Boston — For 50 years, engineers have dreamed of tapping the tides around Maine's Passamaquoddy Bay for power. But it may be the Passamaquoddy Indians who finally do it.
The Down East tribe expects to have a tidal plant generating electricity for about 5,000 homes by 1985 -- the first such large-scale project in the US.
The last report of Indians helping the white man harness the ocean's ebb and flow was in 1600, when a tribe in Canada helped colonist build a waterwheel mill on an ocean inlet.
The Passamaquoddys' plans for a 12-megawatt plant near Eastport, Maine, could leave Uncle Sam behind. For more than 20 years, the US Army Corps of Engineers has studied a project in the same bay of northeast Maine -- and now may find its tidal territory taken.
"Our project is farthest along, less expensive, and less damaging to the environment," says Dr. Normand L. Laberge, project director for the tribe.
Steep petroleum price hikes in the last two years have revived the economic potential of tidal power, lond considered an alternative to fuel-based power generation.
Yet, only two US coastal areas have the right combination of inlets that can be closed off with large enough differences between high and low tides to justify the expense of building dams and turbines that can capture the immense energy of the twice-daily cycles.
Alaska's tides rise as high as 29 feet, while Maine records 18-foot fluctuations. In November, Alaska launched a $220,000 study on the potential for tidal power along Cook Inlet near anchorage.
After four years of studies, the Passamaquoddy tribe plans to file an application in January with the Federal Energy Regulatory commission (FERC) to begin a $34 million project on Half-Moon Cove in Cobscook Bay.
Money for the project, says Dr. Laberge, will come from selling bonds. Construction of a 1,200-foot dam could start as early as mid1982, with power coming on line by 1985. The resulting tidal pool will harness a flow of 400 million cubic feet of seawater.
In a region still highly dependent on imported oil for generating electricity , the project will be making money within three years -- even at the current world oil prices, he adds. And with a life span of up to 100 years, the fuelless plant could prove a worthy, long-term investment.
A Maine state committee has been set up to streamline the permit processing, and talks are under way with the Bath Iron Works to prefabricate the turbine plant.
A similar tidl project is further ahead on the Bay of Fundy on the coast of Nova Scotia in Canada. The Tidal Power Corporation, owned by the province, has ordered a $15 million turbine for a plant that will use an already-built causeway at the mouth of Nova Scotia's Annapolis River as a dam. Startup for the 20-megawatt generator is slated for June 1983.
his pilot plant, relying on a novel turbine design never tried at a diameter of 23 feet, could be Canada's only entry into tidal power for some time to come despite the high potential to tap the 44-foot tides in the Bay of Fundy. Two proposed sites, for instance, could produce the equivalent electricity of four nuclear reactors for an estimated construction cost of over $5 billion, according to Canadian studies.
But an electricity surplus is expected in the Maritime Provinces as conventional power plants and Quebec's giant James Bay hydroelectric project come on line. "Prospects look rather uncertain for more projects," says Tidal Power's vice-president, George Baker. Canada's present incentive for harnessing the tides may be to export electricity to the United States in the 1990s, although that may be a risky venture.
France has had a 240-megawatt tidal plant on the La Rance estuary since 1967, and the Soviet Union built a 400-kilowatt plant in 1968 on the Barents Sea. The People's Republic of China reportedly has more than 100 very small tidal plants. "Most countries that have good sites are seriously looking at tidal again," says Warner W. Wayne JR. of Stone & Webster Engineering Corporation in Boston.
Korea, for instance, recently awarded a $2.1 million study on a potential site in the Inchon area. Worldwide, Mr. Wayne says, the potential tidal energy per year equals about 1 billion barrels of oil burned for generating electricity. The US share of this potential energy is less than 1 percent.
Alaska's tidal power sites are particularly uncertain -- the dams would sit over an earthquake-prone fault. And equally troublesome would be the floating ice, beluga whales, and spawning salmon that now enter Cook Inlet. Still, the state is looking to tidal power as one possible energy alternative to two controversial river dam proposals.
The Corps of Engineers, meanwhile, plans to update a 1979 study of Cobscook Bay which showed five sites with a total a 680-megawatt potential would be economically feasible if world oil prices reached $48 a barrel by 1994 (in 1979 dollars). If built, however, the proposed dams would reverse tidal flows into a Passamaquoddy tidal pool. "We warned the Indians that they may have to reverse their turbines," Says an Army Corps spokesman. That issue, responds Dr. Laberge , still remains unresolved.