Horizontal Axis Turbine
These turbines are similar in design to traditional horizontal axis wind turbines, but have one major difference. The blades of these turbines spin in both directions to take advantage of the ebb and flow of the ocean, thereby providing a constant electricity output. Similar to wind turbines, these turbines convert the tidal energy into electricity by forcing the blades to spin, which power a generator.
Horizontal Axis Venturi Turbine
Horizontal Axis Venturi Turbines look and function the same as a regular, open turbine, however the Venturi shroud helps channel more tidal power through the turbine blades. A 2006 study found the shrouded system could increase efficiency by a factor of 3.