The Authority shall have the power to borrow money and issue its bonds in amounts the Authority determines to be necessary or convenient to provide funds to carry out its purposes and powers and to pay all costs and expenses incurred in connection with the issuance of bonds. The Authority shall also have the power to issue credit enhancements with respect to local obligations issued to finance or refinance the cost of any project. The total outstanding aggregate principal amount of bonds issued by the Authority and local obligations guaranteed by the Authority pursuant to credit enhancements, that in either case are secured by a capital reserve fund pursuant to the provisions of § 62.1-215, shall not exceed the sum of $1.5 billion without prior approval of the General Assembly. Notwithstanding the foregoing, the Authority shall not exceed the sum of eight million dollars in the total principal amount of bonds outstanding at any one time for the purpose of financing any heavy rail transportation facilities.