Hydrogen economy

Numerous technical challenges prevent the creation of a large-scale hydrogen economy.

These include the difficulty of developing long-term storage, pipelines, and engine equipment; a relative lack of off-the-shelf engine technology that can currently run safely on hydrogen; safety concerns regarding the high reactivity of hydrogen fuel with oxygen in ambient air; the expense of producing it by electrolysis; and a lack of efficient photochemical water splitting technology.

Hydrogen can also react in a fuel cell, which efficiently produces electricity in a process that is the reverse of the electrolysis of water.

The hydrogen economy is nevertheless slowly developing as a small part of the low-carbon economy. The idea of hydrogen economy has been heavily criticized from the moment it was proposed.

The main issues with the H2E scenario are as follows: The human civilization does not have a clean, energy-efficient and low-cost source of H2.

The current production methods either produce a large amount of carbon dioxide per kW than direct burning of coal, or are more expensive or are less energy efficient.

Storage of H2 within a transportation vehicle for its own motive power faces cost and safety issues. Conversion of H2 into electricity in fuel cells have a low (ca. 60%) energy efficiency, with issues of durability and cost remaining unresolved.