Speaking at the National Meeting of the American Chemical Society in California, MIT professor Daniel Nocera claims to have created an artificial leaf made from stable and inexpensive materials that mimics nature’s photosynthesis process.
The device is an advanced solar cell, no bigger than a typical playing card, which is left floating in a pool of water. Then, much like a natural leaf, it uses sunlight to split the water into its two core components, oxygen and hydrogen, which are stored in a fuel cell to be used when producing electricity.
Actually what happens in a leaf is carbon dioxide is combined (via harnessing photons) into sugar, which is later metabolized to provide the plant energy.
Nevertheless, Mr. (Dr.? Probably Dr.) Daniel Nocera's method is ingenius. Using solar energy to harvest hydrogen and then use a hydrogen-powered fuel cell to produce electricity could solve many world problems, especially in developing nations where utilities are unreliable.
However, so is access to water.
What is unclear is what percentage of the water will be retained after catalysis in the hydrogen cell. Will the device go on forever, taking that same gallon of water and cycling it back and forth from gases to liquid? And how cheap would such a device be? It's a tank of water, this wafer of hydrogen gas production, and a hydrogen fuel cell generator. My guess is the "refrigerator sized generator" that Tata Group has bought the rights to develop will not have a final cost of $5. And so I wonder if Tata Group and Dr. Nocera's device will run into the same brick wall that Segway inventor Dean Kamen hit when he invented his sterling-engine-powered water purification device...the price tag was up, up and away, while the market was poorer than ever. Kamen's device purified a lot of water, and did so pretty quickly. But it cost, by one estimate, $2,800/unit. That's six time the annual income of many of the people that need it.
Someone will probably counter-argue that "the price of these technologies always goes down dramatically once mass production is achieved, and sustaining innovations drive down production costs."
Tell that to Dean Kamen.
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