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  • richardmitnick 1:31 pm on December 3, 2016 Permalink | Reply
    Tags: California Energy Commission, , Massive US Solar Farms Will Deliver Power to Millions, Solar Power   

    From Seeker: “Massive US Solar Farms Will Deliver Power to Millions” 

    Seeker bloc

    SEEKER

    1
    California Energy Commission Blog

    A recent report by the U.S. Department of Energy finding that U.S. solar power capacity will have nearly tripled in less than three years by 2017 is a milestone not only as a technology whose time has come but also as a major shift where the embrace of solar power is a result not just of environmental principle but of practical necessity.

    Ten percent of total U.S. energy consumption comes from renewables, and solar currently makes up 6 percent of that segment, according to the U.S. Energy Information Administration, and is among the fastest-growing sources of energy.

    Once a cottage industry of small-scale producers, the solar energy landscape has grown and seen a number of major projects go online in recent years. Based on the recent Major Solar Projects List by the Solar Energy Industries Association, last updated in September, combined solar capacity for the more than 4,000 projects currently operating, under construction or under development stands above 72 gigawatts. To put that number in perspective, a single gigawatt, the equivalent output of two coal-fired power plants, can power 750,000 homes.

    “Consumers are now starting to demand more from their energy providers and are beginning to play a more active role in their interaction with the grid, which is ultimately changing the way utilities are serving them,” John Berger, CEO of Sunnova, told Seeker. “As a result, we are currently witnessing the beginning of the greatest shift in the electricity industry that we’ve seen during its 100-plus year existence. It’s also the biggest shift we’ve seen in the energy industry since oil started to be used in transportation 100 years ago.”

    States like California provide solar energy companies the political and geographic advantages to operate and expand. Last year, the Solar Star project (in Los Angeles and Kern counties) was completed, bringing online a 579-megawatt solar plant. The Desert Sunlight Solar Farm, a 550-megawatt solar power station in the Sonoran Desert, was also finished in 2015. The year prior, the Topaz Solar Farm, a 550-megawatt solar plant San Luis Obispo Count, became fully operational.

    The solar energy market in Hawaii, a state that generates more solar electricity per capita than any other state in 2015, is “one of the shining lighthouses of what’s possible on a state-level basis,” Alan Russo, senior vice president at REC Solar, tells Seeker. Solar energy adoption rates in Hawaii are among the highest in the nation, Russo adds, in large part because the utility costs are so high. Hawaii traditionally has had to import most of its energy and is the first state to legally commit itself to generating 100 percent of its energy from renewables in 2045.

    But solar is even growing in states with competing energy interests from traditional sources. Take Texas, for example. “Texas, a traditionally oil and gas state and subsequently a wind state, is leading the way in new utility-scale solar projects,” Berger notes of the Lone Star state, where Sunnova is based. “Texas is currently the fastest growing utility-scale solar market in the country, and by the end of 2016, the state’s total installed solar capacity is expected to more than double.”

    The reason for the growth of solar isn’t simply one of environmental conscience but also cost. “Solar costs just a small fraction of what it did even a few years ago,” notes Eli Hinckley, head of the energy group at Sullivan & Worester. “In addition to the absolute price drop, the cost is certain, basically just the price of installation.”

    As the spread between the price of renewables like solar closes with that of traditional energy sources like oil and coal, the decision to move to solar power becomes more enticing to both consumers and businesses, the latter of whom have the added benefit of touting their green credentials to the former.

    “Kind of like the IT transformation back in the ’90s versus where it is today, solar is going from — or renewables in general are going from kind of an esoteric, technology-driven decision to a mainstream provider of business value,” Russo said. “With that, it’s becoming less a matter of ‘Do I do it?’ vs. ‘How much do I do it?’ ‘When do I do it?’ and ‘How do I do it?'”

    And it’s not just in the United States where the cost of renewables is becoming more competitive. Take the example of Abu Dhabi, whose government just received bids for the construction of a large solar farm. “Prices were as low as 2.42 cents per kWh,” Hinckley said. “That is less than it costs to generate power from some coal and gas plants that are already built and is a fraction of what it would cost to build and operate a new fossil fuel plant.”

    The move by Abu Dhabi, a major player in energy markets, has chosen solar over natural gas, of which it controls nearly 5 percent of global reserves, represents “an enormous shift in the perception of solar as the future of energy,” Hinckley said.

    See the full article here .

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  • richardmitnick 1:27 pm on May 28, 2016 Permalink | Reply
    Tags: , Hot new solar cell, , , Solar Power   

    From MIT: “Hot new solar cell” 

    MIT News
    MIT News
    MIT Widget

    May 23, 2016
    David L. Chandler

    1
    While all research in traditional photovoltaics faces the same underlying theoretical limitations, MIT PhD student David Bierman says, “with solar thermal photovoltaics you have the possibility to exceed that.” In fact, theory predicts that in principle this method could more than double the theoretical limit of efficiency, potentially making it possible to deliver twice as much power from a given area of panels. Photo courtesy of the researchers.

    System converts solar heat into usable light, increasing device’s overall efficiency.

    A team of MIT researchers has for the first time demonstrated a device based on a method that enables solar cells to break through a theoretically predicted ceiling on how much sunlight they can convert into electricity.

    Ever since 1961 it has been known that there is an absolute theoretical limit, called the Shockley-Queisser Limit, to how efficient traditional solar cells can be in their energy conversion. For a single-layer cell made of silicon — the type used for the vast majority of today’s solar panels — that upper limit is about 32 percent. But it has also been known that there are some possible avenues to increase that overall efficiency, such as by using multiple layers of cells, a method that is being widely studied, or by converting the sunlight first to heat before generating electrical power. It is the latter method, using devices known as solar thermophotovoltaics, or STPVs, that the team has now demonstrated.

    The findings are reported this week in the journal Nature Energy, in a paper* by MIT doctoral student David Bierman, professors Evelyn Wang and Marin Soljačić, and four others.

    While all research in traditional photovoltaics faces the same underlying theoretical limitations, Bierman says, “with solar thermophotovoltaics you have the possibility to exceed that.” In fact, theory predicts that in principle this method, which involves pairing conventional solar cells with added layers of high-tech materials, could more than double the theoretical limit of efficiency, potentially making it possible to deliver twice as much power from a given area of panels.

    “We believe that this new work is an exciting advancement in the field,” Wang says, “as we have demonstrated, for the first time, an STPV device that has a higher solar-to-electrical conversion efficiency compared to that of the underlying PV cell.” In the demonstration, the team used a relatively low-efficiency PV cell, so the overall efficiency of the system was only 6.8 percent, but it clearly showed, in direct comparisons, the improvement enabled by the STPV system.

    The basic principle is simple: Instead of dissipating unusable solar energy as heat in the solar cell, all of the energy and heat is first absorbed by an intermediate component, to temperatures that would allow that component to emit thermal radiation. By tuning the materials and configuration of these added layers, it’s possible to emit that radiation in the form of just the right wavelengths of light for the solar cell to capture. This improves the efficiency and reduces the heat generated in the solar cell.

    The key is using high-tech materials called nanophotonic crystals, which can be made to emit precisely determined wavelengths of light when heated. In this test, the nanophotonic crystals are integrated into a system with vertically aligned carbon nanotubes, and operate at a high temperature of 1,000 degrees Celsius. Once heated, the nanophotonic crystals continue to emit a narrow band of wavelengths of light that precisely matches the band that an adjacent photovoltaic cell can capture and convert to an electric current. “The carbon nanotubes are virtually a perfect absorber over the entire color spectrum,” Bierman says, allowing it to capture the full solar spectrum. “All of the energy of the photons gets converted to heat.” Then, that heat gets re-emitted as light but, thanks to the nanophotonic structure, is converted to just the colors that match the PV cell’s peak efficiency.

    In operation, this approach would use a conventional solar-concentrating system, with lenses or mirrors that focus the sunlight, to maintain the high temperature. An additional component, an advanced optical filter, lets through all the desired wavelengths of light to the PV cell, while reflecting back any unwanted wavelengths, since even this advanced material is not perfect in limiting its emissions. The reflected wavelengths then get re-absorbed, helping to maintain the heat of the photonic crystal.

    Bierman says that such a system could offer a number of advantages over conventional photovoltaics, whether based on silicon or other materials. For one thing, the fact that the photonic device is producing emissions based on heat rather than light means it would be unaffected by brief changes in the environment, such as clouds passing in front of the sun. In fact, if coupled with a thermal storage system, it could in principle provide a way to make use of solar power on an around-the-clock basis. “For me, the biggest advantage is the promise of continuous on-demand power,” he says.

    In addition, because of the way the system harnesses energy that would otherwise be wasted as heat, it can reduce excessive heat generation that can damage some solar-concentrating systems.

    To prove the method worked, the team ran tests using a photovoltaic cell with the STPV components, first under direct sunlight and then with the sun completely blocked so that only the secondary light emissions from the photonic crystal were illuminating the cell. The results showed that the actual performance matched the predicted improvements.

    “A lot of the work thus far in this field has been proof-of-concept demonstrations,” Bierman says. “This is the first time we’ve actually put something between the sun and the PV cell to prove the efficiency” of the thermal system. Even with this relatively simple early-stage demonstration, Bierman says, “we showed that just with our own unoptimized geometry, we in fact could break the Shockley-Queisser limit.” In principle, such a system could reach efficiencies greater than that of an ideal solar cell.

    The next steps include finding ways to make larger versions of the small, laboratory-scale experimental unit, and developing ways of manufacturing such systems economically.

    This represents a “significant experimental advance,” says Peter Bermel, an assistant professor of electrical and computer engineering at Purdue University, who was not associated with this work. “To the best of my knowledge, this is a new record for solar TPV, using a solar simulator, selective absorber, selective filter, and photovoltaic receiver, that reasonably represents actual performance that might be achievable outdoors.” He adds, “It also shows that solar TPV can exceed PV output with a direct comparison of the same cells, for a sufficiently high input power density, lending this approach to applications using concentrated sunlight.”

    The research team also included MIT alumnus Andrej Lenert PhD ’14, now a research fellow at the University of Michigan, MIT postdocs Walker Chan and Bikram Bhatia, and research scientist Ivan Celanovic. The work was supported by the Solid-State Solar Thermal Energy Conversion (S3TEC) Center, funded by the U.S. Department of Energy.

    *Science paper:
    Enhanced photovoltaic energy conversion using thermally based spectral shaping

    See the full article here .

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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 6:16 am on May 20, 2016 Permalink | Reply
    Tags: , , Solar Power,   

    From CSIRO: “Solar efficiency goes through the roof with UNSW world-first” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    20th May 2016
    Natalie Kikken

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    Who would’ve thought a prism could be so energy efficient? Dr Keevers showcases his research Photo credit: Rob Largent/UNSW

    We love a world-first here at CSIRO. Every day, our scientists are working to crack the next best thing to benefit the nation. Back in 2014 in the energy domain, we were the first to create super critical steam at the hottest temperature ever outside of fossil fuel sources. Instead, we used concentrating solar thermal technology (a field of heliostat mirrors that concentrate heat from the sun). That’s pretty darn impressive as it shines the light on, or in this case, steams up the conversation about the critical role the sun plays for a low emissions energy future in Australia.

    Another world-first was achieved this week by our friends at the University of New South Wales, in particular the researchers’ Professor Martin Green and Dr Mark Keevers, who have found a way to improve the light-gathering ability of solar cells.

    U NSW bloc

    Cutting shapes in the solar stakes

    We’re not sure what sort of shapes the researchers can cut on the dancefloor, but they sure know how to use shapes for the advantage of solar efficiency, in this case, a prism. But how can a prism potentially change the future of solar efficiency we hear you ask?

    Our own Dr Chris Fell of the CSIRO Photovoltaic Performance Laboratory explains.

    “The UNSW device captures light from all directions onto two separate cells, while only taking up the space of a single cell. The cells and the prism work together to extract the maximum energy from sunlight, using a special reflective layer and multi‑junction technology to split the light into four separate colour bands,” he says.

    Easy! Well, not quite.

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    Those panels on your roof would’ve started out in a lab, in the form of a solar cell.

    Rooftops are where it’s at

    It may be about 10 years until we may see this technology deployed on rooftops across Australia due to the manufacturing costs. Dr Keevers said, “This encouraging result shows that there are still advances to come in photovoltaics research to make solar cells even more efficient. Extracting more energy from every beam of sunlight is critical to reducing the cost of electricity generated by solar cells as it lowers the investment needed, and delivering payback faster.”

    Advance Australia solar

    Research Group Leader for Solar Energy Systems, Dr Greg Wilson, commenting on the record announcement said, “The UNSW result is a fine example of how Australian R&D is breaking the mould and shaping the future of solar on the international stage. At CSIRO we carry out extensive research across the entire technology chain for solar including new materials discovery, device fabrication and optimisation, materials characterisation and cell performance determination, energy yield and system design.”’

    “The advances made by UNSW build on a long history of breakthroughs in solar photovoltaics led by Professor Green that have helped grow a world-wide industry. Research investment in solar is not only an investment in our future, it’s an investment in innovation for Australia” added Greg.

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    Our researchers aren’t holding a purple snake; it’s printable solar cells.

    What’s next for solar cells?

    As the leading research agency in Australia (we like saying that, it makes us feel all warm and fuzzy), we have a whole energy business unit dedicated to renewable energy research including two solar research fields to test all the latest whizz-bang developments in large-scale solar technology. Our approach to renewable energy incorporates understanding of the impacts of solar on the electrical grid to ensure we have access to stable electricity, and how to use it in the most efficient way.

    Find out more about our work in renewables and energy on our website.

    See the full article here .

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    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
  • richardmitnick 8:41 am on February 5, 2016 Permalink | Reply
    Tags: , , , Solar Power   

    From GIZMODO: “Morocco Switches on First Phase of the World’s Largest Solar Plant” 

    GIZMODO bloc

    GIZMODO

    2.5.16
    Jamie Condliffe

    Solar Panels in Morocco
    Image by AP

    Yesterday, Morocco switched on the first section of its new Ouarzazate solar power plant. The new installation already creates 160 megawatts of power and is expected to grow to cover 6,000 acres by 2018—making it the largest in the world.

    The first wave of power production is known as Noor 1. Situated in the Sahara Desert, its crescent-shaped solar mirrors follow the sun to soak up sunlight all day long. The mirrors, each of which is 40 feet tall, focus light onto a steel pipeline that carries a synthetic thermal oil solution. The oil in those pipes can reach 740℉, and that’s what’s used to create electricity: The heat is used to create steam which drives turbines. The hot oil can be stored to create energy overnight, too.

    Noor 1 will be joined over time by Noor 2 and 3 which are expected to be finished by 2018. When those sections come online, the whole plant will cover an areas of over 6,000 acres, which is larger than the country’s capital city of Rabat. With the extra mirrors in place, the plant will generate 580 megawatts of electricity—enough to provide energy for 1.1 million people.

    But, as our own George Dvorsky has pointed out, that wasn’t always to be the case. The initial plan was to deliver the generated electricity to Europe but several partners pulled out. Interventions by the African Development Bank and the Moroccan government saved the project, though, and are now using it to meet Morocco’s own power demands. As of today, it will do just that.

    See the full article here .

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    “We come from the future.”

    GIZMOGO pictorial

     
  • richardmitnick 1:19 pm on January 18, 2016 Permalink | Reply
    Tags: , , Solar Power   

    From EPFL: “Cheaper solar cells with 20.2% efficiency” 

    EPFL bloc

    École Polytechnique Fédérale de Lausanne EPFL

    18.01.16
    Nik Papageorgiou

    Temp 1
    EPFL scientists have developed a solar-panel material that can cut down on photovoltaic costs while achieving competitive power-conversion efficiency of 20.2%.

    Some of the most promising solar cells today use light-harvesting films made from perovskites – a group of materials that share a characteristic molecular structure. However, perovskite-based solar cells use expensive “hole-transporting” materials, whose function is to move the positive charges that are generated when light hits the perovskite film. Publishing in Nature Energy, EPFL scientists have now engineered a considerably cheaper hole-transporting material that costs only a fifth of existing ones while keeping the efficiency of the solar cell above 20%.

    As the quality of perovskite films increases, researchers are seeking other ways of improving the overall performance of solar cells. Inadvertently, this search targets the other key element of a solar panel, the hole-transporting layer, and specifically, the materials that make them up. There are currently only two hole-transporting materials available for perovskite-based solar cells. Both types are quite costly to synthesize, adding to the overall expense of the solar cell.

    To address this problem, a team of researchers led by Mohammad Nazeeruddin at EPFL developed a molecularly engineered hole-transporting material, called FDT, that can bring costs down while keeping efficiency up to competitive levels. Tests showed that the efficiency of FDT rose to 20.2% – higher than the other two, more expensive alternatives. And because FDT can be easily modified, it acts as a blueprint for an entire generation of new low-cost hole-transporting materials.

    “The best performing perovskite solar cells use hole transporting materials, which are difficult to make and purify and are prohibitively expensive, costing over €300 per gram, preventing market penetration,” says Nazeeruddin. “By comparison, FDT is easy to synthesize and purify, and its cost is estimated to be a fifth of that for existing materials – while matching, and even surpassing their performance.”

    This study was led by EPFL’s Group for Molecular Engineering of Functional Materials, in collaboration with the Istituto di Scienze e Tecnologie Molecolari del Consiglio Nazionale delle Ricerche (Italy), Panasonic Corporation (Japan), EPFL’s Laboratory for Photomolecular Science and Laboratory of Photonics and Interfaces, and the Qatar Environment and Energy Research Institute. It was funded by the European Union Seventh Framework Programme (MESO; ENERGY; NANOMATCELL), the Swiss National Science Foundation, and Nano-Tera.

    Reference

    Saliba M, Orlandi S, Matsui T, Aghazada S, Cavazzini M, Correa-Baena J-P, Gao P, Scopelliti R, Mosconi E, Dahmen KH, De Angelis F, Abate A, Hagfeldt A, Pozzi G, Graetzel M, Nazeeruddin MK. A molecularly engineered hole-transporting material for e cient perovskite solar cells.Nature Energy 15017, 18 January 2016. DOI: 10.1038/NENERGY.2015.17

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    EPFL is Europe’s most cosmopolitan technical university with students, professors and staff from over 120 nations. A dynamic environment, open to Switzerland and the world, EPFL is centered on its three missions: teaching, research and technology transfer. EPFL works together with an extensive network of partners including other universities and institutes of technology, developing and emerging countries, secondary schools and colleges, industry and economy, political circles and the general public, to bring about real impact for society.

     
  • richardmitnick 10:50 am on December 6, 2015 Permalink | Reply
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    From The Conversation: “How a global solar alliance can help developing countries” 

    Conversation
    The Conversation

    December 4, 2015
    Xavier Lemaire

    The International Solar Alliance announced by India at the Paris climate conference invites together 120 countries to support the expansion of solar technologies in the developing world.

    The cost of solar cells has decreased spectacularly over the past four decades, and the trend seems likely to continue. Solar energy has moved from a niche market for providing power in remote places (at the very beginning in 1958 to space satellites) to a mainstream technology which feeds into the national grid.

    Most richer countries have been supporting solar power for some time and the rest of the world is now catching up, turning to solar not only for energy access in remote areas but to power cities. Emerging countries such as China, India, Brazil, Thailand, South Africa, Morocco or Egypt are investing in large solar plants with ambitious targets. In developing countries such as Bangladesh, Ethiopia, Kenya, Rwanda, Senegal or Ghana, solar farms or the large roll-out of solar home systems are a solution to unreliable and insufficient electricity supplies.

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    Most developing countries benefit from high solar radiation. Source: SolarGIS © 2015 GeoModel Solar

    Large solar farms can be built in just a few months – compared to several years for a coal plant and even longer for a nuclear plant – without generating massive environmental and health damages. Modular decentralised generation with solar is a way to increase access to energy while still remaining on top of rapidly increasing appetites for electricity.

    Culture of innovation

    This alliance could boost the solar market in the Global South by accelerating the circulation of knowledge, facilitating technology transfer and securing investments. Such a partnership would aim to create a common culture among people working in solar energy. Permanent innovation is the key to success in a field where technologies evolve fast and where norms and standards are not yet established. So an alliance could help countries exchange policy ideas while benchmarking performance against each other.

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    The decrease of the price of solar cells: a long term trend. Source: Bloomberg New Energy Finance & pv.energytrend.com Author provided

    Indeed in developing countries, where regulations and regimes tend to be less stable, investments suffer from a perceived risk. Given that the initial construction of solar plants makes up most of their cost (sunlight, after all, is free so ongoing expenses are minimal), the business model requires them to run for a long period. High risk means higher costs of financing the initial investment. Countries with well-designed regulatory frameworks and policies can reduce risk and attract investors.

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    Not California or Spain – this is Egypt. Green Prophet, CC BY

    The alliance could also support a network of universities and local research centres in each country to capitalise on local experience and build knowledge. Research and development can then more easily target the specific needs of developing countries.
    … and the real politics of renewables

    The intensification of globalisation and competition between technology firms and utilities is sparking a revolution in the electricity sector which could result in a new world of energy providers. A number of countries are keen to position themselves as leaders.

    For the moment, both China and India want massive investments in solar only on top of further investments in new coal and gas plants. They need to make their growth less carbon intensive – but do not yet consider solar power as a complete substitute for fossil fuels.

    But renewables accounted for nearly half of all new power generation capacity across the world last year. As the cost of solar power is falling to the same level as traditional energy supplies all over the world, some players in the electricity sector are – willingly or not – shifting away from fossil fuels. The decarbonisation of the electricity sector may be not just an empty political pledge, but an economic necessity.

    See the full article here .

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    The Conversation US launched as a pilot project in October 2014. It is an independent source of news and views from the academic and research community, delivered direct to the public.
    Our team of professional editors work with university and research institute experts to unlock their knowledge for use by the wider public.
    Access to independent, high quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to promote better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversation.

     
  • richardmitnick 10:41 am on August 26, 2015 Permalink | Reply
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    From ars technica: “Quantum dots may be key to turning windows into photovoltaics” 

    Ars Technica
    ars technica

    Aug 26, 2015
    John Timmer

    1
    Some day, this might generate electricity. Flickr user Ricardo Wang

    While wind may be one of the most economical power sources out there, photovoltaic solar energy has a big advantage: it can go small. While wind gets cheaper as turbines grow larger, the PV hardware scales down to fit wherever we have infrastructure. In fact, simply throwing solar on our existing building stock could generate a very large amount of carbon-free electricity.

    But that also highlights solar’s weakness: we have to install it after the infrastructure is in place, and that installation adds considerably to its cost. Now, some researchers have come up with some hardware that could allow photovoltaics to be incorporated into a basic building component: windows. The solar windows would filter out a small chunk of the solar spectrum and convert roughly a third of it to electricity.

    As you’re probably aware, photovoltaic hardware has to absorb light in order to work, and a typical silicon panel appears black. So, to put any of that hardware (and its supporting wiring) into a window that doesn’t block the view is rather challenging. One option is to use materials that only capture a part of the solar spectrum, but these tend to leave the light that enters the building with a distinctive tint.

    The new hardware takes a very different approach. The entire window is filled with a diffuse cloud of quantum dots that absorb almost all of the solar spectrum. As a result, the “glass” portion of things simply dims the light passing through the window slightly. (The quantum dots are actually embedded in a transparent polymer, but that could be embedded in or coat glass.) The end result is what optics people call a neutral density filter, something often used in photography. In fact, tests with the glass show that the light it transmits meets the highest standards for indoor lighting.

    Of course, simply absorbing the light doesn’t help generate electricity. And, in fact, the quantum dots aren’t used to generate the electricity. Instead, the authors generated quantum dots made of copper, indium, and selenium, covered in a layer of zinc sulfide. (The authors note that there are no toxic metals involved here.) These dots absorb light across a broad band of spectrum, but re-emit it at a specific wavelength in the infrared. The polymer they’re embedded in acts as a waveguide to take many of the photons to the thin edge of the glass.

    And here’s where things get interesting: the wavelength of infrared the quantum dots emit happens to be very efficiently absorbed by a silicon photovoltaic device. So, if you simply place these devices along the edges of the glass, they’ll be fed a steady diet of photons.

    The authors model the device’s behavior and find that nearly half the infrared photons end up being fed the photovoltaic devices (equal amounts get converted to heat or escape the window entirely). It’s notable that the devices are small, though (about 12cm squares)—larger panes would presumably allow even more photons to escape.

    The authors tested a few of the devices, one that filtered out 20 percent of the sunlight and one that only captured 10 percent. The low-level filter sent about one percent of the incident light to the sides, while the darker one sent over three percent.

    There will be losses in the conversion to electricity as well, so this isn’t going to come close to competing with a dedicated panel on a sunny roof. Which is fine, because it’s simply not meant to. Any visit to a major city will serve as a good reminder that we’re regularly building giant walls of glass that currently reflect vast amounts of sunlight, blinding or baking (or both!) the city’s inhabitants on a sunny day. If we could cheaply harvest a bit of that instead, we’re ahead of the game.

    Nature Nanotechnology, 2015. DOI: 10.1038/NNANO.2015.178 (About DOIs).

    See the full article here.

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    Ars Technica was founded in 1998 when Founder & Editor-in-Chief Ken Fisher announced his plans for starting a publication devoted to technology that would cater to what he called “alpha geeks”: technologists and IT professionals. Ken’s vision was to build a publication with a simple editorial mission: be “technically savvy, up-to-date, and more fun” than what was currently popular in the space. In the ensuing years, with formidable contributions by a unique editorial staff, Ars Technica became a trusted source for technology news, tech policy analysis, breakdowns of the latest scientific advancements, gadget reviews, software, hardware, and nearly everything else found in between layers of silicon.

    Ars Technica innovates by listening to its core readership. Readers have come to demand devotedness to accuracy and integrity, flanked by a willingness to leave each day’s meaningless, click-bait fodder by the wayside. The result is something unique: the unparalleled marriage of breadth and depth in technology journalism. By 2001, Ars Technica was regularly producing news reports, op-eds, and the like, but the company stood out from the competition by regularly providing long thought-pieces and in-depth explainers.

    And thanks to its readership, Ars Technica also accomplished a number of industry leading moves. In 2001, Ars launched a digital subscription service when such things were non-existent for digital media. Ars was also the first IT publication to begin covering the resurgence of Apple, and the first to draw analytical and cultural ties between the world of high technology and gaming. Ars was also first to begin selling its long form content in digitally distributable forms, such as PDFs and eventually eBooks (again, starting in 2001).

     
  • richardmitnick 4:22 pm on August 23, 2015 Permalink | Reply
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    From Yale: “With Polymer Blend, Researchers Develop More Efficient Solar Cells” 

    Yale University bloc

    Yale University

    08/12/2015
    No Writer Credit

    1

    Yale researchers have significantly increased the efficiency of a polymer solar cell by using a technique that mimics how plants use solar energy and forcing two otherwise incompatible molecules to work together to cover the full color spectrum.

    The researchers, in Dr. Andre Taylor’s Transformative Materials & Devices Lab, developed a solar cell that performed 22.5 percent better than conventional organic solar cells. Their results were published online this month in the Journal of Materials Chemistry A demonstrating a power conversion efficiency of 8.7 percent.

    Most commercial solar cells today are made from silicon. But polymer cells cost less and weigh less, making them an appealing alternative. The problem is that they’re not very efficient – they fail to convert nearly half their absorbed light energy to electrical power. That’s partly because the polymers used in these cells don’t line up well enough to allow energy to exit the cell easily.

    However, because polymers have a mechanical flexibility that silicon cells don’t, researchers are hopeful that they will find ways around these shortcomings.
    “We are starting to approach the limits for improvements that can done with conventional silicon solar cells,” Taylor said. “But with organic polymers you can tweak and do things to them with significant results.”

    In a 2013 study in Nature, Taylor’s lab was the first to show that this can occur between small molecules and a polymer known as P3HT. It’s now demonstrating some of those same benefits in polymer blends.

    Conventional organic solar cells, known as binary solar cells, have one polymer serving as an electron donor and a fullerene derivative as the electron acceptor. Ternary cells – the kind used in this study – can have either two donors and one acceptor or one donor and two acceptors. In most cases, though, more efficient ternary cells usually have two donors and one acceptor since donors are predominantly responsible for light absorption.

    The most recent study uses two polymers, P3HT and PTB7, which are both light-sensitive molecules known as chromophores. In one sense, the two are complementary: P3HT absorbs the blue-green side of the light spectrum, while PTB7 absorbs primarily at the yellow-red spectrum. Together, the two cover a large portion of the visible-light spectrum. Rather than working independently, the proximity of the two polymers also facilitates what’s known as Förster resonance energy transfer (FRET) to occur. That’s when energy is transferred between two chromophores over long distances.

    The problem is how these two polymers align.

    “We are blending two different types of polymers, so they align in different ways,” said TengHooi Goh, lead author of the paper. “P3HT aligns in a way that it stands like a wall and PTB7 is positioned more like a stack of pancakes.”

    “They work well optically, but the contradicting alignment is bad for electron transport,” added Taylor, senior author of the paper.

    To get around this problem, the researchers used a technique known as solvent vapor annealing (SVA), in which they chemically modify the properties of the polymers to better align. The more commonly used method is thermal annealing, but heat has been found to diminish the performance of the polymers. Goh said that SVA can potentially solve incompatible alignment problems in complex polymer systems and drive the efficiency of organic photovoltaics to a new heights.

    The other authors of the paper, Panchromatic Polymer-polymer Ternary Solar Cells Enhanced by Förster Resonance Energy Transfer and Solvent Vapor Annealing, are Jing-Shun Huang, Benjamin Bartolome,Matthew Y. Sfeir, Michelle Vaisman, and Minjoo Lee.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

     
  • richardmitnick 9:53 am on August 18, 2015 Permalink | Reply
    Tags: , , Solar Power   

    From wired: “How Much Can You Save With Solar Panels? Just Ask Google” 

    Wired logo

    Wired

    08.18.15
    Cade Metz

    1
    Google

    If you’re considering solar power but aren’t quite sure it’s worth the expense, Google wants to point you in the right direction. Tapping its trove of satellite imagery and the latest in artificial intelligence, the company is offering a new online service that will instantly estimate how much you’ll save with a roof full of solar panels.

    3
    The first three concentrated solar power (CSP) units of Spain’s Solnova Solar Power Station in the foreground, with the PS10 and PS20 solar power towers in the background

    On Monday, the company unveiled Project Sunroof, a tool that calculates your home’s solar power potential using the same high-resolution aerial photos Google Earth uses to map the planet. After creating a 3-D model of your roof, the service estimates how much sun will hit those solar panels during the year and how much money the panels could save you over the next two decades. “People search Google all the time to learn about solar,” says Google’s Joel Conkling. “But it would be much more helpful if they could learn whether their particular roof is a good fit.”

    2
    Google

    The service is now available for homes in the San Francisco Bay Area, central California, and the greater Boston area. Google is headquartered in California, you see, and project creator Carl Elkin lives in Boston. Based in the company’s Cambridge offices, Elkin typically works on Google’s search engine, but he developed Project Sunroof during his “20 percent time“—that slice of the work week Googlers can use for independent projects.

    How Google Parses Your Roof

    Elkin’s own home has solar panels, and he once volunteered with Solarize Massachusetts to promote solar in the Bay State. He and Google see Project Sunroof pushing solar use further still. “We people want to go solar but don’t understand how cheap it is,” Elkin says. “I wanted people to understand that they can actually save money.”

    As Google notes in a blog post announcing Project Sunroof, the time is ripe for such a tool. “This is an extremely useful thing,” says Roland Winston, a professor at the University of California, Merced, who specializes in solar energy. “Solar technology is cheaper than ever.” Indeed, others have developed services along these lines, including academics and companies like Geostellar and Mapdwell.

    But Google’s service is a bit different. It has Google behind it—and the company is taking a particularly comprehensive approach. In analyzing satellite images of your home, Google uses “deep learning” neural networks to separate your roof from the surrounding trees and shadows. “Even a strong solar advocate like me wouldn’t recommend putting solar panels on your trees,” Elkin says. Mimicking the web of neurons in the human brain, this sort of neural network is the same technology used to recognize faces on Facebook or instantly translate from one language to another on Skype.

    Project Sunroof also simulates the shadows that typically cover your home on any given day (see animation above), and it tracks local weather patterns. “We’re able show how much energy is hitting each part of your roof,” Conkling says. And if you like, you can further hone that company’s calculations by providing how much you typically spend on electricity (otherwise, the service relies on public utility rates in your area).

    Beyond Elkin’s personal crusade, Google has a long history of advocating for solar power. In addition to investing in solar as a means of powering its global network of data centers, the company previously has invested in residential solar projects. But this isn’t mere charity work. Project Sunroof also recommends solar providers in your area, and it plans to eventually take a referral fee from these providers. “We want to help people understand the potential of solar power,” says Conkling. “But we can make some money off of that as well.”

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

     
  • richardmitnick 12:35 pm on December 27, 2014 Permalink | Reply
    Tags: , , Solar Power   

    From Discovery: “World’s Largest Floating Solar Plant Planned for Japan” 

    Discovery News
    Discovery News

    Dec 24, 2014
    Glenn McDonald

    An image of the Kyocera Corporation’s existing Kagoshima Nanatsujima power plant in Japan. The company’s new project will be the largest fully-floating solar installation in the world.

    1

    If you’ve ever been out in a boat on a hot summer day, you know that open water gathers a lot of sun and heat. Engineers in Japan are hoping to harness that power with the construction of what will be the planet’s largest floating solar power installation.

    Japan’s Kyocera Corporation has already leveraged the power of open water with shoreline solar installations like the fixed Kagoshima Nanatsujima plant, pictured above. The new project, however, will be built around 50,000 solar collection modules actually afloat on the Yakamura Dam reservoir.

    The modules will cover a water surface area of around 180,000 square meters. Engineers estimate the plant will generate more than 15.6 megawatt hours (MWh) per year. That’s enough to power approximately 4,700 average households.

    More numbers: According to the company’s projections, the floating power plant will gather enough solar power from the surface of the dam to offset about 7,800 tons of carbon dioxide emissions annually. The facility will also include an education center adjacent to the plant, to provide classes for local students on environmental issues.

    Floating Nuclear Plant Would Ride Out Tsunamis

    “When we first started R&D for solar energy in the mid 1970’s, the technology was only viable for small applications such as street lamps, traffic signs and telecommunication stations in mountainous areas,” said Nobuo Kitamura, Kyocera senior executive officer, in press materials for the project.

    “Since then, we have been working to make solar energy use more ubiquitous in society. We are excited to work with our partners on this project, taking another step forward by utilizing untapped bodies of water as solar power generation sites.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
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