An Ethanol and/or Solar and/or Wind 
and/or Fusion Future?
(Top Posts - Science - 100908)

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Anything Into Ethanol

Forget about corn-future biofuels will be
made of wood chips and trash.

by Robb Mandelbaum

published online October 3, 2008
  http://discovermagazine.com/2008/oct/03-anything-into-ethanol
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Excerpts:

Biofuels could be a crucial weapon against both
rising temperatures and dwindling global oil sup-
plies. They are made from organic material such
as plants, so they essentially recycle existing car-
bon in the atmosphere instead of releasing new
carbon from the depths of the earth; they are also,
in principle, endlessly renewable.

But the best-known biofuel, ethanol, is looking
decidedly unpromising right now. Today most
ethanol in the United States is made from corn,
using an energy-intensive process that may not
actually save a lot of fossil fuel, and in any case
America cannot produce enough ethanol from
corn to really matter.

Scientists have long tried to devise an efficient
way to make ethanol from a wider range of raw
materials, especially waste products rather than
food. The U.S. government has calculated that
the country could generate 1.4 billion tons of
biomass a year. This could make 100 billion
gallons of fuel or more, enough to meet much
of America's demand for motor gasoline.

One approach to tapping into all that biomass
focuses on cellulose, the material that gives
plant cells their strong walls. The cellulose is
converted into sugar and then from sugar into
ethanol. But despite decades of research, the
technology is still far from commercially viable.

Now several companies, including Coskata
and Range Fuels, say they have cracked the
problem. They are pursuing a different strategy,
one that turns any carbon-rich matter into a gas,
which is then converted to liquid fuel. This
approach can use any organic material, so the
potential sources for this fuel are virtually
unlimited. Soon, the companies claim, they
will be able to refine vast quantities of non-
corn ethanol.

...

Click here to see the rest of
DISCOVERmagazine.com's
special energy coverage.
  http://discovermagazine.com/2008/oct/24-the-future-of-energy

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Powering the Planet With Sun-Harnessing Balloons

One innovator says the greatest threat to a clean-
energy world is kids with BB guns.

by Fred Hapgood

published online September 19, 2008
 
http://tinyurl.com/sunharnessingballoons
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Excerpts:

...

A few years back, a group of West Coast engineers
were puzzling over a practical way to tackle the
problem, looking for a hydrocarbon-free, clean,
and renewable energy system that required no
major technical breakthroughs and could be put
to work in the next few years.

The result: the start-up Cool Earth Solar ... and
its new-think technology, an inexpensive plastic-
film balloon a bit over eight feet tall.

Millions of these balloons could hover low over
the landscape, each concentrating sunlight onto
a photovoltaic cell inside, and pumping out elec-
tricity more cheaply than power from fossil fuels,
the company says.

...

Why is solar power a better energy source than
wind, geo­thermal, biofuels, and nuclear? Don't
we need them all?

Solar seems to have the best economics. It cer-
tainly has all the energy we need and will need
for a long time.

What are the potential problems with solar bal-
loons?

It would be nice to put this out in the field and
have it last 30 years. But the thin film won't last
that long, so we intend to replace it every couple
of years. On a 1-kilowatt concentrator, that's a
couple dollars' worth of plastic, so it's not some-
thing that hurts us.

...

By this time next year, we hope to start building
a series of standardized plants, each consisting of
thousands of balloons and about 10 to 30 million
watts in size. [A 30-million-watt plant would have
about 30,000 balloons.]

The goal would be selling electricity directly to
utility companies. A few years from now, we
would like to be adding hundreds of megawatts
of capacity every year.

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High-Flying Windmills Blow Away
Their Ground-Based Cousins

Next-generation turbines may catch
all the energy we need, thousands of feet up.

by Fred Hapgood

published online September 24, 2008
  
http://tinyurl.com/highflyingwindmills
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Excerpts:

Wind power has long been touted as a major
energy resource, but for decades no one knew
how much energy it could actually yield.

Then three years ago Stanford University atmos-
pheric scientists ... did a detailed calculation
based on known patterns of air motion. Using
a conservative approach, they counted only the
energy that could be generated from winds blow-
ing over land at an altitude of 80 meters, the
approximate height of a typical modern wind
turbine.

Under perfect conditions, the total would be 72
trillion watts.

It is a handsome quantity. In 2007 the entire elec-
trical generating capacity of the United States was
just a bit more than 1 trillion watts.

But Archer realized that this number barely hints
at the potential. Wind speed rises with altitude,
and available power rises at the cube of wind
speed. This means that 72 trillion watts is a low-
ball estimate.

A few miles up, a turbine blade could generate
up to 250 times the energy of the same blade
near the ground. The prospect, Archer says, "is
just super-incredibly exciting."

One scheme for harvesting that breezy bounty
comes from Bryan Roberts, an engineering
professor at the University of Technology in
Sydney, Australia, and Sky WindPower, the
San Diego-based company developing his
work.

The team is designing kites with rotors that fly
helicopter-style to altitudes of a mile or more,
where the winds are strongest. Upon arrival,
the rotors switch to generating mode, sending
current down their tethers, which might be many
miles long.

...

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Can Engineers Achieve the Holy Grail
of Energy: Infinite and Clean?

All they need to do is tame 200-million-
degree plasma-without using too much
energy.

by Charles Seife

published online October 6, 2008
  
http://tinyurl.com/fusion-holygrailofenergy
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Excerpts:

For more than half a century, engineers have
been trying to build a miniature sun in a bottle:
a fusion reactor. Now an international team is
embarking on the most intense effort ever to
make it happen. If the group succeeds, we could
soon generate nearly boundless power from an
isotope of hydrogen that is plentiful in our oceans.

That's a big if, though.

...

Researchers from Europe, Japan, the United States,
China, India, South Korea, and Russia are working
to break the power barrier by building the best
plasma container ever devised, known as the Inter-
national Ther­mo­nuclear Experimental Reactor, or
ITER. After more than two decades of planning, the
$15 billion project is finally getting under way in
southern France.

ITER will house a doughnut-shaped magnetic vessel,
called a tokamak, with a diameter of 17 meters [56
feet]. It will be surrounded by superconducting nio-
­bium coils that create magnetic fields 100,000 times
as powerful as Earth's. These fields will do double
duty: They will heat a cloud of hydrogen to the sear-
ing temperature required for fusion while forcing the
resulting plasma to sit in a ring-shaped cloud away
from the tokamak's walls.

The goal of fusion physicists is to use the heat from
a fusing plasma to keep the reaction going indefinitely,
without the need to pump in external energy.

ITER will not quite get to that point, but with luck,
when the reactor is turned on in 2018, it will be able
to hold a burning plasma for five minutes or more,
allowing it to release 10 times as much energy as is
put in. That would make ITER the first fusion reactor
to produce a net surplus of energy. Scientists can then
begin working out how to harvest fusion energy for
practical use.

...

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