A wind energy system 10 comprises a wind tunnel module 12 having openings 14a and 14b at opposite ends. The openings have substantially the same cross-sectional area although the cross-sectional area of the wind tunnel module 12 decreases from the openings 14a and 14b in a direction toward an intermediate portion 16 of the tunnel module. The intermediate portion 16 has a substantially constant cross-sectional area. One or more wind turbines with equal or different number of blades may be mounted in the wind tunnel in or adjacent to the intermediate portion 16. The intermediate portion 16 is bendable to enable the module 12 to conform to a roof 20 of any pitch.