Seawater Plus Fresh River Water Plus Nanotech Equals Green Electricity

Research at Stanford has resulted in a rechargeable 'battery' that uses a mix of sea and fresh water and a dash of nanotech to generate electricity. Green power plants at river mouths could be the ultimate result.
By radically tweaking the way saltwater/freshwater batteries work, a research team led by professor Yi Cui has put together a new technology that could supply about 2 terawatts of electricity annually--that's about 13% of the world's current energy needs. The unlikely scenario behind this figure would require every single one of the world's river's mouths to be converted into saltwater power-generation systems. But even at a smaller scale, the technology could result in useful clean power-generation systems anywhere you can bring salt and freshwater together.
The technology works through an incredibly simple process (though it requires a complex explanation). Two electrodes are immersed in a liquid bath that contains freshwater. A very small electric current is applied across the electrodes to charge up the 'battery,' then the freshwater is drained to be replaced by seawater. The seawater's greater concentration of ions from the dissolved salt (60 to 100 times more, in fact) results in an increase to the voltage across the two electrodes--meaning the battery can then be discharged to extract more energy than was initially applied to charge it.
Batteries that utilize this technology already exist, but they can be fragile and typically only rely on one type of ion migration. The Stanford system is much more resilient and also uses both the sodium ions and chlorine ions from the salt in the seawater to generate power--making it more efficient. Greater efficiency still is achieved by building the positive electrode out of manganese dioxide nanorods, which hugely increase the surface area of the electrode (by around 100 times compared to traditional electrode materials).
The idea for power plant production would be to locate huge versions of these batteries where seawater and freshwater are readily available. One could protect sensitive coastal areas from the impact of the plants by using a proportion of the electricity produced to pump seawater inland. Or instead of using river water, a different source of freshwater would suffice--rain run-off, gray water by-products from industry, and possibly even treated sewage.
Does it all sound too good to be true? Well, it gets better: A supply of just 50 cubic meters of freshwater per second could produce up to 100 MW of power, enough to power 100,000 homes. And the waste byproduct is merely a mix of sea- and fresh water, easily pumped into the ocean. Even the nanotech coating on the electrodes is environmentally benign.
[Image via Flickr user Sbeebe].
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Related: How Resource-Strained Cities Can Save Water

"

Algae holds promise for nuclear clean-up

By Richard A. Lovett of Nature magazine

Common freshwater algae might hold a key to cleaning up after disasters such as Japan's Fukushima nuclear accident, scientists said yesterday at a meeting of the American Chemical Society in Anaheim, Calif.

The algae, called Closterium moniliferum, are members of the desmid order, known to microbiologists for their distinctive shapes, said Minna Krejci, a materials scientist at Northwestern University in Evanston, Illinois. But the crescent-shaped C. moniliferum caught Krejci's eye because of its unusual ability to remove strontium from water, depositing it in crystals that form in subcellular structures known as vacuoles--an knack that could include the radioactive isotope strontium 90.

Strontium is very similar in properties and atomic size to calcium, so biological processes can't easily separate the two elements. That makes strontium 90 a particularly dangerous isotope: it can infiltrate milk, bones, bone marrow, blood and other tissues, where the radiation that it emits can eventually cause cancer.

"That's what makes strontium 90 one of the dominant health risks of spent fuel for the first 100 years or so after it leaves the reactor," says Krejci. The radioisotope has a half-life of about 30 years.

Unfortunately, reactor waste and accidental spills can contain up to 10 billion times more calcium than strontium, making it very difficult to clean up the strontium without also having to dispose of a mountain of harmless calcium. "We need a highly efficient and selective method of separating it," says Krejci.

Enter C. moniliferum. The organism has no particular interest in strontium: it mostly collects barium. But strontium is midway between calcium and barium in size and properties, so any of it that happens to be around gets crystallized as well. Meanwhile, even though calcium is far more abundant than either of the other two elements, it is different enough to barium that it gets left behind.

The result is a crystal that is mainly composed of barium, but is massively enriched in strontium.

How do they do that?

Much of Krejci's research so far has focused on trying to work out how the algae generate the crystals, with an eye to making the process even more strontium-selective. For the moment, she knows that the organism isn't purposefully bringing excess barium and strontium through its cell walls. Rather, she says, the crystals appear to form because the vacuoles in which they collect are rich in sulfate. Barium and strontium have relatively low solubility in sulfate solutions, so any barium and strontium that make their way into these vacuoles easily precipitate out to form crystals.

Microbiologists don't know whether the crystals have any function for the organism. Perhaps they are simply waste, forming by accident in vacuoles that serve as storage depots for sulfate, said Krejci.

Whatever purpose the crystals serve, Krejci's research has found that it is possible to enhance the uptake of strontium by tailoring the amount of barium in the algae's environment. This, she says, means that it might prove possible to seed nuclear waste, or a spill of radioactive material, with barium to encourage the algae to grab the strontium--easy to do, she says, because "it would only be a small amount" of barium.

It might also be possible to improve the process by tinkering with sulfate levels in the environment, thereby changing the amount of sulfate in the vacuoles. "Once we learn about how the cells respond to conditions, we can think of more elegant ways to manipulate them," says Krejci.

Once isolated by the bacteria, the strontium could be sequestered in high-level nuclear waste repositories, while the rest of the waste could go to a less expensive lower-level repository, saving space and money. Currently, Krejci says, there are hundreds of millions of liters of stored nuclear waste in the United States alone, much of which contains strontium. "So we know it's a big problem," she says.

Radiation exposure

Krejci and her colleagues have not yet tested how well the algae survive in the presence of radioactivity. But even if the organisms respond poorly, she says, they would probably live long enough to start removing strontium, because the process begins quickly. "The cells precipitate crystals within 30 minutes to an hour," she says. And if more are needed, "they are easy to culture."

Gija Geme, a chemist at the University of Central Missouri in Warrensburg, organized the symposium at which Krejci presented her work. Geme, who grew up in an area of Russia not far from Chernobyl and so has a personal interest in nuclear clean-up, was one of the few people at the meeting who knew the significance of Krejci's presentation in advance: the talk's title, focusing on biomineralization, did not mention Japan, radioactivity or nuclear accidents.

"It's a hot topic right now," says Geme. "But when I put this symposium together, there was no tragedy [in Japan]. I was looking for any studies about sequestration of metals that would be of significance to society."

Geme urges Krejci's team not to spend too much time trying to discover precisely why the algae does what it does before they start testing the process with nuclear wastes.

"Sometimes, just getting it out is very, very important," she says. "I would like to see field studies using actual waste as soon as possible."

This article is reproduced with permission from the magazine Nature. The article was first published on March 30, 2011.

Artificial Leaf Could Be More Efficient Than the Real Thing

By Mark Brown, Wired UK

Speaking at the National Meeting of the American Chemical Society in California, MIT professor Daniel Nocera claims to have created an artificial leaf made from stable and inexpensive materials that mimics nature’s photosynthesis process.

The device is an advanced solar cell, no bigger than a typical playing card, which is left floating in a pool of water. Then, much like a natural leaf, it uses sunlight to split the water into its two core components, oxygen and hydrogen, which are stored in a fuel cell to be used when producing electricity.

Nocera’s leaf is stable — operating continuously for at least 45 hours without a drop in activity in preliminary tests — and made of widely available, inexpensive materials — like silicon, electronics and chemical catalysts. It’s also powerful, as much as 10 times more efficient at carrying out photosynthesis than a natural leaf.

With a single gallon of water, Nocera says, the chip could produce enough electricity to power a house in a developing country for an entire day. Provide every house on the planet with an artificial leaf and we could satisfy our 14-terrawatt need with just one gallon of water a day.



Those are impressive claims, but they’re also not just pie-in-the-sky, conceptual thoughts. Nocera has already signed a contract with a global megafirm to commercialize his groundbreaking idea. The mammoth Indian conglomerate, Tata Group has forged a deal with the MIT professor to build a small power plant, the size of a refrigerator, in about a year and a half.

This isn’t the first ever artificial leaf, of course. The concept of emulating nature’s energy-generating process has been around for decades and many scientists have tried to create leaves in that time. The first, built more than 10 years ago by John Turner of the U.S. National Renewable Energy Laboratory, was efficient at faking photosynthesis but was made of rare and hugely expensive materials. It was also highly unstable, and had a lifespan of barely one day.

For now, Nocera is setting his sights on developing countries. “Our goal is to make each home its own power station,” he said. “One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology.”

Image: sahmeepee/Flickr

Original story from Wired.co.uk

See Also:

• Thin-Film Solar Startup Debuts With $4 Billion in Contracts
• Roofing Company Develops Peel-and-Stick Solar Panels
• How To Make a Solar Cell with Donuts and Tea
• See-Through Solar Hack Could Double Panel Efficiency
• InkJet-Printed, Flexible, Organic Solar Cells?

"

Why Color Matters: Augmented Reality And Nuanced Social Graphs May Finally Come of Age

March 23, 2011

By John Battelle

I read with interest about Color, a new social photo app that was much in the news today. The main angle of coverage was the size of the pre-revenue company's funding - $41 million from Sequoia and Bain. Hell, the company isn't just pre-revenue, it's pre-product....at least for now. Tomorrow the actual product launches.

If it works as advertised, it may well be the first truly execution of augmented reality that truly scales.

I for one hope it works.

The service's founder, Bill Nguyen, is the real deal. He has a particular ability to see around corners, and is a veteran of more than half a dozen startups. So why am I fired up about Color's service? Because I think it bridges an important gap in how we use the web today. And please know that my definition of "the web" is in no way limited to "PC based HTML". When I say web, I mean the digital platform through which we leverage our lives.

OK, now that we've clarified that, what does Color actually *do*? Well, let me explain it as best I can, based on a great piece here by Bruce Upbin (OK and this piece and this one too).

In short, Colors combines the public social graph and instant sharing of Twitter with the "capture the moment" feel of an Instagram or Path. But the real twist is in the service's approach to location. To my mind, Colors has the opportunity to be the first breakout application fueled by the concept of "augmented reality."

Now, let me back up and remind readers of my oft-repeated 2010 maxim: Location is the most important signal to erupt from the Internet since search.

OK, that said, what Colors does is offer up a visual public timeline of any given location, in real time. Every single image captured at any given location is instantly "placed" at that location, forever, and is served up as an artifact of that location to anyone using the Colors application.

Put your brain to that idea for a second, and you realize this is one of those ideas that is both A/ Ridiculously huge and B/ Ridiculously obvious in retrospect. And pretty much every idea that passes those two tests only has to pass a third to Be Really Big. That third test? Execution.

Wait Battelle, you may be saying. What are you on about? I'm not getting it?!

In short, if Color is used by a statistically significant percentage of folks, nearly every location that matters on earth will soon be draped in an ever-growing tapestry of visual cloth, one that no doubt will also garner commentary, narrative structure, social graph meaning, and plasticity of interpretation. Imagine if Color - and the fundaments which allow its existence - had existed for the past 100 years. Imagine what Color might have revealed during the Kennedy assassination, or the recent uprisings in North Africa and the Middle East, or hell, the Rodney King beating?

But that's just the stuff that's important to us all. What Color really augurs is the ability to understand our shared sense of place over time - and that alone is mind-bendingly powerful. Back in 2008 I was struck with a similar concept, which at FM we turned into Crowdfire - a fleeting, early antecedent to the Color concept focused on music and festivals.

To me the key here is plasticity. By that I mean the ability to bend the concept of "social graph" beyond the inflexible "one ring to rule them all" model of Facebook to a more nuanced set of people you might care about in the context of place or moment. I love these kinds of steps forward, because it's just so damn clear we need them.

Trust me on this. If Colors fails, it will be due to execution, and someone else will get it right. Because the world wants and needs this, and the time is now. (By the way, I'm not encouraged by the website, which focuses on group sharing and such. I think the service is way bigger than that. But I guess you have to start somewhere...)

Oh, and note to Facebook, Twitter, and Foursquare: If you don't get this feature into your service, pronto, you will more likely than not be rueing the day Color launched.

Read more: http://battellemedia.com/archives/2011/03/why_color_matters_augmented_reality_and_nuanced_social_graphs_may_finally_come_of_age.php#ixzz1HrLOD55j

Back to the Wild to Build Better, Climate-Resilient Wheat

A genetic archaeologist of sorts, Cary Fowler works to save the wild species threatened by crop domestication.

Fowler is the executive director of the Global Crop Diversity Trust, an organization that seeks to preserve the genetic diversity ofplants in seed banks. By providing a backup of wild varieties for their domesticated crop cousins, seed banks provide insurance in the case of a devastating blow to yields.

Given the losses in Russia and Australia in the past year that constricted global supply and generated conflicts over rising food prices, this insurance against climate uncertainty is critical. "Diversity equals options," said Fowler. "One of the things I know we're going to need is resilience. We're going to have to broaden the genetic base of our crops, because we're going to experience a lot of fluctuation."

Gene banks around the world hold tens of thousands of examples of wild wheat varieties. In the Middle East, Europe and China, where wheat is believed to originate, the number of wild varieties is countless.

Given wheat's importance in the global diet -- providing approximately 20 percent of the world's calories -- a resilient variety is essential. A 1-degree-Celsius increase in temperature correlates with a 10 percent decrease in overall crop yield, said Fowler.

For example, wild varieties could help control plant pollination to adapt to rising temperatures. Many domesticated plants pollinate in the middle of the day. If temperatures continue to rise as predicted, the heat could potentially sterilize the pollen.

But there are certain wild varieties of crops that pollinate in the wee hours of the morning, before sunrise. Less heat would give plants a significant head start to spread their seed.

Legacy from our ancestors -- limited diversity
"In the domestication process for agriculture, our Neolithic ancestors domesticated a rather small portion of wild plants that had around them," said Fowler. "Genetically speaking, that was a bottleneck. We went from having a lot of diversity to limited diversity."

This oversight from our well-intentioned ancestors is biting back now, he said, especially in the face of climate change.

"It's a big drag," said Susan McCouch, a professor of plant breeding and genetics at Cornell University who specializes in finding wild varieties of rice for breeding. "The wheat community has some constraints," compared to other crops.

The paring down of wheat's genetic diversity over generations is not easy to rebuild, but Mark Sorrells, another professor of plant breeding at Cornell, is optimistic: "It is possible to make [these] kind of broad generalizations ... but it is easy to cite examples in the other direction," he said, mentioning the durum wheat used for pasta. "Breeders have many tools to increase genetic diversity, and monetary resources are generally the limiting factor," rather than genetic potential.

Another major drag is a shortage of qualified breeders. The wild varieties are out there, said Fowler. The problem is there is no one going into the field to find them. Plant breeders, especially in the developing world, are scarce, and the time to develop new varieties is running out.

"We're systematically underinvesting," he said. "So we're at a stage now where we don't have the people power to make some of these changes."

When breeding for climate change-related stresses, hurdles center around the fact that plants' response to these stresses is controlled by many genes, said Peter Langridge, chief executive of the Australian Centre for Plant Functional Genomics, and those genetic changes may have different benefits depending on location -- drought in the United Kingdom is not the same as in Kazakhstan.

"The traditional approach is to carefully define the target environment and select for lines in the breeding program in these environments over several years," he said. "Today, we can be a bit more sophisticated." "A bit more sophisticated" turns out to be an understatement.

Given the losses in Russia and Australia in the past year that constricted global supply and generated conflicts over rising food prices, this insurance against climate uncertainty is critical. "Diversity equals options," said Fowler. "One of the things I know we're going to need is resilience. We're going to have to broaden the genetic base of our crops, because we're going to experience a lot of fluctuation."

Gene banks around the world hold tens of thousands of examples of wild wheat varieties. In the Middle East, Europe and China, where wheat is believed to originate, the number of wild varieties is countless.

Given wheat's importance in the global diet -- providing approximately 20 percent of the world's calories -- a resilient variety is essential. A 1-degree-Celsius increase in temperature correlates with a 10 percent decrease in overall crop yield, said Fowler.

For example, wild varieties could help control plant pollination to adapt to rising temperatures. Many domesticated plants pollinate in the middle of the day. If temperatures continue to rise as predicted, the heat could potentially sterilize the pollen.

But there are certain wild varieties of crops that pollinate in the wee hours of the morning, before sunrise. Less heat would give plants a significant head start to spread their seed.

Legacy from our ancestors -- limited diversity
"In the domestication process for agriculture, our Neolithic ancestors domesticated a rather small portion of wild plants that had around them," said Fowler. "Genetically speaking, that was a bottleneck. We went from having a lot of diversity to limited diversity."

This oversight from our well-intentioned ancestors is biting back now, he said, especially in the face of climate change.

"It's a big drag," said Susan McCouch, a professor of plant breeding and genetics at Cornell University who specializes in finding wild varieties of rice for breeding. "The wheat community has some constraints," compared to other crops.

The paring down of wheat's genetic diversity over generations is not easy to rebuild, but Mark Sorrells, another professor of plant breeding at Cornell, is optimistic: "It is possible to make [these] kind of broad generalizations ... but it is easy to cite examples in the other direction," he said, mentioning the durum wheat used for pasta. "Breeders have many tools to increase genetic diversity, and monetary resources are generally the limiting factor," rather than genetic potential.

Another major drag is a shortage of qualified breeders. The wild varieties are out there, said Fowler. The problem is there is no one going into the field to find them. Plant breeders, especially in the developing world, are scarce, and the time to develop new varieties is running out.

"We're systematically underinvesting," he said. "So we're at a stage now where we don't have the people power to make some of these changes."

When breeding for climate change-related stresses, hurdles center around the fact that plants' response to these stresses is controlled by many genes, said Peter Langridge, chief executive of the Australian Centre for Plant Functional Genomics, and those genetic changes may have different benefits depending on location -- drought in the United Kingdom is not the same as in Kazakhstan.

"The traditional approach is to carefully define the target environment and select for lines in the breeding program in these environments over several years," he said. "Today, we can be a bit more sophisticated." "A bit more sophisticated" turns out to be an understatement.