(1) The motor fuel equivalent gallon means the following for:(a) Compressed natural gas gallon: 5.66 pounds, or per each 126.67 cubic feet.
(b) Liquefied natural gas gallon: 6.06 pounds.
(c) Liquefied petroleum gas gallon: 1.35 gallons.
(2) Effective January 1, 2026, the following taxes shall be imposed:(a) An excise tax of 4 cents upon each motor fuel equivalent gallon of natural gas fuel.
(b) An additional tax of 1 cent upon each motor fuel equivalent gallon of natural gas fuel, which is designated as the “ninth-cent fuel tax.”
(c) An additional tax of 1 cent on each motor fuel equivalent gallon of natural gas fuel by each county, which is designated as the “local option fuel tax.”
(d) An additional tax on each motor fuel equivalent gallon of natural gas fuel, which is designated as the “State Comprehensive Enhanced Transportation System Tax,” at a rate determined pursuant to this paragraph. Before January 1, 2026, and each year thereafter, the department shall determine the tax rate applicable to the sale of natural gas fuel for the following 12-month period beginning January 1, rounded to the nearest tenth of a cent, by adjusting the tax rate of 5.8 cents per gallon by the percentage change in the average of the Consumer Price Index issued by the United States Department of Labor for the most recent 12-month period ending September 30, compared to the base year average, which is the average for the 12-month period ending September 30, 2013.
(e)1. An additional tax is imposed on each motor fuel equivalent gallon of natural gas fuel for the privilege of selling natural gas fuel. Before January 1, 2026, and each year thereafter, the department shall determine the tax rate applicable to the sale of natural gas fuel, rounded to the nearest tenth of a cent, for the following 12-month period beginning January 1, by adjusting the tax rate of 9.2 cents per gallon by the percentage change in the average of the Consumer Price Index issued by the United States Department of Labor for the most recent 12-month period ending September 30, compared to the base year average, which is the average for the 12-month period ending September 30, 2013.
2. The department is authorized to adopt rules and publish forms to administer this paragraph.
(3) Unless otherwise provided by this chapter, the taxes specified in subsection (2) are imposed on natural gas fuel when it is placed into the fuel supply tank of a motor vehicle as defined in s. 206.01(23). The person liable for payment of the taxes imposed by this section is the person selling or supplying the natural gas fuel to the end user, for use in the fuel supply tank of a motor vehicle as defined in s. 206.01(23). 
