Skip to main content

View Diary: Recent DOE Break-Through with Hydrogen Fuel Cells, should make them Affordable (275 comments)

Comment Preferences

  •  Not true. (19+ / 0-)

    Compare NASA's safety guidelines for working with hydrogen to those for working with gasoline.  Not even close.

    1) Hydrogen ignites with 1/10th the ignition energy of gasoline.  that means even the tiniest of static sparks will set it off.
    2) Gasoline will only burn within a very narrow mix of fuel and air.  Hydrogen burns with almost any mix of fuel and air, 4-75%.
    3) Gasoline will only conflagrate (burn) without being compressed.  Hydrogen can and will detonate (explode).
    4) Both hydrogen and gasoline can "escape".  Gasoline escapes downward (flowing), hydrogen upward (rising).  Just like an enclosed space on the ground can contain gasoline, an enclosed space overhead (such as a garage or rain shelter) can contain hydrogen.
    5) Hydrogen is absurdly good at passing through materials.  For example, hydrogen pipes have to be the highest pipe in a series of pipes, or gas may pass out of the lower pipe and into the upper pipes, follow them to their destinations, pool there, then detonate (this has happened many times).
    6) Hydrogen is very prone to embrittling metals.
    7) Hydrogen is not carcinogenic, but it is an aspyhxiant which destroys ozone.
    8) Due to #1, #2, #3, and #4, buildings which will contain at least 1kg of hydrogen at any point in time, according to NASA's guidelines, should be designed with:

    A) Roofs designed to be blown away
    B) Hydrogen suppression/active ventilation systems
    C) Hydrogen sensors to detect the pooling of leaked hydrogen
    D) Every last electronic device being rated to not give the required miniscule spark needed to set of hydrogen.

    And a bunch of other stuff.  Does that sound like your garage?  The explosions that devastated the Fukushima reactors were hydrogen explosions.  These were buildings designed to not set of hydrogen in the event of a leak.  But that's an incredibly hard challenge; the stuff explodes so damned easily.

    This is a 18x7 hydrogen/oxygen balloon, so about 200ft^2.  Watch the video.  Assuming stoichiometry, that's about 133ft^2 of H2, or 1/3 of a kilogram.  Being a mix of H2/O2 yields about twice the explosive force of H2/air, at this scale, so we'll double the amount of hydrogen to about 2/3rds of a kilogram.  The Honda FCX clarity stores 4.1 kilograms of hydrogen.  Picture that going off in a confined space.  And that's just a car; just picture a hydrogen-powered SUV (a dozen kg).  Or a hydrogen semi (a hundred kg) in the Lincoln Tunnel, for that matter.  I think we could safely call that "a cannon".

    It's fun to pretend that hydrogen is some docile chemical in order to play into fantasies about a hydrogen economy, but that's simply not the facts.

    To try to counter this, the hydrogen hype-rs usually like to pretend that there's no way a hydrogen tank could ever fail.  Yeah, we've heard that before.  And let's just ignore that the failure doesn't have to occur in the tank itself -- the valve could rupture, the controls for the flow rate in the vehicle could fail and leave it open (allowing for a failure in any part of the drivetrain), and so on.  But let's just look at the tank itself.  Hydrogen tanks are generally high pressure carbon fiber tanks, for a wide range of reasons.  Well you know what, the exact same sort of tanks are used in (much more common) CNG vehicles.  And guess what?  They do fail.  There have been a surprisingly large number of failures of them.  Here's pictures from one.

Subscribe or Donate to support Daily Kos.

Click here for the mobile view of the site