On Tuesday, Clean Energy Fuels (CLNE 4.53%) and General Electric (GE 8.28%) announced a "collaboration to expand the infrastructure for natural gas transportation in the United States."

Specifically, Clean Energy is buying a pair of ecomagination MicroLNG plants from GE -- small modular units designed to liquefy natural gas for use as fuel in specially designed automotive vehicles. Exact purchase terms were not disclosed, but GE said it is providing up to $200 million in financing for the purchase.

For its part, Clean Energy will use the plants to produce fuel for a chain of liquid natural gas fueling stations it intends to build, providing fuel for LNG-capable tractor-trailers plying the nation's highways. Clean Energy aims to have 70 such fueling stations built by the end of this year. The GE MicroLNG plants will not be up and running until 2015, and even then will produce no more than 250,000 gallons of LNG per day. Ultimately, the companies say the plants can be expanded to produce up to 1 million gallons per day if demand warrants.

The companies estimate that the plants will produce enough LNG to replace conventional diesel fuel usage in "approximately 28,000 heavy trucks."

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