Harnessing the power of the tides is not a new idea. As early as the 11th and 12th centuries, tidal mills were built in Britain, France and Spain. There were a number of tidal mills active in the 17th century along the Bay of Fundy.
1607: a mill powered partially by tidal energy was built in Nova Scotia, converting roughly 25 to 75 kilowatts of power.
1935: work began (but was later abandoned) on a proposed 350 megawatt Passamaquoddy Bay tidal project along the US-Canada border.
1984: North America’s first and only tidal generating station was built in Annapolis Royal, Nova Scotia. Still in operation, when running the plant produces about 20 megawatts — enough to power about 6000 homes (see below).
2009: North America’s first and only commercial-scale in-stream tidal turbine deployed in Minas Passage: NSPI/OpenHydro 1 megawatt device.
Since 1984, Nova Scotia has been home to one of just three tidal power plants in the world and the only one in the Western Hemisphere (the other two are in France and Russia).
The 20 megawatt Annapolis Tidal Power Plant has a daily output of roughly 80-100 megawatt hours, depending on the tides.
The Annapolis technology is very similar to a conventional hydro-electric dam, called a barrage. The tidal plant funnels water into the tidal generating plant and through a large turbine as it flows out with the ebb tide.