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Working Tidal UMaine engineers, marine scientists weigh trade-offs of harnessing the ocean’s power by Margaret Nagle

Editor’s note: Full-length version of story.

Eastport, Maine

In Cobscook Bay, Ocean Renewable Power Co. is testing the largest ocean energy device installed in U.S. waters. Photo by Dave Cleaveland/

For most of the world, ocean waters rise and fall roughly every 12 hours under the gravitational influence of the moon and sun — regularity that’s particularly attractive when humans attempt to harvest and utilize tidal energy.

But that predictability stands in sharp contrast to the myriad of unknowns involved in tapping the tides.

The quest to harness marine kinetic energy has been ongoing for decades and has focused largely on the engineering needed to efficiently and cost-effectively generate electricity from the sea. In Maine, that technology has taken the form of mill dams along the coast and the ill-fated Depression-era Quoddy tidal project in Cobscook Bay.

While the tidal energy industry is still considered to be in its infancy, a new chapter has begun in the last decade, this time with technology in the form of in-stream turbines. And the research and development continues in an effort to engineer devices to turn the tide into an alternative energy source.

But at the University of Maine, the questions go deeper than that. A team of engineers and marine scientists from UMaine and Maine Maritime Academy has formed the Maine Tidal Power Initiative to conduct research that will inform responsible tidal energy development in the state. In their four-pronged approach, the researchers are pursuing questions in engineering — turbine design, modeling and testing. But they’re also assessing the energy resource — from determining the amount of in-stream tidal energy to quantifying the impact of energy extraction on tidal flow. And then there are the two major concerns about the impact of tidal energy projects on area residents — both those living in the marine environment and in human communities.

Michael Peterson

Michael Peterson

“We consider those four functional areas to be equals,” says Michael “Mick” Peterson, University of Maine Libra Professor of Engineering and the coordinator of the Maine Tidal Power Initiative, based at UMaine and part of Maine’s Sustainability Solutions Initiative. “There’s nothing subordinate, because any one of them will stop the entire progress of the industry.

“I think we’ve (got) a new paradigm on how engineering can function,” Peterson says. “In the past, you’d build something, you’d look at the impacts and you’d try to mitigate them. Philosophically, what we want to do (today in tidal energy) is understand the impacts and decide whether it’s an appropriate place to develop it. Then, if we decide it’s appropriate, minimize the impacts. So we design around the location, the impacts, the culture, environment and resource.”

The Maine Tidal Power Initiative works with developers, communities and device manufacturers to create an informed framework for tidal energy projects. That framework is tailored to the local social and ecological conditions of each site, with a focus on sustainability and broad benefits to citizens.

The goal is to understand the value of the energy resource related to a tidal project and to determine if a site is commercially viable, locally accepted and environmentally suitable prior to making further investment. The reality, according to the researchers, is sustaining quality of place in coastal Maine will require developing energy extraction in a socially acceptable and environmentally sensitive manner.

“Maine people need to understand and be informed about how large the resource is and what the impact is, because it’s going to be their decision as to which sites we move forward on and which sites are appropriate for tidal energy,” Peterson says of the initiative’s research efforts. “With tidal energy, it’s important for them to know what it means to their community, their fishing grounds and their industrial development. (Maine) stands out in tidal energy; nobody else has this kind of (tidal energy) resource in the continental United States. And so we should be leading (the tidal energy industry).”

Fall 2011

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