When you think of the future of solar power, you normally envision flat panels out in some massive field, blinding the sheep for miles around, or even the small panel up on your roof. What you’re unlikely to imagine is a bloody great big tower in the middle of nowhere.

A not so new energy concept has been unveiled by EnviroMission Limited in South Melbourne, Australia, and it harkens back to an idea demonstrated more than 20 years ago. It is basically small amount of panels on the ground, centering around a massive tower. The collectors warm the air near the surface, and then channel it up the tower. Turbines placed at the bottom make electricity created by the updraft.

“It’s a combination chimney, windmill, greenhouse,” said Kim Forté of EnviroMission Limited, who have designed a kilometer-high tower, and now are hoping to build it somewhere in southwestern USA.

This is basically an improved and improvised version of a solar chimney, a centuries old technique for providing ventilation throughout a home, using an updraft to move air throughout a home. EnviroMission are hoping though, to build much larger structures, in both width and height. The width is obvious, as the more solar panels there are the more chance there is of generating the heat at ground level. But the taller the tower is, the more powerful the suction is going up the chimney.

EnviroMission are looking at building a tower that would reach 800 to 1000 meters in to the sky. It would be surrounded by a greenhouse canopy some 2.5 kilometers in radius. “It is a sizeable footprint [on the land], but with the rising cost of carbon fuels, it’s becoming more commercial,” Forté said.

The advantage of a solar tower over normal solar cells is definitely not efficiency, as a tower is only a tenth that efficient as cells. But on the other hand, a tower is much less expensive to build. A 200-megawatt tower such as described above would cost upwards of a billion dollars. But according to a 2005 industry report, this would imply a 10 cent per kilowatt-hour charge, which equals out to be roughly a third of the cost of electricity generated from solar cells.

Solar power is definitely one aspect of our power generation future. But whether we will look towards efficiency or cost is yet to be determined.

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Photo Credit: EnviroMission Ltd.

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