By definition, the act of buying and selling of stocks indicates that each of those securities has both bulls and bears ready to line up behind it. And the same can be said for entire industries -- perhaps none more so than energy.

However, that's a dichotomy that's far more pronounced for natural gas these days than for oil. Crude has been slowly but steadily rising in price for approximately the past 18 months. Indeed, it currently hovers at $90 per barrel. And while we hardly appear headed for $200 or even $150 a barrel during the next couple of years, neither are we apt to chance upon serious forecasts that a downward spiral to, say, $50 or $60, is in the offing.

The slurping sound from gas
But natural gas is quite another story. Only a few years ago, we were convinced that we were about to hear that slurping sound that occurs when a straw reaches the bottom of an empty glass. As most Fools know, however, new natural gas exploration and production technology has allowed us to tap unconventional reserves, rapidly providing more gas at lower prices than expected.

Hydraulic fracturing -- or "fracking" -- involves drilling wells and then pumping millions of gallons of water, sand, and chemicals into the formation to break open the rocks and thereby release the trapped gas. When combined with horizontal drilling, the result has been untold amounts of new natural gas from places like the Marcellus Shale of Ohio, Pennsylvania, New York, and West Virginia, along with the Barnett Shale of North Texas, and the Haynesville Shale of Texas and Louisiana.

But there's one difficulty that's been blamed on this revolutionary process: The undisclosed chemicals used in the fracking process have been held accountable for contaminating nearby water tables. However, most problems ultimately have solutions, and there just might be a way around this ballyhooed water contamination conundrum.

What's in those chemicals?
While the Obama administration is mulling a policy to require gas drillers to reveal the chemicals they use when fracking on federal lands, and the New York State Assembly passed a bill late last month banning the process until mid-2011, the producers are loathe to specify the chemicals they employ, citing the need to maintain trade secrets.

But wonder of wonders, the big oilfield services companies that are involved in formulating the chemicals appear to be reconstituting their mixtures such that they will be environmentally harmless. For instance, Halliburton (NYSE: HAL), which leads the pack in U.S. shale drilling, has developed a fluid called CleanStim, which is comprised of ingredients used in processed foods.

At the same time, Baker Hughes (NYSE: BHI) is producing BJ SmartCare, which the company says employs ingredients that also find their way into condiments and toothpaste. And smaller Houston-based Flotek (NYSE: FTK) appears to have completed trials of biodegradable chemicals that employ citrus products.

Gassing up the trucks
So if these apparently benign ingredients end up diminishing efforts by landowners, environmentalists, and public bodies to stop fracking, the results could include reductions in both transportation fuel costs and greenhouse gases. For instance, Robert Transport, a Boucherville, Quebec hauler of dry and frozen food products has ordered 180 new liquefied natural gas trucks from PACCAR (Nasdaq: PCAR) subsidiary Peterbilt. The trucks are powered by Cummins (NYSE: CMI) engines.

Cummins' compressed natural gas engines, along with its liquefied models, offer comparable power efficiency to diesel engines. I'm wagering that other over-the-road truckers will turn to natural gas-powered equipment, thereby providing positive environmental effects and reduced transportation costs for the companies and their customers.

In the meantime, until prices for dry gas increase materially as a result of its heightened use in power generation and transportation -- as Jack Williams, the president of ExxonMobil's (NYSE: XOM) recently acquired XTO unit predicted last month -- a number of exploration and production companies that heretofore have concentrated on shale gas will likely transition to (higher priced) shale oil. Chesapeake Energy (NYSE: CHK), for instance, is aiming for about 30% of its total production from liquids by 2015 and is shifting its capital spending budget from 90% gas focused down to 35% in two years.

Tough to knock ExxonMobil from first place
My conclusion from these anticipated changes is that they bode especially well for ExxonMobil. The company sits atop the world's public energy companies, boasts globally disseminated crude production, has assumed new leadership in U.S. gas output, and anticipates potential new gas production from the likes of Indonesia, Canada, Germany, and Poland.  

That, it seems to me, is a formidable combination, one that will remain tough to top.

Chesapeake Energy is a Motley Fool Inside Value recommendation. PACCAR is a Motley Fool Stock Advisor choice. The Fool owns shares of ExxonMobil. Try any of our Foolish newsletter services free for 30 days.

We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Fool contributor David Lee Smith doesn't own shares of any of the companies named above. The Motley Fool has a disclosure policy.