(a) Notwithstanding any provision of law, there is levied in addition to any other taxes an additional excise tax on persons selling, distributing, storing, or withdrawing from storage gasoline and motor fuel in an amount not to exceed two cents ($0.02) per gallon and may require every distributor, retail dealer, or storer to pay the excise tax. The additional excise tax imposed pursuant to this part may not be imposed upon the sale of gasoline or motor fuel used in interstate commerce or any form of fuel such as propane gas that is sold for lighting, heating, or industrial use. If the additional excise tax has been paid by a distributor, retail dealer, or storer, the payment shall be sufficient, the intention being that the tax shall not be paid but once. The additional excise tax shall apply to persons, retail dealers, or distributors storing gasoline or motor fuel and distributing or withdrawing from storage, whether the withdrawal is for sale or other use. Sellers of gasoline or motor fuel paying the tax herein provided may pay the tax computed and paid on the basis of sales, and storers and distributors shall compute and pay the tax on the basis of withdrawals or distributions. The county commission shall not impose any tax upon any gasoline or motor fuel when used in essential governmental functions by the State of Alabama or any agency thereof, the federal government or any agency thereof, or county commissions, municipalities, or boards of education.

(b) Any company or retailer of fuel products located or under construction in Macon County that has entered into a formal project agreement for economic development with a local government of Macon County in the past 24 months from the date of this part shall hereby be exempt from this additional two cent ($0.02) fuel tax for a period of not less than 24 months from the date of the final engrossment of this part.