Science Advisory Report 2009/064

Assessment of Tidal and Wave Energy Conversion Technologies in Canada

Summary

• A small number of tidal in-stream (TISEC) and wave (WEC) energy conversion technology demonstrations are in place internationally, and a number have been recently initiated in Canada. Much of the development work on these technologies is driven by the private sector. To ensure that these technologies are consistent with Canada’s conservation and sustainability priorities, it is essential to acquire a firm understanding of their potential environmental implications and, thus, feasibility for deployment in Canadian coastal waters.
• TISEC and WEC technologies have the potential to result in changes to current flows, wave exposure, and associated sediment and coastal processes that could have direct and indirect effects on marine and coastal ecosystems. The extent of the effect of any project would depend on the technology characteristics, project scale, distance from the coast, and natural coastal structure and processes (hydrodynamic and sedimentary).
• Changes to habitat characteristics resulting from the deployment of marine energy conversion technologies will vary by size, design, and location but may include direct loss or alteration of existing benthic and pelagic habitat, as well as marine organism responses to the addition of artificial structures. Comprehensive analysis of the relationships between changes in physical processes associated with TISEC and WEC development and risks to habitats and wildlife populations has not been conducted to date.
• Like other marine industries, TISEC and WEC development has the potential to degrade local water quality (through increased suspended sediment concentrations and introduction of oil, lubricants, antifoulants and other contaminants), with long-term implications for marine life.
• While there is a global effort to study the effects of noise in the marine environment, there have been very few directed studies of the response of fish and marine mammals to noises and vibrations produced by operational TISEC and WEC devices. Long-term physiological, behavioural, and population-scale impacts of noise are still poorly understood. Sound intensities, frequencies and patterns, and therefore threats, will be technology and environment-specific.
• There is considerable uncertainty regarding the effects of electromagnetic fields on marine organisms. Reliable evidence of responses of marine life to existing underwater cables in Canadian or international waters is lacking. There is some evidence suggesting that EMF levels that could be emitted from underwater cables (and other electrical devices) associated with TISEC and WEC arrays may be detectable by some species. Organisms that spend all or part of their life cycles in, on, or close to the benthos may be particularly at risk due to their physical proximity to the EMF source and thus stronger field strengths.
• There is an absence of peer-reviewed articles within the scientific literature addressing the impact of physical encounters (either directly with structures, e.g., strikes and entanglement, or indirectly, e.g., through pressure changes) between marine life and WEC or TISEC technologies at existing facilities. The risk of such encounters and the effectiveness of potential mitigation measures to avoid impacts of encounters are unknown.
• While the importance of being able to evaluate the potential for cumulative impacts, including the interaction among multiple energy conversion technologies and the interaction of those technologies with other human activities over time, is recognized, there has been no attempt to predict or model these interactions due to limited data and no requirement for this information under regulatory compliance procedures.
• There is not yet sufficient information on the scope of impacts from the wide variety of TISEC and WEC technologies that have been, and are continuing to be, produced to develop a relevant Statement of Canadian Practice. However, this issue should be re-visited as experience and knowledge from demonstration projects is gained.
• Broad-scale research priorities to assist in the development of policy and regulations related to TISEC and WEC include: development of science-based monitoring protocols for marine energy extraction (pre and post deployment); development of new monitoring technologies; development and evaluation of technologies and protocols for the assessment of environmental effects; development, evaluation, and validation of relevant models; and collection and archiving of relevant baseline data.
• Priority topics requiring science research include: modeling of ocean processes, e.g., tidal movements, waves, sediment behaviour and dynamics; habitat surveys and analysis in areas of interest; modeling and field investigation of marine organism physiological, behavioural and population-scale responses to marine energy development; assessment of resilience of benthic and pelagic communities and the time scales of recovery from disturbance; evaluation of mitigation, restoration and enhancement options; and modeling of cumulative and synergistic interactions among multiple arrays and between arrays and other marine activities.

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