Uknow I agree with you on many points. Thinking about the Hydrogen economy, I often wonder if the trend that which we consume oil currently, will be any example of our stratigy with water in the same respect. What I mean is, electrolisis with pure water it probably best, since salt water will emit tons of clorine on the Oxy side. So theres another energy sink besides compression of gas and liquifaction(supercooling), as de-salination energy needs would accumulate cumulaive on the energy balence thats needed to produce usable hydrogen, regardless of the energy sources used to produce it. Nevertheless the balence is out of wack in this regard, since hydrogen is only an energy carrier and it takes more energy to produce a given quantity, then is released at an end use point, such as a fuel cell. Considering generally fuel cells are only 60% efficient, then 40% of the original hydrogen used is lost to heat, as in-efficiency. Even though water is in fact recovered as a result of the fuel cell process, 40% of the original Hydrogen consumed from electrolisis is lost thru heat of just the fuelcell process. This means water is infact being consumed irreversably if thru only the fuelcell, let alone liquifaction losses and distribution losses, and end use losses.

 By the way,   I have heard any plastic that can be made from oil can be made fron corn. Often bio-mass can replace the complex organic materials that oil produces for us now. But conservation is alway censible. Thinking about this, it remindes me that sponges and other rare marine oganisms living in the Worlds Oceans, exist because of a delicate balence of water volume, thermodynamically and salination wise this is an important nursery of life and potental cancer curing drugs extracts, that could be derived from sea life. Let alone preventing drought in protected rain forest areas. We can live without oil, but can we live without water? Just an opinion, directed at generallity.