MIT scientists have developed a revolutionary process to store solar energy, inspired by the photosynthesis performed by plants.  This process allows the sun's energy to be used to split water into hydrogen and oxygen gases. The oxygen and hydrogen are then recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night.

According to this article, the system can duplicate the water splitting reaction that occurs during photosynthesis:  James Barber, a leader in the study of photosynthesis who was not involved in this research, called the discovery by Nocera and Kanan a "giant leap" toward generating clean, carbon-free energy on a massive scale. "This is a major discovery with enormous implications for the future prosperity of humankind," said Barber, the Ernst Chain Professor of Biochemistry at Imperial College London.

An inexpensive, easy to deploy system that can seperate hydrogen and oxygen for use by fuel cells.  This could be the Holy Grail of alternative energy.