Drawing Power From The Tides
Faced with real-time scenes of oil gushing from the sea floor in the Gulf of Mexico, it might be time to illuminate an ocean energy project its developers say will harvest energy for electricity without trashing the place.
The Ocean Renewable Power Company (ORPC), based in Portland, Maine, is developing hydrokinetic energy by using ocean tides and currents to twirl electricity-producing turbines.
They are testing a Beta version of their Turbine Generator Unit (TGU) in Cobscook Bay at Eastport, Maine. The Beta TGU is the largest ocean energy device deployed in U.S. waters thus far.
ORPC’s president and CEO Christopher R. Sauer co-founded the company in 2004. A civil engineer, Sauer has more than 35 years of experience in industrial engineering, energy project management, and startup company formation. When he describes the work his company does, he says: “We’re in the ingenuity business.”
The company has several proprietary tidal power technologies in development. As part of its permitting process, the company developed and tested a prototype TGU, the forerunner to the Beta version, in Western Passage off the coast of Eastport. Once they were able to show the Federal Energy Regulatory Commission that the prototype could create electricity, ORPC was ready to move ahead with the Beta, to prove that the power they produced would be compatible with the nation’s power grid.
The sequence of steps leading to the research, development and deployment of these tidal technology systems is methodical, by necessity. The company plans to have a TidGen Power System working and connected to the grid by 2011, ORPC marketing manager Susy Kist explained. More powerful generators will follow.
I visited Eastport in mid-May, just before the arrival of summer tourists. Kist, Director of Operations Bob Lewis and boat captain Skip Harris spent a day showing me the ropes.
Eastport is the easternmost city in the U.S., although it is not quite the easternmost point. It is located at the intersection of Cobscook Bay and Passamaquoddy Bay, all part of the Bay of Fundy. Most of Eastport is on Moose Island but bits and pieces of the town that numbers about 1,600 during the high season are scattered about on Carlow Island, Spectacle Island, Goose Island, and Treat Island. New Brunswick, Canada, is just a shout away.
The important thing about Eastport in terms of producing power is that it has the highest tides in the continental United States, with currents reaching about 6 knots, or 7 miles per hour, at peak flows four times a day.
Development that begins in rural America often stays in rural America. Sauer’s goal was to create jobs and economic opportunity where the company was working, and, so far, that’s happening. Julianne Couch
For example, Morrison Manufacturing in Perry, Maine, built the giant barge that launched the Beta TGU into the water. The deployment system for the TGU was built by Alexander’s Welding and Machine in Greenfield. Fabrication of the 100 percent composite turbine foils was done in Bath, Maine, by U.S. Windblade.
Harbor Technologies of Brunswick, Maine, made composite parts of the TGU frame. Steel parts of the TGU frame and overall assembly of the frame was by Stillwater Metalworks in Bangor. The generator itself was built in Marlboro, Massachusetts. The Boat School in Eastport helped put the pieces together.
To give me a better understanding of the Beta TGU’s potential, Kist and Lewis arranged for me to see the contraption close up. Eastport native Capt. Skip Harris gave Kist and me an hour-long ride on his cousin Butch’s converted lobster boat, the Lady H. “It’s been Coast Guard certified to take passengers,” Harris assured us.
It was late morning when we took to the water and clouds were beginning to roll in. It felt good to stand near the boat heater and warm our hands, watching the scenery of green islands and blue water roll and bob past the windshield. Harris and Kist pointed out landmarks along the way in Maine and New Brunswick.
After about 15 minutes we closed in on the Energy Tide 2, moored to a position where the TGU would be held in a fairly constant location. The waters here are not only cold (about 52 degrees at the time of our trip) they are 160 feet deep. Kist explained that the Energy Tide 2, and therefore the TGU, swing with the tide. The location for the placement of the Energy Tide 2 was one that fishermen and others in the community had approved because it would not interfere with their commercial or recreational activities.
At the time of our visit, the TGU was out of the water. Earlier testing had revealed that more tweaking of the underwater permanent magnet generator would be required. So it was removed and sent to Massachusetts for work. That was unfortunate for ORPC because it meant no data was being collected. But it was fortunate for me because I got to see first hand the hydraulic arms that raise and lower the TGU into the water, the blue and white turbine foils, and the gap in the middle where the generator would go.
When the TGU is commercially operational and putting power onto the grid, the Energy Tide 2 barge will no longer be needed, Kist explained. Instead, the generator will be secured to the ocean floor. It is likely that several turbines would be configured together to make the most of the movement of the tides. “We’re still testing our stuff out on the water. We learn a lot from that,” she said.
Tides come in and they go back out. But they also stop in order to reverse directions, in a phase known as slack tide. Bob Lewis had explained that although power can’t be produced during these times, at least they are predictable. “You can’t always know when the wind will blow or the sun will shine,” he said in a comparison to wind and solar power. “But we can predict the tides.”
ORPC’s power systems produce no emissions of any kind and require no fossil fuels to operate, deriving their power solely from the renewable resource of the earth’s oceans and rivers. Julianne Couch
Nor do the slow-spinning turbines pose much threat to sea life. According to Christopher Sauer, “To date, our Turbine Generator Unit testing has caused no negative effects on either fish or sea mammals, which tend to simply avoid the unit the way they would a rock or other natural barrier, by swimming around it.”
As technology to convert just about any object into energy advances, the land rush to develop power has moved into the ocean, bringing controversy with it. In some locations, towering wind farms are being erected offshore, capturing the steady ocean breezes. Some question the efficiency of this method and object to the intrusion of the turbines on the horizon.
Tidal projects that are variations on ORPC are in various stages of planning or construction on the shores in Florida, Alaska, Canada, and around Europe and Australia. The environmental impacts of these technologies have yet to be fully understood. And no one can doubt the debate about off-shore drilling in both shallow and deep water will rage on.
Bob Lewis describes what ORPC is doing in aviation terms: “We are like the Wright brothers when they learned to fly at Kitty Hawk.”
No one has done this sort of work before and it takes a great deal of effort and patience, he said. Most of us can’t imagine a world without airplanes today, thanks to the Wright brothers. Perhaps one day we won’t be able to imagine a world in which polluting or disaster-prone forms of power were the norm.
This story is based upon work supported by the University of Wyoming School of Energy Resources through its Matching Grant Fund Program.