According to wikipedia, electrolysis has an efficiency of about 70%, with a theoretical limit of 94%. Cracking water will always require more energy than it wil

According to wikipedia, electrolysis has an efficiency of about 70%, with a theoretical limit of 94%. Cracking water will always require more energy than it will produce, i.e. there is no free lunch. The point of electrolysis is that it could be used as "clean energy storage" for other clean energy (e.g., solar). Hydrogen gas can be moved long distances, unlike other storage options that are more stationary (like a hydroelectric dam), and has higher energy density (120 MJ/kg for what I can find online) then even the best batteries available (2.54 MJ/kg for Lithium-ion nanowire?).