Wednesday, September 28, 2011

Latest from: CleanTechnica

Latest from: CleanTechnica

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Quantum Dot Solar Cell Improvements Show Remarkable Potential to Balance Solar Performance & Cost

Posted: 28 Sep 2011 01:43 PM PDT

Innovations in quantum dot solar cells may reduces costs while improving performance

Next time someone needs an extra PV panel, they might think about bringing along a spray can so they can create their own spray-on quantum dot solar cells.

For those wondering about this odd-sounding configuration, qizmag has written about the very heady topic of colloidal quantum dot solar cells. This report is based on an innovative study recently published in Nature Materials. "Quantum dot solar cells use nanoscale semiconductors to produce electricity and promise low-cost production. Better, because they can be sprayed or painted on, they provide many low-cost benefits in terms of installation," concludes Noel McKeegan at gizmag.

As far as innovation on the technology front, this one is a winner. In tabulating efficiency ratings, however, quantum cells don’t seem to perform as well as either silicon-based or CIGS solar cells. This may soon change. Nature Materials writes that a new efficiency record for wrapping colloidal quantum dot solar cells may represent a step towards narrowing the gap.

To make quantum dot solar cells that can be sprayed or painted on, the tiny nanoscale semiconductors need to be dispersed evenly within another substance – this is known as a colloid. Organic molecules have successfully been used to create colloidal quantum dot (CQD) solar cells but the minute space they take up between the nanoparticles has a negative impact on the flow of electrons and in turn the efficiency of the cell.

On improving the efficiency of a colloidal quantum dot solar cell, researchers from the University of Toronto, King Abdullah University of Science & Technology and Pennsylvania State University report having developed a way to coat or passivate the quantum dots in inorganic ligands. This approach improves efficiency by reducing electron “traps” in the material and packing more quantum dots into the same amount of nanospace, while at the same time retaining the colloid characteristics of quantum dots bound together by organic molecules.

“We wrapped a single layer of atoms around each particle,” explains Dr. Jiang Tang, the first author of the paper. “As a result, they packed the quantum dots into a very dense solid.”

The University of Toronto and King Abdullah University of Science & Technology have signed a licensing agreement in order to commercialize this technology, which also has other potential applications.

“The world – and the marketplace – need solar innovations that break the existing compromise between performance and cost,” said Ted Sargent, the author on the work and holder of the Canada Research Chair in Nanotechnology at the University of Toronto.

The researchers outline their work in the paper Collodial-quantum-dot photovoltaics using atomic-ligand passivation in the latest issue of Nature Materials.

Photo Credit: Pink Sherbet Photography and University of Toronto


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Shake Remote, Turn Off Television

Posted: 28 Sep 2011 09:01 AM PDT

With potential laptops powered by typing and watches powered by moving one’s arm, energy harvesting is a growing field with a number of cool products.  In Japan, Murata Manufacturing is firmly on board the trend with sensors to detect and convert vibration, temperature gradient, ambient heat, and light into small amounts of electricity. Their most recent offering uses a variety of sensors in combination with a flexible plate to send several different signals without the need for batteries.

The heart of Murata's new idea is its new flexible film at the center and its combination with both sensors and a wireless transmitter. The movement of the flexible plate triggers the sensors at the edge, which use the energy harvested from the motion to send a signal. Which signal is sent depends on how the plate was manipulated – bent, twisted, shaken, etc.

While there are a number of uses for the plate, Murata has incorporated it into the common and widespread TV remote control to showcase its versatility. Bending the plate slowly changes the volume, while bending it quickly (or taking it by one end and shaking it) sends a signal to turn the TV on or off. Twisting the plate changes the channel, and twisting it quickly changes the input source.

Murata Manufacturing hopes to use its new combination of no-battery energy harvesting, sensors, and wireless transmission to provide products in a number of fields. The company will present the many uses of energy harvesting and their practical applications at the Cutting Edge IT & Electronics Comprehensive Exhibition (CEATEC JAPAN 2011) at the Makuhari Messe International Convention Center in Chiba from October 4th to October 8th.

Source: Eco Japan. Picture: Murata Manufacturing Co., Ltd


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Responding to a Trillion-Dollar Call to Retrofit Buildings

Posted: 28 Sep 2011 08:57 AM PDT

Positherm thermal demo.

The serial entrepreneur Sir Richard Branson brought to life an international need and business opportunity centered on thermally upgrading existing buildings, the world's biggest users of energy. NYC's Empire State Building was able to reduce its energy use by 40%, saving ~$400,000/year thanks to a retrofit. Sir Richard founded the "Carbon War Room" based in Washington D.C. to unite international entrepreneurs, business leaders, researchers, policy experts, thinkers, to focus on solutions, not rhetoric, in efforts to tangibly combat climate change while creating 1000's of "green" jobs.

One game-changer leveraging Sir Richard's vision is a LEED-rated composite which is many times stronger than concrete but is 80% lighter in weight. Positherm (PT) has ballistic properties, is water-, insect-, hailstone- and hurricane-resistant, but has thermal properties akin in part to NASA Space Shuttle tiles. PT is a multi-billion dollar global economic and environmental opportunity to make a difference.

Traditional tile, shingle and membrane roofing are cosmetic vestiges of the past. PT becomes an integral part of a structure, residential or commercial. PT is seamless, permanent and can be colored and textured to appear as traditional roofing. PT substantively adds strength and saves energy. PT more than pays for itself compared to what we know does not work in the 21st century.

There are no adhesives nor mechanical fasteners required. PT is sprayed or applied by a trowel. When "setting," photovoltaic (PV) equipment or tracks for mounting PV' can be imbedded in PT, thus "Solarizing the World on the Cheap" by cutting installed solar costs by half, or more*.

PT can be applied to exterior walls to cosmetically and structurally upgrade both existing and new construction. PT can be applied on the interior of a structure on walls and floors serving as a radiant heat source, as an option.

A 5/16 inch (5mm) thick section of PT will support the weight of a pickup truck.

PT cuts energy costs as well as property insurance premiums, adds appraisal value, and is eligible for energy rebates and tax credits depending on local incentives.

In the 27-nation EU, which has adopted cap-and-trade legislation, PT has enormous markets. Alone, the cost of thermal upgrading of buildings built in Germany prior to 1970 is estimated to be $40 Trillion!

Walter Feuchs, founder of PT, and his partner in this development will unveil PT at Abu Dhabi's World Future Energy Summit (WFES 2012) in January in "The International Year for Sustainable Energy for All." Abu Dhabi invested $15 billion to build a sustainable city in the desert, Masdar City, which is symbolic of that region's commitment to the issue. An Abu Dhabi foundation recently committed to fund 5000 houses in Columbia, South America, employing PT as the basis for walls, roofs and interior.

world house nyc

World House exhibit at the UN in NYC.

Feuchs and his business partner will franchise PT internationally. Feuchs is already noted for the 30-minute assembly of a "World House" at the UN in NYC and other “game-changing” innovations such as a zero-energy house (ZEH) platform technology. A house that energizes itself and a form of transportation saves, domestically, $560,771 in the course of a 30-year mortgage. This standard could be the basis for 100's of sustainable communities. Spin-offs include sustainable classrooms/clinics, food "factories", and beyond.

*LBNL estimates that solar installation costs represent 75%-80% of total costs. By combining “Positherm” a permanent seamless roofing that fuses to a substrate could include embedding PV’s, or mounting tracks in Positherm as it “sets” represents a significant savings. The foregoing can be prepared in a factory environment with a 8 ft x 24 ft fiber composite structural and insulated roof panel that is fire-, insect- and water-resistant. In the case of the foreging panel, when selecting a peel and stick PV such as Uni-Solar, the task is simpler. There is no need for a membrane.


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SolarWindows from New Energy Technologies

Posted: 28 Sep 2011 07:25 AM PDT

skyscraper windows

We’ve covered these Solar Windows from New Energy Technologies in the past, but sister site Green Building Elements recently did a slightly more detailed piece on them, so I thought I’d share it with you. Here’s the first part of it:

Solar technologies are constantly evolving, becoming more and more effective as new designs and discoveries are made in the field. New Energy Technologies continues this trend with the advent of their new product, the SolarWindow. The new windows will be the first see-through windows that can also generate electricity through a specially designed spray put on the window.

They are developing six different types of SolarWindows for different situations:

  • Commercial- A flat glass window for installation in commercial buildings
  • Structural Glass- Structural glass walls and curtains for tall structures
  • Architectural Glass- Textured and decorative interior glass walls, room dividers, etc.
  • Residential- Window glass for installation in residential homes
  • Flex- Flexible films that can be applied to existing windows
  • BIPV- Building product components associated with building-integrated-photovoltaic(BIPV) applications in homes, buildings, and office towers.

Read the second part here: New SolarWindows Would Be First See-Through Windows To Generate Electricity

Image Credit: AttributionNoncommercialShare Alike Some rights reserved by swisscan


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German Small Solar Cheaper Than U.S. Big Solar

Posted: 28 Sep 2011 04:00 AM PDT

The U.S. has a hodge-podge of utility, state and federal tax-based incentives.  The Germans have a comprehensive feed-in tariff, providing CLEAN contracts (in the U.S. parlance) to anyone who wants to go solar (or wind, or biogas, etc).  What does that mean for the price of solar?

From a study of U.S. solar prices reported in Renewables International:

Perhaps most surprisingly, the study found that the planned arrays [in the U.S.] larger than one megawatt have an average installed price of $4.50 per watt, with only a third of the systems in the pipeline coming in at prices below four dollars per watt. As Renewables International reported in January, the installed system price of photovoltaics in the US was easily 60 percent above the level in Germany in 2010 for equivalent system sizes (arrays smaller than 100 kilowatts).

While large-scale U.S. solar comes in at $4.50 per Watt, small-scale German solar (10-100 kilowatts) averaged $3.90 per Watt in 2010 and $3.40 per Watt in the 2nd quarter of 2011.  The German price advantage in solar is like having a pint of your favorite craft or microbrew beer for less than a Budweiser.

Of course, price comparisons are tricky, because the U.S. has no clearinghouse for solar installation data (again, the result of its hodge-podge federal-state-local policies).  A just-released study of U.S. solar prices by the Solar Energy Industries Association found utility-constructed solar in the U.S. is now being installed at $3.75 per Watt.  It’s not clear how much overlap there is between that data and the Renewables International report of $4.50 per Watt for solar 1 megawatt and larger.

Either way, small German rooftop solar is still beating U.S. large-scale solar.  Here’s a chart illustrating that cost differential, with U.S. and German prices updated for the 2nd quarter of 2011.

germany solar prices us solar prices

If the German solar prices are wunderbar, that makes the U.S. “furchtbar.”

This post originally appeared on Energy Self-Reliant States, a resource of the Institute for Local Self-Reliance’s New Rules Project.


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Ford Unveils Plans to Build Chinese Electric Vehicle

Posted: 28 Sep 2011 02:30 AM PDT

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