- The quest for a new form of green energy has taken a
significant step with the purchase of a 25,000-acre sheep farm in the Australian
outback. The huge alternative energy project isn't driven by manure, but
by a 1-kilometer-high thermal power station called the Solar Tower.
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- Announced several years ago, the 3,280-foot Solar Tower
is one of the most ambitious alternative energy projects on the planet:
a renewable energy plant that pumps out the same power as a small reactor
but is totally safe. If built, it will be nearly double the height of the
world's tallest structure, the CN Tower in Canada.
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- The Solar Tower is hollow in the middle like a chimney.
At its base is a solar collector -- a 25,000-acre, transparent circular
skirt. The air under the collector is heated by the sun and funneled up
the chimney by convection -- hot air rises. As it rises, the air accelerates
to 35 mph, driving 32 wind turbines inside the tower, which generate electricity
much like conventional wind farms.
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- But the Solar Tower has a major advantage over wind farms
and solar generators: It can operate with no wind, and 24 hours a day.
Thanks to banks of solar cells, the tower stores heat during the day, allowing
it to produce electricity continuously.
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- Originally slated to be operational this year, construction
of the massive project won't begin until 2006 at the earliest, said Roger
Davey, chairman of EnviroMission Limited, the Melbourne, Australia, company
behind the venture.
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- But the purchase of the farm, which cost $1 million,
near Mildura, New South Wales, is a "very big step" in getting
the project built, Davey said.
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- So far, the main impediment to building the tower has
been the cost, with estimates ranging from $500 million to $750 million.
Davey won't say how much the project will ultimately cost but said the
company is considering two new engineering innovations that will reduce
construction costs and improve efficiency.
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- "It will make the project a totally different business
case," Davey said.
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- The timing couldn't be better. With the price of oil
topping $50 a barrel, many countries are looking for cheap energy and to
cut greenhouse gas emissions.
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- "The time is now here," Davey said. "The
world is looking for a major renewable energy source."
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- It's estimated the Solar Tower will generate 200 megawatts,
enough electricity to power 200,000 homes, and will keep 830,000 tons of
greenhouse gases out of the atmosphere annually.
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- "Solar chimneys (towers) have become a hot area
of research recently," said S.A. Sherif, a professor of mechanical
and aerospace engineering at the University of Florida, who wrote several
papers on the technology in the early 1990s and is the technical editor
of the Solar Energy journal.
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- Although expensive to build, solar towers "essentially
produce energy for free," said Sherif. In addition, the technology
has been proven to work: A 650-foot solar tower was built in Manzanares,
Spain, in 1981 by German structural engineers Schlaich Bergermann and Partner.
Producing 50 kilowatts, it operated for seven years. But with oil prices
at $15 a barrel in the mid-1980s, there was little interest in building
a larger one, Sherif said.
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- And when it comes to solar power towers, size matters.
"The higher the tower, the greater the efficiency," said Sherif.
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- Despite the iconic scope of Australia's Solar Tower project,
private investors may be deterred by the fact it may take 10 years or more
to see a return on an investment. "It will need some government funding
to make it happen," said Sherif.
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- The same was true for nuclear power -- a much more complex
and dangerous technology. However, the U.S. government invested enormous
sums of money to create a new source of energy from the atom. But it wasn't
a particularly wise investment, according to Sherif.
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- "Energy from nuclear power plants remains very expensive
and there is the huge waste problem," he said.
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- And while there's renewed interest in nuclear power,
the world's supply of uranium is limited, while the sun's energy is not,
he said.
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- EnviroMission has signed a joint-venture agreement with
a Chinese company that will build several solar towers in China, said Davey.
"China has big future energy needs and has set renewable energy targets."
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- Other areas -- southern Asia, the Middle East and the
southwestern United States-- have enough solar radiation to be excellent
locations for solar towers, he said.
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- Solar power is at a tipping point, especially on the
utility power plant scale, said Brad Collins, executive director of The
American Solar Energy Society. "The governors of the Western states
have said they want to generate 1,000 megawatts from solar in the near
future," said Collins.
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- "Solar towers are a good fit for power companies
because they operate 24/7 and deliver maximum energy output during the
hottest part of the day just when everyone's air conditioners are on high,"
he said.
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- Despite the advantages of solar power towers, especially
over the long term, it's unlikely one will be built in the United States.
The federal government is pinning hopes on hydrogen as a new energy source,
while continuing to overexploit fossil fuels, said Collins. "Not many
years from now we'll have to choose between using oil for energy, plastics
or fertilizers," he said.
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- Meanwhile, it's important that the Australians get their
Solar Tower built, Collins said. "There's nothing like taking policy
makers and investors to see something like that and kick the tires,"
he said.
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