Wired News :Solar Power Within Your Grasp
Tue, 10 Jul 2001 09:36:31 -0700 (PDT)
A note from bc:
solar and fuel-celled electronic devices
From Wired News, available online at:
Solar Power Within Your Grasp
By Reiner Gaertner
2:00 a.m. July 10, 2001 PDT
FREIBURG, Germany -- Solar energy and fuel-cell power may soon be in
the palm of your hand.
The Fraunhofer Institute in Freiburg has introduced prototypes of
handheld devices that run on either solar or fuel cells -- completely independent from the grid -- that could be in mass production in one to three years.
Right now, handheld manufacturers' promises of total mobility end with
the life of the batteries. Experienced road warriors usually carry several rechargeable battery packs, but even then time is limited to the power on hand. So in an ever more portable and mobile world, batteries are the weakest link.
When it comes to solar modules, space is always an issue: The more
space there is, the easier it is to collect light. Itís also cheaper to use more solar cells with a lower efficiency rate than more efficient solar cells on a smaller surface.
For instance, silicon modules in photovoltaics have efficiency rates
of 28 percent. Although the Fraunhofer Institute in Freiburg has engineered solar modules with an efficiency rate of 23.5 percent in its labs, it is very expensive and complicated to achieve such a high efficiency rate. Fraunhofer decided instead to look into developing products with less efficiency, but cheaper processing costs.
At the InterSolar conference in Freiburg, Fraunhofer showed two
solar-powered prototypes: a Casio palmtop computer and a Siemens mobile phone. Solar modules with efficiency rates of about 20 percent power both devices.
Fraunhofer glued solar modules on top of the palmtop cover, which
generate energy of 1 watt -- enough to charge the rechargeable batteries. The unit may cost about $100 more than a conventional one, said Dr. Christopher Hebling, an energy and technology manager at Fraunhofer.
"Since these solar cells are highly efficient, even low sunlight or a
halogen lamp should be enough to keep the organizer alive," said Hebling. Thus far, the mobile phone is powered only in standby mode.
In the next research round, Fraunhofer will power a more
energy-devouring color palmtop. Although Fraunhofer usually works closely with technology companies, the institute is still looking for commercial companies interested in bringing this technology to market as soon as possible.
"Time to market could be within a year (since) only mechanical matters
have to be solved," Hebling said.
Fraunhofer tries to attract both manufacturers of portable devices
like mobile phones or PDAs and producers of accessories like batteries and solar cells. "Hypothetically," Hebling said, "such solar cells should be producible for about $20 per watt, (with) maybe $20 added for modules and mechanical parts."
To power more energy-hungry laptops or Camcorders, Fraunhofer built
hydrogen-powered fuel cell systems that fit right into the battery slot of the devices. Fuel cells convert hydrogen and oxygen into energy, where the only byproduct is water. For example, the Sony camcorder is powered by a miniature fuel cell with a performance capability of 10 watts at 8 volts, Hebling said.
Hydrogen is stored in a little cigar-shaped metal container, which
holds about 20 to 30 liters of hydrogen.
"This is enough to power a 30-watt laptop computer for about one to
two hours," Hebling said.
A larger container at the bottom of a laptop computer could hold much
more hydrogen, enough to be sufficient for more than 10 hours of operating time, according to Hebling. The container is filled with a metallic powder ("Nano powder"), whose consistency is like meal. Hydrogen is absorbed by the surface of the powder.
But are these fuel cells economically viable?
"In mass production, fuel cells are already competitive with
rechargeable lithium-ion batteries, because they are also high-price technologies," Hebling said. He estimates that metal-hydride containers will be available for about $30 Ė- much cheaper than the $200 for rechargeable batteries. "Whatís missing is a clever distribution method for hydrogen. Why not sell or replace it like soda (dispensers) at gas stations?"
Hebling said the "uneducated consumer" is the biggest concern for the
fuel cell industry. "Batteries are well known and trusted. Hydrogen-powered fuel cells have to be safe and reliable. This has to be proven and communicated."
Another concern for consumers -- wet spots on their pants caused by
water drips produced by the conversion of hydrogen and oxygen into energy -- has already been solved. Fraunhofer has developed a mechanism that converts drops of water into damp air.
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