It’s a dead-calm antipodean winter’s day, the silence of this vast ranch called Tapio Station broken only by the cry of a currawong bird. Davey, chief executive of Melbourne renewable-energy company EnviroMission, aims to break ground here early next year on the world’s first commercial “solar tower” power station.
“The tower will be over there,” Davey says, pointing to a spot a mile distant where a 1,600-foot structure will rise from the ocher-colored earth. Picture a 260-foot-diameter cylinder taller than the Sears Tower encircled by a two-mile-diameter transparent canopy at ground level. About 8 feet tall at the perimeter, where Davey has his feet planted, the solar collector will gradually slope up to a height of 50 to 60 feet at the tower’s base.
Acting as a giant greenhouse, the solar collector will superheat the air with radiation from the sun. Hot air rises, naturally, and the tower will operate as a giant vacuum. As the air is sucked into the tower, it will produce wind to power an array of turbine generators clustered around the structure.
The result: enough clean, green electricity to power some 100,000 homes without producing a particle of pollution or a wisp of planet-warming gases.
“We’re aiming to be competitive with the coal people,” says Davey, 60. “We’re filling a gap in the renewable-energy market that has never been able to be filled before.”
With a solar tower, there’s no fuel to dig out of the ground, transport, or dispose of, no smog, no scarred landscapes from open-pit mining. The sun rises every day and is not subject to embargoes, geopolitics, or commodity markets.
And once the solar tower’s capital costs are paid off, the price of producing electricity should drop dramatically, as operating and maintenance costs are expected to be minimal. Despite its monolithic scale, the technology behind the tower is based on an elemental scientific truth: Hot air rises. The solar tower’s only moving parts are its turbines.
But out at Tapio Station, Davey insists that the solar tower will be built whether or not the government gives EnviroMission $75 million. “This used to be a dream,” he says, staring out at the horizon where the tower will rise. “Then it became a concept. Now it’s becoming reality.”