[mrinterweb]

I've never understood why hydrogen is not considered as an energy storage medium. Energy produced by solar panels could be used to create hydrogen, via electrolysis, that would later be burned to create energy at night. I guess the risk is that hydrogen is very explosive and maybe it is too difficult to mitigate that risk.

Update: I did find that people are using hydrogen as an energy store. http://schatzlab.org/projects/archive/schatz_solar.html

[EdwardMSmith]

It's a storage issue. Storing a useful quantity of hydrogen is very difficult.

[curtis]

Storage is certainly difficult, but there's also a fairly serious efficiency loss as well.