Liquid Hydrogen would be a pretty good fuel for airplanes, so let’s see how many solar cells would be needed to make the fuel to keep one in the air. A 747 jet uses on average 140 megawatts of power, incidentally even the old fashioned nuclear reactor on a Nimitz class aircraft carrier can generate 190 megawatts, a LFTR could be much smaller because it's much more energy dense. The electrolysis process to make hydrogen from water is only about 60% efficient so that brings the power requirement up to 233 megawatts, but then you need another 30% to liquefy the hydrogen (it’s not easy to do) so the grand total is you need a solar cell installation that on average produces 333 megawatts each and every hour to keep a hydrogen powered 747 in the air.
Averaged over 24 hours a square meter of solar cells might produce 30 watts each hour, so you’d need 11,100,000 square meters of solar cells, that’s a square 2787 meters on a side. We conclude that to keep just one jet in the air we need a fuel factory that covers 3 square miles of the Earth’s surface. And that is why I don’t think solar is the answer to all our energy needs. There are only 2 other sources that have the potential to power our civilization for the next billion years: 1) Fusion reactors, but nobody is close to figuring out how to build even a working model much less a practical machine. 2) Thorium fission reactors, and we’ve known how to build them for half a century. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
