US Patent 9866094 Fluid driven electric generator

A fluid driven electric generator includes a shaft, an inner tubular member rotatably surrounding the shaft, an outer tubular member rotatably surrounding the inner tubular member, a plurality of first blade modules driven by a fluid flow to bring rotation of the inner tubular member only in a first rotational direction, and a plurality of second blade modules driven by a fluid flow to bring rotation of the outer tubular member only in an opposite second rotational direction. At least one power generating unit includes inner and outer rotors coupled with the inner and outer tubular members, respectively, so as to be rotated in opposite rotational directions to induce a current.