Hydrogen evolution is trivial, the real issue is that hydrogen has a very poor volumetric density. Without the ability to store it in a lower volume form it won't be viable. No fun using 13 gallon tanks to store 1 gallon of gas of energy value. Doesnt matter how efficient it is if it takes a skyscraper to store. Just went over this stuff in graduate level environmental chemistry class this semester so it's pretty fresh in my mind.

This post was edited by Thor123422 on May 29 2015 10:36pm

Simple compressed hydrogen storage systems are decent for current day automotive markets. The price of hydrogen is just too high.
Right now, in terms of "green", solar water splitting is being pursed much more than trying to find a way to better store hydrogen.

Wrong, compressing drastically takes away from the efficiency since it takes a lot of energy, and after that the volumetric energy density is still only 1/13th of gasoline. You have no idea whats being pursued...... Currently the largest section of research is focusing on storing hydrogen as metal hydrides. Source: graduate student in chemistry who just got done with the class on this.....