Photosynthetic plants are the inspiration for MIT Professor Daniel Nocera's invention for splitting water into it hydrogen and oxygen. Together with postdoctoral fellow Matthew Kanan, he discovered that by simply adding cobalt and phosphate to water and running a current through it, water could be split into its constituent oxygen molecules. This method is far cheaper than any previous method, opening the door for the efficient storage of electricity created by solar panels. The primary draw back to solar energy is that it is only available during sunlight hours and excess energy is expensive and impractical to store. But with this latest invention from MIT, if solar generated electricity can cheaply create and store hydrogen, then the hydrogen can efficiently be converted back to electricity with a fuel cell at night when power is needed. From Popular Mechanics:
The problem of how to store solar energ—or any energy at a large scale—is very real. Batteries are simply too expensive and don't yet have enough capacity. The Andasol solar thermal plant in Spain will test one interesting option later this year: Liquid heated by its mirrors will be stored in what is essentially a giant Thermos, so that the plant can continue to generate six hours of electricity each night. Abengoa recently announced a similar plant in Arizona; thermal storage will power the air-conditioning usage peak that continues after sunset in the Southwest.The fact that they are using heat as a means to store solar energy in Spain is an indication of how sorely needed an efficient energy storage method is needed. Nocera's invention appears to just such a method and this is why it is being greeted with a significant amount of press and media attention.
Nocera's scheme has several advantages, though. Because it can work on a small scale, it's suitable for distributed power in homes.