With their sights on stores of low-grade coal beneath the coasts of England, the ranches of Wyoming, and the fields of Inner Mongolia, entrepreneurs around the world are touting the promise of yet another “unconventional” approach to energy extraction.

 

The technique resembles the hydraulic fracturing technology that has produced an oil and gas boom across North America. (See related interactive, “Breaking Fuel From the Rock.”)

 

The key element in this process, however, is not water. It's fire.