[Dan Day]

and will stand in the center of a massive glass roof spanning seven kilometers in diameter. Despite its size, the technology is simple -- the sun heats air under the glass roof, which slopes upwards from three meters at its outer perimeter to 25 meters at the tower base.

Let's see... An essentially flat circular glass building with 414.2 MILLION square feet of glass... What size army of window washers is it going to take to keep this thing clean as dirt and dust settle down on it?

And one good hail storm could ruin their whole day.

[redbaiter]

What size army of window washers is it going to take to keep this thing clean as dirt and dust settle down on it?

The homeless guy presently hassling you for a windshield wash at every stoplight, would be a good start. Him, and a really big bottle of Windex.

Unfortunately it won't happen because for this to technology to be built would mean the end of the Kyoto treaty. Cheap clean electricity = no more fossil fuel 'crisis' = no more dismantling the US economy in favor of third-world redistributionist socialism and the European style punitive taxes. You're stuck with the homeless guy.

[RightWhale]

Another thing: What will be the effects on farms under the glass? The original artist's concept drawing showed agricultural fields under there.