

DOE OSTI2018

Modeling underwater noise propagation from marine hydrokinetic power devices through a time-domain, velocity-pressure solution

Marine hydrokinetic (MHK) devices generate electricity from the motion of tidal and ocean currents, as well as ocean waves, to provide an additional source of renewable energy available to the United States. These devices are a source of anthropogenic noise in the marine ecosystem and must meet regulatory guidelines that mandate a maximum amount of noise that may be generated. In the absence of measured levels from in situ deployments, a model for predicting the propagation of sound from an array of MHK sources in a real environment is essential. A set of coupled, linearized velocity-pressure equations in the time-domain are derived and presented in this paper, which are an alternative solution to the Helmholtz and wave equation methods traditionally employed. Discretizing these equations on a three-dimensional (3D), finite-difference grid ultimately permits a finite number of complex sources and spatially varying sound speeds, bathymetry, and bed composition. The solution to this system of equations has been parallelized in an acoustic-wave propagation package developed at Sandia National Labs, called Paracousti. This work presents the broadband sound pressure levels from a single source in two-dimensional (2D) ideal and Pekeris wave-guides and in a 3D domain with a sloping boundary. Furthermore, the paper concludes with demonstration of Paracousti for an array of MHK sources in a simple wave-guide.

13 HYDRO ENERGY↗

DOE OSTI2014

Sandia National Laboratories Environmental Fluid Dynamics Code V. 1 0.0 (Beta)

Jones, Craig↗

DOE OSTI2016

Delft3D turbine turbulence module

Chartrand, Chris↗

DOE OSTI2018

Sandia's Current Energy Conversion module for Flexible-Mesh Delft3D flow solver v. 1.0

The DOE has funded Sandia National Labs (SNL) to develop an open-source modeling tool to guide the design and layout of marine hydrokinetic (MHK) arrays to maximize power production while minimizing environmental effects. This modeling framework simulates flows through and around a MHK arrays while quantifying environmental responses. As an augmented version of the Dutch company, Deltares’s, environmental hydrodynamics code, Delft3D, SNL-Delft3D-CEC-FM includes a new module that simulates energy conversion (momentum withdrawal) by MHK current energy conversion devices with commensurate changes in the turbulent kinetic energy and its dissipation rate. SNL-Delft3D-CEC-FM modified the Delft3D flexible mesh flow solver, DFlowFM. The Following is a description of Deltares’s open-source code Delft3D from which Delft3D-CEC is built upon. “Delft3D is a world leading 3D modeling suite to investigate hydrodynamics, sediment transport and morphology and water quality for fluvial, estuarine and coastal environments. As per 1 January 2011, the Delft3D flow (FLOW), morphology (MOR) and waves (WAVE) modules are available in open source. The software is used and has proven his capabilities on many places around the world, like the Netherlands, USA, Hong Kong, Singapore, Australia, Venice, etc. The software is continuously improved and developed with innovating advanced modelling techniques as consequence of the research work of our institute and to stay world leading. The FLOW module is the heart of Delft3D and is a multi-dimensional (2D or 3D) hydrodynamic (and transport) simulation program which calculates non-steady flow and transport phenomena resulting from tidal and meteorological forcing on a curvilinear, boundary fitted grid or spherical coordinates. In 3D simulations, the vertical grid is defined following the so-called sigma coordinate approach or Z-layer approach. The MOR module computes sediment transport (both suspended and bed total load) and morphological changes for an arbitrary number of cohesive and non-cohesive fractions. Both currents and waves act as driving forces and a wide variety of transport formulae have been incorporated. For the suspended load this module connects to the 2D or 3D advection-diffusion solver of the FLOW module; density effects may be taken into account. An essential feature of the MOR module is the dynamic feedback with the FLOW and WAVE modules, which allow the flows and waves to adjust themselves to the local bathymetry and allows for simulations on any time scale from days (storm impact) to centuries (system dynamics). It can keep track of the bed composition to build up a stratigraphic record. The MOR module may be extended to include extensive features to simulate dredging and dumping scenarios. For over 30 years Deltares has been in the forefront of these types of combined morphological simulation techniques.”

Chartand, Chris↗

DOE OSTI2017

Chapter 11: Marine and Hydrokinetic Power Generation and Power Plants

Marine and hydrokinetic (MHK) power generation is a relatively new type of renewable generation. Predecessors such as wind power generation, hydropower plant generation, geothermal generation, photovoltaic generation, and solar thermal generation have gained a lot of attention because of their successful implementation. The successful integration of renewable generation into the electric power grid has energized the power system global communities to take the lessons learned, innovations, and market structure to focus on the large potential of MHK to also contribute to the pool of renewable energy generation. This chapter covers the broad spectrum of MHK generation. The state-of-the-art power takeoff methods will be discussed. Types of electrical generators will be presented, and the options for implementation will be presented.

16 TIDAL AND WAVE POWER↗

DOE OSTI2017

Multi-scale temporal patterns in fish presence in a high-velocity tidal channel

The natural variation of fish presence in high-velocity tidal channels is not well understood. A better understanding of fish use of these areas would aid in predicting fish interactions with marine hydrokinetic (MHK) devices, the effects of which are uncertain but of high concern. To characterize the patterns in fish presence at a tidal energy site in Cobscook Bay, Maine, we examined two years of hydroacoustic data continuously collected at the proposed depth of an MHK turbine with a bottom-mounted, side-looking echosounder. The maximum number of fish counted per hour ranged from hundreds in the early spring to over 1,000 in the fall. Counts varied greatly with tidal and diel cycles in a seasonally changing relationship, likely linked to the seasonally changing fish community of the bay. In the winter and spring, higher hourly counts were generally confined to ebb tides and low slack tides near sunrise and sunset. In summer and fall of each year, the highest fish counts shifted to night and occurred during ebb, low slack, and flood tides. Fish counts were not linked to current speed, and did not decrease as current speed increased, contrary to observations at other tidal power sites. As fish counts may be proportional to the encounter rate of fish with an MHK turbine at the same depth, highly variable counts indicate that the risk to fish is similarly variable. The links between fish presence and environmental cycles at this site will likely be present at other locations with similar environmental forcing, making these observations useful in predicting potential fish interactions at tidal energy sites worldwide.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2014

The Contribution of Environmental Siting and Permitting Requirements to the Cost of Energy for Wave Energy Devices

Responsible deployment of marine and hydrokinetic (MHK) devices in estuaries, coastal areas, and major rivers requires that biological resources and ecosystems be protected through siting and permitting (consenting) processes. Scoping appropriate deployment locations, collecting pre-installation (baseline) and post-installation data all add to the cost of developing MHK projects, and hence to the cost of energy. Under the direction of the U.S. Department of Energy, Pacific Northwest National Laboratory scientists have developed logic models that describe studies and processes for environmental siting and permitting. Each study and environmental permitting process has been assigned a cost derived from existing and proposed tidal, wave, and riverine MHK projects. Costs have been developed at the pilot scale and for commercial arrays for a surge wave energy converter

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2016

Effects of EMF Emissions from Cables and Junction Boxes on Marine Species

Studies have shown that diverse aquatic species are electrosensitive. Many fishes, and marine mammals, can either detect, navigate by, or are affected by electromagnetic fields (EMF) with various sensitivities, and their behavior may be impacted by unnatural EMF emissions in the water column. Sharks, rays and skates are known to have the highest sensitivity to electric fields. Electric field emissions in the range 0.5–100 micro volt/m appear to attract them, and emissions over 100 micro volt/m to repulse them. A marine hydrokinetic MHK device will have multiple components and associated multiple submarine cables on the seafloor and running through the water column and would potentially increase the level of EMF emissions to which the marine species at the site may be exposed to. There are therefore concerns amongst stakeholders that EMF emissions associated with MHK devices and their components may act as barriers to species migration, cause disorientation, change community compositions and ecosystems, and that they may attract sharks, leading to a local increase in the risk of shark attacks. However, field data to validate and model potential relationships between observed responses and the EMF emissions in situ are sparse. A program of experimental field surveys were conducted off the coast of South Florida, USA to characterize the electromagnetic field (EMF) emissions in the water column from a submarine cable, and to monitor for responses of local aquatic species. The field surveys were conducted at the South Florida Ocean Measurement Facility (SFOMF) off Fort Lauderdale, which is a cabled offshore in-water navy range. It consists of multiple active submarine power cables and a number of junction boxes, with the capability to transmit AC/DC power at a range of strength and frequencies. The site includes significant marine life activities and community structure, including highly mobile species, such as sharks, stingrays, mammals and turtles. SFOMF therefore typifies a setting representative of an offshore location where a MHK device may be sited. Background electromagnetic field (EMF) levels and EMF emissions due to submarine cables were measured using a custom E-field sensor and a commercial magnetometer deployed from an autonomous underwater vehicle (AUV) at various fixed altitudes above the seafloor. EMF signatures detected from power cables and junction boxes are contrasted against ambient background levels and other EMF sources. The potential responses of local marine species were observed at selected representative locations using divers on SCUBA, complemented with fixed cameras on the sea bottom and by a set of video cameras mounted on the AUV. The objectives of the study were: 1) to characterize the EMF emission levels associated with submarine cables 2) to monitor potential responses of aquatic animals to the emissions and 3) to develop an associated database of field observations. As control, observations of EMF levels and in situ marine species were conducted with power in the cable turned off. Good quality measurements of EMF emissions were obtained using the mobile AUV platform and the data from the surveys were used to develop contour maps of the EMF levels in the water column above the live cable as well as to provide information about how the field decays away from the cable. The measurements show good agreement with theoretical models of the how EMF levels decay away from the cable in deep and shallow water environment. Electric fields in excess of 200µV/m were measured in the vicinity of the cable during the power on state. Quarterly surveys by SCUBA divers were conducted, using point and transect count methods, over a period of one year at three locations, one at a shallow site where the water depth is approximately 5m, and the other at the Barracuda Reef where the water depth is approximately 10m. The sampling results were analyzed to determine if the presence of an SFOMF generated EMF alters: (1) abundance, species richness, and assemblage structure of coral reef fishes, (2) the behavior of fishes including elasmobranchs, and (3) the distribution of marine turtles and mammals. Diver observations were also used in attempt to discern if there were any noticeable organismal responses during the transitional period between ambient OFF to energized AC or DC power states, and video footage was intended to augment the in-situ visual survey data and aid in interpretation of the results. Comparisons are provided between observation datasets between the three sites and between the point and transect count methods. Presence of several individual elasmobranch species, including sharks and stingrays, were recorded during the surveys. No apparent effect on richness could be discerned between the power on and off states. No apparent sudden animal movements were observed during transitions between power states.

16 TIDAL AND WAVE POWER↗

DOE OSTI2021

The Storage of Marine Hydrokinetic Power through Hydrogen Production

Marine hydrokinetic (MHK) power is likely to play a crucial role in future energy diversification and remote energy supply efforts. Providing a means of direct energy storage for MHK power would provide additional benefits to applications in ship microgrids and remote communities. Hydrogen (H 2 ) has long been pursued as a means of green energy storage and can be generated through electrolysis of water in an electrolyzer. However, electrolyzer technology for H 2 production is currently only possible on the commercial scale using fresh water, also a precious resource in our society. The direct electrolysis of seawater would alleviate the fresh water constraints for a new H 2 feedstock and a seawater-fed electrolyzer could be powered locally at a MHK platform. Several technical challenges exist before efficient direct seawater electrolysis can be realized. This project was designed as a demonstration of efficient direct seawater electrolysis that limits chlorine evolution, avoids use of platinum (Pt) group metals and overcomes cathode fouling over long service times.

08 HYDROGEN↗