Scale Up

BEC is presently developing a commercial demonstration for the scale up of its tidal bridge turbine design.  The company has completed the preliminary design for a 10 meter turbine with the following performance specifications through the tidal range:

Water Velocity m/s	Tip Speed	RPM	Power Output 10 meter MW
1	2.75	5.70	0.02
2	5.5	11.50	0.18
3	8.25	17.20	0.62
4	11	23.00	1.47
5	13.75	28.70	2.88

 

Physical Device Structure (Materials/Construction)

The caisson is constructed of a thin-shelled marine concrete reinforced with steel.  The rotor will be constructed of stainless steel and composite materials.  The rotor shaft will be made of alloyed steel coated with a corrosion resistant coating.

Generator

The Blue Energy turbine will use a variable speed, direct drive, permanent magnet generator.  The generator will have an in line vertical axis orientation to the shaft and its output will either be AC or DC, depending on voltages and distances to the nearest utility grid connection point.

Mooring Systems/Foundation

The foundation for the system will vary with site location. In general, the turbine modules will be gravity mounted on a prepared level crushed rock substrate that will “step down” to accommodate various working depths for turbine banks.  These foundations will accommodate the stacking of turbines for depths of up to 50 meters.  The centerline of the array will be supported by an I-beam and the caisson footings will be supported by pin pilings that will be driven into mud or sandy bottoms, or socket drilled into scoured rock substrates.

Grid Interconnection

All transmission cabling will be run within the tidal bridge and will grid connect to the nearest utility via a land based substation. If the output from the tidal generators is direct current (DC), then this substation will also include an invertor. The turbine modules may be organized into banks through which the electricity will be conditioned to the appropriate local alternating current (AC) frequency and voltage.