An improved transverse axis fluid turbine and system thereof are disclosed. The turbine has a base structure, rotor rotatably attached to the base structure, and at least three blades rotatably attached to the rotor. The blade has an elongated member, having first and second ends, and a blade member, the first end being rotatably attached to the rotor and the blade member is attached to the second end. The first end has a helical gear. An actuating device is disposed in the rotor and engages with the helical gear with a corresponding gear to control and actuate rotation of the blade. The rotation is controlled to maximize the effective exposed area of the blade when the blade moves in the direction of the flowing fluid and minimize the area when the blade moves thereagainst. The actuating device can be controlled by a direction vane to accommodate changes in direction of fluid flow.