What: Shares of Clean Energy Fuels (CLNE -0.87%) jumped more than 12% yesterday following a rally in oil prices that lifted the entire energy sector.

So what: In reality, oil prices aren't directly correlated with the success of Clean Energy Fuels, as the company deals exclusively in natural gas. However, as a company in the energy space, it will likely see some gains on days with higher oil prices simply because it's a part of energy indexes and ETFs.

The real driver for Clean Energy Fuels long term is the price spread between refined petroleum prices such as diesel and natural gas. Since the company's business is built on developing the fueling infrastructure for natural gas vehicles, the higher the price of diesel in relation to natural gas, the better. Over these past couple of trading days, oil prices have increased much faster than natural gas, which bodes well for that diesel/natural gas spread. It should be noted, though, that this is only a couple of trading days, and it's not out of the realm of possibility to see oil prices lose everything they have gained in just as short of a time. 

Now what: Clean Energy Fuels may have gained 12% yesterday, but keep in mind that the company's shares are still down by more than half since its IPO in 2007. Building out the assets necessary to make natural gas a viable alternative to diesel for fleet vehicles and long-haul trucking -- two of Clean Energy Fuels' largest markets -- is going to take a long time and a lot of capital spending to get it done. So investors need to take this into account when either looking at or owning shares of Clean Energy Fuels. There is a big opportunity there, but you will need to be very patient to let it develop.