David Kirkpatrick

October 26, 2010

World’s largest solar installation coming to California

Via KurzweilAI.net — That’s some serious solar capacity.

US approves world’s biggest solar energy project in California

October 26, 2010 by Editor

The U.S. Department of Interior approved on Monday a permit for Solar Millennium, LLC to build the largest solar energy project in the world — four  plants at the cost of one billion dollars each — in southern California.

The project is expected to generate up to 1,000 Megawatts of energy, enough electricity to annually power more than 300,000 single-family homes, more than doubling the solar electricity production capacity of the U.S.

Once constructed, the Blythe facility will reduce CO2 emissions by nearly one million short tons per year, or the equivalent of removing more than 145,000 cars from the road. Additionally, because the facility is “dry-cooled,” it will use 90 percent less water than a traditional “wet-cooled” solar facility of this size. The Blythe facility will also help California take a major step toward achieving its goal of having one third of the state’s power come from renewable sources by the year 2020.

The entire Blythe Solar Power Project will generate a total of more than 7,500 jobs, including 1,000 direct jobs during the construction period, and thousands of additional indirect jobs in the community and throughout the supply chain. When the 1,000 MW facility is fully operational it will create more than 220 permanent jobs.

Adapted from materials provided by Solar Millennium, LLC.

 

 

 

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October 20, 2010

Fresh drinking water through solar power

This has the potential to be a real game changer. Among all the other problems out there, one very pervasive issue that gets intermittent lip service is potable, or the lack thereof, water. A portable desalination device could save lives in a variety of situations.

From the link:

The portable system could also be used in remote areas where supplying energy and clean water can be logistically complex and expensive, such as desert locations or farms and small villages in developing countries.

Led by Steven Dubowsky, a professor in both the Department of Mechanical Engineering and the Department of Aeronautics and Astronautics, and graduate students Amy Bilton and Leah Kelley, the group built a small prototype of the system last spring to test algorithms they had developed to run it. They have since demonstrated that the prototype is capable of producing 80 gallons of water a day in a variety of weather conditions. They estimate that a larger version of the unit, which would cost about $8,000 to construct, could provide about 1,000 gallons of water per day. Dubowsky and his students also estimate that one C-130 cargo airplane could transport two dozen desalination units — enough to provide water for 10,000 people.

The team presented a paper reporting preliminary results about its prototype system last week at the EuroMed 2010-Desalination for Clean Water and Energy Conference.

October 2, 2010

Quantum dots may lead to ultraefficient solar cells

This sounds promising.

From the link (emphasis mine):

Although researchers have steadily increased the amount of electricity that solar cells can produce, they face fundamental limits because of the physics involved in converting photons to electrons in semiconductor materials. Now researchers at the University of Wyoming have demonstrated that by using novel nanomaterials called quantum dots, it might be possible to exceed those limits and produce ultraefficient solar cells.

The theoretical limitation of solar cells has to do with the widely varying amounts of energy from photons in sunlight. The amount varies depending on the color of the light. No matter how energetic the incoming photons are, however, solar cells can only convert one photon into one electron with a given amount of energy. Any extra energy is lost as heat. Scientists have hypothesized that quantum dots, because of their unusual electronic properties, could convert some of this extra energy into electrons. They’ve calculated that this approach could increase the theoretical maximum efficiency of solar cells by about 50 percent.

Solar dots: A micrograph shows lead-sulfide quantum dots, each about five nanometers across, coating an electrode of titanium dioxide.
Credit: Science

September 6, 2010

Self-assembling and reassembling solar cells

Okay, just yesterday I blogged that a lot of the time the mundane “a ha” moment that puts together well-known materials and processes leads to scientific advancement (the case I was referring to in the post was a simple acid bath technique that made creating solar cells much cheaper). And then again sometimes the big sexy breakthrough gets the headline (as usual) and really deserves it.

If this technique for solar cells that self-assembles the light-harvesting element in the cell, and then breaks it down for re-assembly essentially copying what plants do in their chloroplast, is able to reach acceptable levels of efficiency, it will be an absolute game-changer. Instead of a solar cell that’s (hopefully) constantly bombarded with the full effect of the sun and constantly degrading under the solar assault, these cells will essentially be completely renewed by each reassembly. No degradation over time, just a brand new light-harvesting element with a relatively simple chemical process.

From the second link:

The system Strano’s team produced is made up of seven different compounds, including the carbon nanotubes, the phospholipids, and the proteins that make up the reaction centers, which under the right conditions spontaneously assemble themselves into a light-harvesting structure that produces an electric current. Strano says he believes this sets a record for the complexity of a self-assembling system. When a surfactant — similar in principle to the chemicals that BP has sprayed into the Gulf of Mexico to break apart oil — is added to the mix, the seven components all come apart and form a soupy solution. Then, when the researchers removed the surfactant by pushing the solution through a membrane, the compounds spontaneously assembled once again into a perfectly formed, rejuvenated photocell.

“We’re basically imitating tricks that nature has discovered over millions of years” — in particular, “reversibility, the ability to break apart and reassemble,” Strano says. The team, which included postdoctoral researcher Moon-Ho Ham and graduate student Ardemis Boghossian, came up with the system based on a theoretical analysis, but then decided to build a prototype cell to test it out. They ran the cell through repeated cycles of assembly and disassembly over a 14-hour period, with no loss of efficiency.

September 5, 2010

Acid bath creates cheaper solar cells

A relatively simple brute force manufacturing step creates solar cells at much lower cost. The big, sexy breakthroughs are great  and technological leaps are fun, but a lot of the time it’s the almost mundane “a ha” moment that puts together well-known materials and processes that take a technology to the next step. This particular discovery sounds very promising since it both reduces production costs and almost retains maximum solar efficiency.

From the link:

A new low-cost etching technique developed at the U.S. Department of Energy’s National Renewable Energy Laboratory can put a trillion holes in a silicon wafer the size of a compact disc.

As the tiny holes deepen, they make the silvery-gray silicon appear darker and darker until it becomes almost pure black and able to absorb nearly all colors of light the sun throws at it.

At room temperature, the black silicon wafer can be made in about three minutes. At 100 degrees F, it can be made in less than a minute.

The breakthrough by NREL scientists likely will lead to lower-cost  that are nonetheless more efficient than the ones used on rooftops and in solar arrays today.

R&D Magazine recently awarded the NREL team one of its R&D 100 awards for Black Silicon Nanocatalytic Wet-Chemical Etch. Called “the Oscars of Invention,” the R&D 100 awards recognize the most significant scientific breakthroughs of the year.

Also from the link (and conveniently making my point above about “almost mundane ‘a ha’ moment”s):

In a string of outside-the-box insights combined with some serendipity, Branz and colleagues Scott Ward, Vern Yost and Anna Duda greatly simplified that process.

Rather than laying the gold with vacuums and pumps, why not just spray it on? Ward suggested.

Rather than layering the gold and then adding the acidic mixture, why not mix it all together from the outset? Dada suggested.

In combination, those two suggestions yielded even better results.

A silver wafer reflects the face of NREL research scientist Hao-Chih Yuan, before the wafer is washed with a mix of acids. The acids etch holes, absorbing light and turning the wafer black. Credit: Dennis Schroeder

August 23, 2010

200x fuel cell efficiency boost

The idea of a personalized energy system is very attractive. Talk about being able to go off the grid …

The release:

200-fold boost in fuel cell efficiency advances ‘personalized energy systems’

IMAGE: A new catalyst could help speed development of inexpensive home-brewed solar energy systems for powering homes and plug-in cars during the day (left) and for producing electricity from a fuel…

Click here for more information.

BOSTON, Aug. 23, 2010 — The era of personalized energy systems — in which individual homes and small businesses produce their own energy for heating, cooling and powering cars — took another step toward reality today as scientists reported discovery of a powerful new catalyst that is a key element in such a system. They described the advance, which could help free homes and businesses from dependence on the electric company and the corner gasoline station, at the 240th National Meeting of the American Chemical Society, being held here this week.

“Our goal is to make each home its own power station,” said study leader Daniel Nocera, Ph.D. “We’re working toward development of ‘personalized’ energy units that can be manufactured, distributed and installed inexpensively. There certainly are major obstacles to be overcome — existing fuel cells and solar cells must be improved, for instance. Nevertheless, one can envision villages in India and Africa not long from now purchasing an affordable basic system.”

Such a system would consist of rooftop solar energy panels to produce electricity for heating, cooking, lighting, and to charge the batteries on the homeowners’ electric cars. Surplus electricity would go to an “electrolyzer,” a device that breaks down ordinary water into its two components, hydrogen and oxygen. Both would be stored in tanks. In the dark of night, when the solar panels cease production, the system would shift gears, feeding the stored hydrogen and oxygen into a fuel cell that produces electricity (and clean drinking water as a byproduct). Such a system would produce clean electricity 24 hours a day, seven days a week — even when the sun isn’t shining.

Nocera’s report focused on the electrolyzer, which needs catalysts — materials that jumpstart chemical reactions like the ones that break water up into hydrogen and oxygen. He is with the Massachusetts Institute of Technology in Cambridge, Mass. Good catalysts already are available for the part of the electrolyzer that produces hydrogen. Lacking, however, have been inexpensive, long-lasting catalysts for the production of oxygen. The new catalyst fills that gap and boosts oxygen production by 200-fold. It eliminates the need for expensive platinum catalysts and potentially toxic chemicals used in making them.

The new catalyst has been licensed to Sun Catalytix, which envisions developing safe, super-efficient versions of the electrolyzer, suitable for homes and small businesses, within two years.

The National Science Foundation and the Chesonis Family Foundation provided funding for this study. Nocera did the research with post-doctoral researcher Mircea Dinca and doctoral candidate Yogesh Surendranath. The U.S. Department of Energy’s Advanced Research Projects Agency has recently awarded the team with a grant, which it plans to use to search for related compounds that can further increase the efficiency of its electrolyzer technology. The team hopes that nickel-borate belongs to a family of compounds that can be optimized for super-efficient, long-term energy storage technologies.

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The American Chemical Society is a non-profit organization chartered by the U.S. Congress. With more than 161,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

Update 9/2/10 — Someone really likes this story because here’s a follow-up release from yesterday.

August 17, 2010

Nanotech and solar efficiency

Nanotechnology and solar energy get a lot of virtual ink around here, and I always enjoy getting the chance to blog about both topics in the same post. This study finds that incorporating quantum dots in photovoltaic solar cells through nanoscience should both increase the efficiency of the cells and reduce their cost. A win-win all the way around.

From the link:

As the fastest growing energy technology in the world, solar energy continues to account for more and more of the world’s energy supply. Currently, most commercial photovoltaic power comes from bulk semiconductor materials. But in the past few years, scientists have been investigating how semiconductor nanostructures can increase the efficiency of solar cells and the newer field of solar fuels.

Although there has been some controversy about just how much nanoscience can improve solar cells, a recent overview of this research by Arthur Nozik, a researcher at the National Renewable Energy Laboratory (NREL) and professor at the University of Colorado, shows that semiconductor nanostructures have significant potential for converting solar energy into electricity


August 10, 2010

Ten percent solar boost with a mere sticker

Filed under: Business, Science — Tags: , , , — David Kirkpatrick @ 12:39 am

And these things can be applied to solar installations in the field. Talk about a simple improvement that goes a long, long way. Solar efficiency tends to go up in tiny increments unless it involves some sort of materials or process breakthrough. This news really is impressive.

From the link:

The power output of solar panels can be boosted by 10 percent just by applying a big transparent sticker to the front. Developed by a small startup called Genie Lens Technologies, the sticker is a polymer film embossed with microstructures that bend incoming sunlight. The result: the active materials in the panels absorb more light, and convert more of it into electricity.

The technology is cheap and could lower the cost per watt of solar power. Also, unlike other technologies developed to improve solar panel performance, this one can be added to panels that have already been installed.

The polymer film does three main things, says Seth Weiss, CEO and cofounder of Genie Lens, based in Englewood, CO. It prevents light from reflecting off the surface of solar panels. It traps light inside the semiconductor materials that absorb light and convert it to electricity. And it redirects incoming light so that rather than passing through the thin semiconductor material, it travels along its surface, increasing the chances it will be absorbed.

Power film: A thin plastic sheet covered with microscopic structures is applied to the front of a solar panel to increase the amount of light it absorbs.
Credit: Genie Lens Technologies

August 9, 2010

Is solar power cheaper than nuclear?

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 9:04 pm

Surprisingly, maybe so.

From the link:

One of the issues associated with shifting from using fossil fuels to alternative energy sources is the cost. While adherents of alternative energy tout its benefits, many are skeptical, pointing out that such alternatives are just too expensive. Advocates of nuclear power point out that it is less polluting (if you don’t count storage of spent fuel) than fossil fuels, and that it costs less than alternatives like solar power.

A new study out of Duke University, though, casts doubt on the idea that  is cheaper than . Using information from North Carolina, the study shows that solar power may be more cost efficient than nuclear power. With costs dropping on the production of photovoltaic cells, and with solar cells becoming increasingly efficient, it appears that — in North Carolina at least — solar installations offer a viable alternative to nuclear power, which is the source for about 20% of the electricity in the U.S.

August 5, 2010

Environmental Graffiti

Filed under: et.al., Media — Tags: , , , , — David Kirkpatrick @ 2:22 pm

I’m doing some posting at Environmental Graffiti on solar and other alternative energy sources. You can check out my first effort here. That post was built from one appearing here a couple of days ago.

Selenium improves solar efficiency

I like the “anti-sunscreen” intro to this news on improving the efficiency of photovoltaic solar cells with selenium.

The release:

Selenium makes more efficient solar cells

This release is also available in Chinese.

IMAGE: This is a sunset over the Pacific Ocean as seen from Highway 1 south of Monterey, Calif. LBNL’s Marie Mayer, who took the photo, calls sunlight and water “two sustainable…

Click here for more information.

College Park, MD (August 3, 2010) — Call it the anti-sunscreen. That’s more or less the description of what many solar energy researchers would like to find — light-catching substances that could be added to photovoltaic materials in order to convert more of the sun’s energy into carbon-free electricity.

Research reported in the journal Applied Physics Letters, published by the American Institute of Physics (AIP), describes how solar power could potentially be harvested by using oxide materials that contain the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, embedded selenium in zinc oxide, a relatively inexpensive material that could be promising for solar power conversion if it could make more efficient use of the sun’s energy. The team found that even a relatively small amount of selenium, just 9 percent of the mostly zinc-oxide base, dramatically boosted the material’s efficiency in absorbing light.

“Researchers are exploring ways to make solar cells both less expensive and more efficient; this result potentially addresses both of those needs,” says author Marie Mayer, a fourth-year University of California, Berkeley doctoral student based out of LBNL’s Solar Materials Energy Research Group, which is working on novel materials for sustainable clean-energy sources.

Mayer says that photoelectrochemical water splitting, using energy from the sun to cleave water into hydrogen and oxygen gases, could potentially be the most exciting future application for her work. Harnessing this reaction is key to the eventual production of zero-emission hydrogen powered vehicles, which hypothetically will run only on water and sunlight. Like most researchers, Mayer isn’t predicting hydrogen cars on the roads in any meaningful numbers soon. Still, the great thing about solar power, she says, is that “if you can dream it, someone is trying to research it.”

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The article, “Band structure engineering of ZnO1-xSex alloys” by Marie A. Mayer, Derrick T. Speaks, Kin Man Yu, Samuel S. Mao, Eugene E. Haller, and Wladek Walukiewicz will appear in the journal Applied Physics Letters. See: http://apl.aip.org/applab/v97/i2/p022104_s1

ABOUT APPLIED PHYSICS LETTERS

Applied Physics Letters, published by the American Institute of Physics, features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, Applied Physics Letters offers prompt publication of new experimental and theoretical papers bearing on applications of physics phenomena to all branches of science, engineering, and modern technology. Content is published online daily, collected into weekly online and printed issues (52 issues per year). See: http://apl.aip.org/

ABOUT AIP

The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world’s largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.

August 4, 2010

Lower cost solar cells

Yesterday I blogged about a new solar energy process that might supplant photovoltaics, at least in large-scale desert installations because of dramatically increased efficiency. Today it’s a breakthrough with photovoltaic solar cells in regards to production cost. I like seeing all this innovation is the solar space, especially since it’s a bit all over the map. Incremental improvement is always nice, but anytime research is going after all sorts of targets the odds of a major breakthrough go up.

From the second link:

One of the most promising technologies for making inexpensive but reasonably efficient solar photovoltaic cells just got much cheaper. Scientists at the University of Toronto in Canada have shown that inexpensive nickel can work just as well as gold for one of the critical electrical contacts that gather the electrical current produced by their colloidal quantum dot solar cells.

The change to nickel can reduce the cell’s already low material costs by 40 to 80 percent, says Lukasz Brzozowski, the director of the Photovoltaics Research Program in Professor Ted Sargent’s group. They present their research in the July 12, 2010 issue of Applied Physics Letters.

August 3, 2010

A completely new path to solar efficiency?

Maybe so. And if so this sounds very promising. I’ll go ahead and repeat my solar energy mantra — two things both have to happen before solar is truly economically viable: costs must come down quite a bit, and the efficiency has to at least be within spitting distance of petroleum and other traditional natural resources. This sounds like very good news on the efficiency front. Might even offer some cost benefits as well.

From the link:

Stanford engineers have figured out how to simultaneously use the light and heat of the sun to generate electricity in a way that could make solar power production more than twice as efficient as existing methods and potentially cheap enough to compete with oil.

Unlike photovoltaic technology currently used in  – which becomes less efficient as the temperature rises – the new process excels at higher temperatures.

Called ‘photon enhanced thermionic emission,’ or PETE, the process promises to surpass the efficiency of existing photovoltaic and thermal conversion technologies.

“This is really a conceptual breakthrough, a new  process, not just a new material or a slightly different tweak,” said Nick Melosh, an assistant professor of materials science and engineering, who led the research group. “It is actually something fundamentally different about how you can harvest energy.”

And the materials needed to build a device to make the process work are cheap and easily available, meaning the power that comes from it will be affordable.

A small PETE device made with cesium-coated gallium nitride glows while being tested inside an ultra-high vacuum chamber. The tests proved that the process simultaneously converted light and heat energy into electrical current. Credit: Photo courtesy of Nick Melosh, Stanford University

August 2, 2010

“Smart grid” electric meters and hackers

Food for uneasy thought.

I have a smart grid meter on my house. At the time it was installed I liked the idea because they more easily allow you to sell electricity back to the grid, you know like if you have a solar array on your roof and produce more than you use (if you read this blog often at all you know I’m very interested in solar and I’d love to have an array on my sun-drenched roof right now). This news gives me quite a bit of pause on smart grid meters.

From the link:

The hurried deployment of smart-grid technology could leave critical infrastructure and private homes vulnerable to hackers. Security experts at the Black Hat conference in Las Vegas last week warned that smart-grid hardware and software lacks the necessary safeguards to protect against meddling.

Utilities are being encouraged to install this smart-grid technology–network-connected devices to help intelligently monitor and manage power usage–through funding from the U.S. government’s 2009 stimulus package. The smart systems could save energy and automatically adjust usage within homes and businesses. Customers might, for example, agree to let a utility remotely turn off their air conditioners at times of peak use in exchange for a discount.

But to receive the stimulus money, utilities will have to install new devices across their entire customer base quickly. Security experts say that this could lead to problems down the road–as-yet-unknown vulnerabilities in hardware and software could open up new ways for attackers to manipulate equipment and take control of the energy supply.

Smart enough? This image shows the interior of a smart grid meter tested by Mike Davis of IOActive.
Credit: Mike Davis

July 16, 2010

Solar plus nanotech equals lower cost cells

I always love covering news that combines solar and nanotechnology, particularly when the combo leads to lower costs for solar power. I’ve previously blogged about nanopillars leading increased solar efficiency.

From the first link:

A material with a novel nanostructure developed by researchers at the University of California, Berkeley could lead to lower-cost solar cells and light detectors. It absorbs light just as well as commercial thin-film solar cells but uses much less semiconductor material.

The new material consists of an array of nanopillars that are narrow at the top and thicker at the bottom. The narrow tops allow light to penetrate the array without reflecting off. The thicker bottom absorbs light so that it can be converted into electricity. The design absorbs 99 percent of visible light, compared to the 85 percent absorbed by an earlier design in which the nanopillars were the same thickness along their entire length. An ordinary flat film of the material would absorb only 15 percent of the light.

Thick and thin: A scanning electron microscope image shows dual-diameter light-trapping germanium nanopillars.

Credit: Ali Javey, UC Berkeley

July 13, 2010

Efficiency record for for large-area epitaxial thin-film silicon solar cells

Filed under: Business, Science — Tags: , , , — David Kirkpatrick @ 6:10 pm

Good solar news. I may sound like a broken record, but for solar to be market-viable two things have to happen — costs must come way down and efficiency must go way up. This is a step in the right direction.

From the link:

Imec scientists realized large-area (70cm2) epitaxial solar cells with efficiencies of up to 16.3% on high-quality substrates. And efficiencies of up to 14.7% were achieved on large-area low-quality substrates, showing the potential of thin-film epitaxial solar cells for industrial manufacturing. The results were achieved within imec’s silicon solar cell industrial affiliation program (IIAP) that explores and develops advanced process technologies aiming a sharp reduction in silicon use, whilst increasing cell efficiency and hence further lowering substantially the cost per Watt peak.

Imec large-area (70cm2) epitaxial solar cell with an efficiency of up to 16.3% on high-quality substrat

Colorado boasts first coal/solar hybrid power plant

Sounds like a great idea to begin integrating solar energy into viable power production.

From the link:

The first ever hybrid solar-coal power plant is now operating at Unit 2 of the Cameo Generating Station near Palisade in Colorado. The demonstration project was built by Xcel Energy as part of its new Innovative Clean Technology (ICT) Program, and is designed to decrease the use of coal, increase the plant’s efficiency, lower carbon dioxide emissions, and test the commercial viability of combining the two technologies.

The project was developed by Xcel Energy in conjunction with Abengoa Solar, which developed the solar parabolic trough technology that concentrates solar energy to produce heat. The demonstration project is expected to cut the use of coal at the power plant by around two or three percent, and could be scaled up to cut it by 10 percent.

July 4, 2010

Obama gives $2B to two solar companies

As a nation we must find energy sources beyond petroleum. Chiefly because it’s a finite resource and will eventually — and that eventually may be a long ways off — run out. And it is the root of almost every vexing military and statecraft problem the United States faces. The problem is oil, gas and coal are so incredibly cheap and efficient compared to any feasible alternative.

Solar power has seen breakthrough after breakthrough (see the link in the sidebar under “interesting blog topics”) over the last several years, and many of these breakthroughs affect the current solar marketplace so it’s not all pie-in-the-sky activity. One way to ramp up improvements in solar efficiency and lower practical costs is to infuse the R&D process with enough money to not have to pick and choose among untested ideas. This investment from the government will allow Abengoa Solar and Abound Solar Manufacturing to implement large solar installations, create some jobs along the way, and, yes, continue to improve solar energy as a viable alternative to petroleum.

This is good news to blog about on Independence Day. Kudos to President Obama.

From the link:

US President Barack Obama announced on Saturday the awarding of nearly two billion dollars to two solar energy companies that have agreed to build new power plants in the United States, creating thousands of new jobs.

“We’re going to keep fighting to advance our recovery,” Obama said in his weekly radio address. “And we’re going to keep competing aggressively to make sure the jobs and industries of the future are taking root right here in America.”

One of the companies, Abengoa Solar, has agreed to build one of the largest solar plants in the world in Arizona, which will create about 1,600 construction jobs. When completed, this plant will provide enough  to power 70,000 homes.

The other company, Abound Solar Manufacturing, is building two new plants, one in Colorado and one in Indiana.

US President Barack Obama (R) tours a solar energy centre in Arcadia, Florida in 2009. Obama has announced the awarding of nearly $2 bln to two solar energy companies that have agreed to build new power plants in the US, creating thousands of new jobs

June 17, 2010

Quantum dot research may lead to dramatic solar efficiency increase

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 11:47 pm

This seems like a week full of a lot of good solar efficiency news. As I’ve written many, many times (hit the solar link in the sidebar), solar power needs continued breakthroughs in two areas to become market-viable — costs must continue to come down and efficiency needs to continue to increase. This news out of UT Austin points toward potential very dramatic efficiency increases.

From the link:

Conventional solar cell efficiency could be increased from the current limit of 30 percent to more than 60 percent, suggests new research on semiconductor nanocrystals, or quantum dots, led by chemist Xiaoyang Zhu at The University of Texas at Austin.

Zhu and his colleagues report their results in this week’s Science.

The scientists have discovered a method to capture the higher energy sunlight that is lost as heat in conventional .

The maximum efficiency of the silicon solar cell in use today is about 31 percent. That’s because much of the energy from sunlight hitting a solar cell is too high to be turned into usable electricity. That energy, in the form of so-called “hot ,” is lost as heat.

If the higher energy sunlight, or more specifically the hot electrons, could be captured, solar-to-electric power conversion efficiency could be increased theoretically to as high as 66 percent.

If you prefer the raw feed, here’s the release the linked story is based on.

June 16, 2010

Sanyo tops solar efficiency

Filed under: Business, Science — Tags: , , , , — David Kirkpatrick @ 8:54 pm

Impressive, over 20 percent energy conversion efficiency.

From the link:

The new N230 solar cell module is claimed to have an  of 20.7 percent, which makes it the most efficient solar module produced so far. The unprecedented efficiency was achieved by increasing the number of solar cell tabs from two to three and making each tab thinner. They also applied AG coated glass to the cells, and this reduces the amount of scattering and reflection of light. The increase in energy conversion efficiency could make the solar modules useful in areas with less than ideal amounts of sunshine.

June 15, 2010

The thick or thin solar question …

… has been solved by nanotech based on coaxial cable.

From the link:

“Many groups around the world are working on nanowire-type solar cells, most using crystalline semiconductors,” said co-author Michael Naughton, a professor of physics at Boston College. “This nanocoax cell architecture, on the other hand, does not require crystalline materials, and therefore offers promise for lower-cost solar power with ultrathin absorbers. With continued optimization, efficiencies beyond anything achieved in conventional planar architectures may be possible, while using smaller quantities of less costly material.”

Optically, the so-called nanocoax stands thick enough to capture light, yet its architecture makes it thin enough to allow a more efficient extraction of current, the researchers report in PSS’s Rapid Research Letters. This makes the nanocoax, invented at Boston College in 2005 and patented last year, a new platform for low cost, high efficiency solar power.

Boston College researchers report developing a “nanocoax” technology that can support a highly efficient thin film solar cell. This image shows a cross section of an array of nanocoax structures, which prove to be thick enough to absorb a sufficient amount of light, yet thin enough to extract current with increased efficiency, the researchers report in the journal Physica Status Solidi. Credit: Boston College

May 27, 2010

Renewable power and the US electric grid

Seems like a bit more compatible than once thought. At least for the western power grid.

From the link:

More than a third of the electricity in the western United States could come from wind and solar power without installing significant amounts of backup power. And most of this expansion of renewable energy could be done without installing new interstate transmission lines, according to a new study from the National Renewable Energy Laboratory (NREL) in Golden, CO. But the study says increasing the amount of renewables on the grid will require smart planning and cooperation between utilities.

The NREL findings provide a strong counterargument to the idea that the existing power grid is insufficient to handle increasing amounts of renewable power. As California and other states require utilities to use renewable sources for significant fractions of their electricity, some experts have warned that measures to account for the variability of wind and solar power could be costly. At the extreme, they speculated, every megawatt of wind installed could require a megawatt of readily available conventional power in case the wind stopped blowing. But the NREL findings, like other recent studies, suggest that the costs could be minimal, especially in the West.

“The studies are showing the costs are a lot lower than what people thought they were going to be,” says Daniel Brooks, project manager for power delivery and utilization at the Electric Power Research Institute. Even if wind farms had to pay for the necessary grid upgrades and backup power themselves, they could still sell electricity at competitive rates, he says.

May 12, 2010

Doubling organic solar cell efficiency …

Filed under: et.al. — Tags: , , , , , — David Kirkpatrick @ 12:39 pm

… with “light pipes.” If this research bears fruit it will be a major solar breakthrough — drastically increased efficiency coupled with lower cost manufacturing. A win-win.

From the link:

Researchers in North Carolina have developed a way to more than double the performance of organic solar cells by adding a layer of upright optical fibers that act as sunlight traps.

David Carroll, a professor of physics at Wake Forest University, led the development of a prototype solar cell incorporating the fibers. He is the chief scientist at a spinoff company called FiberCell that is developing a reel-to-reel manufacturing process to produce the cells. “We’re on the cusp of having working demonstrators that would convince someone to go into production with this,” said Carroll.

The best organic solar cells today are nearly 8 percent efficient, although efforts are ongoing to develop organic chemistries that would push the efficiency of such cells above 10 percent. But Carroll says improved chemistries alone won’t be enough to catch up to the performance of silicon cells. “The answer doesn’t lie in chemistry–it lies in the architecture of the cell itself,” he says. Carroll adds that the dollar-per-watt cost of manufacturing fiber-based organic cells should be about the same cost as for flat organic cells. “But they can be produced in a factory costing one-tenth that of a silicon foundry,” he says. This would make them much cheaper to produce than silicon cells.

Fiber forest: This prototype solar panel is covered with optical fibers. Photons bounce around inside the fibers before being absorbed, and this doubles the panel’s efficiency compared to regular organic cells.
Credit: Wake Forest University

April 4, 2010

Roadblock to effective transparent, current-carrying nanocoating

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 4:20 pm

This is something of a setback in an exciting area of solar panel improvement.

The release:

NIST scientists address ‘wrinkles’ in transparent film development

IMAGE: This atomic-force microscopy image shows wrinkling in a single-wall carbon nanotube membrane; the inset shows an optical reflection micrograph of the membrane without any strain. The random arrangement of the…

Click here for more information.

A closer look at a promising nanotube coating that might one day improve solar cells has turned up a few unexpected wrinkles, according to new research* conducted at the National Institute of Standards and Technology (NIST) and North Dakota State University (NDSU)—research that also may help scientists iron out a solution.

The scientists have found that coatings made of single-walled carbon nanotubes (SWCNTs) are not quite as deformable as hoped, implying that they are not an easy answer to problems that other materials present. Though films made of nanotubes possess many desirable properties, the team’s findings reveal some issues that might need to be addressed before the full potential of these coatings is realized.

“The irony of these nanotube coatings is that they can change when they bend,” says Erik Hobbie, now the director of the Materials and Nanotechnology program at NDSU. “Under modest strains, these films can develop irreversible changes in nanotube arrangement that reduce their conductivity. Our work is the first to suggest this, and it opens up new approaches to engineering the films in ways that minimize these effects.”

High on the wish list of the solar power industry is a cheap, flexible, transparent coating that can conduct electricity. If this combination of properties can somehow be realized in a single material, solar cells might become far less expensive, and manufacturers might be able to put them in unexpected places—such as articles of clothing. Transparent conductive coatings can be made of indium-tin oxide, but their rigidity and high cost make them less practical for widespread use.

Carbon nanotubes are one possible solution. Nanotubes, which resemble microscopic rolls of chicken wire, are inexpensive, easy to produce, and can be formed en masse into transparent conductive coatings whose weblike inner structure makes them not only strong but deformable, like paper or fabric. However, the team’s research found that some kinds of stretching cause microscopic ‘wrinkles’ in the coating that disrupt the random arrangement of the nanotubes, which is what makes the coating conduct electricity.

“You want the nanotubes to stay randomly arranged,” Hobbie says. “But when a nanotube coating wrinkles, it can lose the connected network that gives it conductivity. Instead, the nanotubes bundle irreversibly into ropelike formations.”

Hobbie says the study suggests a few ways to address the problem, however. The films might be kept thin enough so the wrinkling might be avoided in the first place, or designers could engineer a second interpenetrating polymer network that would support the nanotube network, to keep it from changing too much in response to stress. “These approaches might allow us to make coatings of nanotubes that could withstand large strains while retaining the traits we want,” Hobbie says.

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* E. K. Hobbie, D. O. Simien, J. A. Fagan, J. Y. Huh, J. Y.Chung, S. D. Hudson, J. Obrzut, J. F. Douglas, and C. M. Stafford. Wrinkling and Strain Softening in Single-Wall Carbon Nanotube Membranes. Physical Review Letters, March 26, 2010, 104, 125505.

April 2, 2010

Black silicon bringing down the cost of efficient solar

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 7:03 pm

The latest news in one of the two areas — cost in this case — solar needs to continue to see improvement for widespread use.

From the link:

A simple chemical treatment could replace expensive antireflective solar cell coatings, bringing down the cost of crystalline silicon panels. The treatment, a one-step dip in a chemical bath, creates a highly antireflective layer of black silicon on the surface of silicon wafers, and it would cost just pennies per watt, say researchers at the National Renewable Energy Laboratory (NREL). They’ve used it to create black silicon solar cells that match the efficiency of conventional silicon cells on the market.

Solar goes black: These two solar cells were fabricated on a silicon wafer treated to create an antireflective black silicon surface. The silvery areas around the cells are a different color because the highly absorbent black layer has been etched away.
Credit: Hao-Chih Yuan

March 24, 2010

GE getting into thin-film solar field

This can only mean advances in production and manufacturing coupled with a likely cost reduction. A win for the field since GE is going to bring to bear its corporate might on process improvements.

From the link:

GE has confirmed long-standing speculation that it plans to make thin-film solar panels that use a cadmium- and tellurium-based semiconductor to capture light and convert it into electricity. The GE move could put pressure on the only major cadmium-telluride solar-panel maker, Tempe, AZ-based First Solar, which could drive down prices for solar panels.

Last year, GE seemed to be getting out of the solar industry as it sold off crystalline-silicon solar-panel factories it had acquired in 2004. The company found that the market for such solar panels–which account for most of the solar panels sold worldwide–was too competitive for a relative newcomer, says Danielle Merfeld, GE’s solar technology platform leader.

March 16, 2010

Increasing plastic solar cell efficiency

Even though I think it’s going to be the thin-film photovoltaic space is where we will see the most market ready advances in cost and efficiency, breakthroughs in other areas, like polymer solar cells, keep the entire field moving forward and might well lead to the next big thing down the road. It truly is promising to follow and read about the sheer volume of basic research and incremental improvements going on in solar and other alternative energy sources. The faster the United States can end dependency on Middle East petroleum, the faster one of the more vexing national security issues gets solved.

From the second link:

Polymer solar cells are finding use in solar charging backpacks and umbrellas, but they still only convert around 6 percent of the energy in sunlight into electricity–or around a third of what conventional silicon panels are capable of. If the efficiency of polymer solar cells–which are cheaper and lighter than silicon cells–can be boosted significantly, they could be ideal for plastering on rooftops or laminating on windows.

Solarmer Energy, based in El Monte, CA, is on target to reach 10 percent efficiency by the end of this year, says Yue Wu, the company’s managing director and director of research and development. Organic cells will likely need at least that efficiency to compete on the photovoltaic market.

Hit the first link above in the very first sentence of this post for a story on U.S. firms seeking to push the cost of thin-film solar cells down.

March 5, 2010

Silicon nanowires may improve solar costs

Silicon photovoltaics offer incredible solar cell efficiency and now it looks like nanotechnology may offer a way to add low production cost to that mix. This type of headway and improvement is what will make solar a market-viable power option.

The release:

Trapping Sunlight with Silicon Nanowires

MARCH 03, 2010

Lynn Yarris

This photovoltaic cell is comprised of 36 individual arrays of silicon nanowires featuring radial p-n junctions. The color dispersion demonstrates the excellent periodicity present over the entire substrate. (Photo courtesy of Peidong Yang)

This photovoltaic cell is comprised of 36 individual arrays of silicon nanowires featuring radial p-n junctions. The color dispersion demonstrates the excellent periodicity over the entire substrate. (Photo from Peidong Yang)

Solar cells made from silicon are projected to be a prominent factor in future renewable green energy equations, but so far the promise has far exceeded the reality. While there are now silicon photovoltaics that can convert sunlight into electricity at impressive 20 percent efficiencies, the cost of this solar power is prohibitive for large-scale use. Researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab), however, are developing a new approach that could substantially reduce these costs. The key to their success is a better way of trapping sunlight.

“Through the fabrication of thin films from ordered arrays of vertical silicon nanowires we’ve been able to increase the light-trapping in our solar cells by a factor of 73,” says chemist Peidong Yang, who led this research. “Since the fabrication technique behind this extraordinary light-trapping enhancement is a relatively simple and scalable aqueous chemistry process, we believe our approach represents an economically viable path toward high-efficiency, low-cost thin-film solar cells.”

Yang holds joint appointments with Berkeley Lab’s Materials Sciences Division, and the University of California  Berkeley’s Chemistry Department. He is a leading authority on semiconductor nanowires – one-dimensional strips of materials whose width measures only one-thousandth that of a human hair but whose length may stretch several microns.

“Typical solar cells are made from very expensive ultrapure single crystal silicon wafers that require about 100 micrometers of thickness to absorb most of the solar light, whereas our radial geometry enables us to effectively trap light with nanowire arrays fabricated from silicon films that are only about eight micrometers thick,” he says. “Furthermore, our approach should in principle allow us to use metallurgical grade or “dirty” silicon rather than the ultrapure silicon crystals now required, which should cut costs even further.”

Yang has described this research in a paper published in the journal NANO Letters, which he co-authored with Erik Garnett, a chemist who was then a member of Yang’s research group. The paper is titled “Light Trapping in Silicon Nanowire Solar Cells.”

A radial p-n junction consists of a layer of n-type silicon forming a shell around a p-type silicon nanowire core. This geometry turns each individual nanowire into a photovoltaic cell.

A radial p-n junction consists of a layer of n-type silicon forming a shell around a p-type silicon nanowire core. This geometry turns each individual nanowire into a photovoltaic cell.

Generating Electricity from Sunlight

At the heart of all solar cells are two separate layers of material, one with an abundance of electrons that functions as a negative pole, and one with an abundance of electron holes (positively-charged energy spaces) that functions as a positive pole. When photons from the sun are absorbed, their energy is used to create electron-hole pairs, which are then separated at the interface between the two layers and collected as electricity.

Because of its superior photo-electronic properties, silicon remains the photovoltaic semiconductor of choice but rising demand has inflated the price of the raw material. Furthermore, because of the high-level of crystal purification required, even the fabrication of the simplest silicon-based solar cell is a complex, energy-intensive and costly process.

Yang and his group are able to reduce both the quantity and the quality requirements for silicon by using vertical arrays of nanostructured radial p-n junctions rather than conventional planar p-n junctions. In a radial p-n junction, a layer of n-type silicon forms a shell around a p-type silicon nanowire core. As a result, photo-excited electrons and holes travel much shorter distances to electrodes, eliminating a charge-carrier bottleneck that often arises in a typical silicon solar cell. The radial geometry array also, as photocurrent and optical transmission measurements by Yang and Garrett revealed, greatly improves light trapping.

“Since each individual nanowire in the array has a p-n junction, each acts as an individual solar cell,” Yang says. “By adjusting the length of the nanowires in our arrays, we can increase their light-trapping path length.”

While the conversion efficiency of these solar nanowires was only about five to six percent, Yang says this efficiency was achieved with little effort put into surface passivation, antireflection, and other efficiency-increasing modifications.

“With further improvements, most importantly in surface passivation, we think it is possible to push the efficiency to above 10 percent,” Yang says.

Combining a 10 percent or better conversion efficiency with the greatly reduced quantities of starting silicon material  and the ability to use metallurgical grade silicon, should make the use of silicon nanowires an attractive candidate for large-scale development.

As an added plus Yang says, “Our technique can be used in existing solar panel manufacturing processes.”

This research was funded by the National Science Foundation’s Center of Integrated Nanomechanical Systems.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research for DOE’s Office of Science and is managed by the University of California. Visit our website at http://www.lbl.gov.


Peidong Yang (Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)

Peidong Yang (Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)

Additional Information

For more about the research of Peidong Yang and his group, visit the Website at http://www.cchem.berkeley.edu/pdygrp/main.html

For more about the Center of Integrated Nanomechanical Systems (COINS) visit the Website at http://mint.physics.berkeley.edu/coins/

March 2, 2010

Google is serious about developing solar

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 4:35 pm

Very serious.  A solar thermal plant pumping out electricity at 5 cents/kWh (or less!?!) would be pretty amazing. This advance in efficiency is coming through a redesign of the mirrors with new material on both the reflective surface and the substrate.

From the link:

Google announced last year that they were working on new technology that would make solar thermal energy cheaper than coal.  Just a few months later, they have a prototype and expect a product to be ready in as little as a year.

And:

The prototype is being internally tested before more rigorous external testing, but two solar companies, BrightSource and eSolar, are already interested in the technology.  Google is a major investor in both companies and has said if the prototype works, the companies would use the technology.

February 24, 2010

DoE makes major solar investment

Technically it’s a loan guarantee rather than a true investment, but this Department of Energy move shows just how serious the Obama administration is concerning alternate energy sources. There are a lot of exciting developments in solar power right now and government money in this amount only helps grease the wheels of innovation and private-sector investment.

From the first link:

The U.S. Department of Energy has announced a $1.37 billion conditional loan guarantee for the Ivanhoe Solar Complex in the Mojave Desert. The project, managed by Brightsource Energy, will use mirrors to concentrate sunlight, creating high temperatures that can be used to generate electricity. The complex will include three power plants that together will produce about 400 megawatts of electricity.

Basically, the guarantees would cover the loans in the case of default. The money for the loans is expected to come from the Federal Financing Bank.

One of the biggest challenges that large solar developments face is getting financing, particularly because few such solar power plants have been built. The DOE guarantees help on this front.

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