Hydrogen power: hype or hope?

Under my national consumption accounting for emissions, hydrogen made in Australia, exported to Japan, would record production emissions as Japanese imports. All Japanese exports would then be exempted. That's how our GST works. There'd be no emissions 'price' on national exports, but full 'price' on national imports. The same applies to Australian fossil fuel exports and imports. Globally, all exports are some country's imports. All traded goods emissions are accounted for via imports. None are double-counted.

International trade emissions incentives would be trade-competitiveness neutral across all energy and its emissions. That removes a fatal policy design flaw – national production-based measurement – inherent in current emissions accounting. This flaw impedes a global response to an assumed global problem – human caused global warming. The current accounting incentives haven't, don't, and won't cut global emissions.

What about the science and cost implications? The HAF report says using hydrogen produces only water, and no CO₂, 'or any other greenhouse gas', plus energy. The chemical reaction for use is:

2H₂ + O₂ Þ2H₂O + energy

This is only half the full hydrogen cycle story. There's almost no free hydrogen on earth. For the full cycle, we need two equations, one for producing hydrogen (eg, electrolysis), plus one for using it (oxidisation). A simplified 'full cycle' version of extracting as well as using hydrogen might be expressed as follows:

2H₂O + energy_electrolysis Þ2H₂ + O₂ (1)

2H₂ + O₂ Þ 2H₂O + energy_{usinghydrogen} (2)

Substituting (2) into (1), and assuming perfectly efficient electrolysis and hydrogen use:

energy_electrolysis = energy_{usinghydrogen} (3)

Perfectly efficient machines or processes are physics pipe-dreams. Efficiency losses always apply. So:

energy_electrolysis > energy_{burninghydrogen} (4)

Converting water to hydrogen and then using hydrogen to produce water again loses energy – maybe a lot.