Hydrogen powered BMW

[knirfie]

We don't have a nuclear plant anymore... idiotic government...

[Brian Ellis]

Originally posted by UtwigMU

Brian: Based on above and based on most powerful plant being Chooz in France at 1435MW, your estimate at 1.6GW for typical PWR is over optimistic.

Sorry, the EuroPR, which is a consortium project with Areva, Siemens and Fromatome, has a reactor power of 1.6 GW. A complete power station has an output max of 1.5 GWe. This is a relatively new design where the emphasis is on safety, efficiency and the recyclability of the fuel, with reasonably low constructional costs because of its standardised modularity which will also ensure low decommissioning costs after 40 years service. For the moment, none have been built, the first one having been started in Finland and a second one in France was ordered a few months ago.

[agallag]

That's more than enough to power a flux capacitor!

[Duty]

Originally posted by The PIT
You'd then get the wet house effect and the heavy rain would turn to snow on mountains and you'd get the next ice age.

Originally posted by Brian Ellis
If every car in the world ran of hydrogen, the difference it would make to rainfall or humidity would be negligible.

a) present-day cars produce vast quantities of water vapour. As H2 cars are more fuel-efficient, the quantity of H2O produced might actually diminish.

b) the total water content of the atmosphere at any one time is estimated at ~12E12 tonnes, ie 12 trillion tonnes. If you have a global 1 billion vehicles spewing forth an average 4 kg/water per day, that represents only 0.03% of the total and that is absolute, not the difference from present-day vehicles.

c) the water content of the atmosphere undergoes a strong negative feedback effect, because the major source is evaporation from the oceans. If the RH rises, for any reason, the oceanic evaporation at any given conditions of temperature and atmospheric pressure lessens. Therefore, the 12E12 tonnes is essentially very constant, averaged over the earth's surface. This is why, although water vapour is a strong greenhouse gas, man-made water vapour from burning fossil fuels does not influence climate change (as opposed to CO2, CH4 etc., which do).

d) in terms of RH, it might make a 1-2% increase in large, congested cities where buildings prevent air movements to dissipate the water vapour, especially in periods of temperature inversion.

I therefore believe that, in the unlikely event that H2 cars do become a major reality, they will not play any significant role in either weather or climate change, per se. OTOH, if the H2 is generated either from cracking natural gas or other hydrocarbons, or by electrolysis from fossil fuel power stations, there will be a severe concomitant generation of CO2.

Killjoy...