In recent years, the total number of wind turbines operating globally has steadily increased due to the relatively high technological readiness level and relatively low environmental footprint. An additional boost in this trend is expected in the near future, as costs of other “green” energy sources (i.e. natural gas) are rapidly rising. In the present work, the performance enhancement of a small horizontal wind turbine (SHWT) is examined by applying riblet geometries. The SHWTs typically have a disk blade radius of 1.5 to 3.5 m and a hub height of about 15m and operate inside the atmospheric boundary layer in high turbulence conditions. The use of riblets aims at reducing the turbine blade’s skin friction drag by altering the boundary layer characteristics in the near wall region and increasing the SHWT’s efficiency. More specifically, CFD computations are performed on the SHWT, by solving the steady RANS equations, along with the two-equation k-? SST eddy viscosity turbulence model. The presence of riblets in the boundary layer region is modelled as transitional roughness and is implemented on the SHWT by using a dedicated boundary condition for the specific turbulence dissipation rate transport equation. The drag reduction and power output gain of the overall SHWT is estimated to be around 8 % and 1.5 % for the application of optimal-sized riblets.