Di seguito gli interventi pubblicati in questa sezione, in ordine cronologico.
Assange has been under house arrest in England for over six months, following a ruling in February at a London district court that the extradition of Assange to Sweden was valid and would not breach any of his human rights.
Assange’s lawyers argued unsuccessfully that he would face an unfair trial in Sweden since the press and the public are excluded from parts of sexual assault trials.
Assange voluntarily turned himself in to the police in the UK after Sweden filed a European Arrest Warrant for him.
A widely held view amongst WikiLeaks’ supporters is that the extradition to Sweden is a preface to an eventual trial in the US; and that extradition for the charges against Assange would not be pursued if it was any ordinary citizen.
Assange and his colleagues at the whistle-blowing website WikiLeaks have subjected the US government to extreme duress and embarrassment due to its publication of many thousands of US diplomatic cables including: the July 12 Baghdad Collateral Murder Video and other Iraq war documents; material on extrajudicial killings in Kenya, and the Guantanamo Bay files, to name a few.
Julian Assange is an Australian citizen and deserves all the support our government can offer him. Instead he was thrown to the wolves. Australian Prime Minister Julia Gillard failed to support Assange and called the leaks “an illegal act” according to an article in The Australian in 2009.
Gillard came under widespread condemnation for failing to give support to Assange. Hundreds of prominent lawyers, journalists, editors, and academics signed a letter to the Gillard government calling for her to support Assange but the government has maintained its hardline stance from the outset.
Assange’s legal team will include prominent human rights lawyers Gareth Peirce and Ben Emmerson, a change from his representitives at the original hearing.
Wikileaks continues its release of over 250,000 US diplomatic cables with 16,068 of the 251,287 cables published so far; and the cables will continue to come out, day by day.
A University of Missouri researcher says people who overuse credit have very different beliefs about products than people who spend within their means. Following a new study, Marsha Richins, Myron Watkins Distinguished Professor of Marketing in the Trulaske College of Business, says many people buy products thinking that the items will make them happier and transform their lives.
"There is nothing wrong with wanting to buy products," Richins said. "It becomes a problem when people expect unreasonable degrees of change in their lives from their purchases. Some people tend to ascribe almost magical properties to goods -- that buying things will make them happier, cause them to have more fun, improve their relationships -- in short, transform their lives. These beliefs are fallacious for the most part, but nonetheless can be powerful motivators for people to spend."
Richins identified four types of changes that materialistic people expect when making purchases. Previous research has shown that often these expectations are not fulfilled. The four types of transformations expected are:
-> Transformation of the self is the belief that a purchase will change who you are and how people perceive you. This is commonly held by young people and people in new roles. For example, a woman interviewed for the study wanted to have cosmetic dental surgery because she thought it would improve her appearance and self-confidence.
-> Transformation of relationships is the expectation that a purchase will give someone more or better relationships with others. For example, a woman interviewed for the study wanted to buy a new home because she thought it would enable her to entertain more often and make more friends.
-> Hedonic transformation implies that a purchase will make life more fun. For example, a man in the study wanted a mountain bike because he thought it would give him more incentive to get out and go on "an adventure."
-> Efficacy transformation is the expectation that purchases will make people more effective in their lives. For example, some study participants wanted to buy a vehicle because they thought it would make them more independent and self-reliant.
People who have strong and unrealistic transformational beliefs are more likely than others to overuse credit and take on excessive debt. According to Richins, this finding highlights a limitation of financial literacy and credit counseling programs. She recommends that financial literacy and credit counseling programs be revised to help people better understand their motivations for purchasing goods and to help them recognize that products are not a quick fix for improving their lives.
"Many financial literacy programs seek to prevent people from getting into financial problems by presenting the facts about interests rate and loans," Richins said. "However, few programs seek to directly influence behavior or focus on why people purchase things they cannot afford and go into debt."
WITNESS a howling gale or an ocean storm, and it's hard to believe that humans could make a dent in the awesome natural forces that created them. Yet that is the provocative suggestion of one physicist who has done the sums.
He concludes that it is a mistake to assume that energy sources like wind and waves are truly renewable. Build enough wind farms to replace fossil fuels, he says, and we could seriously deplete the energy available in the atmosphere, with consequences as dire as severe climate change.
Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany, says that efforts to satisfy a large proportion of our energy needs from the wind and waves will sap a significant proportion of the usable energy available from the sun. In effect, he says, we will be depleting green energy sources. His logic rests on the laws of thermodynamics, which point inescapably to the fact that only a fraction of the solar energy reaching Earth can be exploited to generate energy we can use.
When energy from the sun reaches our atmosphere, some of it drives the winds and ocean currents, and evaporates water from the ground, raising it high into the air. Much of the rest is dissipated as heat, which we cannot harness.
At present, humans use only about 1 part in 10,000 of the total energy that comes to Earth from the sun. But this ratio is misleading, Kleidon says. Instead, we should be looking at how much useful energy - called "free" energy in the parlance of thermodynamics - is available from the global system, and our impact on that.
Humans currently use energy at the rate of 47 terawatts (TW) or trillions of watts, mostly by burning fossil fuels and harvesting farmed plants, Kleidon calculates in a paper to be published in Philosophical Transactions of the Royal Society. This corresponds to roughly 5 to 10 per cent of the free energy generated by the global system.
"It's hard to put a precise number on the fraction," he says, "but we certainly use more of the free energy than [is used by] all geological processes." In other words, we have a greater effect on Earth's energy balance than all the earthquakes, volcanoes and tectonic plate movements put together.
Radical as his thesis sounds, it is being taken seriously. "Kleidon is at the forefront of a new wave of research, and the potential prize is huge," says Peter Cox, who studies climate system dynamics at the University of Exeter, UK. "A theory of the thermodynamics of the Earth system could help us understand the constraints on humankind's sustainable use of resources." Indeed, Kleidon's calculations have profound implications for attempts to transform our energy supply.
Of the 47 TW of energy that we use, about 17 TW comes from burning fossil fuels. So to replace this, we would need to build enough sustainable energy installations to generate at least 17 TW. And because no technology can ever be perfectly efficient, some of the free energy harnessed by wind and wave generators will be lost as heat. So by setting up wind and wave farms, we convert part of the sun's useful energy into unusable heat.
"Large-scale exploitation of wind energy will inevitably leave an imprint in the atmosphere," says Kleidon. "Because we use so much free energy, and more every year, we'll deplete the reservoir of energy." He says this would probably show up first in wind farms themselves, where the gains expected from massive facilities just won't pan out as the energy of the Earth system is depleted.
Using a model of global circulation, Kleidon found that the amount of energy which we can expect to harness from the wind is reduced by a factor of 100 if you take into account the depletion of free energy by wind farms. It remains theoretically possible to extract up to 70 TW globally, but doing so would have serious consequences.
Although the winds will not die, sucking that much energy out of the atmosphere in Kleidon's model changed precipitation, turbulence and the amount of solar radiation reaching the Earth's surface. The magnitude of the changes was comparable to the changes to the climate caused by doubling atmospheric concentrations of carbon dioxide (Earth System Dynamics, DOI: 10.5194/esd-2-1-2011).
"This is an intriguing point of view and potentially very important," says meteorologist Maarten Ambaum of the University of Reading, UK. "Human consumption of energy is substantial when compared to free energy production in the Earth system. If we don't think in terms of free energy, we may be a bit misled by the potential for using natural energy resources."
This by no means spells the end for renewable energy, however. Photosynthesis also generates free energy, but without producing waste heat. Increasing the fraction of the Earth covered by light-harvesting vegetation - for example, through projects aimed at "greening the deserts" - would mean more free energy would get stored. Photovoltaic solar cells can also increase the amount of free energy gathered from incoming radiation, though there are still major obstacles to doing this sustainably (see "Is solar electricity the answer?").
In any event, says Kleidon, we are going to need to think about these fundamental principles much more clearly than we have in the past. "We have a hard time convincing engineers working on wind power that the ultimate limitation isn't how efficient an engine or wind farm is, but how much useful energy nature can generate." As Kleidon sees it, the idea that we can harvest unlimited amounts of renewable energy from our environment is as much of a fantasy as a perpetual motion machine.
Is solar electricity the answer?
A solar energy industry large enough to make a real impact will require cheap and efficient solar cells. Unfortunately, many of the most efficient of today's thin-film solar cells require rare elements such as indium and tellurium, whose global supplies could be depleted within decades.
For photovoltaic technology to be sustainable, it will have to be based on cheaper and more readily available materials such as zinc and copper, says Kasturi Chopra of the Indian Institute of Technology, New Delhi.
Researchers at IBM showed last year that they could produce solar cells from these elements along with tin, sulphur and the relatively rare element selenium. These "kesterite" cells already have an efficiency comparable with commercially competitive cells, and it may one day be possible to do without the selenium.
Even if solar cells like this are eventually built and put to work, they will still contribute to global warming. That is because they convert only a small fraction of the light that hits them, and absorb most of the rest, converting it to heat that spills into the environment. Sustainable solar energy may therefore require cells that reflect the light they cannot use.
Con il decollo avvenuto poco tempo fa della navetta Endeavour, l’era degli Shuttle volge al termine e con la missione STS 135, la cui partenza è prevista per l’inizio di luglio, il Programma Shuttle della NASA sarà definitivamente concluso.
(© NASA/Dimitri Gerondidakis)
Quali sono i motivi che hanno decretato il pensionamento dei gloriosi velivoli spaziali? Da cosa saranno sostituiti? Che ne sarà della Stazione Spaziale Internazionale e dei suoi occupanti? E quale sarà il futuro dell’esplorazione del cosmo? Ve lo spieghiamo in 7 domande e risposte.
1) Perchè gli Shuttle vengono dismessi?
Le navicelle Shuttle hanno costi di missione e manutenzione che crescono con il passare degli anni. Sono in servizio dal 1981 e il loro compito, cioè la costruzione della ISS, è praticamente terminato. La NASA vuole quindi utilizzare le risorse assorbite dal Programma Shuttle in qualcosa di nuovo.
L'idea di pensionare gli Shuttle non è comunque nuova: già nel 2003 la commissione d’inchiesta sull’incidente del Columbia concludeva il suo rapporto con la frase "È nell’interesse del paese rimpiazzare gli Shuttle il prima possibile"
2) Chi ha deciso di fermare gli Shuttle?
La decisione fu presa dal Presidente degli Stati Uniti George Bush nel 2004. Il Presidente chiese alla NASA di sviluppare un nuovo programma spaziale che portasse nuovamente l’uomo sulla Luna e magari anche su Marte.
Per raggiungere questi obiettivi l’agenzia spaziale aveva però bisogno di ingenti fondi e sospendendo il programma Shuttle si potevano liberare oltre 4 miliardi di dollari l’anno.
Lo scorso anno il Presidente Obama ha però annullato tutti i progetti lunari per concentrarsi sulla costruzione di un grande razzo in grado di portare l’uomo sugli asteroidi e su Marte.
Il trasporto di materiali e uomini da e verso la Stazione Spaziale Internazionale dovrebbe essere affidato ai vettori russi e alle future compagnie private.
3) Quando terminerà il programma Shuttle?
L’ultimo volo degli Shuttle sarà compiuto dall’Atlantis ed è programmato per luglio: porterà sulla ISS componenti elettronici e pezzi di ricambio.
4) Quali erano gli obiettivi del programma Shuttle?
Questi cargo cosmici avrebbero dovuto permettere voli spaziali sicuri ed economici, e la possibilità di lanci frequenti, addirittura settimanali.
Così non è stato: le navette si sono rivelate costose e insicure. In trent' anni di servizio, i due gravi incidenti che hanno coinvolto le navette Columbia e Challenger hanno causato la morte di 14 astronauti.
Ma gli Shuttle, a metà strada tra un tir spaziale e una gru, si sono rivelati il mezzo più idoneo per la messa in orbita e la manutenzione di grandi apparecchiature come il telescopio spaziale Hubble.
5) Che fine faranno le navicelle?
Andranno a vari musei degli States: l’Endeavour verrà esposto al California Space Center di Los Angeles, l’Atlantis rimarrà a disposizione dei visitatori del Kennedy Space Center e il Discovery andrà in un hangar della Smithsonian Institution presso l’aeroporto Dulles di Washington.
L’Enterprise, un prototipo utilizzato per alcuni voli di prova fin dalla fine degli anni ‘70, fa già bella mostra di sè nei locali del New York City's Intrepid Sea, Air and Space Museum
6) E la Stazione Spaziale Internazionale? Che ne sarà?
La ISS continuerà a funzionare almeno fino al 2020. Ora è abbastanza grande da poter ospitare 6 persone e tutti gli esperimenti e le ricerche propedeutici alla conquista di Marte.
Gli astronuauti raggiungeranno la Stazione a bordo delle capsule russe Soyouz affittate dalla NASA per questo scopo, in attesa che gli americani dispongano nuovamente di vettori spaziali propri.
7) Quanto costa mandare un uomo nello spazio?
Con le capsule Soyouz il costo del traporto di un astronauta da e per la Stazione Spaziale Internazionale si aggirerà sui 50 milioni di euro. Una cifra mostruosa, ma comunque inferiore a quella di un volo dello Shuttle. Nei prossimi 2 - 3 anni saranno pronti anche i primi vettori spaziali privati e i costi dei biglietti per la ISS potrebbero scendere.
La NASA infatti, all’inizio del 2011, ha affidato a Space X, Boeing, Blu Origin e Sierra Nevada, una commessa da oltre 200 milioni di euro per la progettazione di un missile e una capsula in grado di portare uomini sulla ISS.
It has long been thought that, even though light has electric and magnetic components, the effects of the magnetic field are so weak that they could effectively be ignored. Now researchers at the University of Michigan (U-M) have discovered that under the right conditions, a light field can generate magnetic effects that are 100 million times stronger than previously expected. The researchers say the discovery paves the way for the creation of an "optical battery" that could harness power from the sun without the use of solar cells.
Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics, and his colleagues found that if light focused to an intensity of 10 million watts per square centimeter (W/cm2) is traveling through a material that does not conduct electricity, such as glass, the light field can generate magnetic effects with the strength equivalent to a strong electric effect.
"This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation," Rand said. "In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source."
William Fisher, a doctoral student in applied physics at U-M, says that a previously undetected brand of "optical rectification" is what makes this possible. In traditional optical rectification, light's electric field causes a pulling apart of the positive and negative charges in a material, which sets up a voltage similar to that in a battery. This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry, but Rand and Fisher found that light's magnetic field can also create optical rectification in other types of materials, under the right circumstances.
"It turns out that the magnetic field starts curving the electrons into a C-shape and they move forward a little each time," Fisher said. "That C-shape of charge motion generates both an electric dipole and a magnetic dipole. If we can set up many of these in a row in a long fiber, we can make a huge voltage and by extracting that voltage, we can use it as a power source."
Although the light must be focused through a non-conductive material to an intensity of 10 million W/cm2, which is much higher than the roughly 0.136 W/cm2 intensity of sunlight on its own, the researchers are looking for new materials that would work at lower intensities.
"In our most recent paper, we show that incoherent light like sunlight is theoretically almost as effective in producing charge separation as laser light is," Fisher said.
The researchers predict that with improved materials, they could achieve 10 percent efficiency, which is comparable to today's commercial-grade solar cells. They add that, because their technique doesn't require the extensive semiconductor processing required for traditional solar cells, it could also make solar power much cheaper.
"All we would need are lenses to focus the light and a fiber to guide it. Glass works for both. It's already made in bulk, and it doesn't require as much processing. Transparent ceramics might be even better," said Fisher.
Over the summer, the researchers will first work on harnessing power with laser light, and then sunlight.
The researcher's paper is titled, "Optically-induced charge separation and terahertz emission in unbiased dielectrics," and the University of Michigan is pursuing a patent for the technology.
Italy is again at a crossroads about freedom and quality of its media. On July 6, Italy's telecommunication regulator, AGCOM, will decide how long will let the public debate about the new enforcement tools to fight copyright infringement the Agency is introducing. The law, introduced by the present government, generally requires AGCOM to adopt anti-piracy tools, but the AGCOM proposal gives the Authority itself the power to remove content from Italian websites or to block access to foreign websites accused by copyright holders to break their rights. There will be no need to go through a regular trial, no judge will be involved in the decision making. Accused sites will have only 5 days to explain their position and their right to defend themselves will be quite limited.
The issue has generated very polarized reactions.
Strong approvers have been some publishers associations such as TV producers (APT), film (ANICA), music (FIMI). But they limit their support to new rules that are able to suppress only those sites that do business selling intellectual property that they don't own, while explicitly excluding from the desired effects of the new regulations all private blogs, sites, platforms, search engines and other operators whose business is not piracy.
Critics include groups like Agora Digitale and Altroconsumo, personalities such as Stefano Rodotà - former European data protection commissioner and very respected jurist - and scholars such as Juan Carlos De Martin - one of Nexa founders and fellow at Harvard's Berkman Center - and many others. They think that the AGCOM proposal is worded in a way that enables the Authority to shut down any site, including those that are not in the piracy business and are focused on gathering and analysing the news, without granting a real right to defense.
In many past cases, copyright trials have shown different controversial interpretations about, for example, the freedom of the press and the fair use of some copyrighted content. For sure, copyright is not always a matter that can be decided through simple administrative solutions. Without recourse to the courts in these matters, unilateral decisions are likely.
In a country that has allowed some of the weirdest irregularities in the media system for a western democracy, with a Prime Minister personally owning three of the seven major national television networks and controlling the three public networks through his political power, the regulation of the internet seems to be a fundamental subject for any local democratic development. The Economist has covered some of the consequences, while showing how television was used by the government to silence the issues at stake in the recent referendums. As a matter of fact, the government has lost those referendums and many experts considered this setback as a victory for new social media and the internet.
There are not many news about this subject in English. Who reads Italian can take a look at Juan Carlos De Martin piece published by la Stampa. AGCOM's head Calabrò's answer. And many other links at the end of previous posts. Vocal opposition to the AGCOM decision is growing on the Italian network: LatoSinistro, EsserePrimisuGoogle, IsolaCassintegrati, ValigiaBlu, DoppioCieco, MatteoPlatone, Ciwati, LucaNicotra, YesPolitica, Semioblog, Gilioli, Nichilista, DamianoZito, Avaaz, MinimaAcademica, PiccoloSocrate, Ilmiopaesealtrove, Pozzallo, Pasteris, Perdukistan, GuidoVetere. And many more...
FIMI (association of music publishers) has circulated a mail about Obama's administration support to AGCOM, quoting this Us document: "The United States encourages Italy to ensure that the AGCOM regulations are swiftly promulgated and implemented, that these regulations create an effective mechanism against copyright piracy over the Internet, and that they address all types of piracy that takes place online."
Source: blog.debiase.com - Author: Luca De Biase (An Italian journalist writes about perspective, a notion that Italy sort of invented and then forgot. Because the future is the consequence of what we do today. Subjects: knowledge economy and happiness, social media and information ecology, value and vision.)
A study of Israeli new spapers indicates that both religious and secular newspapers are using their ability to select and present information to divide groups of Israeli citizens, said Matt Evans, a ssistant professor, political science.
"The media has immense power to influence people by the way they frame information," said Evans. "Instead of working to heal differences, they are actually exacerbating the social cleavages."
Journalists frame information by determining what articles they publish, where articles are placed in the paper and how the articles are written. They can also use photos and artwork to frame the information, said Evans, who reported his findings in the current issue of the Middle East Journal.
Evans said media framing is often unintentional.
"I do not think the media are being used to deliberately divide people," said Evans. "Rather there is a downward spiral as each side makes its case to its core audience."
According to Evans, media framing in Israeli newspapers is largely aimed at separating secular and religious Jewish communities. Newspapers run by the ultra-orthodox Haredim, such as Yated Ne'eman and HaModia, provide more obvious examples of how media framing divides people.
Since most Haredi avoid secular media, the newspapers are the primary news sources for the group's members. However, the Haredi press typically omits stories about religious public officials involved in crimes or scandals. Haredi reporters also use such phrases as "wonderful boys" or "brilliant young men," to sarcastically describe secular political figures.
Secular newspapers use more subtle media framing techniques to divide groups, according to Evans. For example, secular newspapers use pictures of conservatively clad Haredi five times more than moderate modern orthodox community members, even though the majority of orthodox citizens are modern orthodox. Evans said that the portrayal of religious citizens as Haredi plays on fears that orthodox citizens are threatening to exert political influence. Secular citizens fear change in the neighborhood standards, such as closing stores on the Sabbath.
Newspapers are important sources of news in Israel. Most Israelis read two or more newspapers on the weekend and in a 1995 survey on Israeli newspaper readership, 88 percent of the Jewish respondents read a daily paper, according to Evans. Israel is the only country in the Middle East that has a free press, according to the Global Press Freedom Rankings.
Evans said the use of media framing to divide groups is a global problem.
"The power the media is using to divide people isn't just found in Israel, and it's not just being used to exacerbate the differences between secular and religious groups," Evans said. "In the United States, for instance, you can see how MSNBC, on the left, and Fox News, on the right, frame coverage to change how we see Republicans and Democrats."
Provided by Pennsylvania State University.
I risultati di un recente studio condotto tra i ghiacci dell’Antartide attribuiscono un nuovo e inquietante ruolo agli oceani, che per colpa del riscaldamento delle loro acque si trasformerebbero in enormi e potenti amplificatori dell’effetto serra.
Gli oceani catturano circa il 30% della CO2 prodotta dalle attività umane (30 miliardi di tonnellate l’anno secondo l’ONU) e la nascondono nelle loro profondità. Questo sequestro naturale dell’anidride carbonica contribuisce a contenere il surriscaldamento globale del pianeta e i suoi effetti.
Lo stoccaggio oceanico della CO2 non è però permanente: secondo gli studi ha una durata compresa tra i 400 e i 1300 anni, al termine dei quali viene di nuovo rilasciata nell’atmosfera.
Ma qualcosa in questo meccanismo sembra essersi inceppato: il progressivo aumento delle temperature avrebbe infatti velocizzato il processo e gli oceani avrebbero cominciato a rilasciare le loro scorte di CO2 dopo soli 2 secoli, aumentando così la quantità totale di gas serra nell’atmosfera.
Ma quanta fretta, dove corri...
Tas van Ommen della Australian Antarctic Division di Hobart ha analizzato delle bolle di CO2 intrappolate nei ghiacci di Siple e Byrd, nell’Antartico Occidentale, le ha datate e la confrontate con i ati sulle temperature medie di quello stesso periodo.
Lo scienziato ha scoperto che all’aumento delle temperature segue regolarmente un incremento nelle emissioni di CO2 oceanica e che l’intervallo di tempo tra il sequestro e il rilascio del gas sta diventando inferiore ai 200 anni.
Ma in che modo l’aumento delle temperature influenza le emissioni di CO2? "Pensate a una bottiglia di Coca Cola: aumentando la temperatura, l’andiride carbonica disciolta nel liquido sale verso la superficie e fugge" ha spiegato Ommen ai media. Non solo: l’aumento delle temperature favorisce il rimescolamento delle acque profonde e la salita verso la superficie delle bolle di gas.
Ommen ha presentato i dati del suo studio alla conferenza sul clima Greenhouse 2011 che si è tenuta a Cairns, in Australia, nei giorni scorsi ma ha ammesso che prima di poterli applicare alla situazione attuale per trarre conclusioni sull’evoluzione del clima del pianeta occorreranno ancora attente verifiche.
They also believe rescue attempts are futile as billions more euros will be paid to bail out Greece.
A poll by German newspaper, the Frankfurter Allgemeine, found 71 per cent had “doubt,” “no trust” or thought there is “no future” for the euro. Only 19 per cent expressed “confidence” in it.
Sixty eight per cent said they did not think the emergency bail out of Greece would work.
A separate poll last week showed more than half of Germans thought that Greece should be thrown out of the euro.
Rumours are also rife in Germany that Deutsche Mark bank notes are being printed again in preparation for ditching the euro.
It is said Germany’s central bank, the Bundesbank, has been ordered to print marks as part of contingency plans to leave Europe’s single currency.
This would be an extraordinary step for Germany and would deepen the growing divide between Europe’s leading states.
Since its introduction in 1999, the euro has had a tough time trying to win over a sceptical German public, who saw the mark – one of the world’s most stable currencies – as a symbol of post-war prosperity, second only to the US dollar as the reserve option for investors.
Chancellor Angela Merkel now faces her biggest crisis. The opposition is speculating her government may fall as Germans become more vocal in their opposition to bailing out Greece.
If a new development from labs at MIT pans out as expected, someday the entire surface area of a building’s windows could be used to generate electricity — without interfering with the ability to see through them.
Richard Lunt, one of the researchers who developed the new transparent solar cell, demonstrates its transparency using a prototype cell. Photo: Geoffrey Supran
The key technology is a photovoltaic cell based on organic molecules, which harnesses the energy of infrared light while allowing visible light to pass through. Coated onto a pane of standard window glass, it could provide power for lights and other devices, and would lower installation costs by taking advantage of existing window structures.
These days, anywhere from half to two-thirds of the cost of a traditional, thin-film solar-power system comes from those installation costs, and up to half of the cost of the panels themselves is for the glass and structural parts, said Vladimir Bulovi?, professor of electrical engineering in the Department of Electrical Engineering and Computer Science. But the transparent photovoltaic system he developed with Richard Lunt, a postdoctoral researcher in the Research Laboratory of Electronics, could eliminate many of those associated costs, they say.
A paper by Bulovi? and Lunt describing their new system has been published online in the journal Applied Physics Letters, and will appear in a forthcoming issue of the print edition.
Previous attempts to create transparent solar cells have either had extremely low efficiency (less than 1 percent of incoming solar radiation is converted to electricity), or have blocked too much light to be practical for use in windows. But the MIT researchers were able to find a specific chemical formulation for their cells that, when combined with partially infrared-reflective coatings, gives both high visible-light transparency and much better efficiency than earlier versions — comparable to that of non-transparent organic photovoltaic cells.
A prototype of the MIT researchers' transparent solar cell is seen on top of a promotional item for MIT's 150th anniversary celebrations. Photo: Geoffrey Supran
In a new building, or one where windows are being replaced anyway, adding the transparent solar cell material to the glass would be a relatively small incremental cost, since the cost of the glass, frames and installation would all be the same with or without the solar component, the researchers say, although it is too early in the process to be able to estimate actual costs. And with modern double-pane windows, the photovoltaic material could be coated on one of the inner surfaces, where it would be completely protected from weather or window washing. Only wiring connections to the window and a voltage controller would be needed to complete the system in a home.
In addition, much of the cost of existing solar panels comes from the glass substrate that the cells are placed on, and from the handling of that glass in the factory. Again, much of that cost would not apply if the process were made part of an existing window-manufacturing operation. Overall, Bulovi? says, “a large fraction of the cost could be eliminated” compared to today’s solar installations.
This will not be the ultimate solution to all the nation’s energy needs, Bulovi? says, but rather it is part of “a family of solutions” for producing power without greenhouse-gas emissions. “It’s attractive, because it can be added to things already being deployed,” rather than requiring land and infrastructure for a whole new system.
Fine-tuning the cells
The work is still at a very early stage, Bulovi? cautions. So far, they have achieved an efficiency of 1.7 percent in the prototype solar cells, but they expect that with further development they should be able to reach 12 percent, making it comparable to existing commercial solar panels. “It will be a challenge to get there,” Lunt says, “but it’s a question of excitonic engineering,” requiring optimization of the composition and configuration of the photovoltaic materials.
The researchers expect that after further development in the lab followed by work on manufacturability, the technology could become a practical commercial product within a decade. In addition to being suitable for coating directly on glass in the manufacture of new windows, the material might also be coated onto flexible material that could then be rolled onto existing windows, Lunt says.
Using the window surfaces of existing buildings could provide much more surface area for solar power than traditional solar panels, Bulovi? says. In mornings and evenings, with the sun low in the sky, the sides of big-city buildings are brightly illuminated, he says, and that vertical “footprint” of potential light-harvesting area could produce a significant amount of power.
Max Shtein, associate professor of materials science and engineering at the University of Michigan, says, “This work demonstrates a useful effect, and is based on very sound science and engineering.” But he adds that “it is but one of the many other methods by which a similar functionality could be achieved,” and says the biggest uncertainty at this point is that because they are so new, “the lifetime of organic PV cells is a bit of an unknown at this point, though there is some hope.”
In addition, Shtein says, “The potential of this technology is good if projected far into the future,” but only if the efficiency can be improved as the researchers expect it can.
As added benefits, the manufacturing process for the MIT researchers' solar cells could be more environmentally friendly, because it does not require the energy-intensive processes used to create silicon solar cells. The MIT process of fabricating solar cells keeps the glass panes at ordinary room temperature, Bulovi? noted. Installations of the new system would also block much of the heating effect of sunlight streaming through the windows, potentially cutting down on air conditioning needs within a building.
The research was funded by the Center for Excitonics, an Energy Frontier Research Center funded by the U.S. Department of Energy.