CAMBRIDGE, Mass. - In what they call a “revolutionary leap” that could transform solar power from a minor alternative energy source into a mainstream source, researchers at Massachusetts Institute of Technology (MIT) say they have overcome a major barrier to widespread deployment: storing solar energy for use when the sun doesn’t shine.

Until now, solar power has been a daytime-only energy source, because storing solar energy for later use is prohibitively expensive and grossly inefficient, says MIT. With this announcement, MIT researchers say they have hit upon a simple, inexpensive, and highly efficient process for storing solar energy.

According to Daniel Nocera, the Henry Dreyfus Professor of Energy at MIT and senior author of a paper describing the research work, “Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon.”

Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera’s lab, have developed a process that will allow the sun’s energy to be used to split water into hydrogen and oxygen gases. At night, the stored hydrogen and oxygen can then be recombined using a fuel cell to generate power while the solar panels are inactive.

Sunlight has the greatest potential of any power source to solve the world’s energy problems, said Nocera. In one hour, enough sunlight strikes the Earth to provide the entire planet’s energy needs for one year. More engineering work needs to be done to integrate the new scientific discovery into existing photovoltaic systems, but Nocera said he is confident that such systems will become a reality.

Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell.

This research project is part of the MIT Energy Initiative, a program designed to help transform the global energy system to meet the needs of the future.

Publication date: 08/11/2008