The first tidal generating station in North America, this station opened in 1984, after four years of construction. It is one of only three such generating stations in the world.
The station uses sluice gates in a long, low dam across the mouth of the Annapolis river to fill a reservoir in the river during high tide, then when the tide becomes sufficiently low, closes the sluice gates and empties the reservoir into the bay, channeling the water past low head turbines which drive alternators, generating electricity. The turbines require a head of only 1.6 metres to begin producing power.
Given that the tide rises and falls twice daily, the plant generates electricity for only 8 to 10 hours per day, in two four to five hour cycles. With the on again, off again cycle the 20 Megawatt plant is capable of generating about 30 gigawatt hours annually, enough to supply about 40,000 homes.
Though the tides further up the bay average 12 metres and can reach heights of 16 metres, the tides here average about 7 metres. This plant is actually somewhat of a pilot project, the first one on the bay, creating data that can be used in the design of more and larger tidal generating projects. One project proposed for the Minas Basin would span eight kilometres, be outfitted with 97 sluice gates, a three-kilometre long powerhouse with 128 double-effect turbines (these produce power on both incoming and outgoing tides), and have an installed capacity of more than 5 gigawatts.
For the complete story on this tidal station, see
Nova Scotia Power