Storing solar energy in batteries remains costly and inefficient. But that may not be true for much longer.

MIT researchers have discovered a way to store solar energy that could make solar power in homes a mainstream energy option and might even make power companies obsolete, at least for residential needs.

Daniel Nocera, a professor of chemistry and energy at MIT, and postdoctoral fellow Matthew Kanan have figured out how to split water into hydrogen and oxygen cheaply and efficiently at room temperature. The process can later be reversed, allowing the recombination of hydrogen and oxygen in a fuel cell to create carbon-free electricity.

"This is the nirvana of what we've been talking about for years," Nocera told the MIT News Service. "Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon."

Nocera's breakthrough could enable the "hydrogen economy," a possibility that many have dismissed as impractical.

Nocera told the MIT News Service that within 10 years, he expects that homeowners will be able to use solar power to provide electricity during the day and to store unused solar energy to power a household fuel cell for evening use. This would eliminate the need for electricity delivered over power lines.

According to the MIT News Service, James Barber, a professor of biochemistry at Imperial College in London, characterized the research by Nocera and Kanan as "a major discovery with enormous implications for the future prosperity of humankind."

Nocera and Kanan's research is described in an academic paper, "In Situ Formation of an Oxygen-Evolving Catalyst in Neutral Water Containing Phosphate and Co2+," that has just been published in Science magazine.