Cobscook Bay Tidal Energy Project: 2013 Environmental Monitoring Report


Title: Cobscook Bay Tidal Energy Project: 2013 Environmental Monitoring Report
Authors: ORPC Maine
Publication Date:
March 03, 2014
Pages: 502
Technology Type:

Document Access

Website: External Link
Attachment: Access File
(28 MB)


ORPC Maine (2014). Cobscook Bay Tidal Energy Project: 2013 Environmental Monitoring Report. Report by Ocean Renewable Power Company (ORPC). pp 502.

ORPC Maine, LLC, a wholly-owned subsidiary of Ocean Renewable Power Company, LLC (collectively ORPC), submits this 2013 Environmental Monitoring Report for Phase I of the Cobscook Bay Tidal Energy Project (Project), in compliance with the Federal Energy Regulatory Commission (FERC) pilot project license P-12711-005. This report represents a significant achievement for the Project and its Adaptive Management Plan and demonstrates improved knowledge of our TidGen® Power System’s operation and interaction with the marine environment.


The purpose of FERC’s pilot project license process is to advance new marine hydrokinetic technology while minimizing the potential for environmental impacts. The process allows developers to test and evaluate new hydrokinetic technologies and determine environmental  effects of the technologies, while maintaining FERC oversight and agency input. Pilot projects must be temporary, limited in size, removable, and able to shut down on short notice. License terms ensure environmental monitoring and safeguards during the short project term.


ORPC is using this licensed pilot project to advance, demonstrate, and accelerate deployment of its tidal-current based marine hydrokinetic energy conversion technology, associated power electronics, interconnection equipment, and environmental monitoring program within a replicable full-scale, interconnected array of devices capable of reliably delivering electricity to the domestic power grid. The Project consists of designing, building, installing and monitoring a commercial-scale array of multiple, grid-connected TidGen® devices on the sea floor in Cobscook Bay off Eastport and Lubec, Maine.


The Role of Adaptive Management

The Project has successfully demonstrated the ability to modify license requirements based on the results of science-based data collection, the engagement and concurrence of the Adaptive Management Team (AMT), and clear communication with FERC. This process has garnered international attention as a model for adaptive management.


ORPC provided the 2012 Environmental Monitoring Report to the AMT in February 2013 with a subsequent meeting held on March 12, 2013. This meeting was an opportunity for ORPC to summarize the early results of the monitoring program and solicit feedback from the AMT, including any recommendations for program modifications. ORPC subsequently met with the AMT on September 10, 2013 to provide updated environmental monitoring and project status information.


Through the adaptive management process, ORPC has requested modifications to environmental monitoring to clarify elements of the plan and reduce frequency of monitoring surveys based on increased knowledge of species presence and environmental effects. With concurrence from the AMT, ORPC’s license modifications have been accepted by FERC. This process demonstrates a clear reduction in effort and cost on the part of ORPC based on the risk reduction demonstrated by environmental monitoring results.


Environmental Monitoring Results

The 2013 environmental monitoring results continued to build an increased knowledge of marine life interaction with the TidGen® Power System and indicated negligible environmental effects for many elements of the monitoring plans.


Article 405. Acoustic Monitoring Plan
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 turbine was rotating, both while generating and when freewheeling. Further, the integrated rms levels from 20 Hz to 20 kHz did not exceed 120 dB re 1 µPa2, the level some regulators have used to establish level B harassment of marine mammals.


Article 406. Benthic and Biofouling Plan

Observations of the exposed cable(s) indicated there continues to be little, if any, evidence of scouring or disturbance to the bottom or the associated faunal community. Results of the post deployment benthic sampling survey indicated a healthy and highly productive benthic community with no discernible continuing effects from either the installation or operation of the cable. Assessments conducted in July 2013 indicated minor biofouling on the TidGen® turbine generator unit (TGU) with more significant growth on the bottom support frame; however, the functionality of the system did not appear to be compromised.


Article 407. Fisheries and Marine Life Interaction Plan

Hydroacoustic assessments conducted by the University of Maine (UMaine) demonstrate that while fish density was indeed variable, patterns were repeatable and will be useful in understanding the effects of devices. Data collected from the side-looking sonar during operation was minimal and only limited to when the TidGen® was not generating. However, available data allowed UMaine to identify some key issues that should be addressed in the future with the goal of collecting data while the turbine is generating power.


Article 409. Hydraulic Monitoring Plan

Hydrodynamic modeling conducted by Sandia National Laboratories continued to contribute to an understanding of hydraulic effects of the TidGen® Power System. Their work investigated velocity deficits created by the turbines and wake recovery as well as optimization of turbine arrays. Results of the scour monitoring continued to indicate minimal change in seabed elevation around the foundation piles.


Article 410. Marine Mammal Monitoring Plan

Marine mammal observations made by trained ORPC personnel in 2013, including during periods of operation, maintenance and retrieval, did not indicate changes in marine mammal presence or behavior. There was no evidence of marine mammal strike with system components during deployment and retrieval or with TGU foils during operation. In addition, the continued presence of marine mammals in the vicinity of the Project indicated that the TidGen® Power System was not acting as a deterrent or a barrier to passage into the inner portions of the Bay.


Article 412. Bird Monitoring Plan

The Center for Ecological Research (CER) observed a decline in several species of seabirds in the Cobscook Bay study area in 2012-2013; however, they determined that it was unlikely that the operation of the TidGen® affected seabird numbers because it was not deployed in November 2012, a period when no eiders or Red-breasted Mergansers were observed.


Temporary Variance Period


ORPC requested to place environmental monitoring on a hiatus during the technology optimization period at the AMT meeting in September 2013. ORPC presented the following rationale for the appropriateness of the request:

  • Comprehensive pre-deployment environmental studies have contributed to an understanding of inter-annual variability.
  • Results-to-date indicated negligible effects to marine life from ongoing operations.
  • TGU operational status made adherence to license conditions impractical and did not advance the conditions purpose.
  • No undue impacts or impedance of other license requirements were anticipated. ORPC plans to return to adherence of conditions once TGU operation recommences. 

Following the meeting, ORPC submitted the temporary variance request to FERC with the concurrence of the AMT. FERC issued a license order approving the temporary variance request on October 29, 2013.


Despite the temporary variance from environmental monitoring for the Project, ORPC will work with UMaine to conduct fisheries monitoring associated with a test of its floating OCGen® turbine technology in 2014. The OCGen® Module Mooring Project represents a significant advancement in marine hydrokinetic technology and deployment procedures while reducing potential environmental effects (elimination of the bottom support frame). Even though the mooring project will not be grid connected (and thus not under FERC jurisdiction), ORPC provided the AMT with detailed project information and requested concurrence on the relocation of the testing from off Shackford Head to within the FERC-licensed Project site.

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