Cobscook Bay Tidal Energy Test Site

Multiple ORPC power systems have been tested at the Cobscook Bay test site. ORPC initially tested and commercially operated its TidGen® Power System (TidGen) at the site in 2012-2013. The core component of the TidGen is ORPC’s proprietary turbine generator unit (TGU). The TGU utilized four advanced design crossflow (ADCF) turbines to drive a permanent magnet generator mounted between the turbines on a common driveshaft. The TGU was 30 meters in length (98 feet), 5 meters high (17 feet), and 5 meters wide (17 feet). It was attached to a bottom support frame, which held the TGU in place approximately 4.5 meters (15 feet) above the sea floor. The bottom support frame is 30 meters long (98 feet) by 15 meters wide (50 feet) by 4.5 meters high (15 feet) and secured to the seafloor with ten 30-inch diameter stell piles. The bottom support frame is constructed of steel, and the TGU was constructed of steel and composite material. The coupled TGU and bottom support frame comprised the TidGen device. The TidGen device was connected to an underwater power consolidation module, which was then connected to an onshore station through a single underwater power and data cable. Power from this device was delivered to shore and incorporated into the local electrical distribution system. The TidGen TGU was removed from the site in 2013 and the bottom support frame remained on site to allow for continued test activities.

ORPC also tested its OCGen® Module Mooring System (OCGen) at the Cobscook Bay test site in 2014. The prototype OCGen device consisted of a buoyancy pod attached to a chassis with two turbines placed in the water column 10 meters (35 feet) below mean low water. It had no generator and was not grid connected. The turbines were re-used from a previous turbine model. The device was secured using gravity anchors and a tension-leg mooring system. The OCGen was removed from the site after almost three months of testing.

ORPC’s next generation, full-scale TidGen® Power System is presently under development and partially funded by the U.S. Department of Energy (DOE) Water Power Technologies Office (WPTO). A single TidGen system is rated at 80 kilowatts (kW) of output at 2.25 meters per second (m/s) of water velocity, with a peak output of 160 kW at 3.5 m/s of velocity. The approximate dimensions of a TidGen device will be 17.8 meters wide (58 feet) by 6 meters high (20 feet). Prior to testing a full-scale iteration of the TidGen device, ORPC tested a single turbine TidGen system during summer 2023 in Cobscook Bay. Information gathered during the single turbine TidGen test phase is being utilized to complete designs, installation plans, and buildout for the full scale TidGen device.

Device/Array Installation Date:
TidGen® Power System: September 13, 2012
OCGen® Module Mooring System: June 27, 2014
Single Turbine TidGen® System: May 28,2023

Device/Array Removal Date:
TidGen® Power System: July 15, 2013
OCGen® Module Mooring System: September 17, 2014
Single Turbine TidGen® System: September 20, 2023

Location

The site is located in Cobscook Bay on State of Maine submerged lands, near Eastport and Lubec, Maine, United States.

Licensing Information

ORPC obtained a Federal Energy Regulatory Commission (FERC) Preliminary Permit for the Cobscook Bay and Western Passage Project sites on July 23, 2007. On January 13, 2011, FERC issued a successive Preliminary Permit for ORPC’s continued research specifically for the Cobscook Bay site. Feasibility studies, including environmental surveys, and pre-filing consultation were conducted, resulting in ORPC’s filing of a draft pilot project license application with FERC on July 24, 2009 and subsequently, the final pilot project license application on September 1, 2011. ORPC received a FERC pilot project license for the Cobscook Bay Tidal Energy Project on February 27, 2012 (FERC Project No. P-12711).

While the Cobscook Bay site serves as an excellent device testing area, ORPC has determined that the tidal current velocities at the site do not justify pursuing a commercial FERC license for the site at this time. In a March 14, 2017 submittal to FERC, ORPC stated that it did not intend to move on to the next step in the licensing process to file a notice of intent (NOI) or a Pre-Application Document (PAD) to commercially license the project. On January 26, 2022, ORPC filed documentation evidencing completion of Cobscook Bay Tidal Energy Project removal and site restoration activities. The FERC pilot license is now closed.

In accordance with FERC order dated November 19, 2021, ORPC gained permission to maintain the Cobscook Bay bottom support structure to allow for continued testing of next generation tidal energy devices at the Cobscook Bay site. Federal agency jurisdiction presiding over continued use of the Cobscook Bay site and the associated bottom support structure has been transitioned from FERC to the U.S. Army Corps of Engineers (USACE). As such, the bottom support frame remains in place to allow for continued device testing activities.

Complete licensing information can be found on the FERC eLibrary website using docket number P-12711.

Project Progress

In March 2012, ORPC began construction at the Cobscook Bay site. A single-device TidGen Power System with a rated capacity of 150 kW was secured to the bottom support frame, which was fully installed with piles driven on April 8, 2012. The TGU was deployed on August 14, 2012. Subsea power and data cables were deployed on the seafloor and connected to the TidGen device.

The TidGen Power System delivered electricity to the grid from September 2012 to July 2013. This was the first grid-connected installation of an ORPC power system. Electricity generated by the TidGen Power System was delivered by an underwater power cable to an onshore station in Lubec, Maine, where it was power-conditioned and connected to the Bangor Hydro Electric Company (now Versant Power) utility grid on September 13, 2012. ORPC entered into a 20-year agreement with Bangor Hydro Electric Company on January 1, 2013, for up to 5 megawatts at a price of $215/MWh, escalating at 2.0% per year. The project provided numerous lessons learned related to installation, maintenance, and retrieval. For retrieval a novel catamaran barge system was utilized that significantly reduced cost of operation. The TGU was transported to shore, placed on blocking, and lifted onto a trailer for transfer to concrete blocking pads on July 16, 2013.

In 2014, the OCGen Module Mooring System was deployed at the Cobscook Bay site. This system was designed to demonstrate the feasibility of a floating tensioned mooring system operating in a reversing flow tidal environment which could expedite future device installations and improve water column siting. The mooring system was installed from June 27, 2014 to September 17, 2014 and turbines rotated from July 24 to August 10, 2014. The results of this test have informed ORPC’s latest TidGen power system designs, as a similar tensioned mooring system design is being utilized for TidGen.

A subscale of ORPC’s latest TidGen System, the single turbine TidGen system, was developed with assistance from the DOE WPTO and tested from June 2023 – September 2023. The Cobscook Bay site was not grid connected during these testing exercises.

Key Environmental Issues

The following table includes a list of the federal and/or state listed threatened (T) and endangered (E) species with potential to occur in the Cobscook Bay test site area.

Common Name	Scientific Name	Federal Status	State Status
Birds
Roseate Tern	Sterna dougallii dougallii	E	E
Terrestrial Mammals
Northern Long-eared Bat	Myotis septentrionalis	T	E
Fish
Shortnose Sturgeon	Acipenser brevirostrum	E	E
Atlantic Sturgeon (Gulf of Maine DPS)	Acipenser oxyrinchus oxyrinchus	T	N/A
Atlantic Sturgeon (New York Bight, Chesapeake Bay, Carolina, and South Atlantic DPS)	Acipenser oxyrinchus oxyrinchus	E	N/A
Atlantic Salmon (Gulf of Maine DPS)	Salmo salar	E	N/A
Aquatic Reptiles
Green Sea Turtle (N Atlantic DPS)	Chelonia mydas	T	N/A
Kemp’s Ridley Sea Turtle	Lepidochelys kempi	E	E
Leatherback Sea Turtle	Dermochelys coriacea	E	E
Loggerhead Sea Turtle (NW Atlantic DPS)	Caretta caretta	T	T
Marine Mammals
Sei Whale	Balaenoptera borealis	E	E
Fin Whale	Balaenoptera physalus	E	E
North Atlantic Right Whale	Eubalaena glacialis	E	E
Sperm Whale	Physeter macrocephalus	E	E
Humpback Whale	Megaptera novaeangliae	DL	E

ORPC designed and carried out the following monitoring plans over the course of the FERC licensing process and as part of FERC license compliance to ascertain the Cobscook Bay Tidal Energy Project’s environmental effects:

Acoustic Monitoring
Benthic and Biofouling Monitoring
Fisheries and Marine Life Interaction Monitoring
Hydraulic Monitoring
Marine Mammal Monitoring
Sea and Shorebird Monitoring

In addition, as required by ORPC’s FERC pilot license, an Adaptive Management Plan was implemented to outline and manage the process for evaluating environmental monitoring data and license modifications where appropriate. An Adaptive Management Team was created and was comprised of jurisdictional federal and state agencies, and ORPC. The team met on an annual basis over the course of the FERC license to review project updates, project operations, study results, and proposed study plans.

ORPC Environmental Webpage: https://orpc.co/project-monitoring/

Environmental Monitoring: Cobscook Bay Tidal Energy Test Site

Phase

Stressor

Receptor

Searches description, design & methods, results.

ID	Phase	Stressor & Receptor	Design and Methods	Results
6263	Baseline	Attraction, Avoidance, Collision, Noise Marine Mammals	Marine mammal presence and interactions. Incidental visual observations; testing of active acoustic monitoring (AAM) system.	Completed Visual observations recorded primarily harbor seals at the project site; AAM testing indicated positive results for detecting and tracking marine mammal sized targets.
6274	Baseline	Noise Physical Environment	The primary goals of the Acoustic Monitoring Plan were to identify and characterize the noise radiated by the TidGen® Power System in the high-velocity environment of the Project site by gathering acoustic data under various environmental and mechanical conditions prior to and during Project deployment. Measurements were collected at the project site using a drifting noise measurement system (DNMS).	Completed Measurements of the in-water noise level related to the TidGen® Power System demonstrate that sound levels in the vicinity do not exceed 120 dB re 1 µPa2/Hz at any frequency while the turbine is rotating, both while generating and when freewheeling.
6264	Baseline	Attraction, Avoidance, Collision, Noise Fish	Fisheries presence and turbine interactions. Hydroacoustic and trawl surveys of project and control sites; interaction studies around ORPC’s beta turbine.	Completed Hydroacoustic and trawls surveys combined to detail fisheries presence (seasonality, vertical distribution, diurnal patterns, etc.) and speciation. Interaction studies demonstrated fish behavior.
6265	Baseline	Attraction, Avoidance, Collision Birds	Species presence and behavior. Land-based and water-based visual observations.	Completed Species presence, behavior, and seasonality documented.
6266	Baseline	Habitat Change Invertebrates	Benthic community survey. Benthic dive survey of deployment area and cable route.	Completed Species presence and distribution documented. Sediment type also documented.
6267	Baseline	Habitat Change Physical Environment	Bathymetric mapping and sediment characterization. Detailed bathymetric mapping, side-scan sonar, sub-bottom profiling and magnetometer surveys. Data used to characterize the bottom and identify potential cultural resources and marine hazards.	Completed Preliminary results led ORPC to change deployment strategy of turbines in Cobscook Bay primarily due to thickness of unconsolidated sediments.
6268	Baseline	Changes in Flow Physical Environment	Water velocity surveys. Acoustic Doppler Current Profiler (ADCP) surveys. Hydraulic circulation modeling.	Completed ADCP surveys and hydraulic modeling contributed to the selection of turbine deployment locations.
6269	Baseline	Noise Physical Environment, Marine Mammals	Underwater acoustic survey. Drifting Noise Measurement System (DNMS) at project site and around ORPC’s beta turbine.	Completed Beta turbine operation did not elevate underwater sound levels more than 10 dB above ambient levels and is not expected to cause harassment to marine mammals.
6270	Post-Installation Monitoring	Collision Marine Mammals	The primary goal of the Marine Mammal Monitoring Plan is to identify the species, number of animals and their behavior to characterize changes in marine mammal use in and around the deployment area due to the presence of hydrokinetic devices. ORPC conducted visual observations of marine mammals in and around the Project area concurrently with other project-related tasks conducted in 2013.	Completed Marine mammal observations made by trained personnel in 2013, including during periods of operation, maintenance and retrieval did not indicate changes in marine mammal presence or behavior. There is no evidence of marine mammal strike with system components during deployment and retrieval or with TGU foils during operation.
6271	Post-Installation Monitoring	Habitat Change Invertebrates	The primary goals of the Benthic and Biofouling Monitoring Plan are to evaluate the benthic community during the Project and to study whether the structures introduced into the marine system contribute to biofouling accumulation that may alter the habitat within the Deployment Area. ORPC deployed video transect lines and video recordings were made by scuba divers. Benthic sampling was conducted in situ by the divers along the transect. ORPC performed biofouling assessments. The TidGen® TGU was assessed for percent coverage of biofouling on distinct structural components, and biological samples were taken from representative locations. In 2014, the installation of the OCGen® Module Mooring Project at the Cobscook Bay Tidal Energy Project site provided an opportunity to inspect the TidGen® bottom support frame, shore cable termination anchor, and the Simrad tower for benthic growth.	Completed MER Associates review of ORPC’s November 9, 2013 benthic survey of the cable route concluded that exposed sections of the cable were causing minimal disturbance to the seabed and were not adversely impacting the surrounding habitat or benthic epifauna. In addition, the buried portion of the cable was stationary and was not expected to cause any disturbance impacts. Review of the dive video and visual inspection following retrievals of the TidGen® indicate minimal biofouling of the TidGen® device. The July 2014 observations were generally consistent with those previously recorded and confirmed a continued presence of benthic organisms on subsea structures.
6272	Post-Installation Monitoring	Attraction, Avoidance, Collision Fish, Marine Mammals	The goal of the Fisheries and Marine Life Interaction Monitoring Plan was to collect pre-deployment and post-deployment information to provide an initial description of fish distribution and relative abundance within Cobscook Bay to supplement existing information for the general Passamaquoddy Bay area.The Fisheries Monitoring Plan is a continuation of research started by UMaine researchers in 2009. The study was designed to capture tidal, seasonal and spatial variability in the presence of fish in the area of interest (near the TidGen® device deployment site). The design involved down-looking hydroacoustic surveys during several months of the year, and examined the vertical distribution and relative abundance of fish at the project and control site (for relative comparison). Pre-deployment data were collected in 2010, 2011, and early 2012, and post-deployment data were collected from August 2012 through September 2013. In 2015 UMaine’s Fish Assessment Study Team completed research related to marine life interaction data around the OCGen® Module deployed in 2014. In 2016 UMaine’s Fish Assessment Study Team continued processing, analyzing, and interpreting data collected at the Project site in 2012-2014.	Completed The hydroacoustic surveys indicated that there was a significant decline in fish density closer to the turbine beginning approximately 140 m from the free-spinning OCGen® prototype device. Noise and natural flow patterns appeared to be the most plausible explanations for the observed patterns in fish behaviour. The study provides additional confirmation that a single turbine is unlikely to result in more than negligible impacts to fish communities.
6273	Post-Installation Monitoring	Attraction, Avoidance, Displacement Birds	The primary goal of the Bird Monitoring Plan was to determine the species, number, and time of peak use of sea and shore birds in the Deployment Area, the onshore landing site where the underwater P&D cables of the TidGen® Power System comes ashore, and the waters immediately off the landing site. Post-deployment sea and shore bird monitoring was conducted by the Center for Ecological Research (CER) using trained observers familiar with local bird species and behavior.	Completed CER observed a decline in several species of seabirds in the Cobscook Bay study area in 2012- 2013, compared to the previous two winters. It seems unlikely that the operation of the TidGen® Power System affected seabird numbers. CER surveys did not find any federally or state endangered or threatened species.
6275	Post-Installation Monitoring	Changes in Flow Physical Environment, Sediment Transport	The primary goal of the Hydraulic Monitoring Plan was to characterize the hydrological zone of influence, area for the Project. ORPC worked with Sandia National Laboratories (SNL) and Sea Engineering, Inc. to apply their SNL-EFDC Model to assess hydrodynamics at the Project site. TidGen® foundation piles were marked prior to installation for the purpose of measuring changes to seabed elevation from scour.	Completed Results of the scour monitoring indicate minimal change in seabed elevation around the foundation piles.
513208	Post-Installation Monitoring	Noise Fish, Marine Mammals	In compliance with its Incidental Harassment Authorization, ORPC also conducted various environmental monitoring and mitigation procedures to limit and evaluate the impacts of pile driving activities between March 24 and April 4, 2012. Additional hydroacoustic monitoring continued after the removal of the TidGen. Acoustic monitoring during pile driving activities included in-air acoustic monitoring and hydroacoustic monitoring at various near and far field ranges. Marine mammal observations on vessels around the site and on land also occurred during installation. Acoustic monitoring continued post-installation.	Completed A final report on the acoustic, marine mammal and bird monitoring studies during Phase I pile driving activities was prepared for NOAA. Pile driving source levels were below regulatory thresholds.
513209	Post-Installation Monitoring	Noise Physical Environment	The primary goals of the Acoustic Monitoring Plan were to identify and characterize the noise radiated by the TidGen Power System in the high-velocity environment of the Project site by gathering acoustic data under various environmental and mechanical conditions prior to and during Project deployment. Measurements were collected at the project site using a drifting noise measurement system (DNMS).	Completed Measurements of the in-water noise level related to the TidGen Power System demonstrated that sound levels in the vicinity did not exceed 120 dB re 1 µPa2 /Hz at any frequency while the TidGen turbine was rotating, both while generating and when freewheeling.
513210	Post-Installation Monitoring	Habitat Change Fish	The goal of the Fisheries and Marine Life Interaction Monitoring Plan was to collect pre-deployment and post-deployment information to provide an initial description of fish distribution and relative abundance within Cobscook Bay to supplement existing information for the general Passamaquoddy Bay area. The Fisheries Monitoring Plan is a continuation of research started by UMaine researchers in 2009. The study was designed to capture tidal, seasonal and spatial variability in the presence of fish in the area of interest (near the TidGen device deployment site). The design involved down-looking and side-looking hydroacoustic surveys during several months of the year, and examined the vertical distribution and relative abundance of fish at the project and a control site in Cobscook Bay. Pre-deployment data were collected in 2010, 2011, and early 2012, and post-deployment data were collected from August 2012 through July 2015. In 2015 UMaine’s Fish Assessment Study Team completed research related to marine life interaction data around the OCGen Module deployed in 2014. In 2016 and 2017 UMaine’s Fish Assessment Study Team continued processing, analyzing, and interpreting data collected at the Project site in 2012-2015.	Completed Hydroacoustic data found variable fish densities and vertical distributions across diel and tidal cycles. The OCGen hydroacoustic surveys indicated that there was a significant decline in fish density closer to the turbine beginning approximately 140 m from the free-spinning OCGen prototype device. Noise and natural flow patterns appeared to be the most plausible explanations for the observed patterns in fish behaviour. Single devices spanning a small prorportion of a channel are not expected to generate avoidance behaviors that may significantly delay or reduce overall fish passage. Hydroacoustic studies provided additional confirmation that a single turbine is unlikely to result in more than negligible impacts to fish communities.
513211	Post-Installation Monitoring	Habitat Change Birds	The primary goal of the Bird Monitoring Plan was to determine the species, number, and time of peak use of sea and shore birds in the Deployment Area, the onshore landing site where the underwater P&D cables of the TidGen Power System comes ashore, and the waters immediately off the landing site. Post-deployment sea and shore bird monitoring was conducted by the Center for Ecological Research (CER) using trained observers familiar with local bird species and behavior.	Completed CER observed a decline in several species of seabirds in the Cobscook Bay study area in 2012- 2013, compared to the previous two winters. It seems unlikely that the operation of the TidGen Power System affected seabird numbers. CER surveys did not find any federally or state endangered or threatened species. In addition, no significant disturbance to seabirds were observed during installation activities.

Cobscook Bay Tidal Energy Test Site

Contents

MRE Project Site

Details

Description

Location

Licensing Information

Project Progress

Key Environmental Issues

Papers, Reports, Research Studies