Atlantic Canada"s Bay of Fundy has some of the world"s highest and most powerful tides. Every day, 100 billion tonnes of seawater surge in and out of the bay - a perfect source of clean, reusable alternative energy, if it can be properly harnessed.

Tidal power isn"t new, of course; small grain mills were powered by tides in Europe centuries ago. But tapping into the reliable, natural ebb-and-flow of water to generate electricity didn"t begin until the 1960s.

In 1984, Nova Scotia opened a small plant that takes advantage of the massive Fundy tide as it rushes up the Annapolis River, funnelling the surge through turbines to generate power. That Annapolis plant produces about 20 megawatts a day, enough to power about 4,000 homes.

Now Nova Scotia is preparing for a much bigger Fundy project, one that is unique to North America and could eventually produce 100 MW of electricity, about 10 per cent of the province"s peak load.

The $50-million pilot project, set to begin by next fall or the spring of 2010, will be different from previous tidal efforts not only in size but also in method.

Rather than pushing water through turbines in the "barrage" style of a hydroelectric dam, three experimental turbines will be dropped into the deep waters of the bay and will operate more like underwater windmills.

"If it"s done the way we think it could be done, residents of Nova Scotia wouldn"t know that the tidal farm existed," says James Taylor, general manager of environmental planning and monitoring at Nova Scotia Power Inc. in Halifax.

The provincial government has chosen three companies to take part in what"s called the Fundy Institute of Tidal Energy. The project will test three turbines for at least two years and feed about four MW to the province"s electrical grid for immediate use - something other trial projects don"t do.

A project at Race Rocks off Vancouver Island, for example, charges storage batteries but the power isn"t used commercially.

"Most projects to date have just been burning off energy," says John Woods, vice-president of energy development at Minas Basin Pulp and Power Co. Ltd. of Hantsport, N.S., which will manage the Fundy project.

The test site will be in the Minas Passage, just west of Black Rock. The first challenge will be to put the massive turbines in the water; then underwater cables six-to-eight inches in diameter will be run about three kilometres to shore, where a small facility will feed the turbines" energy to the power grid.

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