A method for installing an offshore wind turbine system includes driving a cylindrical annular monopile or a substructure into the soil. The monopile includes a flanged portion configured to support a wind turbine tower or a superstructure. The flanged portion extends radially from a peripheral surface of the monopile. The method further includes mounting a wind turbine tower directly on to the monopile, wherein the wind turbine is supported by the flanged portion of the monopile.