Right but the advantage of H2 using a system like this could make solar a viable round the clock energy source. If one could run on conventional solar cells during daylight hours whilst also using another array of these to stockpile H2 for use in a fuel cell at night, then it could provide 24hr power vs. Lion batteries with .6MJ/kg. Clearly they have a lot more work to do before it would be viable, but I think it has interesting possibilities.

Right now every solar hydrogen production technology is an order of magnitude more expensive than steam reforming with little opportunity of ever becoming competitive.