Clean Energy Fuels (Nasdaq: CLNE) shares are jumping like that proverbial cat on a hot tin natural gas depot. Up 10% yesterday on news of a major deal inked with UPS (NYSE: UPS), the shares popped another 7% today -- pretty neat tricks, when you consider how the rest of the market has been behaving this week. But is the run-up for real?

The bull case
Bears may believe Clean Energy is just a flash in the pan, but yesterday, the world's " largest package delivery company" inked a contract to have Clean Energy provide fuel to a new fleet of 48 natural gas-powered delivery trucks operating out of Las Vegas. I have to wonder whether UPS would ally itself with a company that's not "for real."

Further evidence of the company's staying power comes in the form of its "chairman emeritus," the legendary T. Boone Pickens. The Texas oil man may have his bets hedged with major investments in oil companies like Suncor (NYSE: SU) and Continental Resources (NYSE: CLR), but he's also laid a big wager on the future of natural gas with his investments in nat-gas plays such as Chesapeake Energy (NYSE: CHK). (Nor is he alone. Remember when ExxonMobil (NYSE: XOM) acquired XTO? That was a pretty big vote of confidence as well.) While Clean Energy isn't profitable yet, its losses have shrunk the past two years running, and operating cash flow is positive (and growing.)

The bear case
"So what?", growl the bears. The fact you've got to talk about operating cash flow at all clearly means there's no free cash flow to speak of -- and that's true. Clean Energy posted negative free cash flow of $32 million over the last 12 months. Arguably, the fact that the company has averaged cash-burn of $30 million or so ever since 2005 shows Clean Energy is going nowhere fast.

What's more, while it's great to see UPS making investment in clean fuels, and will certainly give the "Greens" a warm and fuzzy feeling -- it's hard to see how a couple dozen UPS vans, lined up outside a fuel depot in the desert, change the financial picture for Clean Energy.

Foolish takeaway
If yesterday's UPS contract is more than mere press release puffery, it's also less than a game-changer for Clean Energy Fuels. There's a reason these shares sell today for roughly the same price they fetched five years ago: Simply put, the company's not much closer to turning a profit now, than it was back then.

Think I'm wrong? Want to prove it? Click over to Motley Fool CAPS and go on record in favor of Clean Energy Fuels -- then add the stock to your Fool Watchlist, to make sure when the good news arrives, you're first in line to hear it.

Fool contributor Rich Smith does not own shares of, nor is he short, any company named above. Check out his latest stock recommendations on Motley Fool CAPS. The Motley Fool has a disclosure policy.

Chesapeake Energy is a Motley Fool Inside Value selection. The Fool owns shares of ExxonMobil and United Parcel Service. Motley Fool Alpha owns shares of Chesapeake Energy.

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