I am going to make a few large, unlinked generalizations and provide a rather long winded introduction to an interesting assessment of the potential for shale gas to change the commercial gas game from its volatile history of price peaks and valleys to one of decades worth of low priced gas. If you are short on time, you might want to scroll down near the bottom of this article. If you have a bit more time and are willing to accept a broad brush approach to a complicated subject, read on.
One of the features of the world energy market from about early 2000 until mid 2008 was a reasonably steady increase in the market price for natural gas. A big driver of that price increase was the cumulative effect of more than a decade in which nearly every new controllable power plant was a Brayton cycle gas turbine - either simple or combined cycle - which are limited to burning hydrocarbon fuels that had essentially no ash content and no machinery damaging contaminants like sulfur or vanadium. There are many valid technical reasons why gas turbines cost less than other heat engine options like Rankine cycle steam plants or diesel engines. Brayton cycle machines require a lot less material input than Rankine cycle steam machines because they are designed to use combustion gases directly and eject those gases into the atmosphere. There is no need for high pressure, leak proof heat transfer piping, no need for fuel handling equipment that crushes solid matter, and less need for capital intensive systems to provide cooling water. In a simple Brayton cycle machine, the exhaust gas carries away the waste heat; from a heat engine cycle perspective, the atmosphere is the heat sink.