Ala. Code § 11-62-19
Any authority and all contracts made by it shall be exempt from the laws of the state governing usury or prescribing or limiting interest rates, including, but without limitation to, the provisions of Chapter 8 of Title 8, as such laws may at any time be amended. Further, any payment payable directly or indirectly by any user pursuant to any lease, installment sale contract, loan agreement, or other contract to which an authority is a party, any payment pursuant to any authorized purpose obligation or any payment pursuant to any other obligation constituting the source of payment for any obligation of an authority which, in any such case under the laws of the state in effect at the time, constitutes interest, or a payment in the nature of interest, shall be exempt from all such laws of the state governing usury or prescribing or limiting interest rates.
Ala. Code § 11-62-19 (1975)