A U.S. chemist is trying to determine how the world will produce enough energy to supply 9 billion people by mid-century -- and whether that can be done without pumping off-the-charts amounts of carbon dioxide into the air.
CAMBRIDGE, Mass. A U.S. chemist is trying to determine how the world will produce enough energy to supply 9 billion people by mid-century -- and whether that can be done without pumping off-the-charts amounts of carbon dioxide into the air.
Daniel Nocera, 48, is working to achieve an old, elusive dream: using the bountiful energy in sunlight to split water into its basic components, hydrogen and oxygen. The elements could then be used to supply clean-running fuel cells or new kinds of machinery. Or the energy created from the reaction itself, as atomic bonds are severed and re-formed, might be harnessed and stored.
There is a beautiful model for this: photosynthesis. Sunlight kickstarts a reaction in which leaves break down water and carbon dioxide and turn them into oxygen and sugar, which plants use for fuel.
But plants developed this process over billions of years, and even so, it's technically not that efficient. Nocera and other scientists are trying to replicate that -- and perhaps improve on it -- in decades.
Hydrogen is the most abundant element in the universe, but it's generally locked up in compounds with other elements. Currently, it is chiefly harvested from fossil fuels, whose use is the main cause of carbon dioxide emissions blamed for global warming.
And so while hydrogen fuel cells -- in which hydrogen and oxygen combine to produce electricity and water -- have a green reputation, their long-term promise could be limited unless the hydrogen they consume comes from clean sources.
That's where Nocera's method comes in. If it works, it would be free of carbon and the epitome of renewable, since it would be powered by the sun. Enough energy from sunlight hits the earth every hour to supply the world for months. The challenge is harnessing it and storing it efficiently, which existing solar technologies do not do.
"This is nirvana in energy. This will make the problem go away," Nocera said one morning in his office at the Massachusetts Institute of Technology, where the Grateful Dead devotee has a "Mean People Suck" sticker on his window. "If it doesn't, we will cease to exist as humanity."
Lots of people have explored this challenge, but Nocera had a big breakthrough when he used light to coax multiple hydrogen atoms out of liquid. The key was figuring out the right chemical catalyst.
Nocera's 2001 paper on the process in the journal Science, written with graduate student Alan Heyduk, turned heads. Venture capitalists rang his phone off the hook offering to fund him in an alternative-energy company.
The achievement, and its revolutionary prospects, won Nocera this year's Italgas Prize, a $100,000 award given annually by an Italian utility to a top energy researcher.
"Dan is even-money (odds) to solve this problem," says Harry Gray, a renowned California Institute of Technology chemist who was Nocera's graduate adviser.
But there's a catch. In fact, there's a few, and they illustrate how hard it can be to move alternative energy beyond the proof-of-concept phase.
Nocera has performed the reaction with acidic solutions, but not water yet.
The catalyst he used was a compound that included the expensive metal rhodium. To be a practical energy solution, it will have to be made from inexpensive elements like iron, nickel or cobalt.
Nocera's reaction got the photons in light to free up hydrogen atoms, but that's only half the equation. The harder part will be to also capture the oxygen that emerges when water molecules are split. That way, both elements can be fed into a fuel cell, making the process as efficient as possible.
Nocera and scientists not affiliated with his work say those steps are achievable. But first, major advances in basic chemistry will be necessary for the reactions to be well understood.
As a result, Nocera believes it might be 20 years before engineers might design systems based on his work. And he frets that too few scientists are exploring the problem, with many top minds instead focused on biomedical research.
"This is a massive construction project," he says. "You can go back to building New York City in the '20s and '30s. You can't do it with just a few construction workers. So I need more construction workers, more hard hats, with me as a hard hat."
There's another big hurdle. While Nocera plugs away at trying to save the world, some people don't believe it needs saving.
Most scientists concur that continuing to burn fossil fuels will send the amount of carbon dioxide in the atmosphere -- it's now 35 percent higher than in preindustrial times -- to dangerous levels, causing global temperatures to rise with potentially devastating effects.
"We are literally poisoning ourselves," Nocera says. "People don't get it because they can't see it."
But this is a famously politicized topic in the United States, where some powerful political leaders question the science behind global warming. And that, many scientists say, diverts attention and funds from trying to solve the problem.
And even among people who believe global warming's risks are too great to ignore, there is no consensus on what kind of green energy should come to the rescue.
Nocera cites a calculation by Caltech chemist Nathan Lewis that power demands in 2050 will be so great that just to keep carbon dioxide emissions at twice preindustrial levels, a nuclear plant would have to be built every two days. There's not enough room on the planet's surface for other widely touted solutions such as wind and biomass to have much impact.
Only the sun is the answer, Lewis argues.
Critics of that vision say many energy technologies being explored -- including improved ways of storing electricity and different kinds of fuel cells -- will come online in the next few decades and throw off today's extrapolations about the future.
Arno Penzias, who won the Nobel Prize for confirming the Big Bang and now invests in alternative energy startups for New Enterprise Associates, contends there are dozens of ideas more promising than ones involving hydrogen.
When told about Nocera's project, Penzias gets heated, saying it is unlikely to be practical.
"It is so far from being revolutionary that it's not even worth mentioning," Penzias says. "It will be a big yawn."
Nocera seems to thrive on such opposition, because he expects to prove naysayers wrong.
It's part of his blunt enthusiasm, which manifests itself when he discusses the joys of teaching chemistry to freshmen ("They love me") or when he meets with his grad students to discuss the status of their research.
Those sessions often devolve into arguments over the meaning of some data or the direction that projects ought to take. Provoked by Nocera's intensity -- he'll exclaim, "I'm dying here!" in a tone resembling neurotic comic Larry David -- tempers often rise.
One student recently threw an eraser at Nocera, leaving a pink welt on his back that Nocera later showed off with a laugh.
"There were times I absolutely hated working for him, because he knew how to press all of my buttons and drive me absolutely insane," says Heyduk, now assistant professor of chemistry at the University of California, Irvine. "He knew I was the kind of person that needed to be challenged all the time."
Nocera believes this constant prodding at what's possible is the essence of science. As evidence, he reels off several ancillary developments from his research, including microscopic sensors that detect biological hazards, which attracted funding from the Defense Advanced Research Projects Agency.
Pointing to a whiteboard sketch of his vision for using sunlight to split water, Nocera acknowledges that it ultimately might not be an energy panacea.
"Is it right? Maybe not. But it will be something. And it might be something I can't see right now," he says. "That's OK. But you don't stop doing something because you can't see it. It's antiscientific. It's anti-intellectual."
Source: Associated Press