On 11/4/2013 1:14 PM, Henry Spencer wrote:
On Mon, 4 Nov 2013, Henry Vanderbilt wrote: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.There have been a few small demo projects which have used electrolysis for making hydrogen, usually due to special circumstances of one kind or another. For example, if memory serves, there are a couple of H2-powered buses in Iceland, and their fuel station uses electrolysis because Iceland has (a) lots of hydroelectric and geothermal power, and (b) no natural gas.
Which leaves the question, is hydrogen electrolysis in fact the most economically sensible way to turn cheap electricity into transportation fuel, or mere trendiness? ("The fuel of the future, and always will be...")
I'd be tempted to use the hydrogen produced plus carbon to produce CH4, which can be stored, transported, and used as vehicle fuel in mostly-standard vehicles with a wide range of affordable off-the-shelf technologies.
Yet further off-topic (but wait, there's more!) this reminds me of some recent attempts to use improvements in hydraulic fracturing technology out of the gas/oil drilling industry to produce geothermal power in a far wider range of places than those currently naturally suitable.
Now THAT would be revolutionary - drill two ~$10 million fracked dry wells with the right geometry, pump water down one, get steam out of the other to run some number of megawatts of power plant indefinitely. At a nickel a kilowatt-hour wholesale, that's $438,000 per year per megawatt cashflow, with no fuel costs. Not that many megawatts output needed for such a plant to pay for itself fast...
Henry
