Solar Tower of Power

The story of a 3,280 foot tower of solar power in the Australian Outback.

By Jonathan Kolber

I have recently written of the small -- nanotechnology --
that's enabling solar power to become effective. It does so
by allowing solar cells to be sprayed on like paint,
inexpensively. Also, unlike conventional solar cells, the
nano-solar cells will capture invisible infrared rays,
enabling efficiencies in converting sunlight to electricity
of up to 30%.

Now comes the big. A bold project has begun in the
Australian Outback to build a huge tower that will capture
the sun's energy in a far more efficient way than
conventional solar cells or windmills. It's as simple as it
is awesome.

Funneling Power to Earth

All wind power is really solar power, because the wind's
motion is stimulated by the sun.

The Solar Tower uses this combination in a focused and --
well -- breathtaking way.

Imagine a huge funnel. It's almost flat at the edges and
gradually curves over a distance of several miles until it
reaches a tube in the center. The tube extends quite a
distance down from the rest of the funnel. The tube is like
a 3,280-feet long chimney.

You read that right: 3,280 feet -- more than half a mile.
When finished, this structure will be twice as long as the
world's highest skyscraper.

Now turn that funnel upside down and plant it in the
Australian desert. That's what Enviromission, Ltd. is
planning to do. They've just acquired the land across which
the funnel will spread, 25,000 acres to be precise.

The funnel is made of pieces of clear plastic, so the sun's
rays penetrate it all day long. As the rays penetrate the
plastic, they heat the air below it.

Hot air tends to rise. In this case, rising means moving
toward the center of the funnel. In the middle of the
funnel lies the tube, through which all of the heated air
seeks to escape.

The motion of air outside the tube is slow. Inside the
tube, it's very fast. How? Consider a bellows. A small
squeeze causes a fast puff of air. The reason is that a
large volume of air is trying to squeeze into a small
opening. The only way that can work is for the air to move
faster in the small opening. The Solar Tower uses this
same principle.

As air rises up the tube it accelerates to 35 MPH and
propels 32 wind turbines, which in turn are used to
generate electricity. In the desert, where sunlight is
almost constant during the day, this provides a reliable
source of power. (For nighttime use, some of the excess
power will be diverted to huge arrays of batteries that are
drained at night and recharged during the day.)

The Solar Tower has a huge advantage over conventional
windmills: it generates its own wind.

The length of the tube and overall size of the system are
of great importance. The relationship doesn't scale in a
linear fashion. By that, I mean that a Solar Tower with a
tube five times as long isn't five times as powerful. No,
it's 4,000 times more powerful.

A 650-foot test unit was built in Manzanares, Spain in
1981. It ran for seven years, steadily delivering 50
kilowatts. However, with oil prices at a mere $15 a barrel,
there wasn't much interest in building a larger one.

When constructed sometime after 2006, the 3,280 foot Solar
Tower will generate 200 megawatts. At a typical home
consumption of one kilowatt, this will power 200,000 homes
and reduce the annual production of greenhouse gases by
nearly a megaton.

Brad Collins, executive director of The American Solar
Energy Society, confirms the advantages of the Solar Tower.
He points out that it operates with maximum efficiency
during the hottest times of day, exactly when air
conditioning loads are highest.

Time Magazine even voted the Solar Tower one of the best
inventions of 2002 (though it was older than that).

S. A. Sherif, a professor of mechanical engineering at the
University of Florida, has authored papers on the Solar
Tower and confirms its feasibility. Further, he says they

"essentially produce energy for free."

Now, of course, with oil at $57 a barrel and higher prices
considered realistic, the economics have probably changed
forever.

This isn't some, uh, funnel-in-the-sky pipedream. As I
stated earlier, an Australian public corporation,
Enviromission, Ltd. has acquired $1 million to purchase a
25,000-acre sheep farm which will house the Solar Tower.

Still awaiting funding is the reported $500-750 million
price of actually building the Solar Tower. However, that's
less than the cost of a typical conventional power plant,
and it will require negligible maintenance. Further,
Enviromission claims to have in hand two design proposals
that will significantly reduce the construction cost.

The company claims to have signed a joint venture to
develop several Solar Towers in China.

(Investment disclaimer: I am monitoring Enviromission for
possible investment. However, it is neither a
Transformational Technology nor a Special Situation
purchase at this time. Stay tuned.)

Finally, let's explore how the Solar Tower can completely
meet humanity's needs for electricity by 2050...

Today's materials are limited in tensile strength. A tube
length of 3,280 feet approaches that limit. However, in the
decades to come, nanotechnology will enable production of
materials that make today's steel seem like paper by
comparison.

Tubes many miles high will become possible. At that point,
a handful of Solar Towers can be built on each continent
and produce sufficient electricity to power everything on
that continent.

It will be completely ecological, with no harmful emissions
or side effects. It will run whenever the sun is out,
continuously with very little maintenance. Huge arrays of
batteries will gather and store excess electricity, and
assure adequate distribution of power at night.

Fossil fuels will be relegated to the history books.
Children won't understand what all the hoopla was about.
Tell that to your friends who think the end of oil means
the end of civilization.