Steaming Forward

Five unshaven men with blackened work boots and thick gloves move toward the giant, greasy drill that has just emerged from beneath the ground. Once the drill is unhinged and swings freely, the crew encircles it and locks onto it a 9.5-m extension that will take this subterranean search for the mother lode even deeper into the earth. It is a rugged if familiar ballet of industrial labor, repeated daily from a perch halfway up a 65-m-high steel tower.

But this time the familiar scene is not taking place on a North Sea rig or in a dusty patch of Saudi desert. Instead, the 2,600-m-long steel drill is boring deep into a picturesque corner of Tuscany, fabled land of Renaissance frescoes and Chianti Classico. And the search is not for crude oil, but for boiling underground wells that can produce clean steam energy.

The central Italian region happens to be the world's unrivaled mecca of geothermal energy production. In 1904 the first experiment ever in steam-powered electricity was conducted in Larderello, when five light bulbs were lit by a dynamo propelled by geothermal liquid. Nine years later, the first steam-generated power plant was built in this area — once known as Valle del Diavolo (Devil's Valley) for the boiling liquid that bubbled out of the ground.

But this swath of central Tuscany is not bathing in nostalgia. It continues to produce 10% of the world's geothermal power — about 4.8 billion kW-h per year — while one-quarter of the entire Tuscan region's electricity comes from local steam energy production, feeding around a million households. Guido Cappetti, who heads the geothermal division for Enel, Italy's giant energy provider, puts it plainly: "Larderello is like a permanently unexploded volcano." The natural — and unique — abundance of hot liquids at relatively shallow depths provides a steady and frighteningly powerful torrent of steam to the surface. This steam, which hits the earth's surface at around 200C, shoots through massive steel pipelines and into turbines to produce electricity.

The concentration of conducive geological conditions has allowed Enel to turn this part of Tuscany into a laboratory for the latest technical advances in this little-known form of environmentally friendly power. Since Larderello was the first area to tap into the boiling underground reserves for making energy (in fact, Tuscany remained the only industrial producer of geothermal electricity until 1958, when New Zealand opened a steam power plant), it was the first to see its underground reserves begin depleting, after registering a significant drop in steam pressure output. A closer study revealed that underground liquid reserves had fallen by 30% from the maximum levels of the 1950s. "We began reaching the boundaries and had to confront the problem of sustainability for the first time," Cappetti explains.