"They are true entrepreneurs who happen to make great pizzas," Pickens told CNBC via email. "They have big expansion plans, and a big idea—using a clean, safe and abundant American resource to cook their product. Anyway you slice it, that's good for them, and it's good for America."
This is the first time Clean Energy Fuels has partnered with a mobile food truck, said Peter Grace, the company's senior vice president of sales and finance. More common users include garbage trucks and buses.
"We're always looking for new opportunities to use natural gas as a transportation fuel and other applications that help clean up the environment," Grace added.
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Neapolitan operates eight company-owned food trucks selling individual pizzas ranging from $7 to $13. Three physical stores are set to open in New York City by early next year.
Although small, the company has an ambitious expansion plan to add 25 additional food trucks in Austin and Houston, Texas; California's Venice Beach; Boston, Atlanta, and Philadelphia. The financing will come from Clean Energy, and Crespo hopes it will all be franchised.
By the end of 2015, Neapolitan aims to have a total of 125 trucks. The company also expects to open 50 brick and mortar units, as well as 10 regional distribution centers, it said.