Tenn. Code § 7-5-102
It is hereby declared that a clear need exists in metropolitan areas of Tennessee for improved transportation and navigation for the movement and transportation of people, goods and merchandise, and for the creation of expanded employment opportunities through the promotion of commerce and industry, with minimal pollution, which requires that such metropolitan areas have the option of placing the central operation and financing of such metropolitan port and development agencies within metropolitan instrumentalities, and that such instrumentalities have the authority to acquire from the state, or other owners, real and personal property, and to develop, manage and operate the same for economic and industrial development. It is hereby declared that port authorities created pursuant to this chapter are public and governmental bodies acting as agencies and instrumentalities of the creating and participating municipalities; and that the acquisition, operation, financing and disposal of ports, lands, industrial and other related facilities are hereby declared to be for a public and governmental purpose and a matter of public necessity. The property and revenues of the authority or any interest in the property and revenues shall be exempt from all state, county and municipal taxation.
T.C.A. § 7-5-102