Clean Energy Fuels Corp. has acquired $150 million from a group of investors, one of which is T. Boone Pickens, a founder of the company.

The investments bring the total amount invested in Clean Energy in 2011 to $450 million and adds new support to an expanding natural gas fueling infrastructure in the U.S.

The investments are a result of Pickens' warrants to purchase 15 million shares of common stock at $10 a share. Pickens purchased 1.5 million shares and transferred the balance to the following investors: RRJ Capital, Seatown Holdings, Chesapeake Energy Corp. and Chief Capital LP.

Clean Energy President and CEO Andrew J. Littlefair said the investment is "a tremendous affirmation of both Clean Energy as the leader in natural gas vehicle fueling in America and our America's Natural Gas Highway initiative that is expanding natural gas fueling infrastructure in cities throughout the country."

The shift toward natural gas could mean lower fuel prices for fleet and vehicle owners in addition to less greenhouse gas emissions and less dependence on foreign oil. Currently, depending on the local market, natural gas costs about $1.50 less per gallon than diesel or gasoline, though natural gas vehicles do come with a higher price tag. As for greenhouse gas emissions, natural gas reduces emissions by 30% in light-duty vehicles and 23% in medium to heavy-duty vehicles.

Currently, Clean Energy has operations in CNG (compressed natural gas) and LNG (liquid natural gas) fueling stations, construction and operation of those stations, biomethane production and vehicle conversion and compressor technology. The company fuels more than 25,200 vehicles at 257 locations in the U.S. and Canada.

"We have a significant program underway to develop CNG and LNG fueling stations serving fleets in the long-haul, regional and port trucking markets, as well as for solid waste, transit, airport and municipal transportation nationwide," said Littlefair.