Thursday, January 24, 2013

7 Big Ideas That Can Change the World

From Wired:

Tesla. Prius. Volt. The auto industry is stocked with radical new designs that reduce the environmental impact of driving. The airplane industry has been incrementally improving fuel efficiency for decades, but it’s maxing out the potential of current designs and will soon need to come up with a similarly transformative rethink. And it has to move fast. Air travel is set to explode—more than double by 2031—as developing nations grow more prosperous. That growth could eat away at any other improvements we may make from cleaning up cars or energy grids.

There are a number of ways to tackle the problem. NASA is rethinking airplane design by sponsoring eye-popping concepts like the MIT D Series—in which a double-cylinder body allows for rear-mounted engines and an overall fuel reduction of about 50 percent. (They’re much quieter too.) Smarter navigation systems could let airlines fly shorter, more direct flight paths. And small, short-range planes could eventually become electric: The Slovenian firm Pipistrel has developed an electric four-seater, with double the mileage of a similar plane. “All these technologies are converging to produce capabilities that were not imaginable 10 years ago,” says David Hinton, NASA’s deputy director of aeronautics research. The sky’s the limit. —Clive Thompson
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Harry Gray knows his electrons. In 1982 the Caltech chemist discovered that electrons “tunnel”—skip across long chains of molecules—through proteins. This trick turns out to be the animating breath of life; it’s how living things convert energy into something they can use, from plants locking the energy of sunlight into their cells to pretty much every life-form burning fuels such as glucose to make power. It’s all made possible by hybrid molecules called metalloproteins, which combine the shape-shifting flexibility of proteins with metals’ ability to catalyze chemical reactions.

When Gray figured it out, he was already interested in solar power. If you were trying to develop a near-infinitely renewable power generator, he realized, you might try to hijack a metalloprotein-driven system like photosynthesis. But it wouldn’t work. Biological machinery is too fragile and inefficient—and has to be resynthesized every few minutes to work.

If you want a molecular machine that’ll make power efficiently and reliably, Gray says, you have to build it yourself. He and his colleagues envision microscale batteries with metal oxides at one end and silicon at the other, built like metalloprotein arrays in plant cell membranes. The metal oxides would absorb blue wavelengths of sunlight and use the energy to split seawater into oxygen and protons, and the silicon would absorb red light and combine the protons with electrons. That’s slick, because a proton combined with an electron is actually hydrogen, which can be used as fuel. Shorter version: free hydrogen from sunlight. “The whole emphasis of our work is coming up with molecules or materials that are very robust,” he says, “and will last a long time in solar fuel plants.”

It might even work. Artificial water splitters are already 10 times more efficient than natural photosynthesis, though scale-up is still decades away, as researchers seek new catalysts to drive the chemistry. (The exotic metals they use today are pricey and toxic.) Still, Gray is optimistic. “The natural system had to build something that could actually live,” he says. “All we have to do is make fuel.” Oh, and save the planet. —Thomas Hayden
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