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Turning Over a New Leaf in Energy

India’s Tata Group Offers a Cheap and Renewable Source of Energy for All
Thursday, July 14th, 2011
green energy

Every time you hear about a new technology, people say it will change the world. Rarely does the hardware live up to the hype. But this time, it just might. There is now a low-cost artificial leaf that runs on water and sunlight that can produce enough energy to power a home in the developing world, courtesy of MIT’s Dr. Daniel Nocera and India’s Tata Group. Water and can you go wrong here?

Dr. Nocera announced his research, while unpublished, at the 241st meeting of the American Chemical Society on March 27 in Anaheim, California. He showed a small, thin catalyst the size of a poker card that, when placed within a bucket of water, automatically broke down the water into hydrogen and oxygen.

Millions have seen it done in elementary school science labs, but it usually requires electricity, and a lot of it. But this new reaction requires nothing but sunlight to work. The idea is to capture the hydrogen and re-use it in a fuel cell in order to provide electricity. Dr. Nocera said that one leaf and a gallon of water could power a home for a day, when coupled with an efficient fuel cell. That is where the Tata Group comes in. They have already been working with Dr. Nocera to develop an older artificial photosynthesis device, and will continue to work with him on this latest breakthrough.

The real clincher of this development is not the idea of an artificial leaf - that was first developed by the U.S. National Renewable Energy Laboratory over ten years ago. It lasted only a day and as it was made with expensive, rare minerals, it was obviously quite impractical. This newest leaf is made with nickel and cobalt, and at the time of the announcement, it had operated continuously for 45 hours with no sign of degradation. Estimates of its commercial cost vary from between US$50 to $100. When compared with other solar-powered fuel cell technologies that cost upwards of US$12,000, this is an insanely large dip in affordability. Also, the artificial leaf doesn't even need pure water. It is able to catalyze sea water, dirty water, and even wastewater. It will even work in a puddle.

Dr. Nocera is something of an idealist. He said about this advancement, "A practical artificial leaf has been one of the Holy Grails of science for decades. We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station. One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology."

There are, of course, some unanswered questions about this technology. The basic idea of breaking down water into hydrogen and oxygen using just the power of sunlight is there, but you don't go straight from hydrogen and oxygen to a fully-powered house in Tanzania. There are some missing steps. So by itself, this artificial leaf cannot be the answer to all of the world's energy problems. It must be coupled with a mechanism for collecting the hydrogen and then converting it into electricity. This is where the Tata Group is expected to come in and fill the gap with a fuel cell. Fuel cell technology is rather well-developed and currently in use in some parts of the world. It is a closed catalytic system in which hydrogen and oxygen are combined together to make water and electricity. Fuel cells currently depend on a steady supply of hydrogen, and at current prices hydrogen is more expensive than gasoline, which means it makes more sense to use a diesel generator than a hydrogen fuel cell to produce electricity. This leaf should be able to make hydrogen for simply the cost of the leaf itself and the water it uses. The big question then is how to collect the hydrogen and put it in a fuel cell in an efficient and cheap fashion. If this process is extremely expensive, the entire point of the artificial leaf will be lost. Also, using fuel cells to power a house should also involve a cheap installation, otherwise once again the advantage over other fuels is lost.

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