There is a Rogallo wing having an aerodynamic sheet having a leading end and a trailing edge. The trailing edge is curved to form a sheet of increasing concavity away from the leading edge. At least two folded edges extend between the leading end and the trailing edge are on opposed sides of the aerodynamic sheet, the two folded edges comprising integral ribs. A wind energy extraction apparatus comprises one or more concentrator wings that react with a flow of wind to induce a drop in static air pressure that is then used to drive one or more impellers and one or more power converters. The one or more concentrator wings are Rogallo wings.