How does it work? A real leaf (pictured left) performs photosynthesis – pulling together water and carbon dioxide and using the energy from the sun to turn those ingredients into fuel for the plant. This “artificial leaf,” brainchild of a collection of researchers at MIT, harnesses the power of sunlight and uses it to cut water in half! Actually, into three pieces – with the help of special catalysts, this leaf splits H2O into two H’s and an O. The free H (hydrogen) can then be used as a fuel source.
What makes this “leaf” better than past versions of solar cells? For one, it’s cheap. This kind of technology often requires rare and expensive ingredients, but these scientists have devised new ways of doing it, using relatively inexpensive materials. Not only that, but the leaf works pretty much anywhere. All you need is a bucket of water and a sunny day. Place the leaf in the water and it automatically starts producing hydrogen and oxygen bubbles. As MIT’s Daniel Nocera puts it: “You literally walk outside, hold it up, and it works.” The researchers have been testing it out in the waters of the Charles River in Cambridge, but will soon look into using other water sources, such as seawater.
And when they do, maybe they could put it right next to Stanford’s new water-based battery. This battery takes advantage of the fact that seawater, full of salt ions, conducts electricity far better than freshwater. The battery fills with freshwater, charges at low voltage, then drains and refills with seawater, and discharges at high voltage with the help of the ions in the salty water. This results in an overall gain of energy and voilà! Now you're producing power.
|The Amazon River accounts for one-fifth of |
the annual flow of freshwater into the ocean
One big benefit of this battery: It can be put to use anywhere on Earth where freshwater and seawater mix, say at the mouth of a river, and it recycles all the water it uses. Nice, clean, renewable energy. Keeping in mind, of course, that they’ll need to select locations where the battery won’t get in the way of local wildlife, the researchers have already been picking out prospective locations. The Amazon River, second-longest river in the world, drains a huge portion of South America, which means lots of freshwater flowing into the ocean all the time. Stanford’s battery-team names the Amazon drainage basin as one of the best potential locations for setting up their new tech; that is of course, if the river doesn’t dry up first.
The battery team is also thinking about setting their sights on sewage water. Now that sounds promising to me. If they can pull that off, the future looks bright for this battery.
It’s been a long time coming, but it looks like the race for alternative energy sources is really picking up. MIT’s leaf and Stanford’s battery are really exciting because they’re great examples of renewable resource-use that has the added side-effect of not playing with the dials on the Earth’s thermostat. These new innovations are two more additions to an ever-growing list of new and improved sources of energy – a list that will soon also include a series of goliath wind turbines.
Between the wind, the water and the sun, I’m pretty excited for the future of alternative energy research. We’re definitely making some significant headway these days. Go science go.