pic: Donna CoveneyIn a revolutionary leap that could transform solar power from alternative energy into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.

Scientists are now able to mimic the essence of plants' energy storage system in which sunlight energy captured in a leaf using photosynthesis is made available to the plant at night.

Daniel G. Nocera, the Henry Dreyfus Professor of Energy at MIT, has developed a simple method to split water molecules and produce oxygen gas, a discovery that paves the way for large-scale use of solar power.

MIT researchers have developed a new catalyst, consisting of cobalt metal, phosphate and an electrode. When the catalyst is placed in water and electricity runs through the electrode, oxygen gas is produced. When another catalyst is used to produce hydrogen gas, the oxygen and hydrogen can be combined inside a fuel cell, creating carbon-free electricity to power a house or an electric car, day or night

Requiring nothing but abundant, non-toxic natural materials, this discovery could unlock the most potent, carbon-free energy source of all - the sun. "This is the nirvana of what we've been talking about for years," said MIT's Daniel Nocera, the senior author of a paper describing the work in the July 31 issue of Science. "Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon."

With the new catalyst, homeowners could use solar panels during the day to power their home, while also using the energy to split water into hydrogen and oxygen for storage. At night, the stored hydrogen and oxygen could be recombined using a fuel cell to generate power while the solar panels are inactive.

Read more about the breakthrough here or here.