Tag Archives: solar

Science Academies: renewable power tech ready for big growth

The US National Academies of Science has looked at the potential for renewable power in its home country, and determined that current solar and wind technologies could probably scale to supply 20 percent of our electricity. Beyond that, however, we’re going to need to fix the grid.

A number of renewable energy technologies are poised for significant growth. Wind turbine production is booked for several years, while several companies have reached the point where they’re able to produce a Gigawatt of capacity annually. Although the US has started from a small base, these power sources have grown at an annual rate of about 20 percent for most of the past decade, a period in which demand only grew about one percent annually. The US National Academies of science has now examined the prospects for continued growth, and sees no limits within the next decade and beyond, but, should growth continue, there are going to have to be significant changes to our national grid.

The report was prepared as part of the America’s Energy Future Project, which is supported by everyone from General Electric to the Kavli and Keck charitable foundations. It’s the second of several planned reports; the next one will target prospects for energy-efficient technology.

The report excludes hydropower, which is renewable, but constrained by the availability of appropriate water resources. At the moment, these other sources—geothermal, solar, biomass, and wind—account for about 2.5 percent of US electricity generating capacity, and estimates are that, under a business-as-usual scenario, they would reach eight percent by 2030. The report addresses the question of whether they’d be capable of scaling, should the US determine it wanted to increase reliance on these technologies (the total available solar and wind energy within the US, at 13.9 million TWh, dwarfs any reasonable future projections of demand). The authors limited their consideration of biomass use because they felt it was likely that the government would promote its use as a transportation fuel.


Roll-Up Solar Panels

Xunlight, a startup in Toledo, Ohio, has developed a way to make large, flexible solar panels. It has developed a roll-to-roll manufacturing technique that forms thin-film amorphous silicon solar cells on thin sheets of stainless steel. Each solar module is about one meter wide and five and a half meters long.

As opposed to conventional silicon solar panels, which are bulky and rigid, these lightweight, flexible sheets could easily be integrated into roofs and building facades or on vehicles. Such systems could be more attractive than conventional solar panels and be incorporated more easily into irregular roof designs. They could also be rolled up and carried in a backpack, says the company’s cofounder and president, Xunming Deng. “You could take it with you and charge your laptop battery,” he says.

Amorphous silicon thin-film solar cells can be cheaper than conventional crystalline cells because they use a fraction of the material: the cells are 1 micrometer thick, as opposed to the 150-to-200-micrometer-thick silicon layers in crystalline solar cells. But they’re also notoriously inefficient. To boost their efficiency, Xunlight made triple-junction cells, which use three different materials–amorphous silicon, amorphous silicon germanium, and nanocrystalline silicon–each of which is tuned to capture the energy in different parts of the solar spectrum. (Conventional solar cells use one primary material, which only captures one part of the spectrum efficiently.)


Sahara Solar Panels Can Power the Entire Europe

Constructing a large array of solar panels in the Sahara desert can provide enough electricity to supply all the power needs of the entire Europe, a research expert said this week.

“It [North Africa] could supply Europe with all the energy it needs,” Dr. Anthony Patt, a research scholar at the International Institute for Applied Systems Analysis, in Austria, told scientists at this week’s climate change conference in Copenhagen, Denmark. “The Sun is very strong there and it is very reliable.

He said that falling costs combined with recent technological advances has made it realistic to consider North Africa as Europe’s main source of imported energy.

“There is starting to be a growing number of cost estimates of both wind and concentrated solar power for north Africa… that start to compare favorably with alternative technologies. The cost of moving [electricity] long distances has really come down.”

Dr. Patt estimated that only a fraction of the Sahara, probably the size of a small country, needed to be covered with panels in order to extract enough energy to supply the whole of Europe.


More Efficient Solar Cells Thanks To CNT Films That Transmit Infrared Light

A thin film of carbon nanotubes is probably the most revolutionary material developed in the past twenty years and according to the scientists they haven’t “used” the material at its full potential and there is still a long way to go. Carbon nanotubes are useful in electronic displays, solar cells, and at other devices, but you should know that CNT thin films were used with light in the visible range. “Just in case” the scientists decided to explore their properties in infrared, and their results were very surprising.

The team of researchers from the University of California, Los Angeles, tested single-walled carbon thin films in infrared and they noticed that they have the ability to transmit infrared waves. The infrared properties of the optically-transparent and electrically-conductive CNT thin films were investigated by physicists Liangbing Hu, David Hecht, and George Grüner from UCLA.

“This is the first time that the infrared properties of conductive CNT films are fully studied through measurement and calculations,” said Hu, co-author at the study.


Solar Panel Drops to $1 per Watt: Is this a Milestone or the Bottom for Silicon-Based Panels?

A long-sought solar milestone was eclipsed on Tuesday, when Tempe, Ariz.–based First Solar Inc. announced that the manufacturing costs for its thin-film photovoltaic panels had dipped below $1 per watt for the first time. With comparable costs for standard silicon panels still hovering in the $3 range, it’s tempting to conclude that First Solar’s cadmium telluride (CdTe) technology has won the race. But if we’re concerned about the big picture (scaling up solar until it’s a cheap and ubiquitous antidote to global warming and foreign oil) a forthcoming study from the University of California–Berkeley and Lawrence Berkeley National Laboratory suggests that neither material has what it takes compared to lesser-known alternatives such as—we’re not kidding—fool’s gold.

Even if the solar cell market were to grow at 56 percent a year for the next 10 years—slightly higher than the rapid growth of the past year—photovoltaics would still only account for about 2.5 percent of global electricity, LBNL researcher Cyrus Wadia says. “First Solar is great, as long as we’re talking megawatts or gigawatts,” he says. “But as soon as they have to start rolling out terawatts, that’s where I believe they will reach some limitations.”

Even the current rate of growth won’t be easy to sustain. Despite the buck-per-watt announcement, First Solar’s share price plummeted more than 20 percent on Wednesday, thanks to warnings from CEO Mike Ahearn about the effect of the credit crisis on potential solar customers—as much as 10 to 15 percent of current orders might default. He recently told analysts in a conference call that “as good as things look for the mid-term and beyond, the short-term outlook for the solar industry in our view has never looked more difficult.” (A transcript is available at SeekingAlpha.)

First Solar’s eventual goal is “grid parity,” a phrase that refers to making solar power cost the same as competing conventional power sources without subsidies. Right now the cost of making panels accounts for a little less than half the total cost of installation. The company estimates that it needs to get manufacturing costs down to $0.65 to $0.70 per watt, and other installation costs down to $1 a watt in order to reach grid parity—goals First Solar plans to reach by 2012.


Researchers develop ‘wireless’ activation of brain circuits

And it’s a unique collaboration between chemists and neuroscientists that led to the discovery of a remarkable new way to use light to activate brain circuits with nanoparticles.

Ben Strowbridge, an associate professor in the neurosciences department in the Case Western Reserve School of Medicine and Clemens Burda, an associate professor in chemistry, say it’s rare in science that people from very different fields get together and do something that is both useful and that no one had thought of before. But that is exactly what they’ve done.

By using semiconductor nanoparticles as tiny solar cells, the scientists can excite neurons in single cells or groups of cells with infrared light. This eliminates the need for the complex wiring by embedding the light-activated nanoparticles directly into the tissue. This method allows for a more controlled reaction and closely replicates the sophisticated focal patterns created by natural stimuli.

The electrodes used in previous nerve stimulations don’t accurately recreate spatial patterns created by the stimuli and also have potential damaging side effects.

“There are many different things you’d want to stimulate neurons for-injury, severed or damaged nerve to restore function- and right now you have to put a wire in there, and then connect that to some control system. It is both very invasive and a difficult thing to do,” says Strowbridge.

IIn principle, the researchers should be able to implant these nanoparticles next to the nerve, eliminating the requirement for wired connections. They can then use light to activate the particles.


MIT Researcher Mimics Photosynthesis To Turn Water Into Hydrogen And Oxygen

A MIT researcher has demonstrated a reaction which resembles the photosynthesis process that plants make each day which means that from now on solar power could be deployed at world scale. Using catalysts developed by the chemist, he showed a video where oxygen was generated from water, just like plants do it in photosynthesis.

“I’m going to show you something I haven’t showed anybody yet,” said Daniel Nocera, the MIT chemist. After the lights were tuned off, he pointed to the video and asked – “Can you see that?” Then he explained – “Oxygen is pouring off of this electrode. This is the future. We’ve got the leaf.” This means that the most difficult obstacle was overcame as from now on we efficiently produce hydrogen gas by splitting water thanks to his catalysts.

This is very important as solar power could be deployed at worldwide and it could remove our dependence on fossil fuels. Solar power cannot replace oil with solar panels as solar cells are not very efficient and the sun doesn’t shine all day long. All this can change now, and we could use the catalysts and light to split water to generate hydrogen fuel which could power our cars. Also, according to Nocera, the catalysts could split seawater and if the hydrogen will be processed in a fuel cell then it will produce fresh water.

During recent history many scientists tried to get energy from the sun by resembling photosynthesis and their attempts were successful. The problem is that this process requires high temperatures, expensive catalysts, and harsh alkaline solutions, so it cannot be deployed at world-scale. Well, this will change as Nocera’s catalysts are cheap and they split water in oxygen and hydrogen at room temperature.


New solar cell material achieves almost 100% efficiency, could solve world-wide energy problems

Researchers at Ohio State University have accidentally discovered a new solar cell material capable of absorbing all of the sun’s visible light energy. The material is comprised of a hybrid of plastics, molybdenum and titanium. The team discovered it not only fluoresces (as most solar cells do), but also phosphoresces. Electrons in a phosphorescent state remain at a place where they can be “siphoned off” as electricity over 7 million times longer than those generated in a fluorescent state. This combination of materials also utilizes the entire visible spectrum of light energy, translating into a theoretical potential of almost 100% efficiency. Commercial products are still years away, but this foundational work may well pave the way for a truly renewable form of clean, global energy.

Traditional solar cell materials use a property called fluorescence to gather electricity. Energy from the sun strikes whatever material they are made of resulting in a momentary “dislodging” of electrons into an excited state. The excited electrons exist due to a property called fluorescence. They last only a dozen or so picoseconds (trillionths of a second) in this state, which is also called a “singlet state.” The many picosecond dwell there is fairly typical among traditional solar cell material in use today.

The new material, which was accidentally discovered using supercomputers to determine possible theoretical molecular configurations, causes not only fluorescing electrons in the singlet state to be created, but also phosphorescing electrons in what’s called a “triplet state.”

These triplet state electrons remain in their excited state of phosphorescence for scores of microseconds (up to about 200 microseconds, or 0.0002 seconds). With such a long lasting state of free electron flow, their ability to be captured is theoretically significantly greater than existing technologies.

And if the research team’s current efforts (of using only a few molecules of the hybrid materials suspended in a liquid solution) can be extended into practical real-world scales, then products yielding nearly 100% solar efficiency may soon be achievable.


MIT Energy Storage Discovery Could Lead to ‘Unlimited’ Solar Power

Researchers at Massachusetts Institute of Technology (MIT) have discovered a new way of storing energy from sunlight that could lead to ‘unlimited’ solar power.

The process, loosely based on plant photosynthesis, uses solar energy to split water into hydrogen and oxygen gases. When needed, the gases can then be re-combined in a fuel cell, creating carbon-free electricity whether the sun is shining or not.

According to project leader Prof. Daniel Nocera, “This is the nirvana of what we’ve been talking about for years. Solar power has always been a limited, far-off solution. Now, we can seriously think about solar power as unlimited and soon.”


Harnessing Light’s Full Spectrum: Scientists Claim Solar Power Breakthrough

Chemists at Ohio State University say they have produced a next-generation material that not only absorbs the full spectrum of sunlight, but also make makes the electrons generated more easy to capture.

The hybrid material — a combination of electrically conductive plastic and metals like molybdenum and titanium — is the first of its kind to capture the full solar spectrum, according to Malcolm Chisholm, one of the authors of the paper describing the research, which appears in Proceedings of the National Academy of Sciences. Solar panels in use today capture only a small fraction of the energy contained in sunlight.

The material is years from being made into a commercial product, but is another example of how innovations in the field of solar energy could make vastly more of the sun’s energy available for human use. Recent action by Congress to extend industry tax incentives should keep companies investing in new technology research and development. And according to the Department of Energy, “Under the ongoing global financial crisis, a lack of available credit is causing projects to be delayed or canceled, but the clean energy sector is continuing to attract substantial amounts of investment capital.”

If coupled with new battery technology, solar energy technology has the potential to revolutionize the way we generate electricity. Millions of homes could be outfitted with their own power sources, and they could store enough electricity — if efficient enough — to eliminate the need for power plants in the residential sector.

That’s been the promise of solar energy for a long time. Breakthroughs like this one announced by Ohio State brings the vision that much closer to reality.