For the example, an EROI of 0.88, you get 0.88 gallons of stuff (or BTU's or whatever) for each 1 gallon consumed... still worth it, since you stared with 1 gallon of sticky black crude oil, stuck way down in the ground... and ended up with 0.88 gallons of gasoline or such... so even though you end up with less than you started with, you got a more useful product. By definition, any product that uses petroleum as the feedstock, will have a EROI less than 1. It's not till it gets lower than zero that it's not worth it to do it... Of course, an EROI higher than 1 is even better -- because you aren't just converting crude to something else with some loss...but actually gaining energy (from solar photosynthetic input, for example). At least, that's how I think about it to make those numbers make sense.
Z On Fri, Mar 14, 2008 at 8:25 AM, Chandan Haldar <[EMAIL PROTECTED]> wrote: > Is there something funny about Table 3 (in that pdf) or do I > somehow miss the whole point? > > Why are they adding up all the fractions together?! > > I'd imagine one would add up Domestic Crude Production, Domestic > Crude Transport, Crude Oil Refining, and Diesel Fuel Transport > to get total cost of domestic diesel production. Similarly, add > up Foreign Crude Oil Production, Foreign Crude Transport, Crude > Oil Refining, and Diesel Fuel Transport to get total cost of > foreign origin (with respect to the US) fuel. These totals come > out as 0.6477 and 0.6244, corresponding to EROEIs of 154% and 160% > respectively. Why on earth would one add up all the rows together? > > Or have I misunderstood the whole idea? If petroleum fuel had > a negative ROEI, shouldn't the whole system have fallen flat on > its face decades ago? > > Chandan > > > Keith Addison wrote: > > snip... > > A.k.a. EROEI, energy returned on energy invested. Does it necessarily > > become a losing proposition? Quite a few studies show a negative > > EROEI for petroleum, which doesn't seem to stop anything much (yet): > > > > "1.2007 MJ of primary energy is used to make 1 MJ of petroleum diesel > > fuel. This corresponds to a life cycle energy efficiency of 83.28%." > > An Overview of Biodiesel and Petroleum Diesel Life Cycles, Sheehan, > > Camobreco, Duffield, Graboski, Shapouri, National Renewable Energy > > Laboratory of the U.S. Department of Energy, Midwest Research > > Institute, May 1998. 655kb Acrobat file: > > < > http://www.biodiesel.org/resources/reportsdatabase/reports/gen/19980501-gen-203.pdf > > > > > > "Units of energy produced for 1 unit of energy consumed: Petroleum > > 0.88 units produced " -- USDA > > snip... > > Keith > > > _______________________________________________ > Biofuel mailing list > Biofuel@sustainablelists.org > http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Search the combined Biofuel and Biofuels-biz list archives (70,000 > messages): > http://www.mail-archive.com/biofuel@sustainablelists.org/ > -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/attachments/20080314/4abcb104/attachment.html _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (70,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
