Traditional exploitation of the fossil fuels as primary energy sources put a significant strain on the contrition of environment. Therefore, many countries are introducing regulations regarding fossil fuels utilisation and carbon dioxide emissions. One of the most prominent among the widely considered environmental friendly energy sources is the wind power sector. Rapidly growing demand for the new wind turbine designs creates a demand for a efficient and reliable development tools. The paper presents complex optimisation procedure for optimising the aerodynamic performance of the Vertical Axis Wind Turbine. In the submitted studies, VAWT rotor was defined as a set of vertically oriented blades profiles. The shape of the profiles was based on the 4 digit NACA airfoils. The optimisation procedure was performed with the in-house heuristic optimisation algorithm combined with the commercial software packages. The specific design the VAWT rotor was described by the 4 main design parameters: rotor solidity, blade thickness, blades mounting point and angle of attack of the blades. For the evaluation of the aerodynamic performance of considered VAWT designs, the two dimensional CFD model was developed and utilised. The optimisation was carried out both for the different values of the turbine rotational speeds and different wind velocities. As the utilised two dimensional VAWT model was performing calculations in the transient mode the noticeable computational effort was required. In order to improve the efficiency and reduce computing time, the application of so called Reduced Order Methods - ROMs was investigated. The performed studies resulted in obtaining the near-optimal VAWT designs regarding the specific wind conditions. Also the explored application of the ROMs is discussed.