Abstract: A vertical axis turbine includes a rotatable hub assembly that is configured to be connected to an energy sink and rotatable about an axis of rotation. At least two blades are mounted on the hub assembly, each blade including a leading edge and a trailing edge, the blades being oriented so that the respective leading edges face in a common rotational direction. Each blade further includes a straight section that is substantially parallel to the axis of rotation and two helical sections, the straight section being interposed between the helical sections, and the helical sections extending at least partially around the axis of rotation.

Abstract: A structural duct apparatus includes a cross flow turbine for use in a fluid flow. The turbine has at least one straight vertical aerofoil blade and at least one helical aerofoil blade slanted toward the direction of rotation. Inner and outer walls of the duct apparatus provide an inner diffuser flow passageway that houses turbine power take off modules with the outer surfaces of the duct influencing flow direction so that where there are at least two ducts an open flow barrage is advantageously formed.

Abstract: A Barrage apparatus is a method and device for extracting energy from flowing fluids in an open flow by means of a submerged barrage or barrages that obstruct and channel flows at increased velocities to downstream turbine power take off modules. Increasing the velocity of the flow increases the amount of power available for extraction thereby providing opportunities to extract energy from low flow sites and facilitate the use of low cost small marine turbines to provide an ecologically sound, efficient and cost effective method of renewable energy extraction from fluid flows.

Abstract: A structural duct apparatus includes a cross flow turbine for use in a fluid flow. The turbine has at least one straight vertical aerofoil blade and at least one helical aerofoil blade slanted toward the direction of rotation. Inner and outer walls of the duct apparatus provide an inner diffuser flow passageway that houses turbine power take off modules with the outer surfaces of the duct influencing flow direction so that where there are at least two ducts an open flow barrage is advantageously formed.