what is the most cost-effective way to produce H2 and how to measure output?

Question

How to store output for H2 and Oxygen?

Answer 1

Determining "the most cost-effective" method of Hydrogen gas production will depend highly on the input cost of the materials used in production (obviously).
There are NUMEROUS methods which can be used to produce Hydrogen gas and with each method, several options exist as to how the energy is supplied to the substance in order to extract the Hydrogen.

I will give an example.
Electrolysis of water is one method of producing Hydrogen. Energy in the form of an electric current is supplied to water in order to split the water molecule and produce Hydrogen gas and Oxygen gas. Where does this energy (electricity) come from? The "wall", a battery, a solar cell? These three sources of electricity will have vastly different costs. Also, the energy conversion efficiency is an important factor to consider.

Another H2 producing reaction can be preformed by adding a more reactive metal than Hydrogen to an acid...for example, adding Iron to Hydrochloric acid. In this case, the costs would be determined by the price of the acid and the price of the Iron.


A [virtually] free method of Hydrogen production would be to use a solar cell to power an electrolytic cell to split water in to Hydrogen and Oxygen gas. This assumes one could get free water (not a hard task to accomplish) and a free solar cell, as well as materials to build the cell.

Hydrogen storage is a pretty broad topic which could in and of itself be just as lengthy of a discussion as Hydrogen gas production.
Storage of Hydrogen gas under high pressure, or better yet, in Hydride form, is one of the most practical methods used today.