Sales of compressed natural gas (CNG) and liquefied natural gas (LNG) in Texas have increased 78 percent over financial-year 2014 as measured by increases in tax revenue from the alternative fuels, according to the state Comptroller’s office.

Tax revenue from sales of CNG and LNG motor fuel reached $3.03 million by May 31 for FY-2015, according to Texas Railroad Commissioner David Porter.

“Natural gas vehicles are becoming mainstream faster than expected," Porter said. "These collections are nearly double the amount collected last year at this time."

The state has sold about 20.22 million gallon equivalents of natural gas, which is taxed at 15 cents per gallon equivalent. A “gallon equivalent” is the amount of CNG or LNG with the same energy content as a gallon of gasoline or diesel fuel.

Texas has more than 7,900 natural gas vehicles and 137 natural gas fueling stations, and an additional 44 stations are scheduled for launch in the next 12 to 18 months, according to Porter.