Hi Zeke, Chandan and all Sorry I didn't give refs for the USDA and Minnesota stats on petroleum EROEI (energy returned on energy invested), they're from our website, and I'm embarrassed to admit that it would take me some time to track down the sources.
I don't know how those life-cycle figures on petroleum EROEI should be interpreted. I'm not even sure how life-cycle studies should be interpreted. They seem to assume so many typical scenarios and averages that I wonder if in the end they really represent anything that actually exists. Another assumption is about EROEI itself. Well, what you mostly see about EROEI is assured statements and heated arguments - everybody says everybody else doesn't understand it. Anyway, one thing they seem to agree on is that it's specifically not about money or economic costs - it's calculated purely in units of energy, money is another matter. I think that's a little naive, when it comes to oil companies and their bottom line _nothing_ is another matter. However, it's agreed (sort of) that producing energy at a negative EROEI can be feasible for economic reasons, but only in the short-term, eg.: "Society can't run for long on an EROEI of less than 1.0 or on a negative Net Energy. Doing so is equivalent to withdrawing money from a bank - at some point you have to make some deposits - or at least stop the withdrawals." Not quite - it's more like drawing on your current account, which doesn't matter much if you happen to have massive reserves invested. As is claimed. In which case never mind EROEI, use up all the cheap light oil while you can, leave the heavier stuff for later and put off having to build new, more expensive refineries for as long as possible. I don't know if that's the case, just conjecture, for the sake of an example. Though there's certainly been a lot of foot-dragging in upgrading refineries in the US. It's worth looking at what else is in a barrel of oil. This is from Petroleum.org: Products Gallons per barrel gasoline 19.5 distillate fuel oil (includes both home heating oil and diesel fuel) 9.2 kerosene-type jet fuel 4.1 residual fuel oil (heavy oils used as fuels in industry, marine transportation and for electric power generation) 2.3 liquefied refinery gasses 1.9 still gas 1.9 coke 1.8 asphalt and road oil 1.3 petrochemical feedstocks 1.2 lubricants 0.5 kerosene 0.2 other 0.3 Figures are based on 1995 average yields for U.S. refineries. One barrel contains 42 gallons of crude oil. The total volume of products made is 2.2 gallons greater than the original 42 gallons of crude oil. This represents "processing gain." EIA March 2004 data is similar. We tend to skim over some of those items. I found this estimate of world petroleum use, probably not far wrong: World transportation fuel (about 750 billion L/yr), at least 40% of world electricity (now around 30 million MW) and 50% of world organic chemicals production (in excess of 100 million T/yr). So the 1.2 gallons of petrochemical feedstocks in the barrel accounts for about 50 million tons of chemicals per year. That's a lot of money. There was this amazing claim: "As I stated on many occasions, someone calculated that for every 100 gal oil the industry recovers $100 worth gasoline from half of the barrel and $27 000 in other chemicals from the other half." - Dr. Laszlo Paszner of the Faculty of Forestry at UBC, who developed the Acid Catalyzed Organosolv Saccharification ethanol process (ACOS), in a message to the Bioenergy list (2002). I don't know if that's true or not, but I'd be surprised if Paszner is altogether wrong. Whatever, even if you divide it by two, or four, or ten, it would seem to shrink the overriding importance of EROEI more than somewhat if the fuel portion is only a by-product in money terms. I'm sure ExxonMobil's accountants would have no trouble getting all the numbers to add up nicely, EROEI and all. Especially if they're confident of the oil reserves. If not, they'd probably just postpone the inevitable as long as possible. And lie about it. Like so much else in this discussion, it's hard to say how important petroleum EROEI really is, let alone what the real figures might be. Anyway, how about this, no takers? >why does oil cost four times as much as it did five years ago? >(Answer in no more than 35 words, who, what, where, when, why and >how, thankyou.) I'll even drop the 35-words limitation (it's just a joke, that's the rule for writing the first paragraph of a news article). Best Keith >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/ _______________________________________________ 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/
