hydrogen is just a pain in the royal order to use too, its density is just so very very low. even if we had fusion power I think synthesising methane or some form of hydrocarbon then running that through the fuel cell is the way to go just so we can have sensiblle sized tanks and just a little flamability hazard compared to the big explosion risk H2 poses. -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of William Chops Westfield Sent: Tuesday, 18 November 2003 1:35 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [OT]: Willow tree biomass - multiplies input energy by 11 On Monday, Nov 17, 2003, at 15:44 US/Pacific, Jake Anderson wrote: > > you say that USA uses 100 times the energy of the incident sunlight? > Actually, I think he said that fossil fuel consumption is equivalent to 100 times the incident sunlight energy, after assuming horrendous (but not necessarilly incorrect) conversion factors for each of the stages from sunlight->biomass->...->fossilfuel. This is a way of including the difficulties (ie inefficiency) of creating the fossil fuels; we're using up the fossil fuels at a rate 100 times that with which they could possibly be replaced... But I'm not sure it's relevant. The whole point of alternative energy sources, including solar and biomass, is to replace those inefficient steps with more efficient ones, or eliminate them entirely. So a solar cell converts sunlight directly at better than 10% efficiency (not counting manufacturing/etc, which you do need to count sooner or later), which is better than solar to biomass efficiency, and much much better than solar to fossil fuel to electricity conversion. Biomass research presumably includes finding plants that are more efficient than "average", and I assume the point of the original posting was that someone was claiming that willow trees were more efficient that some other fuels. (Willows make great charcoal for fireworks, btw...) So the article claims that there's about a 10:1 payback for willow biomass, and the counter-argument is that if that "1" HAS to be fossil fuels, it's not nearly efficient enough to reach a steady state... But we don't really know how much of the "1" needs to be fossil fuels, because there isn't a lot of effort directed at running willow harvesting appliances off of willow wood. Yet. Presumably, willow is better than "something else", or there wouldn't be a paper. At least in some growing conditions. Personally, I want direct ethanol fuel cells, at the end of a grow, ferment, fuel cell chain that's both shorter and more efficient than fossil fuel generations. The whole Bush "hydrogen fuel cell" thing is a bit depressing, because large scale hydrogen generation currently uses ... fossil fuels. I guess he had to keep his oil buddies happy :-( BillW -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu