How quickly things change. As we moved from 2007 into 2008, we could look back on a year in which energy names were atop the performance rankings among all sectors.

That stellar record continued into the middle of this year, with crude prices moving within striking distance of $150 a barrel before sliding back to what likely will become double digits. Most stocks in the sector have followed suit. Devon (NYSE:DVN) and Anadarko (NYSE:APC), for instance, a couple of stellar independent producers, rose nicely during the first half of the year, only to be slapped down by falling commodities prices.

Among the big names, ConocoPhillips (NYSE:COP) has given up more since June than it gained in the year's first half, and ExxonMobil (NYSE:XOM) is trading about where it was back in March 2007, when crude was hovering around $60 a barrel. The two biggest oilfield service players, Schlumberger (NYSE:SLB) and Halliburton (NYSE:HAL), also have risen and then dropped back.

As you know, there are short- and long-term influences on energy prices and the values of the group's companies. In the short run, the influences include all manner of factors, from weather to dollar values to geopolitical scares to weekly inventory levels. Given this mix, as my Foolish colleague Joe Magyer noted not long ago, in the short run, prices are entirely unpredictable.

Then there's the long term. Most energy seers think we'll need to add significantly to our current global production in the next couple of decades. I have no idea how we'll get there, especially with production slipping in places like Russia and Mexico and at most of the integrated companies. So there's far more price predictability in the longer term, and the indicated direction is to the north.

It's those unpredictable short-term effects that have held sway of late. But

you probably noticed that energy stocks fell 26.5% last quarter alone. Once the financial world regains its grip, energy could be worth your renewed interest. It just may be that its members are again ready to pay increased attention to their long-run influences.

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Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned. He does, however, welcome your questions, comments, or kibitzing. The Fool has well-oiled disclosure policy.