Bear Diaries

Home of the Anti-Fascist Coalition.

Like, this is weird, man.

From a story in the Guardian:

The key to the design is the fuel it would use. Conventional fuels would not be able to get the A2 up to the necessary speed, and so Reaction Engines has designed an engine that would run on liquid hydrogen. A spin-off is that liquid hydrogen is potentially much greener than conventional fuel - rather than producing vast amounts of carbon emissions it gives off water vapour and nitrous oxide.

But water vapour is a more potent green-house gas than CO2. Like, wow, man.

Thanks to Wretchard.

6 February 2008 - Posted by sleepyoldbear | Uncategorized | | 3 Comments

3 Comments »

  1. “A spin-off is that liquid hydrogen is potentially much greener than conventional fuel - rather than producing vast amounts of carbon emissions it gives off water vapour and nitrous oxide.”

    Yeah, but they have to refine the hydrogen and that uses energy which typically isn’t as green as it appears anyway.

    That sounds like a way cool airplane, though. I hate those long flights to London (you people in the east have it EASY)!

    Comment by Deborah | 6 February 2008

  2. Hahahahahahaha.

    Comment by Michael Vickers | 6 February 2008

  3. “But water vapour is a more potent green-house gas than CO2.”

    Depends on how you look at it. It is probably the biggest contributor to the “greenhouse effect”, but only because there is so much of it. the standard way of comparing gases is on a per mass basis, over time, say 100 years, to account for different atmospheric lifetimes. The global warming potential over 100 years, GWP-100, uses CO2 as a base, so its value is 1. N2O has a value of 296, so it is nasty, but note a correction to the story:
    The following correction was printed in the Guardian’s Corrections and clarifications column, Thursday February 7 2008

    We mistakenly described nitrous oxide, one of the byproducts of an engine powered by liquid hydrogen, as being environmentally safe in the article below. It is a greenhouse gas nearly 300 times more powerful than carbon dioxide. However, the developer, Reaction Engines, has a research project under way to devise ways of eliminating or capturing all of the NOX elements produced by the fuel.

    What about water? From Wikipedia:
    A GWP is not usually calculated for water vapor. Water vapour has a significant influence with regard to absorbing IR-radiation; however its concentration in the atmosphere mainly depends on air temperature. As there is no possibility to directly influence atmospheric water vapour concentration, the GWP-level for water vapour is not calculated.

    Conclusion- the water vapor in the exhaust would have a significant effect, how much we can’t well quantify. However, I imagine that the pollutants (forget global warming) in this exhaust would be much less than from a standard jet.

    Comment by Skeptic | 7 February 2008

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