you are correct on the units, although my point is still valid. batteries absorb and release more net electric than the whole electrolysis process. with electrolysis, 1 kwh into the electrolyzer, gives you less than 1/3 out of the fuel cell.
batteries are 70%+ (at the c20 rate, with 50% DOD) Steve Spence Subscribe to the Renewable Energy Newsletter: http://www.webconx.com/subscribe.htm Renewable Energy Pages - http://www.webconx.com Palm Pilot Pages - http://www.webconx.com/palm X10 Home Automation - http://www.webconx.com/x10 [EMAIL PROTECTED] (212) 894-3704 x3154 - voicemail/fax We do not inherit the earth from our ancestors, we borrow it from our children. -- ----- Original Message ----- From: "F. Marc de Piolenc" <[EMAIL PROTECTED]> To: "Biofuel List" <biofuel@yahoogroups.com> Sent: Friday, July 13, 2001 7:09 AM Subject: [biofuel] Pollution-free car > Steve wrote: > > > "the point is, if you generate 1kw from solar, shouldn't you store 80% > in a > battery (ev) instead of 30% in a hydrogen tank (fuel cell ev)?" > > That should be kilowatt-hours, rather than kilowatts, since we're > talking energy rather than power. > > 1. You'd be darned lucky to actually store 80% of the generated juice in > a battery - or rather, you might store 80%, but you won't get that much > back and still have reasonable battery life. That's in addition to the > weight and cost penalties of batteries, which still have very low energy > storage densities. > > 2. Electrolysis units can be run up to .90+ efficiency if the current > density is kept low - it's a tradeoff between capital cost of the > electrolysis plant and efficiency, as a more efficient plant is more > expensive to build. Of course there's a penalty for compression or > whatever you do with the hydrogen (best is a fuel bladder at or near > atmospheric pressure, but that appeals only to airship maniacs like > myself), but even that doesn't drop you to 30% net. based on heat. If > your goal is electricity, you can run hydrogen through a fuel battery > and recover as much as 85% of input energy in a practical road machine. > > In terms of capital cost, electrolytic hydrogen makes very good sense as > an energy storage medium for power plants with intermittent output > (solar and wind) if stored in gasometers or bladders, especially if > there's a market or a profitable use for the oxygen (an oxygen-enriched > gasifier, for example). With compression ...? > > Best, > Marc de Piolenc > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > Please do NOT send "unsubscribe" messages to the list address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > > Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
