A Utah company says a $70 million tidal energy project in Washington County would generate enough electricity to power 13,000 homes. Pennamaquan Tidal Power wants to build a more than 1,600-foot-long so-called tidal barrage that would stretch across the mouth of Pennamaquan River in Pembroke. The idea is to harness the ebb and flood cycles of the tides where the river flows into Cobscook Bay. But as Jay Field reports, environmentalists, including members of the Passamaquoddy Tribe, worry the project would harm alewives, elvers and other migratory marine species.

Remez Atiya, who's a physicist and the founder of Pennamaquan Tidal Power LLC, says there's one thing that people need to know about the structure he wants to build across the opening of the river Downeast. "Let me just say one thing: It's not a dam," Atiya says. "It operates differently from a dam."

A dam, says Atiya, consists of a massive concrete barricade and a catch basin. "It's full of water all the time and you allow water to run through it. This does not impound water," he says.

Atiya's structure starts with a foundation modeled on the "pile supported" offshore platforms developed by the oil and gas industry. It would support a low wall that would rise 13 feet above the water. Below the surface, the power-generating guts of the structure would include 16 so-called bulb turbines. Atiya says the submarine-like structures pump and turn in whatever direction the water is flowing.

"You virtually cannot tell that the natural tidal cycle has been in any way altered," Atiya says. "It goes up to its natural height, down to its natural height. The inter-tidal zone is exposed and submerged just as it would be if there were no structure at all. This is critical to the preservation of the ecology of the area."

But Atiya's assurances aside, the proposed project is still raising environmental concerns among people in the region, including some who rely on the river as a source of sustenance. This week, staff scientists with the Federal Energy Regulatory Commission have been holding public hearings on the project, as part of the permitting process. Steve Kartalia is a fisheries biologist with FERC.

"The types of issues that people are concerned about would be effects on inter-tidal fluctuations, shellfish, fin fish, anadromous fish running in and out of the Pennamaquan River," Kartalia says.

For years, the alewives that migrate from Cobscook Bay up through the St. Croix River watershed have been a key source of food for the Passamaquoddy Tribe. A tribal official didn't return a call for comment on this story by airtime. But this week, Passamaquoddy representatives met with the FERC delegation behind closed doors to express their concerns about how the project might effect the fishery.

Kartalia says the FERC team will use the information it's gathering this week to write up an environmental analysis of the project. "And then that environmental document, and public comment, all becomes part of the record on which commission would base its decision whether to issues a license, or not to," he says.

It's a process that's likely to take a few years, at the very least.