Abstract: The invention relates to a turbine for generating electricity from a fluid current, comprising: a central bulb (2); first and second groups of blades each mounted on the bulb (2); the first group of blades being arranged to rotate in a first direction under the action of the current, and the second group of blades being arranged to rotate in a second direction opposite the first under the action of the current, the blades of said second group also being arranged to rotate in the space delimited by the blades of the first group. The first and second groups each comprise at least two helical blades (42, 52) and at least two maintaining blades (41, 51). In each of the first and second groups, the number of helical blades (42, 52) is equal to the number of maintaining blades (41, 51): the bases (41a, 51a) of the maintaining blades (41, 51) are fastened to the bulb (2) and extend essentially perpendicularly relative to the bulb (2).