"Steve Firth" wrote in message
. ..
Mark Townend wrote:

"Steve Firth" wrote in message
...
Steven M. O'Neill wrote:

The trouble with hydrogen is that it takes energy to extract it
from water or other compounds.

. . . natural gas stored in tanks
in the roof of the bus which is then catalytically split to CO2 and H2
witht he CO2 being emittted to atmosphere. The lying *******s then
describe this as "zero emission".

Of what though?

"Sero emission" means no emission, of anything.

It may not save CO2 emissions locally but removes other more nasty stuff
to
a remote place where it can be cleaned up more easily - some gain to
local
residents at least?

No, running a bus on methane means that CO2 is emitted from the bus (as
well as water) hence it's not "zero emission".

I never said it was


It would of course be simpler and cheaper simply to burn the methane
in
an IC engine. But it would also be less politically correct and harder
to pull the wool over the eyes of the travelling public.

But wouldn't there be more dirty stuff emitted locally?

Are you hapopy with pollution as long as it's in someone elses back
yard? The products of combustion of methane are water and CO2, exactly
the same as if the same gas is used in a fuel cell. Except of course
that burning the fuel in an engine produces more usable energy, hence
more miles per unit of CO2 emitted.

Is mobile methane combustion in lots of little IC engines as clean as you
claim though? What about lubrication oil losses, wear products, costs of
(possibly?) more frequent replacement etc. I'm not claiming it's any
dirtier, just interested in a comparison of the whole cycle and its effect
on different populations and on ecology. Removing concentrations of any
nastier directly-emitted pollutants from the streets where people live and
work must be laudible. CO2 isn't a particularly dangerous product to human
health locally at the level that transport produces it, but lead-based
additives were, so we (society, government, industry) removed it.

--
Mark