Artificial leaf could debut new era of 'fast-food energy'

Nov 30, 2011

Technology for making an "artificial leaf" holds the potential for opening an era of "fast-food energy," in which people generate their own electricity at home with low-cost equipment perfect for the 3 billion people living in developing countries and even home-owners in the United States. That's among the prospects emerging from research on a new genre of "electrofuels" described in the current edition of Chemical & Engineering News, the American Chemical Society's weekly newsmagazine.

In the article, C&EN Senior Correspondent Stephen K. Ritter describes research on electrofuels, made by using energy from the sun and renewable ingredients like water and carbon dioxide, reported at a gathering of experts sponsored by the U. S. Department of Energy's Advanced Research Projects Agency (ARPA-E). Created in 2009 by the American Recovery & Reinvestment Act, ARPA-E is funding electrofuels research, with the goal of developing technologies that improve on nature's approach — photosynthesis. Electrofuels is one of 12 programs funded by ARPA-E.

The artificial leaf is one of the electrofuels technologies. Made of inexpensive materials, the leaf breaks down ordinary water into the oxygen and hydrogen that can power an electricity-producing fuel cell. Just drop the credit-card-sized device into a bucket of water and expose it to sunlight. With the cost-conscious technology, one door-sized solar cell and three gallons of water could produce a day's worth of for a typical American home. The article describes a range of other electrofuel technologies, including ones based on engineered microbes, being developed in the quest for new ways of making fuels.

Explore further: Researchers create materials that reproduce cephalopods' ability to quickly change colors and textures

More information: “Electrofuels Bump Up Solar Efficiency” cen.acs.org/articles/89/i48/El… olar-Efficiency.html

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Eikka
not rated yet Nov 30, 2011
With the cost-conscious technology, one door-sized solar cell and three gallons of water could produce a day's worth of electricity for a typical American home.


A "door sized" solar panel would produce just about enough electricity to charge up a car battery in one day.

A typical American home consumes 40 car batteries worth per day.

Three gallons of water yields 422 grams of hydrogen, which yields 14.6 kWh of energy, so that assumes that the solar panel has a daily average power of 600 Watts, or 1200 Watts for 12 hours of sunlight per day, which is slighly more than what the sun actually gives you.

The numbers in this article are total bull.
Eikka
not rated yet Nov 30, 2011
Sorry, three gallons yields 42 kWh. I accidentally calculated for one gallon. Still - that makes the figures even more improbable.

The average American home consumes roughly 30 kWh per day. To generate 30 kWh per day, you need an average power of roughly 1250 Watts, and to achieve that average power you need roughly 12.5 kW worth of solar panels. For a solar density of 1 kW/sq-m and a total efficiency of 12% you then need 104 square meters of solar panels.

That's a bit more than a door.
Callippo
1.3 / 5 (3) Nov 30, 2011
The energetic efficiency of artificial leaf technology is way lower, than the efficiency of solid state solar cells. Not to say about instability of photochemical cells and their much higher cost of installation (they're basically flat heavy cuvettes full of water, organic chemicals and dyes prone to corrosion, bubble formation, overheating and growth of algaes and bacterias). This research is just drain of money for really effective technologies, like the cold fusion, the energy density of which is 100.000x higher! We could fire 100.000 solar cells researchers and replace them with single cold fusion physicist.
mrbunnylamakins
1 / 5 (1) Dec 02, 2011
People even think before commenting. Solar energy is the LEAST efficient of energy. Like electric cars. People pay more for a electric car than a regular car. Where did this money come from?? Was it from going to work in a gas powered car? Not to mention where does the power they use to charge come from a coal plant? How often do have to replace the batteries? What raw materials go into making that car? If made in foreign country? How is that boat powered? How is that Semi truck powered or train to get the car to the show room? Now solar, think about the raw material that goes into making one panel. A friend I know is fully off grid and spends over $2,000 a year to maintain his solar equipment. Some of those converters only good for 3 years give or take and cost a lot. He spends more on maintenance than what we spend on electricity for our house for the year. Question then to ask is how much impact to the environment does making solar cell components???
alfie_null
not rated yet Dec 03, 2011
... efficiency ... is way lower, ... instability ... much higher cost of installation ...

How efficient were the first steam engines? How expensive? How reliable?
This research is just drain of money for really effective technologies, like the cold fusion, the energy density of which is 100.000x higher! We could fire 100.000 solar cells researchers and replace them with single cold fusion physicist.

Right. Then they could all go do something useful and productive with their lives; say, developing trading algorithms for some Wall Street money chasers.
Dis-ing everybody else's non-fusion energy research endeavors doesn't help your cause. Spend your efforts ridding fusion research of its flakes and cranks. And snake-oil salesmen. They do you enormous harm.
Callippo
1 / 5 (2) Dec 03, 2011
The artificial leaf solar cells cannot compete with solid state solar cells, not to say about cold fusion and similar technologies. These technologies are actually quite dirty with respect to the life environment, because they're using rare and toxic metals (cobalt salts) as an electrolyte, they're full of fluids, so that their installation costs is much higher, not to say about their recyclability. The hydrogen formed is explosive and prone to leaking. They're prone to overheating, bubble formation, growth of algae.

Whereas I do appreciate the relative progress in photoelectrochemical research, these cells are still in very rudimentary stage of their development and their effectiveness is corresponding. It's difficult to find an electrochemical system, which is both good in photovoltaic, both in electrochemistry and water splitting. The production of electricity and electrolysis of water is better to achieve in separated processes.
Callippo
1 / 5 (2) Dec 03, 2011
The stability of artificial leaf is not higher, than the durability of real leafs and they must be replaced periodically. Not too say, the production of hydrogen directly inside of photocells is disandvantageous from construction reasons: the bubbles of hydrogen and oxygen formed are shielding the light from electrodes, they must be separated carefully for not to form explosive mixture and they prohibit the circulation of electrolyte in pipes. The generation of hydrogen and oxygen mixture is dedicated compact electrolyser powered with solid state solar cells is much more safe and advantageous: you can achieve high pressure and separate the gases more easily by their production at single place, not at the surface of the whole roof covered with "artificial leaves".
Nerdyguy
1 / 5 (6) Dec 03, 2011
People even think before commenting. Solar energy is the LEAST efficient of energy. Like electric cars. People pay more for a electric car than a regular car. Where did this money come from?? Was it from going to work in a gas powered car? Not to mention where does the power they use to charge come from a coal plant? How often do have to replace the batteries?


You raise some good points. But, that's why there are "early adopters" for new technology. I'm perfectly happy to sit back and watch friends of mine that are bleeding-edge adopters buy the latest gadget the moment it comes out. I get it 2-3 years later when the price is 1/10th of what they paid.

It's no different here. Solar keeps getting better. It won't get better unless money is spent on research and people buy the products. No one is forcing them to do this, at least not in the U.S.
Nerdyguy
1 / 5 (6) Dec 03, 2011
Sorry, three gallons yields 42 kWh. I accidentally calculated for one gallon. Still - that makes the figures even more improbable.

The average American home consumes roughly 30 kWh per day. To generate 30 kWh per day, you need an average power of roughly 1250 Watts, and to achieve that average power you need roughly 12.5 kW worth of solar panels. For a solar density of 1 kW/sq-m and a total efficiency of 12% you then need 104 square meters of solar panels.

That's a bit more than a door.


Valid points all.

I suspect the real market, especially in the early stages of development, would be here:

perfect for the 3 billion people living in developing countries


Many of these people have little electricity, inconsistent electricity, or no electricity at all. If the price point is sufficiently low, it would be a far better solution than any other option they have. And please don't say cold fusion, callipo. lol.
Nerdyguy
1 / 5 (6) Dec 03, 2011
The artificial leaf solar cells cannot compete with solid state solar cells,


Is this based on your extensive research on the subject?

How many of you actually read the paper?
Callippo
1 / 5 (1) Dec 03, 2011
I'm talking about "artificial leaf" technology of David Nocera here and I'm expert on this subject.

But you cannot get the comparison just from reading of the single paper. You should know all alternative technologies as well for being able to judge their prospectiveness.
mayan
1 / 5 (1) Dec 12, 2011
The numbers in this article are total bull.

hi Eikka lady but it still produces useful energy instead of wasting sun's heat
mrlewish
not rated yet Dec 12, 2011
Sorry, three gallons yields 42 kWh. I accidentally calculated for one gallon. Still - that makes the figures even more improbable.

The average American home consumes roughly 30 kWh per day. To generate 30 kWh per day, you need an average power of roughly 1250 Watts, and to achieve that average power you need roughly 12.5 kW worth of solar panels. For a solar density of 1 kW/sq-m and a total efficiency of 12% you then need 104 square meters of solar panels.

That's a bit more than a door.


Your math is awful. It only takes about 400 square feet of solar panels to supply power to the average American Home. You might want to check industry information/stats before you go spouting misinformation off.