CalWave Power Technologies Inc. (CalWave) launched their CalWave xWave wave energy device for an open-ocean pilot demonstration off the coast of San Diego (West of the Scripps Pier). This project was awarded by the Department of Energy, Water Power Technologies Office to develop systems to harness wave energy as a complementary renewable energy resource to other forms of clean energy. Key partners in this project are Scripps Institute of Oceanography, NREL, Sandia National Lab, DNV GL, University of California Berkeley, and PNNL. This pilot will provide information to help plan for deployment of a larger unit at the PacWave test site in Oregon.
The device was deployed west of the Scripps Institute of Oceanography pier, close to San Diego, California.
Department of Energy, Water Power Technologies Office DE-EE0008097
Permits and/or permission obtained by the following agencies:
- Landowner Permission: University of California, San Diego – Scripps Institute of Oceanography (SIO)
- Army Corps of Engineers, Permit #: SPL-2019-00424-RRS
- California Coastal Commission, #9-18-0333-W
- California Department of Fish and Wildlife, #SC-013978
- California Waterboards, #R-2019-0158:859178jharris
- National Marine Fisheries Service, #WCRO-2019-00056
- US Coast Guard, Aid to Navigation #CG-2554
The WEC CalWave xWave was deployed on September 16, 2021. Anchors were previously installed in September 2020. The project was initially set to run for 6 months, but was granted an extension to operate for 10 months by the US Department of Energy. Data gathered will be used for a planned larger scale xWave deployment at PacWave.
Key Environmental Issues
Table 1: Listed Species Potentially in the Project Area
|Common Name||Scientific Name||Project in Critical Habitat?||Temporal Distribution||Habitat|
|Haliotis cracherodii||N||Year-round||Rocky reefs, intertidal to shallow subtidal|
|Southern California Steelhead DPS||Oncorhynchus mykiss||Y||Year-round||Open ocean, estuaries, rivers|
|Green Turtle, East Pacific DPS||Chelonia mydas||N||Summer||Open, coastal ocean, beaches|
|Leatherback sea turtle||Dermochelys coriacea||N||Summer, fall||Open, coastal ocean, beaches|
|Loggerhead sea turtle, North Pacific Ocean DPS||Caretta caretta||N||Year-round||Open, coastal ocean, beaches|
|Olive ridley sea turtle||Lepidochelys olivacea||N||Summer||Open, coastal ocean, beaches|
|Guadalupe fur seal||Arctocephalus townsendi||N||Winter, spring, summer||Coastal ocean|
|Gray whale western N Pacific||Eschristius robustus||N||Winter, occasional||Open, coastal ocean|
|Humpback whale, Central America DPS||Megaptera novaeangliae||N||Summer, fall||Continental shelf break, occasionally nearshore|
|Blue whale||Balaenoptera musculus||N||Spring to fall, occasional||Open ocean, continental shelf break, rarely nearshore|
|California least tern||Sterna antillarum browni||N||Spring to fall||Nests on beaches, forages nearshore|
Result of Biological Assessment – Excerpts from Section 5.0: Effects of the Action
The use of a minimal number of buoys, the temporary duration of the deployment, the simplicity of the gear’s basic exterior design, and the location of the project site, combined, support the conclusion that this project would have no adverse effect on the aforementioned fish or invertebrate species and is not likely to adversely affect the listed species, see Table above. Specifically, we anticipate no adverse effects for the following reasons:
- The quantity of gear and the duration of the project are expected to be correlated with the probability and magnitude of any potential effect on listed species or their environment. Sea turtles of all species, including leatherbacks, have been entangled in buoy lines for fishing gear (Adimey et al. 2014), but this appears to be a rare occurrence: Note, for example, the absence of trap-related sea turtle bycatch reported by Moore et al. (2009) in a recent review of U.S. fisheries. We emphasize that the phenomenon is not unknown (e.g., Lutcavage et al. 2001), however, considering the number of buoys in constant use in U.S. waters, the apparent rarity of this particular form of bycatch is compelling. The mooring lines connecting the CalWave demo WEC device to its four gravity anchors are expected to maintain greater tension than those used to mark the commercial fishing gear referenced by Adimey et al. (2014), and, on that basis, pose a discountable threat to sea turtles.
- Humpback, gray, blue, and fin whales have also become entangled in fishing gear (NOAA Fisheries West Coast Entanglement Summary, March 17, 2017; see also Johnson et al. 2005, Cassoff et al. 2011), including buoy lines, particularly those fixed to crab traps (“pots”). Crab pots, however, are deployed in high densities and the resulting concentration of lines and buoys likely represents a substantially more significant threat than the four navigational buoys and their anchor lines to be used in this project. As noted with regard to leatherback turtle entanglement, these buoys are highly unlikely to entangle any of these whale species, due to the short-term deployment duration, and that these whales are unlikely to be in the action area. The mooring lines connecting the CalWave demo WEC device to its four gravity anchors are expected to maintain greater tension than those used to mark the commercial fishing gear referenced by Adimey et al. (2014), and, on that basis, pose a discountable entanglement threat to marine mammals (pinnipeds and cetaceans).
- The characteristics of the gear employed, too, minimize any potential effects to an insignificant level; these buoys and the anchoring system employed are functionally comparable to the most basic of existing buoys, lines and anchors used currently on the California coast and in coastal areas throughout the world for navigation, scientific research and fisheries. Furthermore, the deployment strategy includes measures to minimize the scope of the anchor lines and to maintain tension in those lines to avoid the formation of a bight or loop; these measures are specifically intended to reduce the likelihood of entanglement and thus this effect is regarded as insignificant.
- The umbilical cable would be weighted to the seafloor, and although not buried, is also not anticipated to result in any threat of entanglement, thus regarded as insignificant.
- Vessels used for installation, operations and maintenance, and removal and decommissioning would cause temporary, short term increases in marine traffic and associated acoustic emissions in the vicinity of the action area. Project vessels would cause noise during the infrequent time that they are operating at the project site, but most of the sound pressure produced by vessels would dissipate to ambient levels a short distance from the vessel. The propellers of ships and barges under full power generally create peak sound intensities of 130-160 dB over a frequency range of 20 Hz to 10 kHz. These types of acoustic emissions are within the hearing sensitivity of marine mammals. Vessels would be slow moving or idle in the action area, however, so sound produced by these vessels would be below the levels produced under full power. Additionally, vessels would only be present in the action area for installation, periodic maintenance, and removal activities, and their presence at these times would be for a limited duration; accordingly, sound associated with project vessels would be short-term and temporary, thus regarded as insignificant.
- The movement of the CalWave demo WEC in the water column is another potential source of noise and vibration. The moving parts that could create noise would be in an isolated pressure chamber/vessel. These are expected to generate around 65 decibels inside of the hull, which should absorb most of the noise generated from the CalWave demo WEC. Therefore, operational noise is not expected to reach levels of concern for cetaceans, fish, invertebrates or sea turtles, thus regarded as insignificant.
- Acoustic communication by the WEC is another potential source of noise. It is anticipated that the acoustic communication would operate between 8-30 kHz at a maximum of 180 dB re 1 micro Pascal root mean square (RMS). While these transmissions are in the audible range for many marine mammals, the sound produced will be 1) non-impulsive and below the non-impulse temporary threshold shifts ("TTS") for most marine mammals, as defined in NOAA's "Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammals, v2.0", and 2) intermittent, rare, and short term low-power transmissions of simple commands or status updates to ensure safe operations of the device in event of that the main communications link is out of service. However, the intermittent, non-impulsive sound levels are greater than that for Level B harassment (i.e., 120 dBrms); however, it is expected to have an insignificant effect on marine mammals because of the rarity and short-term intermittency of use, proximity to shore, and likely existing ambient sounds sources (e.g., surf, vessels).
Collision and pinch points
- The movement of the CalWave demo WEC in the water column is another potential source of collision. Marine mammals offshore of California are exposed to a variety of anthropogenic structures that present collision risk, including moored navigation aids and NOAA oceanographic buoys, as well as moored and moving ships. Marine mammals have evolved to avoid colliding with natural features and to avoid predators, but whale collisions with moving, moored or drifting vessels have been recorded (Benjamins et al. 2014). There are no data documenting whale collisions with stationary structure (e.g., piers, oil platforms) along the west coast. Due to the relatively short deployment duration, small project footprint, and low potential for marine mammal collision, this effect is regarded as insignificant.
- The CalWave demo WEC’s mooring lines, attachments and top structure are a potential source of pinch points. The mooring lines and attachments are not anticipated to pinch down onto the WEC surface in a manner that could result in injury to listed species due to the small area of pinch point, and the likely short duration (seconds) that the lines and attachments would be in contact with the WEC.
- The CalWave demo WEC’s anchors and umbilical cable would have insignificant effects on benthic habitat or benthic species that could be prey items for listed species such as gray whales, due to the small footprint and temporary duration of deployment on the unconsolidated substrates likely to occur at the project area. It is anticipated that disturbed areas due to the anchors and umbilical cable would recover in a period of days to weeks after removal and decommissioning by natural sediment transport processes, and therefore effects are considered insignificant. In addition, the deployment, operation, and removal of the CalWave demo WEC would not adversely affect EFH designated for groundfish, coastal pelagic species, and highly migratory species.
- One umbilical cable will run between the CalWave demo WEC and the shore-based facility. The cable is 1 inch in diameter, protected by double sheathed polyurethane and a strength member. In addition, elasmobranchs (e.g., rays, sharks) are most likely to detect EMF and there are none listed in the action area. Due to the relatively low voltage and power level, relatively short duration of deployment, and small footprint of the umbilical cable, it is not anticipated that a relevant EMF would be generated, and effects of EMF on listed species in the action area are therefore considered insignificant. For the same reasons (low voltage, short duration, small footprint), the deployment, operation, and removal of the CalWave demo WEC would not adversely affect EFH designated for groundfish, coastal pelagic species, and highly migratory species.
Discharge and spill
- The potential for spills or discharge from vessels or from the CalWave demo WEC is very low and considered to be discountable. Vessels that will be used in deployment, maintenance and removal of the CalWave demo WEC will be UCSD/Scripps Institution of Oceanography research vessels, as described above. The CalWave demo WEC will contain only 20 gallons of low toxicity, biodegradable, working fluid grade Panoline, certified by Green Marine as an environmentally acceptable lubricant in compliance with EPA’s Vessel General Permit. Effects of spills or discharge on listed species are therefore, considered discountable.
Papers, Reports, Research Studies
- The Nearshore Fish Assemblage of the Scripps Coastal Reserve, San Diego, California (2010)
- Scripps Technical Forum - CalWave - Updates on pilot of wave energy converter off Scripps Pier Q3/21
- H.T. Harvey & Associates, Lehmann M. (2019) Biological Evaluation of CalWave Open Water Demonstration (2019)
- Use of a 360-Degree Underwater Camera to Characterize Artificial Reef and Fish Aggregating Effects around Marine Energy Devices (2022)
Baseline Assessment: CalWave xWave Demonstration
|Receptor||Study Description||Design and Methods||Results||Status|
|Marine Mammals||Biological Evaluation (BE) prepared by H.T. Harvey & Associates||Independent determination of likely project impact on Endangered Species Act (ESA) listed species and/or their critical habitat and on marine mammals not listed under the ESA but protected by the Marine Mammal Protection Act (MMPA). ||Determined the project is exceedingly unlikely (a) to entangle any marine mammal or (b) to contribute substantially to any cumulative adverse effect. Determined that the Proposed Action may affect, but is not likely to adversely affect Guadalupe fur seals, western North Pacific gray whales, blue whales, fin whales, humpback whales, or other federally listed species that could occur in the action area. Established protocols for marine mammal monitoring and avoidance during boat operations at the test site. ||Completed|
|Fish||The fish as assemblage within the Scripps Coastal Reserve was determined through various sampling techniques to assess the importance of the reserve for the species and to provide information for future management decisions.||Multiple survey techniques were used including otter trawl, gill nets, SCUBA-diving surveys and Icthyocide collections.||The fish assemblage of the Scripps Coastal Research was dominated by transient species, with a mix of species from rocky reefs and intertidal species.||Completed, published in 2010|
|Fish||Biological Evaluation (BE) prepared by H.T. Harvey & Associates||Independent determination of likely project impact on Endangered Species Act (ESA) listed species and/or their critical habitat. Also, addresses the potential project effects on Essential Fish Habitat (EFH) and Habitat Areas of Particular Concern (HAPC) under the Magnuson-Stevens Fishery Conservation and Management Act. ||Determined the project is exceedingly unlikely to contribute substantially to any cumulative adverse effect on listed marine organisms on the California coast. The deployment, operation, and removal of the Project would not adversely affect EFH designated for groundfish, coastal pelagic species, and highly migratory species. ||Completed|
|Birds||Biological Evaluation (BE) prepared by H.T. Harvey & Associates||Independent determination of likely project impact on Endangered Species Act (ESA) listed species and/or their critical habitat.||Determined the project is exceedingly unlikely to contribute substantially to any cumulative adverse effect on listed marine organisms on the California coast. ||Completed|
|Invertebrates||Biological Evaluation (BE) prepared by H.T. Harvey & Associates||Independent determination of likely project impact on Endangered Species Act (ESA) listed species and/or their critical habitat.||Determined the project is exceedingly unlikely to contribute substantially to any cumulative adverse effect. ||Completed|
|Reptiles||Biological Evaluation (BE) prepared by H.T. Harvey & Associates||Independent determination of likely project impact on Endangered Species Act (ESA) listed species and/or their critical habitat.||Determined the project is exceedingly unlikely (a) to entangle any sea turtles, or (b) to contribute substantially to any cumulative adverse effect. Determined that DOE’s Proposed Action of providing funding to the Proposed Action may affect, but is not likely to adversely affect green turtles, loggerhead sea turtles, leatherback sea turtles, or olive ridley sea turtles. ||Completed|
|Physical Environment||Biological Evaluation (BE) prepared by H.T. Harvey & Associates||Review of risks due to Entanglement, Sound, Collision and pinch points, Benthic disturbance, EMF, or Discharge and spill.||Determined the project is exceedingly unlikely to contribute substantially to any cumulative adverse effect. ||Completed|
Post-Installation Monitoring: CalWave xWave Demonstration
|Stressor||Receptor||Study Description||Design and Methods||Results||Status|
|Collision||Marine Mammals||Monitoring for marine mammals during vessel operations. Cameras on the device, in the vicinity and periodic dive surveys.||Visual monitoring||Observed marine mammals in the general area, no observance or evidence of collision with deployed system.||Completed|
|Collision||Fish||Cameras on the device, in the vicinity and periodic dive surveys.||Visual monitoring||Observed fish in the general area, no observance or evidence of collision with deployed system.||Completed|
|Collision||Birds||Cameras on the device and in the vicinity.||Visual monitoring||Observed birds in the general area, no observance or evidence of collision with deployed system.||Completed|
|Collision||Reptiles||Cameras on the device, in the vicinity and periodic dive surveys.||Visual monitoring||Observed sea turtles in the general area, no observance or evidence of collision with deployed system.||Completed|
|Noise||Marine Mammals||Hydrophones are deployed for short- and long-term measurements around the WEC following the TC114 Requirements.||Integral Consulting: NoiseSpotter: Short-term mounted measurements |
Drifting Acoustic Instrumentation System (DAISY): short-term drifting measurements 3 bottom mounted hydrophones.
|6 TB of acoustic data was collected from 3 bottom mounted hydrophones deployed for 4 months. Analysis is still underway.||In Progress|
|Habitat Change||Invertebrates||Monitor changes in habitat for sediment visualization and tracking.||Monitor invertebrate activity around one of the device’s anchors, over three days at dawn, noon and dusk using a 360-degree camera (short-term observations).||Few invertebrates were observed: only one octopus and an unidentified invertebrate, possibly a crab.||Completed|
|Habitat Change||Fish||Monitor fish activity for habitat change studies.||Monitor fish activity around one of the device’s anchors, over three days at dawn, noon and dusk using a 360-degree camera (short-term observations).||Fishes were observed at each deployment, more of them near the anchor than away from it. The highest counts of individual fishes and schools of bait fish came from the dusk deployments.||Completed|