It appears that Hesham ElBakoury <helbakoury@xxxxxxxxx> said: > >Hydrogen-powered planes were voted as one of breakthrough technologies this >year. Not by anyone who understands the physics. To get a useful amount of H2 in a reasonable volume, it's compressed to 700 bar (10,000 psi) which requres a big heavy tank to contain it. Unlike kerosene, H2 is extremely flammable if it leaks; 4% in air can explode. Even if someone figured out how to make the big heavy tank fit in an airplane, would you like to ride in a flying bomb? I wouldn't. Battery planes with rarely used jet fuel range backup might make sense if you can deal with the weight of both the battery system, electric motors driving some kind of propellor, and the fuel system, probably something like an existing jet engine. I'm not holding my breath for that, either. I have seen claims about planes running on biodiesel made from plant and food waste but scaling that up will be a challenge. I would rather the IETF stick to plausible technology and start with realistic models of the carbon budgets for our meetings and how they would change if we changed the way we met. R's, John
