The zigzag route to success

DEPENDING on your point of view, hydraulic fracturing—or “fracking”—is either the future of clean, natural gas or an environmental apocalypse. Fracking liberates gas trapped underground by drilling sideways from vertical well-shafts into horizontal layers of shale rock. Millions of gallons of a cocktail of water, sand and chemicals are injected into the horizontal wells at high pressure, fracturing the shale, releasing the gas—and causing violent protests in Europe and parts of America.