What happened What goes up sometimes comes back down for no good reason. Two days ago, natural gas refueling company Clean Energy Fuels (NASDAQ: CLNE) exploded higher on news that it had just signed a five-year contract with the Los Angeles County Metropolitan Transportation Authority (L.A. Metro) to supply 47.5 million gallons of renewable natural gas (RNG) "to fuel the nation's largest transit bus fleet." The momentum carried into Tuesday trading, but by Wednesday, it seems Clean Energy was running on fumes, and so the shares took a breather -- down 9.1%. Image source: Getty Images. So what And that's OK. Clean Energy stock is still up 31% from its closing price at the end of last week. While investors can't be faulted for wanting it to go up just a little bit more, I'd say the stock has already been amply rewarded for its good news. Now what Plus, there's more than a fleeting possibility that Clean Energy stock will go up some more. After all, as Clean Energy explained on Monday, its five-year contract with L.A. Metro contains an option for the transit agency to extend the contract's duration for another three years. That's one future catalyst. And as I mentioned on Monday, there's more good news for the company already, specifically, the fact that Amazon.com (NASDAQ: AMZN) just ordered 1,000 natural gas truck engines from a joint venture between Cummins (NYSE: CMI) and Westport (NASDAQ: WPRT). Those truck engines may not hit the roads immediately, but once they do, someone is going to have to fuel them -- and Clean Energy Fuels is the most recognizable name in this space, and the most logical company to do that. The more the transportation industry leans into using natural gas to fuel its big delivery trucks, the better things will get for Clean Energy Fuels. 10 stocks we like better than Clean Energy FuelsWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Clean Energy Fuels wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of November 20, 2020 John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Rich Smith has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Amazon. The Motley Fool recommends Clean Energy Fuels and Cummins and recommends the following options: long January 2022 $1920 calls on Amazon and short January 2022 $1940 calls on Amazon. The Motley Fool has a disclosure policy.Source