The Artificial Leaf Is Here. Again. An energy source based on photosynthesis still appears tantalizingly close. But consumers first need to become accustomed to what else is needed for it to work

The Artificial Leaf Is Here. Again.
By JACK HITTMARCH 29, 2014

Prof. Daniel Nocera in his laboratory at Harvard. The artificial leaf he developed — mimicking the process of photosynthesis in plants — will require widespread use of fuel cells if it is to become an energy source for the mass market. CreditMylan Cannon/The New York Times
General Electric is promoting a feel-goodcollection of videos these days.
Called “Focus Forward,” it promises “short films, big ideas.” Each of these mini-docs triumphantly chronicles an innovative idea, like Daniel Nocera’s. This Harvard chemist has pioneered the artificial leaf, an invention that generates energy more or less the way a tree does. Light strikes a container of water and out bubbles hydrogen, an energy source.
The three-minute film about his idea blazes with shafts of light spangling off leaves, and its soundtrack clocks more crescendos per minute than a high-school cello recital. There are many low-angle shots of a towering Mr. Nocera telling us that his device will one day be in people’s homes, pumping out energy.
“Close your eyes,” the colossus says, and “think about your house being its own power station.”
Here’s the thing: Such artificial-leaf optimism could also be found a year ago in a Los Angeles Times article that held the artificial leaf “could create enough clean fuel to power a home for a day in developing countries.” And the year before that, in The New Yorker, where Mr. Nocera said the artificial leaf would “turn a home into ‘a self-sufficient power station.’ ” Or go back one more year, to the pages of The New York Times, where Mr. Nocera said, “Our goal is to make each home its own power station.”
So, all right already. Where’s my power station?
Prowl the edges of contemporary invention, and you experience a lot of this frustration. A scientist announces a breakthrough in, say, battery technology or algae biofuel, and the talk ramps up quickly to full-throttle utopian, tapping into a frontier dream that’s so alluring to Americans: energy from light, self-sustaining, untethered from the grid.
But there always seems to be an obstacle between the big idea and self-sufficiency. Sometimes, it’s the idea itself — a technological bug that seems fixable turns out to be weird and inscrutable. (Consider the jet pack with its cascade of problems: fuel, weight, the preposterously unaerodynamic design of the human body.) But in this case, the technology is sound, say researchers including David Tiede of the Argonne National Laboratory in Chicago.
Mr. Nocera’s idea is based on photosynthesis. When light bombards your average leaf, it splits water in the leaf into oxygen, which we breathe, and then binds the hydrogen with carbon dioxide to ultimately make carbohydrates, its food — which, depending on what new diet book is trending, is sometimes food for us, too.
Mr. Nocera’s leaf mimics this process. A vessel of water is exposed to light. A silicon strip coated in catalysts breaks down the water molecule such that on one side oxygen bubbles up, and, on the other, hydrogen, which can be used as a fuel. “You can drop it in a glass of water and hold it up to a window,” he said. “You won’t need heavy engineering.”
Maybe the problem is danger? Hearing about that stored hydrogen, I had a one-word question: Hindenburg? That wasn’t the gas burning, Mr. Nocera said, plunging into this notorious dispute: “All the hydrogen was gone immediately. What you were watching was the shellac on the Hindenburg burn.”
In fact, he says, his idea is very safe: “My system is based on water, so if there was a catastrophe we’d just need a mop.”
The leaf and its technology have been replicated many times, at the Lawrence Berkeley National Laboratory, the University of Wisconsin and Free University Berlin, so technological obstacles in creating cheap, reliable, nonpolluting energy aren’t the problem. In fact, the issue isn’t the invention at all — it’s how to use it.
“If I give you a canister of hydrogen that we got from the artificial leaf, you can’t use it right away,” Mr. Nocera said. To do so, you need a fuel cell, which can turn hydrogen into electricity.
There are efforts to begin incorporating such energy technology into daily life. A number of auto companies have developed hydrogen-powered cars, such as the Honda FCX Clarity and the Mercedes F-Cell. But this is merely the beginning of a much larger change that’s needed.
Discovering a brilliant way to efficiently generate hydrogen is hard enough. Then there’s everything that comes after, such as getting consumers accustomed to what’s needed for it to work, such as fuel cells — which convert hydrogen into usable electricity.
This is comparable to what Elon Musk struggles with in selling Tesla’s electric cars. He has to persuade the public not only to buy a new kind of car, but all that goes with it: the infrastructure of batteries, charging stations, high-voltage home plugs and new kinds of auto mechanics.
“Whenever you make something that’s two steps removed from an infrastructure, that’s the big problem you have going to market: You have to change an entire infrastructure,” Mr. Nocera said. “If we had fuel cells in your house and your car, then everybody would be trying to implement the artificial leaf right now.”
The other obstacle is the marketplace. Only a few years ago, he said, “the magic number was $3 ‘gas gallon equivalent.’ ” In other words, could he produce the energy equivalent of a gallon of gasoline and keep costs around $3? Even as he closed in on that number, the old fossil-fuel industry pulled the rug out from under him with a surge in cheap natural-gas extraction, driven by hydraulic fracturing or fracking. Seemingly overnight, the magic number became “a buck fifty,” he said.
But therein lies a glimmer of hope. Hydrogen can be produced by fracking, although it comes at a cost of carbon pollution. Still, widespread fracking might lead to widespread hydrogen use. In fact, the United States Senate revived a Fuel Cell and Hydrogen Caucus in 2012. “Fracking could drive the establishment of an infrastructure for using hydrogen at the home,” Mr. Nocera said. “And then the next thing everybody might say is, yeah, but that hydrogen is making CO2. Then the artificial leaf would show up. So it’s kind of weird. Fracking is killing me right now, but in the long run it could be an asset.”
In brief, the perfect fuel exists. What doesn’t exist is everything between this new fuel and, say, your electric coffee bean grinder. “And this is my ultimate vision and I believe it will happen sometime,” Mr. Nocera said, unable to resist. “Your house will be its own gas station.”