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By Charles Q. Choi
Ted Kaufman

MANY VISIONS

Backed by big federal grants, far-flung laboratory networks explore the horizons of energy science.


Princeton, N.J.- Think the internal combustion engine is dead? Peer into an Energy Frontier lab here and think again. Amid a tangle of pipes and tubes, that carbon-belching relic from an era of cheap gas and environmental neglect is being conceived anew. In time, researchers here hope, it will be reborn as a powerhouse of efficiency, burning clean, advanced fuels. "Ultimately, we would like to predict how fuels that might not exist yet might work and even suggest to chemical engineers what kind of fuels to synthesize for vehicles," says Chung K. Law, known as Ed, a professor in Princeton's Department of Mechanical and Aerospace Engineering.

Law and his colleagues are explorers in a nationwide, $777 million, five-year federal quest to crack the toughest scientific problems blocking production of abundant, clean, sustainable energy. Princeton, along with six other academic institutions and two government laboratories, forms one of 46 aptly named Energy Frontier Research Centers, each tackling a particular energy challenge within several broad categories.

Princeton’s Chung K. Law (top center) and Emily Carter (below left) see a bright future for the internal combustion engine. - Photograph by Denise Applewhite

The idea, developed under George W. Bush but enthusiastically embraced by the Obama administration, is to tackle energy from numerous research directions with the best skills available. Only with such a multipronged approach, Energy Secretary Steven Chu believes, can America hope to cross the scientific threshold to a prosperous green economy and combat climate change. Chu, a Nobel physics laureate himself, has suggested that several Nobel-level discoveries might be needed. Besides promoting EFRCs, he has championed the Advanced Research Projects Agency - Energy (ARPA-E), which pursues development of potentially transformative technologies that are too chancy for industry to fund, and Energy Innovation Hubs, modeled after grand labs of the past such as Bell Laboratories, which developed the transistor. These larger-scale, highly integrated, multidisciplinary teams pursue the whole research-and-development path, from basic research to commercialization. Greeted skeptically by Congress, plans for the hubs have been scaled back from eight to four. Three have so far been funded.

Of the three DOE initiatives, the one for EFRCs is the most expansive. In all, the 46 centers across the country will employ some 1,800 researchers - approximately 700 senior investigators and 1,100 students, postdocs, and technical staff. Universities lead 31, national laboratories 12, and nonprofits two, and one is led by a corporate laboratory. Twenty are devoted to renewable and carbon-neutral energy, such as solar energy and biofuels; 14 delve into crosscutting science, such as how materials fare in extreme environments; six are dedicated to energy-efficiency challenges, such as superconductivity and solid-state lighting; and six are investigating energy storage, such as improved batteries.

The centers' concept grew out of a 2001 DOE study that analyzed the scientific breakthroughs required to address future energy needs. The upshot was a plan to enable research of a scope and complexity beyond that of lone researchers or small groups - "to have collaborations that would lead to efforts where the whole was hopefully worth considerably more than the sum of its parts," says Altaf Carim, the MIT- and Stanford-trained engineer who leads the EFRC management team.

Pushing forward faster

Emily Carter, professor of mechanical and aerospace engineering and applied and computational mathematics, summed up the logic behind the Princeton-led EFRC for Combustion Science when the center was announced last year. Despite advances in electric cars, combustion engines will remain essential for transportation: "It's hard to imagine a plug-in airplane." she said. Now, Carter says, "some of the best people in combustion science" are collaborating across the participating institutions via teleconference and E-mail, working "to push the field forward faster."

While Carter, who co-directs the center with Law, performs quantum mechanical computer simulations to see how fuel molecules bum, her colleagues on the 15-member team use other means to understand and predict the properties that allow engines to burn fuel in the cleanest, most efficient manner. As burners suck up fuel and air, Associate Prof. Yiguang Ju and fellow researchers tinker with different pressures, temperatures and flow rates, analyzing when and how ignition takes place and how fast combustion might. In other experiments, large, boxy lasers scan flames to measure concentrations of soot and other byproducts. "We want to look at biofuels other than ethanol from corn, where the energy content isn't high enough and which takes so much energy to make, and focus on fuels such as bio-butanols, which have more energy density," says center director Law.

Researchers say they have made rapid progress - for instance, procuring high-quality data on the chemistry and combustion qualities of bio-butanols, including soot formation and ignition characteristics, soon for publication. Such fuels "will burn much cleaner in terms of soot emission than biodiesel and regular diesel, which is good," Law says. "And understanding ignition characteristics is key if you want it to burn nicely, with the heat release rate matching operating conditions, and not extinguishing prematurely, wasting fuel."

Researchers at other EFRCs range widely over a host of energy- related fields, from battery components to the chemistry behind liquefying coal and biomass, and the way liquids and solids react at the subatomic scale. Material defects are being examined for clues to radiation resistance, and scientists are exploring underground storage of carbon dioxide.

Ambitions reach far. At the Solid-State Lighting Science Energy Frontier Research Center, led by Sandia National Laboratories in Albuquerque, N.M., researchers hope their work will yield designs for potentially revolutionary devices. Solid-state technology could substantially reduce the energy required for lighting, which now consumes roughly a fifth of all U.S. electricity at an annual cost of some $50 billion.

"For instance, we're trying to find designs where we can run as much current through LEDs (light-emitting diodes) as possible, to get the same amount of light with half the material, effectively lowering the cost by a factor of two," said Jerry Simmons, a Sandia National Laboratory electrical engineer and physicist who directs the center. "We want to understand what happens at the nanometerscale inside the semiconductors on which solid-state lighting is based when you send electricity in."

In another example, researchers are trying to grow nanometerwide semiconductor columns, almost like grass. Currently, the semiconductor layer that emits light inside an LED develops defects because of tension with the sapphire surface it typically rests on. The semiconductor layers do not sit properly on the sapphire, given how the different atoms in each are arranged. The new semiconductor columns, in contrast, would avoid this tension by resting on a much smaller area.

Other, even more complex structures include photonic lattices, which resemble microscopic blocks of material stacked like logs in a log cabin. These, in principle, could one day emit light only in narrowly controlled visible wavelengths, avoiding energy waste.

Results won't be easy to achieve, Simmons acknowledges. "Growing crystalline semiconductor material for LEDs is a very controlled and precise process, and doing so for a standard LED is complicated enough, but when you start adding more complexity with the photonic lattices we're interested in, the ability to make large area devices requires a great deal of engineering expertise," Simmons says.

Breakthroughs, however, would have clear market potential. "The solid-state lighting industry is very interested in our work and partnering with us, and they keep track of advances we make and at times engage in specific collaborations on specific technologies," Simmons adds.

A Silicon Valley model

Does the broad EFRC approach make sense? Fred Block, a sociologist at the University of California, Davis, who has studied federal funding of innovation, thinks it does. Such diversification "seems like a smart way to go to me," he says. Block likens the decentralized approach to "a Silicon Valley venture capital model, where even if only six of the 46 do really well, those critical breakthroughs could be worth it." A potential weakness, though, lies in duplication and the possibility that separate teams, unaware of each other's work, would make the same mistakes, he says. DOE's Carim agrees: "Coordinating efforts is a major priority. We have regular teleconferences with all the EFRCs, with symposia and more detailed scientific reviews down the road, to stay in close touch and see what kinds of issues researchers might be running into."

The Obama administration doesn't want to stop at 46 EFRCs. DOE is seeking an additional $40 million for up to 10 more. Initially, "we went for the best" of some 260 projects submitted, says William F. Brinkman, who heads the Department of Energy's Office of Science. But the approach "left a few holes. We want to fill the holes in the next year." The added centers, Carim says, would be devoted to new materials, such as crystals, and "fundamental sciences related to carbon capture and advanced nuclear energy systems."

Back at Princeton, the combustion scientists see great potential for interdisciplinary learning, regardless of the EFRCs' impact on U.S. energy demand and consumption. "One idea of ours is a roving postdoc program, where we will select outstanding fresh Ph.D.'s and give them a two-year appointment, spending time roughly equally with two of the principal investigators at two different places, naturally becoming the bridge between those two," says Ed Law. His center also plans a "summer school" offering 30 hours of lectures covering different areas of combustion science. Explains Carter: "Combustion is an interdisciplinary area where one needs to be fairly comprehensive with one's knowledge."


Charles Q. Choi is a freelance writer based in New York.

 

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