MIT Defense Dept. IG Gordon Heddell

A Massachusetts Institute of Technology professor and his associate have discovered a way to mimic plant photosynthesis to store electricity from solar power. The development, announced today in the journal Science, could make 24-hour a day solar power practical and affordable for individual homeowners.

The process, developed by Daniel G. Nocera and Matthew W. Kanan at MIT, uses a catalyst developed by the team to take the sun’s energy to split water into hydrogen and oxygen gases. Those gases are later recombined into a fuel cell for use when the sun isn’t shining.

“This is a major discovery with enormous implications for the future prosperity of humankind,” says James Barber, the Ernst Chain Professor of Biochemistry at Imperial College London. “The importance of their discovery cannot be overstated since it opens up the door for developing new technologies for energy production thus reducing our dependence for fossil fuels and addressing the global climate change problem.”

The storage can be used in homes because the catalytic materials, which include cobalt and phosphate, are plentiful and the reaction occurs in neutral pH water at room temperature.

Multimedia: Video Clip: Daniel Nocera on Converting Water to Energy and Storing It

“That’s why I know this is going to work. It’s so easy to implement,” Nocera says.

Current electrolyzing processes require the use of expensive materials in alkaline solutions. In addition to storing power from photovoltaic cells, the process can also be used to store power from wind or other sources of electricity.

“This is a pretty big breakthrough if they can use room temperature,” says Cara Libby, a project manager with the Electric Power Research Institute, in Palo Alto, Calif.

Nocera says he believes that such solar/fuel cell systems will be in homes within 10 years.

Libby says the biggest obstacle to such a system is the cost. “Making this cost competitive will be the biggest challenge to making it practical for people’s homes,” she says.

Photovoltaic systems are several thousand dollars for home systems, and fuel cells are also expensive.

While storage of solar power in homes is currently possible, it is very expensive, Libby says. Solar power can be collected and stored in thermally, but that’s only cost effective in large central collecting stations.