The best way locally to get the most abundant element in the universe is to dip a bucket into the nearest body of water.
Of course, if you want your hydrogen as H2, then absent ultra-cheap energy H2O isn't the best source. Energy costs, and cracking CH4 takes far less energy than cracking H2O.
And if that "seems somehow wrong", well, perhaps there are some assumptions underlying this seeming that warrant a closer look.
Henry On 11/1/2013 9:30 AM, Derek Clarke wrote:
Yes, but it seems somehow wrong that the best way to get the most abundant element in the universe is to use more fossil fuel. On 1 November 2013 14:13, Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx <mailto:hvanderbilt@xxxxxxxxxxxxxx>> wrote: It's significantly cheaper to crack natural gas directly to obtain your hydrogen. (Consider the alternative of burning that same natural gas in an electric generator then electrolyzing your hydrogen: You have losses in the generation, in the transmission, and in the electrolyzing.) What could change this would be a source of electricity several times cheaper per kwh than natural gas. Not likely anytime soon, between fracking making gas cheaper and the immaturity of all the cheap bulk power alternatives. Oxygen production costs meanwhile are trivial by comparison; distilling it out of the atmosphere is hugely cheaper than getting it by splitting water. Henry On 11/1/2013 2:41 AM, Derek Clarke wrote: Obviously on-demand electrolysis is inappropriate, but there's nothing to stop you using a smaller reactor to produce the fuel and oxidiser you need over time. After all it's going to be burnt in a few minutes, so while the GW rating may be high, it's not so many GWh. On 31 October 2013 00:54, David Weinshenker <daze39@xxxxxxxxxxxxx <mailto:daze39@xxxxxxxxxxxxx> <mailto:daze39@xxxxxxxxxxxxx <mailto:daze39@xxxxxxxxxxxxx>>> wrote: Henry Spencer wrote: > At the upper extreme, big > rocket engines typically are multi-gigawatt machines. Clark calculates the kinetic power of the Saturn V first stage exhaust as about 41 gigawatts... this is on the same scale as the outage of the Eastern Interconnection of the North American power grid in August 2003. (Approximately 60 GW of generation capacity was initially tripped off line - IIRC, roughly 40 GW was still out of service a day later.) -dave w
