Daniel Nocera, a professor of chemistry at MIT, has made a major advance in chemistry that could lead to a cheap way to store energy from the sun, solving one of the key problems in making solar energy a dominant source of electricity.

He has developed a low-cost catalyst that can generate oxygen and hydrogen from water, and the hydrogen can then be burned or run through a fuel cell to generate electricity whenever it’s needed, including when the sun isn’t shining.

Nocera’s advance represents a key discovery in an effort by many chemical research groups to create artificial photosynthesis.