This is huge

Scientists at MIT take a giant step toward a practical means to efficiently split water into its constituents, which would permit hydrogen to become the equivalent of petroleum (and, I think, natural gas). Indeed, given that the Earth is 70 percent covered by water, and that combining hydrogen with oxygen (as in a fuel cell or an internal combustion engine) produces water again, coal, too, might be replaced.

I hasten to add that I don't really understand what this is all about; high-school chemistry was the only subject I flunked. But I think I know enough to realize that if this proves to be practical at scale, it is one of the most important developments since the splitting of the atom. And maybe before that.