PNNL

A typical marine renewable energy device used to harvest natural energy from the ocean's waves, currents, and tides.

Marine renewable energy (MRE), also known as marine and hydrokinetic energy, is the technology of harnessing energy behind tides, waves, and currents to generate electricity. Because water covers 75 percent of the earth's surface, it's easy to imagine the energy potential behind the technology. According to the Ocean Energy Systems, the world oceans have the technical potential to produce 9,100,000 gigawatt hours annually using MRE technology for tidal, wave, and ocean current extraction. The use of MRE could also combat the effects of climate change on the marine environment, such as ocean acidification and increasing ocean temperatures.

As countries around the world begin to develop MRE projects, active research and monitoring efforts are occurring to evaluate their effects on marine animals and their habitats. Research continues to be compiled in order to best understand these effects as there is a need to share the data and best practices being made.

To address these concerns, Annex IV, a collaborative initiative of the Ocean Energy Systems under the International Energy Agency Technology Network, released a 250 page report authored by researchers from around the world titled "State of the Science Report: Environmental Effects of Marine Energy Development Around the World." By sharing data and synthesizing results through the State of the Science report, Annex IV hopes to: retire risk for marine energy technologies; avoid duplication of research and monitoring efforts; promote the sustainable development of marine renewable energy technologies; and ensure accurate and up-to-date information is available to regulators, industry members, and scientists worldwide. The report does not address the effects of offshore wind.

The report has been translated into four different languages and is anticipated to help reduce market barriers for widespread MRE deployment. PNNL senior program manager for Marine and Coastal Waters, Andrea Copping, says, "this report represents the most comprehensive collection of our knowledge of potential effects from marine renewable energy development. It will provide technology developers, government regulators, and scientists with greater certainty as we prepare to deploy wave and tidal devices in marine environments."

The report summarizes research findings regarding collision of marine animals with turbines. Researchers also looked into the effects of additional underwater noise from turbines and the effects of electromagnetic fields from cables used to carry power. Generally, single devices are not expected to harm aquatic life. Other areas of research include the change of natural flow patterns around devices, the health of seafloor habitats and reefs, and the biodiversity of marine ecosystems.

Finally, the report provides four case studies regarding the long permitting and consenting process encountered when installing the first generation of MRE devices, and it provides a path forward for marine energy monitoring and research.

See the Tethys website for more information about Annex IV.

PNNL Research Staff: Andrea Copping, Luke Hanna, Nichole Sather, Jonathan Whiting