Annapolis tidal power station is the first of its kind in North America, operated by Nova Scotia Power, and has been producing electricity since 1984.
The capacity of this tidal power station amounts to 20 MW with a daily output of roughly 80-100 megawatt hours, depending on the tides.
The station’s generating cycle starts with the incoming tide by opening the sluice gates to fill the head pond when the sea level reaches the level of the head pond.
When the pond reaches its maximum level, the sluice gates close to trap the seawater. When the gates open, to release the trapped water, water rushes through the gates turning the turbines, that in turn generate electricity.
This power generating cycle continues until the level of the pond drops, which happens in just over five hours. Then the gates close, and the process is repeated twice a day.
The Annapolis system uses a one directional turbine system – electricity being generated only when the water flows back to the sea.
The Annapolis station feeds electricity to the grid every 12 hours and 25 minutes, and the annual production for the grid amounts to 50 GW/h.
Take a look at the animated video explaining how the Annapolis tidal power station works.
Source/Image: NS Power