Availability Trends Observed at Operational Wind Farms

Over the past decade Garrad Hassan (GH) has assessed the performance of more than 15,000MW of operating wind farms; approximately 15％ of the total worldwide installed capacity. Based on this experience, GH has compiled a database consisting of over 850 wind farm years of availability statistics. High level distributions of average wind farm availability figures are presented, along with trends and plots showing how wind farm availability changes over time. The tendency of wind farm availability to 'ramps-up' over time as teething issues are resolved is highlighted. An insight is given on how wind farms perform as they reach maturity. Commentary is provided on how the presented results can be used to understand the risks associated with availability at all stages of wind farm development from conception to financing and into operation.