Hydrogen: I see your point of being cheaper. Im guessing flex pipe would be good because natural gas should not have the pumping, viscosity, pig cleaning issues of fluid oil? Run it over rivers, mountains, where ever is cheapest. Without spill worries iether? Just put it on rolls carried under a heavy lift helecopter and run it out. Ground crew erecting elevated towers on a smaller lighter scale than the oil pipeline. Just keep adding to it as demand increases. Sounds good to me. Years from now just roll it all up, knock down the stands, and never know it was ever there.