In a major breakthrough, scientists at the Massachusetts Institute of Technology (MIT) have discovered an inexpensive way to store solar energy, mimicking photosynthesis. The paper, published in the July 2008 edition of the journal Science, describes a revolutionary technique to split water into hydrogen and oxygen using solar power. Dr. Daniel Nocera of MIT, the lead author of the paper, believes his team's discovery will open the door for the large scale use of domestic solar power.

Hydrogen power has long been the holy grail for scientists seeking to provide abundant, clean renewable energy. Hydrogen is the most abundant element in the Universe and, when burnt in oxygen to release energy, the only other bi-product is water. Methods to produce hydrogen and oxygen from water, such as electrolysis, have existed for some time. However, the MIT group has discovered a more efficient way of splitting water into hydrogen and oxygen.

Dr. Nocera believes that there is a lesson to be learned from plants. "They need to live when the sun's not out," he says. Critics of solar energy have long pointed to its major weakness. It's impossible to generate solar energy at night. However, the recent breakthrough would overcome this drawback by allowing solar energy to be stored chemically as hydrogen and oxygen and reused when needed.

The process is unique because it works at room temperature and normal atmospheric pressure using inexpensive and readily available materials. It could eventually, according to Dr. Nocera, turn your home into a power station and gas station rolled into one. The breakthrough relies on the type of electrodes used to produce hydrogen and oxygen when immersed in simple water. The electrodes are made from a cobalt-phosphate compound that increases the splitting of water into its two components by acting as a catalyst. The catalyst also renews itself spontaneously during the process.

"The simplicity of the process is amazing," says Luis Echegoyen of the U.S. National Science Foundation, the group responsible for funding the research. He points out that the process uses simple and affordable elements suspended in mere water. "These chemists may have given a future way to efficiently obtain oxygen by splitting water."

Dr. Nocera looks forward to the day when people's homes are powered during the day by photovoltaic panels. Excess energy from the panels would be channeled to a device based on his group's discovery. The device would use the excess energy to split water into hydrogen and oxygen and store the gases safely in fuel cells. The fuel cells could then be used to power homes at night and because the fuel cells are easily transported they could also be used to power vehicles. BMW and other motor manufacturers have long had functioning cars powered by hydrogen fuel cells.

The technology should also be capable of storing energy generated from other clean renewable sources such as wind and wave power. Solar power has the most potential Dr. Nocera noted. He points to the long established fact that enough solar energy falls on the Earth in one hour to power the whole planet for an entire year. "This is just the beginning. The scientific community are really going to run with this." Dr. Nocera says.

Further Reading:

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