MIMICKING NATURE: An artificial leaf might be able to turn sunshine into storable energy
Image: WeFt via WikiMedia Commons
An artificial "leaf" that collects energy in much the same way as a natural one could provide a day's worth of power for homes without access to an electricity grid.
The leaf, a silicon-based square the size of a playing card, closely mimics the way plants use the process of photosynthesis to create energy. The device is dropped into a bucket of water, or even a muddy puddle, and placed in direct sunlight.
"Leaves are buzzing with electricity," said Daniel Nocera, a researcher at the Massachusetts Institute of Technology who heads the research, "they just don't have any wires in them." Neither does the artificial leaf.
The leaf contains catalysts -- or molecules that accelerate chemical reactions -- that split H2O into hydrogen and oxygen gas. The gases are then sent to a fuel cell, which in turn produces a wireless current of electricity. Hydrogen and oxygen catalysts cover each side of a thin silicon layer -- the same material used in solar cells -- to accelerate the water-splitting reaction. The reaction is visible to anyone looking through a clear glass of water, as gases bubble around the leaf.
The idea of an silicon-based leaf is not a new one: Researchers at the U.S. National Renewable Energy Laboratory came up with a similar idea in 1998. That version, however, was created with expensive rare materials, including platinum, and a had a short life span.
Two years ago, Nocera discovered a way to use cheaper, readily available elements, including cobalt and nickel, that make the new leaf up to 10 times more efficient at creating energy than a natural one.
Nocera says this leaf could provide up to 30 kilowatt-hours of electricity per day, on par with the typical American household's electricity use, according to the U.S. Energy Information Administration. The leaf can produce energy for up to 45 hours in the lab, without interruption. He expects to develop an effective prototype for the leaf in the next two to three years.
Energy for the poor and the mobile
This cheap technology is especially promising to communities without electricity in Africa, Asia and other developing regions. Highly mobile units, like military installations, would also benefit, said Nocera.
"Soldiers are killed guarding on supply lines," he said, and if they could carry their energy around, it could lead to less casualties.
Another plus, says Nocera, is that the water source needn't be pure, an advance from past experiments, and a necessity in places where clean water is a luxury.
The direct solar fuels system this technology employs, said Nocera, avoids the need to store energy in a battery for later use, a method he called a "short-term Band-Aid" compared to large-scale, stationary energy storage.
"If you're going to get to terawatts of storage," as will be needed as energy demands continue to rise, especially in developing countries, "there's not going to be enough batteries, because they're not going to have enough energy [storage]."
While the technology, like traditional solar cell technology, still encounters the drawbacks of cloudy days, said Nocera: "It shouldn't stop you from trying to not use fossil fuels and ignore the sun."
Nocera presents his findings today at the American Chemical Society's annual meeting in Anaheim, Calif.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
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10 Comments
Add Comment"Can an artificial system to turn sunlight into storable energy?"
Reply | Report Abuse | Link to thisI seems a certain SA editor needs to attend grammer school.
Did you try nickel-iron? Still cheaper.
Reply | Report Abuse | Link to this"I seems a certain SA editor needs to attend grammer school."
Reply | Report Abuse | Link to thisIt* seems a certain SA (Smart A$$) needs to learn how to spell. If you're going to be a douche you could at least be a correct douche.
Tough croud :)
Reply | Report Abuse | Link to thisI get so excited when I read these articles that hold so much promise (just out of reach). I wish SA authors would be more pragmatic and identify what obstacles need to be overcome. Is this technology lend itself to typical manufacturing practices and processes? Is there any problem in obtaining funding for commercialization?
Reply | Report Abuse | Link to thisCould they state that energy is stored indefinitely in chemical form, rather than imply it? Are there losses or are leaks more possible for long term storage because of the small size of the hydrogen atoms? Is this strictly stationary, or does it lend itself to mobile transportation applications? Can the playing card size be scaled up for commercial applications, or strung together like cells of a battery?
I appreciate being made aware of new technologies and new possibilities, but I just end up with an appetizer, but no dinner, let alone dessert.
If this tech produces hydrogen, what does it cost for a fuel cell to use it. Do we have enough platinum for wide scale implementation of fuel cells? I guess I am left wondering where the problems are, because frankly, I am not confident in the author's claim of two or three years, or even in the source of that claim.
How big is the leaf? Solar radiation in good conditions contains about 1 killowatt per M2 per hour of energy. Nothing can capture more than about 25 or 30% of that energy as electrical energy, so me thinks it needs to be a bigger leaf than from any book I have ever seen. Without any critical detail, this sounds like another puff piece.
Reply | Report Abuse | Link to thisThe article says 'about the size of a playing card.'
Reply | Report Abuse | Link to this"Crowd"
Reply | Report Abuse | Link to thisI'm with Sigma Eyes on this one - everyone interested in renewable energy is desperate for good news. The idea of a cheap photo -electrolytic process sounds great - but the article falls down when we
Reply | Report Abuse | Link to thishear unrealistic claims made - playing card size leaf - "this leaf could provide up to 30kwh of electricity a day. - how many leaves? As a science teacher who has demonstrated the electrolysis of water using a platinum catalyst for over 30 years I'm excited at the prospect of much cheaper cobalt/ nickel catalysts. I guess what I'm saying is that I'd like to hear a more realistic assessment of this "exciting" development.
cheers
Hi,
Reply | Report Abuse | Link to thisWhy no numbers behind this announcement?
First question any scientist should ask is how much power per square meter?
The first questions any business person should ask is how much $ per square meter?
Without these numbers this announcement mean very little on it's own.
Still I am optimistic about this, but can't get to excited with the details as provided.
-E