They didn't comment about it because it's not relevant. As nardi and others have said, think of water splitting as a battery... or a way to store energy as a ch

They didn't comment about it because it's not relevant. As nardi and others have said, think of water splitting as a battery... or a way to store energy as a chemical fuel (i.e. hydrogen gas). Because your energy input can come from any source, it doesn't matter. Agree that hydrogen isn't an ideal fuel though. They're overselling that point. But the science is about how to split water efficiently. It's outside the scope of this research to address how to handle and use hydrogen after that.