Editor's Note: This is a useful inventory of US wind plants as of 2005. A word of caution, however, regarding the column entitled 'Summer (July-September) Capacity Factor. The 'capacity factor' refers to average energy generation, not a plant's 'effective capacity' (a.ka. capacity value) which measures a plant's energy generation during periods of 'peak demand'. As peak demand normally occurs during the warmest/least windy days, a plant's 'effective capacity' is generally considerably lower than its 'average capacity'. This discrepancy, of course, has significant system wide capacity implications and belies the assertion that wind energy can replace conventional, reliable capacity.