In addition to estimating future energy production, the time-series energy capture can be used to model past performance. In order to do this, in addition to loading up the appropriate met data, Openwind needs to know the actual turbine availability in order to output what the Openwind model of the wind farm would say the wind farm should have produced over the period in question. This functionality is aimed at closing the loop between pre-construction energy estimates and post-construction performance monitoring.