Annex IV: Assessment of Environmental Effects and Monitoring Efforts for Ocean Wave, Tidal, and Current Energy Systems

Operating Agent: The United States Department of Energy (DOE), in cooperation with the Bureau of Ocean Energy Management (BOEM) and Federal Energy Regulatory Commission (FERC) and the National Oceanic and Atmospheric Administration (NOAA). Member nations include Canada, Ireland, Spain, Norway, New Zealand, and South Korea.




The primary objective of Annex IV is to increase our understanding of the environmental effects of ocean wave, tidal, and current energy development on the marine environment. The Annex aims to facilitate efficient government oversight of the development of ocean energy systems by expanding our baseline knowledge of environmental effects and monitoring methods. One of the primary goals of the Annex is to ensure that existing information and data on environmental monitoring (and, to the extent possible, practices for environmental mitigation) are more widely accessible to those in the industry; national, state, and regional governments; and the public. The Annex facilitates knowledge and information transfer through the final Annex IV Report and publicly accessible database of information.

Work Program

Between 2009-2012 Annex participants compiled and assessed information from existing and proposed environmental monitoring studies, and from ongoing research studies. Monitoring protocols and results were documented in a prescribed report format and lessons learned were identified. The Annex culminated in an accessible and searchable database and a comprehensive final Annex IV report published by the OES. The process was supported by experts from the Annex IV nations and beyond, coming together in two experts’ workshops and providing input, advice and review of draft products throughout the process. Greater understanding of the environmental effects and monitoring methods related to ocean energy will foster public acceptance and help to advance ocean energy technology. 

Year 1:

Identified potential environmental effects of ocean wave, tidal, and current energy systems; compiled existing monitoring information and identified high priority information gaps; designed and developed a smart and searchable database; and began to enter data.

Specific tasks included:

(a) Identified and reviewed valuable existing syntheses addressing ocean wave, tidal, or current energy systems;
(b) Based on existing syntheses, assembled a master list of potential environmental effects, related monitoring methods, and (when possible) mitigation strategies;
(c) Designed and developed the Annex IV database and began inputting data on environmental effects, monitoring methods, and (when possible) mitigation strategies; and
(d) Identified and prioritized crucial information gaps related to monitoring methods and environmental impacts, and selected higher priority gaps for further evaluation using analogous technologies.

Year 2:

Developed a standard data format; identified, selected, and compiled into the database case study information; and researched analogous technologies (analogues) for additional information.

In an effort to better understand the current state of ocean energy systems and associated environmental challenges, existing projects conducting environmental monitoring studies were identified, selected, and reviewed by participating countries. These environmental case study reports provided detail the specific methods and findings of each project with particular emphasis on identifying potential environmental impacts, environmental monitoring methodologies, and mitigation efforts. Cooperation from project developers was a critical component in this task in order to obtain the information necessary to carry out the proper analysis. The Annex Participants worked closely with identified project managers or developers and only requested information needed to complete the case studies analysis. An experts’ workshop was held to bring together experts from Annex IV nations and other countries to hone the data collection process and analysis.

Specific tasks included:

(e) Developed a standard format for reporting case study information, which may included following fields: type and location of project, device monitored, generating capacity, power source, water depth, special environmental issue of concern, planned duration of monitoring efforts, frequency and timing of monitoring, measurement strategy and technology, estimated project cost, monitoring cost and funding source, relevant findings, and strengths and weaknesses of monitoring approaches and mitigation efforts.
(f) Identified projects where ocean wave, tidal, or current energy devices are operational and for which environmental monitoring was undertaken or planned.
(g) Compiled metadata and other information to support database hosting and analysis.
(h) For priority information gaps, participating nations selected analogue monitoring and mitigation methods that were used to help evaluate the environmental effects of ocean wave, tidal, and current energy systems (e.g., from wind, aquaculture, ocean thermal energy technology, electric or telecommunications sub-sea cables, etc.).
(i) Entered case study and analogue information into the database and distributed for review by all Annex participants.
(j) Organized and hosted experts’ workshop bringing together over 50 experts from 8 nations to help steer and support the Annex.

Year 3:

Final analysis of all information and case studies; completion of preliminary, draft, and final reports; experts workshop; distribution of final report and database on internet website.

The Annex IV report compiled information and analyses from Years 1-3. The Final Annex Report was completed at the end of Year 3. A second experts’ workshop was held to review the progress of the Annex and provide input on potential future activities under an extended Annex. Comments from Annex participants and workshop participants were incorporated into the final database and report products.

Specific tasks included:

(k) Analyzed the synthesis data, case study data, and analogue information and prepared a preliminary report for initial review including a summary of the database information and any lessons learned and best practices for monitoring and mitigating environmental effects of ocean wave, current, and tidal energy devices.
(l) Solicited comments on the preliminary report and held an experts’ workshop (including participating nations and other experts) to discuss the preliminary findings.
(m) Incorporated workshop and written comments into a draft report and distribute the draft report for review by participating nations.
(n) Finalized the Annex IV Report.
(o) Posted final report and database to the internet, and linked the final Annex IV database to other ocean energy databases.

Final Annex IV Report and Database

The Tethys database, named after the Greek titaness of the ocean, is a multimedia database that houses environmental research and monitoring information, as well as an interactive map. The Final Annex IV Report provides an overview of the Annex and contains three case studies of specific interactions of marine energy devices with the marine environment that survey, compile, and analyze the best available information in one location. These case studies address: 1) the physical interactions between animals and tidal turbines; 2) the acoustic impact of marine energy devices on marine animals; and 3) the effects of energy removal on physical systems. Each case study contains a description of environmental monitoring efforts and research studies, lessons learned, and analysis of remaining information gaps. Much of the Annex IV information and metadata were collected through project site and research study metadata forms, which were widely distributed to the representatives of the member nations, members of the OES Executive Committee, marine energy developers, and researchers. 

If you would like to contribute to the Annex IV effort by submitting a project site or research study metadata form, please visit the following website:


Annex Participants, including the Operating Agent, will be required to contribute €5,000 per year for each of the three years of the Annex.

Time schedule

2010 - 2013 

Related links

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