It was a third party. As I recall it was done by the Israelis during their research into the concept. I was the one who posted a link to the video on the board.
There's been 2 Government level research projects to evaluate the technology. Australian and Israeli. Each of them sounded hopeful that downdraft towers would eventually be used to provide inexpensive electricity to their countries.
Each of them put a reasonable amount of time, effort, and resources into the project. If simple things such as cold air rising or high level winds turning the tower into a soda straw were real issues I would imagine that they would have noticed such things early on.
Plus, there's a University that has a patent for a design that is very similar to the one proposed by Solar Wind. They are, of course, "unique enough" since each design was granted a separate patent.
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it."
Upton Sinclair
