Abstract:  Wind energy is important in the mix of the renewable energy worldwide， and there are many methods and indicators available in the assessment of wind energy resources. Previous studies of wind resource assessments are focused on the resource abundance. In terms of siting offshore wind farms， in addition to the consideration of resource abundances， it is significant to study the stability indicator because it influences not only the maintenance of the offshore turbines， but also the cost for transmitting the generated power to the grid. For this purpose， this paper proposes a new index to evaluate the stability of wind resources (continuity coefficient)， which measures the continuous rated power generation capacity of typical offshore wind turbine. In the practice， the continuity coefficient indicates the continuity and stability of the power generation of offshore wind farms when combining with the information on the wind speed probability distribution and the wind turbine characteristics. Via a hypothesized offshore wind farm constructed in the South China Sea， the present study demonstrates that continuity coefficient is a useful supplement to the commonly used wind resource abundance indicators in the site selection of offshore wind farms. Moreover， it is found in the present study that the proposed index implies a new promising area ignored by other indicators (northeast to the Zhongsha Islands).

Key words: wind energy resource assessment, stability, continuity coefficient, offshore