Valhalla is a growing tribe of storytellers out to proliferate freedom culture
by igniting a global passion for sustainability, self-reliance, and collaborative action.

Chicago power company aims for 1 million smart thermostats by 2020

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I’ve written before about my experiences with a Nest learning thermostat, seeing a 22% reduction in my gas bill one month-even though the Nest replaced a programmable (and programmed!) thermostat.

What I’ve often thought since installing the Nest, however, is how many other homes in my neighborhood could do with one. Given that most of our neighborhood was built out in the 40s and 50s, the homes are incredibly leaky and often hard to weatherize effectively. So simply reducing the amount of time that they are heated or cooled would be a relatively simple (and cheap) way of cutting down on bills.

Heck, after several whiskeys I even managed to convince Lloyd (who has traditionally been skeptical of smart home hype), that smart thermostats are a sensible investment in older, more poorly insulated homes.

Now we’ll get to test the impact of smart thermostats out on a grander scale. As reported by the Washington Post, ComEd-the largest power company in Illinois with over 3.8 million customers-is planning a major smart thermostat push, offering heavy $120 rebates on Nest and Ecobee thermostats that will almost halve the price and should mean payback times of just a year or so for many homeowners. The ultimate plan, says ComEd (and several gas utilities it is partnering with) is to install 1 million units by 2020.

Obviously, a roll out of this magnitude could have a significant impact on power demand among ComEd’s customer base. Some initial independent research commissioned by Nest suggests on average, homeowners can save 10 to 12 percent on heating bills and 15 percent on cooling, even compared to traditional programmable thermostats. (My experience would seem to validate this claim.) And while proponents of the Chicago scheme are claiming it will save 709,000 metric tons of CO2 each year, it would be a mistake to think of this purely in terms of reducing overall energy demand. It’s also about managing when that demand happens.

In a fascinating interview with UK-based Business Green (behind a paywall), Nest’s head of energy Ben Bixby suggested that for Nest this is as much about helping utilities to responsively manage demand from customers, adjusting thermostats (and the increasing number of power hungry devices, like electric car chargers, fridges and washing machines, which are designed to communicate with those thermostats) when demand is high-reducing the need for expensive and often polluting peaker power plants. Here’s how Bixby it to Business Green:

“This is a trend that is only really beginning now, but with the decreased costs of adding connectivity, you’ll see an ever-larger portion of the home, slowly, piecemeal, becoming networked.”

Let’s just hope that this smart home push is accompanied by an equal effort to do the simple things right too. From insulation to caulking, there’s no reason that “smart” and “dumb” home technologies can’t coexist.

 

A new AIDS vaccine is about to be trialled in humans for the first time

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A new AIDS vaccine trial is about to begin in the US, and this one is a little different – the vaccine has been developed over the past 15 years by Robert Gallo, the scientist who first proved in 1984 that HIV triggered the disease.

The phase I trial will involve 60 volunteers and will simply test the safety and immune responses of the vaccine, so we won’t know for a while whether it will be more effective than the other 100+ AIDS vaccines that have been trialled over the past 30 years. But extensive testing has been done in monkeys so far with positive results.

Although there have been some promising vaccine candidates in the past, the challenge with AIDS is that HIV directly infects white blood cells called T-cells, so it literally turns our immune system against us. That means that once the virus has entered a T-cell, it’s invisible to the immune system.

The only chance we have to prevent infection is to trigger antibodies against the HIV surface proteins before that happens – something that’s been equally difficult considering the fact that the retrovirus can regularly change its viral envelope to hide particular surface proteins.

But Gallo and his team at the Institute of Human Virology in the US think they may have now found a moment when the HIV surface protein, known as gp120, is vulnerable to detection – the moment the virus binds with our bodies’ T-cells.

When HIV infects a patient, it first links to the CD4 receptor on the white blood cell. It then transitions, exposing hidden parts of its viral envelope, which allow it to bind to a second receptor called CCR5. Once HIV is attached to both these T-cell receptors, it can successfully infect the immune cell. And at that point, it’s too late to do anything to stop it.

Known as the “full-length single chain” vaccine, Gallo’s vaccine contains the HIV surface protein gp120, engineered to link to a few portions of the CD4 receptor. That goal is to trigger antibodies against gp120 when it’s already attached to CD4 and is in its vulnerable transitional state, effectively stopping it from attaching to the second CCR5 attachment.

And before you say anything, Gallo himself admitted to Jon Cohen over at that full-length single chain vaccine is a “terrible name”.

The trial is being run in collaboration with Profectus BioSciences, a biotech spin-off from the Institute of Human Virology, and Gallo explained that they’ve taken so long to get to this point because they’ve been extremely thorough in their testing on monkeys, and then had to scramble for funding to develop the drug into a human-grade vaccine.

“Was anything a lack of courage?” he asked “Sure. We wanted more and more answers before going into people.”

Let’s hope that caution pays off, and we may finally have a viable contender for an AIDS vaccine on our hands. Watch this space.

Electric car owners wage war over charging spots

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There’s a new face of road rage. She composts her coffee grounds, never forgets her reusable grocery bags, and turns into the Hulk over inconsiderate parking spot use. Meet the electric vehicle driver.

The New York Times reports that a shortage of charging stations is leading to bad blood between some EV drivers. From the Times:

Unlike gas stations, charging stations are not yet in great supply, and that has led to sharp-elbowed competition. Electric-vehicle owners are unplugging one another’s cars, trading insults, and creating black markets and side deals to trade spots in corporate parking lots. The too-few-outlets problem is a familiar one in crowded cafes and airports, where people want to charge their phones or laptops. But the need can be more acute with cars – will their owners have enough juice to make it home? – and manners often go out the window.

You can see why there would be problems. The limited range of electric vehicles – usually around 80 miles – means that drivers often have to recharge using public stations. While these stations are cheap or even free to use, there just aren’t that many of them. There is currently one charger for every 10 EVs, according to the Times, and with the vehicles taking anywhere from 30 minutes to four hours to recharge, people get pissy when you hog the pump.

Naturally, there’s a hierarchy among EV drivers, with all-electric cars like Nissan Leafs getting priority at charging stations (at least, according to all-electric car drivers), followed by plug-in hybrids, which can also run on gasoline. At the very bottom are Teslas, which have a range of several hundred miles and, more importantly, you probably can’t afford. From the Times:

Jamie Hull, who drives an electric Fiat, grew apoplectic recently when she discovered herself nearly out of a charge, unable to get home to Palo Alto. She found a charging station, but a Tesla was parked in it and not charging. She ordered a coffee, waited for the driver to return and, when he did, asked why he was taking a spot when he was not charging. She said the man had told her that he was going to run one more errand and walked off.

“I seriously considered keying his car,” she said.

Next time, we hope she does it.

Brain’s activity map makes stable ‘fingerprint’ – BBC News

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Neuroscientists have found that they can identify individuals based on a coarse map of which brain regions “pair up” in scans of brain activity.

The map is stable enough that the researchers could pick one person’s pattern from a set of 126, by matching it to a scan taken on another day.

This was possible even if the person was “at rest” during one scan, and busy doing a task in the other.

Furthermore, aspects of the map can predict certain cognitive abilities.

Presented in the journal Nature Neuroscience, the findings demonstrate a surprising stability in this “functional fingerprint” of the brain.

“The exciting thing… is not that we can identify people by putting them in an MRI machine – because we can identify people just by looking at them,” said Emily Finn, a PhD student at Yale University who co-wrote the study with her colleague Dr Xilin Shen.

“What was most exciting to me was that these profiles are so stable and reliable, in the same person, no matter if it’s today or tomorrow and no matter what your brain is doing when we’re scanning you.”

Predicting intelligence

Crucially, this fingerprint is based on brain activity – not the organ’s physical structure.

In the the myriad links between our billions of brain cells, and even at the level of a normal MRI scan, we are all physically unique.

But Ms Finn and her colleagues drew a map of each brain purely on the basis of which regions, in each individual, tended to leap into action at the same time. They used data from functional MRI (fMRI), which records subtle ups and downs in the busyness of the brain.

Because it is relatively imprecise, fMRI has not typically been used to compare individual brains. Instead, scientists tend to record from several subjects and average the results.

“We were interested in flipping the traditional fMRI analysis on its head, and not asking what are the commonalities – how do all brains look the same, doing the same task – but rather, does the same brain look the same, regardless of what it’s doing?” Ms Finn explained.

So they took fMRI results from the first 126 subjects of the Human Connectome Project, a huge US initiative to gather data about the brain’s “wiring diagram”. These subjects had all been scanned multiple times, on different days, both while they were resting and while they were occupied by various tests.

Within each of those scans, the researchers looked at what was happening in 268 key spots within the brain: how closely did the ups and downs at this spot match the ups and downs at all 267 other spots?

This produced a profile of the flow of activity in each brain. And that profile was consistent enough that the team could use it to pick out the same individual – more than 90% of the time – from a different set of scans, done on a different day.

They also found that they could use the profile to predict, to a certain degree, how well the subjects did at particular cognitive tests that measured “fluid intelligence”.

This is a type of on-the-spot, untrained reasoning that is measured by some IQ tests. Ms Finn is quick to point out that her technique could never substitute for those questionnaires.

“None of us would recommend a brain scan over an IQ test,” she said. “This is just proof-of-concept that these connectivity profiles are relevant to this very sophisticated cognitive behaviour.”

If these individual maps show strong associations with psychological phenomena, she added, they could prove useful in the clinic.

“This opens the door to predicting things that are harder to tell just by looking at someone, or giving them a test – like risk for different mental illnesses.”

Ones and zeros

Recently, a different study used a very similar technique to show that these brain maps can predict a range of characteristics, from someone’s vocabulary to their income.

One of its authors, Prof Thomas Nichols, said he was not surprised that Ms Finn and her colleagues were able to distinguish individuals.

“What this is getting at is the very high-quality nature of this data,” said Prof Nicholls, a brain imaging statistician at the University of Warwick. He said the data emerging from the Human Connectome Project, which also formed the basis of his study, is “bleeding-edge, state-of-the-art” stuff.

“It’s really, really good and there’s a huge volume of data on each subject.”

Tim Behrens, professor of computational neuroscience at Oxford University, said he was most impressed by the consistency between the resting and task-based maps in the study.

“What is particularly interesting is that the way the brain connects… at rest, is so similar to how it connects during a task – when it’s doing something interesting. That’s what’s exciting about it,” Prof Behrens told the BBC.

By comparison, he said, you would not expect “the pattern of ones and noughts” in a busy computer to reflect the pattern in a computer that is not doing anything.

“It tells you that something about the function of the brain is fundamentally built into patterns of activity that just live there, all the time.”

Follow Jonathan on Twitter

Eating Organic Lowers Pesticide Levels in Children

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Researchers have found that when children eat organic fruits and vegetables, the amount of pesticides in their bodies declines significantly.

Most organophosphorus pesticides have been phased out for residential use, but they are still widely used in agriculture. High doses in agricultural workers can be deadly.

The study, in the October issue of Environmental Health Perspectives, included 20 children living in Oakland, Calif., and 20 in the agricultural community of Salinas, about 100 miles south. The children ate a conventional diet for four days and an organic diet for seven days and then returned to conventional foods for five days.

About 72 percent of their urine samples, collected daily, contained evidence of pesticides. Of the six most frequently detected pesticides, two decreased by nearly 50 percent when children were on the organic diet, and levels of a common herbicide fell by 25 percent. Amounts of three other pesticides were not significantly lower on the organic diet. Levels were generally higher in the Salinas children than in the Oakland children.

“There’s evidence that diet is one route of exposure to pesticides, and you can reduce your exposure by choosing organic food,” said the lead author, Asa Bradman, associate director of the Center for Environmental Research and Children’s Health at the University of California, Berkeley. “But I would never say that conventional fruits and vegetables are unsafe. They’re all healthy.”

 

Solar Panels: Cheap, Free, or DIY?

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I would first like to give credit to cleantechnica.com and planetsave.com for the following information on how to obtain cheap/free solar panels and guides on how to make your own solar panels!

If you live in the Triangle Area, then it is almost certain that you have seen solar panels at either a construction site or on top of street signs. Most often, these are used for low power LED lights so that new traffic signs are more noticeable and so that everyone knows that there is a lane shift or some other issue ahead. For the city and state to continue using solar panels, however, they need to be efficient and effective. So when the relatively fragile solar panels catches a rock on its front face or if they simply age past their prime efficiency, the state is required to swap out the panels.

This means that otherwise decent panels are hauled off, because it is easier to replace than it is to repair. These panels are the panels we will be using.

*CAUTION* It is often times illegal to stop on the side of the highway to look at these panels, so practice safety and caution.

Step one is to obtain all the contact information you can; names and phone numbers will become extremely important. This allows you to look up the companies who supply the DOT with solar panels.

Step two is to actually visit these places, as you will have a much greater chance of walking out with solar panels if you have a face to face meeting, instead of a phone conversation. You need to find out where the panels currently are and if they sent them to another company. Always offer money for the panels, as they will appreciate it, and chances are they may be more willing to give them away for free, especially since they can no longer use them. Even if you end up paying for panels, you will end up saving several hundreds of dollars, maybe thousands.

Step three is to test them with a multimeter. This way you can determine if they are worth using or repairing.

Step four is determining where to place and/or mount the panels. More guides can be found on cleantechnica.com, however, to keep it simple, they have to generally be facing true south and at a certain angle (45 degrees seems to be best for most situations); your panels don’t have to fit the angles or be facing true south, but they are more accurate they closer you get to these positions.

If you are a DIY person, solar cells can be purchased, and with the good backing and patience, you can make your own panels, which cuts out the middle man. A more in depth guide can be found at planetsave.com.

With all this information, I hope y’all are more empowered to begin moving away from Duke Energy and in to a more autonomous, energy independent life!

Sources

Picture: hacknmod.com

Cheap/Free Solar Panels: cleantechnica.com

DIY Solar: planetsave.com

Congress to Eliminate Billions in Wall Street Subsidies to Fund Repair of Nation’s Highways

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Both parties of Congress are in agreement on diverting billions in Wall Street subsidies to rebuild America’s crumbling infrastructure. If you’re by a window, look outside for flying pigs.

Currently, the Federal Reserve pays out a 6 percent annual dividend to roughly 2,900 banks – JPMorgan Chase, Citigroup, Bank of America, and Wells Fargo net approximately $350 million apiece each year from the dividend. These banks own stock in the Federal Reserve as a means of becoming members of regional Fed branches around the country, and unlike other stocks, the big banks are guaranteed to never lose money on their investment in the Fed. For years, the Congressional Progressive Caucus has proposed reducing that dividend to 3 percent in order to pay for repairing American infrastructure. After lying dormant for over a year, it appears that idea has now caught on with Republicans as well.

According to Bloomberg, Senate majority leader Mitch McConnell (R-Ky.) recently told a group of Wall Street executives at a Financial Services Roundtable event that he wouldn’t use his power to remove a new rule that allots funding for federal highways by reducing that dividend to 1.5 percent. The House is now weighing whether or not to back the dividend reduction before highway funding runs out at the end of October. Should the proposal go through, America’s highways would benefit from an additional $17 billion in repairs over the next ten years.

Now, Wall Street is in panic mode.

“The idea that going forward that we are going to pay for our nation’s infrastructure on the backs of one industry sector is a really flawed public policy,” said American Bankers Association president Rob Nichols.

While Fed chair Janet Yellen has taken the banks side, saying she believes the policy “could conceivably have unintended consequences,” Washington prognosticators believe the banks will ultimately have to sacrifice their Fed dividend, and possibly more federal handouts further down the road.

“The industry is in a very dangerous spot because it is a pot of gold,” Karen Shaw Petrou, managing partner of Federal Financial Analytics, told Bloomberg. “With the general political climate I don’t know a lot of people on Capitol Hill that like banks.”

The proposal is likely to pass, as past Republican proposals to fund infrastructure repair included a tax repatriation holiday – allowing corporations to bring back some of the $2.1 trillion stashed in overseas tax havens back to the U.S. at a 5 percent rate rather than a 35 percent rate – a proposal that President Obama has promised to veto in the past. As I previously wrote in The Guardian, the only result that came out of past attempts at repatriation was mass layoffs of workers, while corporations used the repatriated cash to buy back their own stock, driving up the value of the options owned by executives.

Bad of an idea as it is, repatriation still attracted the support of Wall street-backed Democrats like Chuck Schumer, and corporations have lobbied Rep. Paul Ryan (R-Wisc.), the House Ways and Means chairman, to include repatriation in a tax reform package. However, lawmakers predicting an Obama veto are rejecting the idea of repatriation for now and are gravitating toward a solution for America’s highways they know Obama will sign by the end of the month.

The dividend cut has already been included in the Senate’s compromise bill, which will fund highways over the next 3 years. That bill passed by an almost two-thirds margin in July.

C. Robert Gibson is editor in chief of US Uncut. His past work has been published in The Guardian, Al Jazeera America, NPR, and the Washington Post. Follow him on Twitter: @crgibs

Coral Worldwide Threatened By Bleaching

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        Corals worldwide are at risk from a major episode of bleaching which turns reefs white, scientists have confirmed.

 

The bleaching has hit reefs in the Pacific, Atlantic and Caribbean.

The US National Oceanic and Atmospheric Administration (NOAA) warned it may affect over 38% of the world’s reefs, and kill over 12,000 sq km of reefs.

The mass bleaching is caused by rising water temperatures resulting from two natural warm currents and exacerbated by man-made climate change.

Bleaching happens when corals under stress drive out the algae known as zooxanthellae that give them colour.

If normal conditions return, the corals can recover. But the process can take decades, and if the stress continues, the corals can die.

Reefs are under multiple threats including pollution, over-fishing, sedimentation and damage from boats and tourism.

The current worldwide bleaching episode is predicted to be the worst on record as the warming Pacific current, El Nino, increases in strength. Water temperatures are being driven further by a separate natural warm-water mass dubbed the Pacific Blob.

Man-made climate change also contributes, as the oceans are absorbing about 93% of the increase in the earth’s heat.

Additionally, corals face ocean acidification as CO2 emissions are absorbed into the oceans, changing the pH of seawater.

Some scientists are warning that spectacular reefs as we know them – with branching corals and fan corals – are unlikely to survive changes in temperature and pH by the end of this century. That’s if they are not killed first by other damaging local activities.

The current bleaching episode was predicted by NOAA and confirmed by researchers and citizen scientists in the Caribbean. The main groups involved are XL Catlin Seaview Survey, the University of Queensland, and Reef Check.

Although reefs represent less than 0,1% of the world’s ocean floor, they help support about a quarter of all marine species. The NOAA says the livelihoods of 500 million people and income worth over $30bn (£19,6bn) are at stake.

Reefs are the breeding ground for tropical fisheries. They also provide shelter from the waves for tropical islands and bring invaluable tourist income.

“Just like in 1998 and 2010, we’re observing bleaching on a global scale, which will cause massive loss of corals. With people relying on fisheries and reefs for sustenance, the repercussions could be potentially disastrous,” said Prof Ove Hoegh-Guldberg from the University of Queensland.

Prof Rupert Ormond, Secretary of the International Society for Reef Studies, told BBC News: “Although corals may live for several days after they bleach, they then usually die. They may recover – but only if the sea temperature drops within a week or so. Mostly it takes much longer, so the reef ends up covered with dead corals, especially on its upper parts.

“The reefs may slowly recover if new coral colonies come in from outside, but this may take years or decades. I know coral reefs in Kenya that lost most of their corals in 1998 and they still only have a few percent of the corals once there.”

Follow Roger on Twitter @rharrabin

Chernobyl Wildlife Thriving Decades After Nuclear Accident : DNews

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On a haunting, contaminated landscape devoid of humans, animals are now thriving. So finds a new study on wildlife populations in the Chernobyl Exclusion Zone, late of the former Soviet Union and now part of Ukraine.

In 1986, Chernobyl was the site of of a nuclear reactor accident, the radiation from which caused the displacement of human life from an area of more than 1,000 square miles. Only animals were left to roam the the area.

Today, a multi-university study finds, the exclusion zone has abundant roe deer, red deer, elk, and wild boar — so many that the researchers say their numbers rival those of nature preserves in the region that are not contaminated.

Wolves, they add, are seven times more populous than animals in those radiation-free areas.

chernobyl-animals-deer-1.jpg

“It’s very likely that wildlife numbers at Chernobyl are much higher than they were before the accident,” said Jim Smith, of the University of Portsmouth, in a press release.

While earlier studies had shown sharp drops in wildlife thanks to radiation effects, the new data, culled from long-term census information and helicopter surveys, argues that mammals are back with a vengeance.

“These results demonstrate for the first time that, regardless of potential radiation effects on individual animals, the Chernobyl Exclusion Zone supports an abundant mammal community after nearly three decades of chronic radiation exposure,” the scientists wrote.

“This doesn’t mean radiation is good for wildlife,” Smith cautioned, “just that the effects of human habitation, including hunting, farming, and forestry, are a lot worse.”

The team’s findings have been published in the journal Current Biology.

Can Celebrity Voices Create Mass Environmental Awareness

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Call Me Reminiscent I like to be reminded of how connected we are to all the particular systems and organisms whom we share the planet with. So I recently returned to an old channel called NatureIsSpeaking.org to admire Hi-Def scenes of this blue rock we call Earth. Helping in the build-up of admiration for our irrefutable symbiosis with air, oceans, rainforest, coral reef, etc. …

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Hamburg Sets Out to Become a Car-Free City in 20 Years

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By Ignasi Jorro in Barcelona

Hamburg City Council has disclosed ambitious plans to divert most cars away from its main thoroughfares in twenty years. In order to do so, local authorities are to connect pedestrian and cycle lanes in what is expected to become a large green network. In all, the Grünes Netz (Green Web) plan envisages “eliminating the need for automoviles” within two decades.

By connecting the entire urban centre with its outskirts Hamburg is expecting to smooth inner traffic flow. In all, the northernmost city is to lay out new green areas and connect them with the existing parks, community gardens and cementeries.

Upon completion of the plan Hamburg will pride itself on having over 17,000 acres of green spaces, making up 40% of the city’s area.

According to an official, the ambitious plan will “reduce the need to take the car for weekend outings outside the city”.

Although vehicles are not to be banned from the main thoroughfares, the council expects residents and tourists alike to be able “to explore the city exclusively on bike and foot.”

At the same time, the green ring will play a crutial role to help the metropolis fight against rising temperatures and urban flooding.

The average temperature in Germany’s second-largest city has risen by 9 degrees Celsius in scarcely half a century, experts warn.

As regards to leisure, the interspersed patches of green areas will let residents “hike, swim, do water sports, enjoy picnics and restaurants, experience calm and watch nature and wildlife right in the city”.

Youtube clip backs idea of traffic anarchy in Rome

Invisibility cloak might enhance efficiency of solar cells

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A special invisibility cloak (right) guides sunlight past the contacts for current removal to the active surface area of the solar cell. Credit: Martin Schumann, KIT

Success of the energy turnaround will depend decisively on the extended use of renewable energy sources. However, their efficiency partly is much smaller than that of conventional energy sources. The efficiency of commercially available photovoltaic cells, for instance, is about 20%. Scientists of Karlsruhe Institute of Technology (KIT) have now published an unconventional approach to increasing the efficiency of the panels. Optical invisibility cloaks guide sunlight around objects that cast a shadow on the solar panel, such as contacts for current extraction.

Energy efficiency of solar panels has to be improved significantly not only for the energy turnaround, but also for enhancing economic efficiency. Modules that are presently mounted on roofs convert just one fifth of the light into electricity, which means that about 80% of the solar energy are lost. The reasons of these high losses are manifold. Up to one tenth of the surface area of solar cells, for instance, is covered by so-called contact fingers that extract the current generated. At the locations of these contact fingers, light cannot reach the active area of the solar cell and efficiency of the cell decreases.

“Our model experiments have shown that the cloak layer makes the contact fingers nearly completely invisible,” doctoral student Martin Schumann of the KIT Institute of Applied Physics says, who conducted the experiments and simulations. Physicists of KIT around project head Carsten Rockstuhl, together with partners from Aachen, Freiburg, Halle, Jena, and Jülich, modified the optical invisibility cloak designed at KIT for guiding the incident light around the contact fingers of the solar cell.

Normally, invisibility cloak research is aimed at making objects invisible. For this purpose, light is guided around the object to be hidden. This research project did not focus on hiding the contact fingers visually, but on the deflected light that reaches the active surface area of the solar cell thanks to the invisibility cloak and, hence, can be used.

To achieve the cloaking effect, the scientists pursued two approaches. Both are based on applying a polymer coating onto the solar cell. This coating has to possess exactly calculated optical properties, i.e. an index of refraction that depends on the location or a special surface shape. The second concept is particularly promising, as it can potentially be integrated into mass production of solar cells at low costs. The surface of the cloak layer is grooved along the contact fingers. In this way, incident light is refracted away from the contact fingers and finally reaches the active surface area of the solar cell (see Figure).

By means of a model experiment and detailed simulations, the researchers demonstrated that both concepts are suited for hiding the contact fingers. In the next step, it is planned to apply the cloaking layer onto a solar cell in order to determine the efficiency increase. The physicists are optimistic that efficiency will be improved by the cloak under real conditions: “When applying such a coating onto a real solar cell, optical losses via the contact fingers are supposed to be reduced and efficiency is assumed to be increased by up to 10%,” Martin Schumann says.

More information: Martin F. Schumann, Samuel Wiesendanger, Jan Christoph Goldschmidt, Benedikt Bläsi, Karsten Bittkau, Ulrich W. Paetzold, Alexander Sprafke, Ralf B. Wehrspohn, Carsten Rockstuhl, and Martin Wegener, “Cloaked contact grids on solar cells by coordinate transformations: designs and prototypes,” Optica 2, 850-853 (2015) DOI: 10.1364/OPTICA.2.000850

Provided by: Karlsruhe Institute of Technology

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