The following two figures show the hourly probability distributions (and min, max, and mean) for Wind Power Production for 23 months from November 2008 to September 2010 (see source of data document in posts over the last couple of days). These statistics were computed from the 5-minute source power data for each hour of the day. Each hour group had approximately 8,388 data points. Showing the data this way demonstrates how the production of data is massively skewed to low power and are not uniformly distributed around the mean (which some may assume is the case).
Wind Power UK Probability Distribution by Hour Nov 2008 to Sep 2010