<p>My morning paper had an article about the guy in Japan that designed the Prius for Toyota, and he’s now working on perfecting a fuel cell car, which this article (and others I’ve read) says is “powered by hydrogen, which combines with oxygen in the air to form water”. Elsewhere I’ve read that a supposed advantage of fuel cell cars is that there are no carbon emissions, they just “emit” water as a byproduct.</p>
<p>Thinking back on my kids elementary school “water cycle” science projects (the same water volume cycles thru evaporation, condensation and rain over and over), does this fuel cell car stuff mean the cars will in effect produce “new” additional water, which when added to the current supply would increase the amount of the world’s water, raise ocean levels, flood coastlines, etc.</p>
<p>Maybe an exaggeration flooding coastlines, but you get the general idea? I am NOT a scientist, just curious. Anyone got an answer?</p>
<p>No, there is little or no net creation of new water when burning hydrogen. The reason why is because there is very little (almost zero) free hydrogen gas available on earth. Thus, nearly all the hydrogen gas used in fuel cells and in other chemical reactions is produced by electrochemically splitting it off from oxygen in water molecules. Thus, you aren’t really creating new water when you burn hydrogen so much as you are restoring water that was earlier “destroyed” when the hydrgen was made.</p>
<p>Mercymom, hydrogen production requires energy, and if this energy comes from a renewable non-polluting source like wind power or sunlight, using hydrogen as fuel makes perfect sense. I think most commercial hydrogen is currently produced from hydrocarbon sources (e.g. natural gas or methane), but it also can be produced from water by the processes called electrolysis (passing electric current through water and splitting it into hydrogen and oxygen) and thermolysis (not that common). So if your hydrogen is produced from water, by burning it as fuel in your car you basically “recycle” this water. If your hydrogen comes from methane, which ultimately came from plant material, you release water which was combined with CO2 by plants to produce this plant material. We produce water all the time by burning natural gas in our heaters and stoves. The amount of water created in this way is small. Im more concerned about melting polar ice.</p>
<p>Thanks for the explanation, it makes sense. I have also read somewhere that the making of the fuel cells themselves is polluting, even if the cars they’d be used in are not (at least compared to gasoline fueled cars). Is that true, and is there a (relatively) simple explanation one way or the other (on the making of fuel cells)?</p>
<p>mercymom,</p>
<p>Have you ever seen the story of how the batteries in the Prius are produced? There’s a fair amount of pollution and energy waste in their production as well (something like the raw materials transiting the ocean to be produced elsewhere to transit the ocean again for more manufacturing, etc.).</p>