Introduction  Currently the SIA (Sequential Iterated Approach) method and process are used in China′s offshore wind projects bidding stage. The wind turbine manufacture usually presents the tower′s design and guarantees the quantity. The whole support structure is hardly the lightest design. This paper aims to present the IDO (Integrated Design Approach) to search for the global optimum for the whole support structure. It also suggests that the wind turbine manufacture and the design institute could present the whole design plan together in the bidding stage to find the global optimum and reduce the offshore LCoE (Levelized Cost of Energy).

  Method  To investigate the mechanisms of IDO, this paper compared the results of 18 designs with different tower bottom diameters and monopile diameters.

  Result  The results we obtained demonstrate that by IDO the mass of the whole support structure is greatly lighter than the lightest tower design which is obtained by SIA.

  Conclusion  This work provides some guidance for the further offshore wind project bidding plan. To reduce the LCoE of offshore wind projects, the IDO method and process could be adopted to obtain the feasible solution with the lightest whole support structure design.