Also, I think we need to be moving towards 100% hydrogen if we want to use combustion as a green replacement for natural gas. However, I don’t think many of the appliances that currently use natural gas could safely use 100% hydrogen because of the properties of hydrogen gas. Primarily, I think the flame speed of hydrogen would require us to redesign the various combustors that use natural gas currently so that we don’t have flashbacks. Additionally, the hotter burning of hydrogen might cause material failure issues in our current natural gas burners. The research I’ve done is shown that we could probably get away with 30 to 40% hydrogen, maybe dependent on the exact burner. I don’t think moving to 100% hydrogen is feasible without a massive replacement of all of our gas burning appliances.
One more thing. Running hydrogen, even in blends of 30% hydrogen/70% natural gas, creates a large amount of extra NOx production. NOx, of course, is a pretty nasty pollutant. We need to redesign our current natural gas burners to help control NOx at high hydrogen blends.