Despite increasing worry about what our energy consumption is doing to the planet, we’re also increasingly tied to power-hungry electronic devices. To keep reliable, renewable energy flowing, some suggest, we must give the power grid a makeover. And one method that could change it is a breath of fresh air. Danielle Fong and her company, LightSail Energy, want to store renewable energy in tanks of compressed air. Because wind and solar can be unpredictable energy sources, the ability to save any surplus for a windless or cloudy day makes them more reliable.
Caleb Garling has written about Fong’s unusual method of storing power for Wired’s World’s Most Wired feature.
For years, solar energy researchers have tried to imitate the success of photosynthesis by building devices like an artificial leaf and a solar cell that hijacks chemistry of photosynthetic bacteria. Now researchers at MIT have come up with an innovative technique that also happens to be very cheap: all you need is some “stabilizing powder” and plant waste. Mowed your lawn lately?
The stabilizing powder is a mix of safe, easily attainable chemicals that preserves photosystem I, a protein complex that captures light energy in plant cells. (In contrast, the newest photovoltaic cells in solar panels require metals that are rare or toxic.) The powder is mixed with plant matter such as grass clippings and crushed, and the resulting green goo is spread onto glass or metal substrate. Hook up wires to capture the electric current and that’s your solar panel.
The efficiency of these solar panels is only 0.1%, compared to the 15 to 18% efficiency of solar panels out in the market right now. Lead researcher Andrew Mershin says the technology still needs to improve 10-fold to become practical. After all, being able to power only one lightbulb with a whole house covered in solar panels isn’t much help. But the great advantage of all this is that it’s easy and
dirt grass cheap. Because the barrier to entry is so low, anyone would be able to order a bag of chemicals and make their own solar panel. Mershin hopes home tinkerers experiment with the cells and find new ways to make improvements.
Correction, February 6: We eliminated a reference to mulch in the headline: mulch is low in chlorophyll, so it wouldn’t actually work for these plant-powered solar cells.
What’s the News: In traditional solar cells, sunlight is absorbed by the cell (made from silicon or titanium dioxide), freeing electrons, which travel across the cell to an electron collector, or electrode. A problem with solar cells is that many electrons don’t find their way to the electrode; carbon nanotubes can be used as bridges between the loosened electrons and the electrode, but nanotubes tend to bunch up, decreasing the efficiency and causing short circuits. Researchers have now created genetically engineered viruses can be used to keep the nanotubes in place, increasing energy conversion by nearly one-third. “A little biology goes a long way,” research group leader Angela Belcher told MIT News, noting that the entire virus-nanotube bridging layer represents only 0.1% of the finished cell’s weight.
What’s the News: President Obama gave a major address outlining his plan for U.S. energy security yesterday. His major goal is quite ambitious: to cut American oil imports by one-third by 2025. And towards that goal, he listed a number of initiatives that many news organizations see as a rehashing of old ideas, however good they might be. According to The Economist, “it is hard to see his recycled list of proposals as anything more than a reassurance to the environmentally minded, and to Americans fretting about rising fuel prices, that the president feels their pain.”
What’s the News: Scientists have created the first rechargeable battery that uses seawater and freshwater to generate electricity. If installed into every ocean-discharging river in the world (that’s not a realistic scenario—just a frame of reference), the process could produce 2 terawatts, or about 13% of worldwide electricity use. As the researchers write, this battery is “simple to fabricate and could contribute significantly to renewable energy in the future.”
How the Heck:
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Next Up: Noting the limited supply of freshwater on Earth, lead author Yi Cui says that “we need to study using sewage water … If we can use sewage water, this will sell really well.”
Reference: Fabio La Mantia et al. “Batteries for Efficient Energy Extraction from a Water Salinity Difference.” Nano Letters. doi: 10.1021/nl200500s
Image: Nano Letters
What’s the News: This week, scientists say that they’ve passed a chemistry milestone by creating the world’s first practical photosynthesis device. The playing-card-sized photosynthetic gadget uses sunlight to split water molecules into oxygen and hydrogen, which can then be used to produce energy, and is reputedly 10 times more efficient than a natural leaf. Researchers say they expect it to revolutionize power storage, especially in remote areas that don’t currently have electricity. “A practical artificial leaf has been one of the Holy Grails of science for decades,” says lead researcher Daniel Nocera, who’s presenting this research at the National Meeting of the American Chemical Society this week.
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Reference: Daniel Nocera et al. 241st National Meeting of the American Chemical Society. March 27-31, 2011 Anaheim, California, USA
Image: Wikimedia Commons / Daniel Schwen
What’s the News: In a much-ignored speech last week (not ignored by Grist), Sen. Jeff Bingaman (D-N.M.) argued that the U.S. could become less vulnerable to spiking oil prices if we used less of it (surprise!). The crux of the talk was a graph he showed of our country’s estimated petroleum imports, and specifically, the significant change inprojection between 2008 and 2011 (blue and red lines above). Our now-declining gas and oil imports are in part a result of the Energy Independence and Security Act of 2007.
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Not So Fast: Some green-tech writers think the EIA’s predictions are more fiction than fact. According to Chris Nelder at Green Chip Stocks, the EIA’s predictions often “present a picture of the future that looks like a continuation of the best parts of the past, with none of the bad parts.” The assumption that our oil imports will keep on declining hinges partly on technologies that haven’t been invented yet and the hope that all the policies included in the Energy Act come to fruition. The only thing you can’t argue against is that petroleum demands right now are much lower than we had expected, thanks in due part to the Energy Act. What’s more, the economy has largely sputtered since 2008, which tends to tamp down demand for energy. The graph might be more valuable if it showed oil consumption per unit of economic activity.