Sunday, Jun. 08, 2003

Steaming Forward

By JEFF ISRAELY | Larderello

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.

This has led over the past two decades to Enel's development of innovative deep exploration techniques that allowed it to drill down past the hotter (up to 400C) subterranean layers that exist at 3,000 to 4,000 m — twice as deep as earlier explorations. The Tuscan approach of looking deeper is now utilized elsewhere in the world during initial explorations, and will be applied when other shallow wells begin to dry up.

Back at the drilling site, a team of geologists demonstrates the latest push to expand the search for new sources of steam. Borrowing from the most recent oil and gas drilling methods, the geologists study mineral composition and seismic activity to be better able to predict where the untapped wells are located. Still, searching underground is painstaking work. But though this one-hectare clearing in the Grosseto province has so far come up empty, the Enel team is confident from the geological findings that they are about to hit pay dirt.

The other key advances are aimed above ground. Local opposition to geothermal projects in Tuscany is growing because the tourism industry is booming, and property owners have begun to organize not-in-my-backyard campaigns to prevent anything spoiling the idyllic landscape. And rising real estate prices crimp on Enel's effort to expand, too. This "clean" energy source, in truth, falls short of immaculate. The old, large cooling towers, which look like nuclear power plants, spoil the view for kilometers around, and the energy production leaves a sulfuric smell in the air. Still, it is safe compared to nuclear power, hardly pollutes the air, and doesn't consume fossil fuel. A new generation of plants with sleeker design, and chemists' efforts to reduce the odor problem, may help.

For Enel, which is among the world leaders in renewable energy, sights are now set beneath the surface for steam generation in such far-flung locations as Bolivia, Tibet, the Philippines and Hawaii. There are few good sites in Europe outside of Tuscany, with significant geothermal resources in Iceland, which is already well-covered by water and hydrogen power. Still, northern Europeans have been among the world leaders in using geothermal pools directly for such things as space heating, spas, greenhouses and fish farms. Overall, the world's geothermal capacity has doubled to about 8,000 MW in the past two decades, with facilities in 20 countries and an annual production of 50 billion kW-h of electricity. Though its output still trails hydropower production, the cost of geothermal tends to run about the same, though it can run higher depending on the discovery of resources and the size of the project.

But Enel is also one of the main players in a sort of ongoing Manhattan Project for geothermal. Experts for many years have been working in Soultz-sous-Forêts, France on something called Hot-Dry Rock. This process aims to simulate natural geothermal wells by strategically fracturing parts of hot subterranean rock formations to form artificial basins where water can be injected. Says Cappetti: "This is the dream. Then there would be no limit." Experiments over the past two years have extended drilling to a depth of 5,000 meters, but a system for converting the manufactured steam into electricity at an economically feasible rate is considered at least a decade away. In the meantime, Tuscany will keep producing the Chianti — and enough local steam to light the way to the sommelier's cellar.