Yet the natural gas revolution has unfolded with no great fanfare, no grand opening ceremony, no ribbon cutting. It just crept up. In 1990, unconventional gas -- from shales, coal-bed methane and so-called "tight" formations -- was about 10% of total U.S. production. Today it is around 40%, and growing fast, with shale gas by far the biggest part.


The potential of this "shale gale" only really became clear around 2007. In Washington, D.C., the discovery has come later -- only in the last few months. Yet it is already changing the national energy dialogue and overall energy outlook in the U.S. -- and could change the global natural gas balance.

From the time of the California energy crisis at the beginning of this decade, it appeared that the U.S. was headed for an extended period of tight supplies, even shortages, of natural gas.

While gas has many favorable attributes -- as a clean, relatively low-carbon fuel -- abundance did not appear to be one of them. Prices had gone up, but increased drilling failed to bring forth additional supplies. The U.S., it seemed, was destined to become much more integrated into the global gas market, with increasing imports of liquefied natural gas (LNG).

But a few companies were trying to solve a perennial problem: how to liberate shale gas -- the plentiful natural gas supplies locked away in the impermeable shale. The experimental lab was a sprawling area called the Barnett Shale in the environs of Fort Worth, Texas.