OK,
I took the bait and did a little googling for Hydrogen fuel boosters and after two pages decided that there was far too much fluff with respect to wild un-substantiated claims, So based on the evasive (or cryptic) explanations that were given I decided to look for a little more concrete info on "hydrogen fuel enhancement" instead. The material I found was much more forthcoming about how the technology works, what kind of results can be expected under certain conditions and most importantly.... was referenced. The link I read is here.
Note this statement;
"Hydrogen fuel enhancement from electrolysis of water can produce fuel efficiency improvements on the order of 4% and similar modest reductions in emissions, and is currently in use in Canada."
I checked their references and the some of the results referenced were generated by ETV (Environmental Technology Verification) program from the government of Canada.
4% or 40%. There seems to be a slight discrepancy. 4% is better than nothing and if you have huge fuel bills because you drive tractor trailers then it's worth it, but I don't think it's going to help the average American balance their check book.
Yup... the X15 was definitely a hydrogen powered craft, and so are all the shuttle craft. But a liquid fuel rocket has very little in common with a jet aircraft and the X15 was no exception. If memory serves me well, one of the X15 engines blew up while being tested on the ground and what happened to Challenger should serve as a sobering reminder hydrogen powered rockets are not ready for the main stream (admitidly, I'd give my left n#t to go for a ride in an X15, safety be damned).
That said, I see no reason why a regular jet liner couldn't run on Hydrogen with little modification. As I understand it, turbines can run on just about anything as long as it's liquid and flammable. Liquid Hydrogen would qualify. The big question is if the plane can carry enough volume of H2.
Hydrogen has a very high energy density per unit mass, but as a liter of liquid hydrogen only weighs 70 grams so it has a low energy density per unit volume. All the credible sources I've checked give liquid hydrogen 1/3rd the energy density of gasoline and jet fuel is even higher density that gasoline as I understand. Therefore, you're going to need to carry 3 times the volume of fuel to make it happen. However, since liquid hydrogen is about 10x lighter than a comparable hydrocarbon I see this as being quite feasible.
Don't get me wrong; I'm not against hydrogen. I don't believe that any of the obstacles that currently bar it's widespread use are insurmountable, but I don't believe it's a magic bullet either. We can transition to it today and you don't need any special knowledge. I can generate it in my basement with a little NaOH (electrolyte) a couple of wires and a DC power source. You can too! It's not rocket science! It's also not cheap!
It's not just about producing Hydrogen, but also processing it. In the very least you have to compress it. Any body out there have any experience with dive compressors and how much it cost's to compress a gas to 300bar? Keep in mind that 27000L (~1000cf) of H2 is equivalent 2.4kg or ~34L of liquid H2. But in reality, storing H2 at high pressure isn't efficient so you really need liquefy it which is even more energetically expensive.
Then you need to consider delivery. Liquid H2 is 20°K (−423 °F/−253°C) is hazardous in it's own right. It's going to require special training, procedures and equipment to be done safely and it takes time and money to put that kind of infrastructure in place.
I do believe that H2 is in our future, but it will be economics that dictates when it is adopted. At this point in time, it simply isn't financially feasible and that is why we don't see it more widely adopted. I don't believe it's because there is any kind conspiracy against it's adoption.