Nature | From Scientific American

A tour of the US's clean energy future

The third annual ARPA-e summit showcases potentially transformative energy technologies.

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  1. IMPROVED INTERNAL COMBUSTION One of the winners of the U.S. Department of Energy's America's Next Top Energy Innovator challenge, Umpqua Energy injects hydrogen into regular gasoline in order to improve its burning—and the power delivered—by today's internal combustion engines. "We've doubled the power for the same fuel consumption," notes U.S. Secretary of Energy Steven Chu. With existing technologies, such as variable transmissions and lighter weight steels, automakers could already cut U.S. oil use by nearly 50 percent as well—an effort boosted by new fuel economy standards.

    David Biello

  2. ALTERNATIVE FUELS Biofuels remain one of the most promising options to clean up oil use in another transportation sector—aviation. The oil derived from the weedy flowering plant known as Camelina can be refined into a bio-jet fuel that has already been used to power commercial and military flights. And there are other options as well. "The most likely source of scalable biofuel for aviation is micro- or macro-algae," says FedEx's Fred Smith. "That's seaweed and pond scum."

    David Biello

  3. STORING SUNSHINE ARPA–e has also funded to create so-called electrofuels—liquid fuels derived from microbes employing waste carbon dioxide and electricity. Here Geobacter lives in a tank on electrodes, taking in CO2 and water and spitting out hydrocarbons for either transportation or chemicals.

    David Biello

  4. CAPTURING CARBON "The U.S. has the largest reserves of coal in the world and we ought to be able to use it in a sustainable way," argues ARPA–e director Arun Majumdar. To that end, the agency is funding work on making carbon capture and storage cheaper so that it might work in the kind of system—incorporating capture at a coal-fired power plant and permanent storage deep underground—laid out in this diagram.

    David Biello

  5. MICROBIAL FUEL CELL Graduate students at the Wyss Institute for Biologically Inspired Engineering at Harvard University explain their microbial fuel cell, a method for producing electrofuels, to ARPA–e founding director Arun Majumdar. Synthetic biology to tinker with the genetics of microbes ranging from E. coli to algae and cyanobacteria has already proven a route to biologically derived fuels and chemicals.

    David Biello

  6. SOLAR THERMAL ENGINE This Rankine cycle engine from Cyclone Power Technologies can run on everything from sunshine to syngas derived from garbage at temperatures as low as 260 degrees Celsius. The engine employs heat from these fuels—or waste heat—to create the steam that powers the engine.

    David Biello

  7. BETTER BIOREACTORS Glass giant Corning is working on this technology to improve algae growth in so-called bioreactors. Quantum dots shift incoming sunshine to wavelengths the human eye perceives as red, which is also the best wavelength for photosynthesis. It also blocks ultraviolet light to help keep things cooler for the algae.

    David Biello

  8. FLEXIBLE BATTERIES Flat 100-square centimeter rechargeable cells equivalent to one AA battery power this flashing vest and LED head lamp, stylishly modeled by the black mannikin. FlexEl also makes a one meter square "battery cloth."

    David Biello

  9. SEMICONDUCTOR REFRIGERATOR Without compressors or hydrofluorocarbons, Sheetak technology employs semiconductors to create refrigeration—and may enable cheap cooling for the poorest people in developing countries. "It will enable people who never had access to refrigeration in their lives to use refrigeration to preserve food and medicine," says ARPA–e director Arun Majumdar, noting the company has a deal with a distributor in India to make such coolers. "We can make locally and sell globally."

    David Biello

  10. ARTIFICIAL PHOTOSYNTHESIS Sunlight kicks off a chemical reaction that splits water, releasing oxygen and hydrogen, which can be used as a fuel—just as plants use sunlight to split water to make carbohydrates. Sun Catalytix hopes to turn its system into a cheap power plant for homes.

    David Biello

  11. CONSTANT WIND High in the stratosphere the wind is always blowing, a steady source of energy. But how to harness it? Makani Power's carbon fiber "kite" would circle high in the sky, harvesting constant wind power and transmitting it via its tether to the ground. The kite-wing has already flown in tests.

    David Biello

An article from Scientific American.

At least three forms of security depend on inventing a future of cheap, clean energy--national, economic and environmental. President Barack Obama launched the Advanced Research Projects Agency for Energy (ARPA-e) in 2009 to fund innovative research in the hopes of delivering such technologies.

"We need a second industrial revolution," argues U.S. Secretary of Energy Steven Chu. "A revolution that gives the developed and developing world the energy they want and need but that can also be clean energy. It is important for our national prosperity and posterity."

ARPA-e is holding its third annual summit this week, where it is showcasing the 180 projects it has funded to help seed that clean revolution, as well as many others. "We are also showcasing those teams we could not fund," says ARPA-e founding director Arun Majumdar. "We want them to succeed as well."

ARPA-e's current projects include genetically engineering plants to improve photosynthesis and finding less costly ways to capture the carbon dioxide released by coal-burning power plants. Upcoming efforts will focus on creating cheap technology to turn natural gas into fuel for cars as well as a potential open call for proposals with no guidelines. "Give us your best ideas," Majumdar says. "We will see if it works."

Already, ARPA-e has begun to deliver: one of its first awardees--Envia Systems--has now developed a lithium-ion battery with the highest energy density in the world, potentially enabling long-distance electric cars in the future. Those electric cars--combined with improvements in the fuel efficiency of existing internal combustion engines, new hybrid power trains and even fuel cell vehicles--could begin to reduce the roughly $1 billion a day the U.S. spends importing oil. "We are engaged in the largest transfer of wealth in the history of the world, from the industrialized countries into oil producing regions," says FedEx chairman Fred Smith. "The U.S. cannot operate as a growing industrial society without access to low cost energy."

More from Scientific American.

It's not just for the U.S., of course. "Cheaper energy is on the list of three to four things you would most want to happen for the poorest people in the world," notes former Microsoft CEO Bill Gates. "Having energy determines whether they can afford fertilizers or lighting& Without advances in energy they stay stuck where they are."

At the center of that effort to invent a brighter, cleaner and cheaper future for energy is ARPA-e. "Pound for pound, dollar for dollar, it's hard to find a more effective thing government has done than ARPA-e," Smith adds.

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