An authority shall have power to issue bonds from time to time in its discretion, for any of its corporate purposes, including the issuance of refunding bonds for the payment or retirement of bonds previously issued by it. An authority may issue such type of bonds as it may determine, including (without limiting the generality of the foregoing):
1. Bonds on which the principal and interest are payable: a. Exclusively from the income and revenues of the project or facility financed with the proceeds of such bonds; or b. Exclusively from the income and revenues of certain designated projects or facilities whether or not they are financed in whole or in part with the proceeds of such bonds; or c. From its revenues generally.
2. Bonds on which the principal and/or interest are payable solely from contributions or grants received from the federal government, the Commonwealth or any other source, public or private. Any such bonds may be additionally secured by a pledge of any grants or contributions from the federal government, the Commonwealth or any political subdivision of the Commonwealth, or other source, or a pledge of any income or revenues of the authority, or a mortgage of any particular projects or facilities or other property of the authority. Neither the commissioners of an authority nor any person executing the bonds shall be liable personally on the bonds by reason of the issuance thereof. The bonds and other obligations of an authority (and such bonds and obligations shall so state on their face) shall not be a debt of the Commonwealth, or any political subdivision thereof (other than the issuing authority), and neither the Commonwealth nor any political subdivision thereof (other than the issuing authority) shall be liable thereon, nor shall such bonds or obligations be payable out of any funds or properties other than those of the authority. The bonds shall not constitute an indebtedness within the meaning of any debt limitation or restriction. Bonds of an authority are declared to be issued for an essential public and governmental purpose.