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.
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.)
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.
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.
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.
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.