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After Partially Digesting Veridian Note 00470 Posted: July 30 2006
I got concerned that no one is talking about the water it takes to make biofuels. Water is a resource we are running out of faster than petroleum. I wrote to Bruce immediately to point out that no one he had quoted or linked to had so much as mentioned WATER in their rush to make money making ethanol out of switchgrass. I am left in a state between bewilderment that you did not mention water. That is the other component of the photosynthetic equation H20 + CO2 > CH2OH etc And changing from corn to switchgrass may make the energetics of ethanol production pencil a bit better, but it does not make the problem of water go away. The general understanding - near as I can tell - is that water is already scarcer than petroleum - that most of the major aquifers that we have been mining, at least in the US, are closer to depletion than the oilfields. I apologize in advance for sending less-than-up-to-date links, but I have been busy doing other stuff lately. http://petroleum.berkeley.edu/papers/patzek/CRPS416-Patzek-Web.pdf http://www.fao.org/newsroom/en/news/2005/100274/index.html He replied, quoting Pope: "If there's nothing left in the aquifers, all those deserted cities will be full of prairie grass. " Which got me worried. So I started writing this thing. I believe that Pope's scenario "If there's nothing left in the aquifers, all those deserted cities will be full of prairie grass." - which is certainly worthy of Ed Abbey - literally requires that those Cities stop using the water for consumptive (lossy) purposes - discharging groundwater into the air or ocean in sewage outfalls, air conditioners, nuke cooling towers, etc. Otherwise, we just get desertification, not rich oceans of switchgrass. There is little or no switchgrass in either the Mohave or the Sahara. In our little eco-region, stuck between saltwater and mountains, we figure that over 80% of the water used in non-sewered residential development is non-consumptive, meaning that it returns to groundwater, a closed loop. The primary losses involve evapotranspiration resulting from irrigated lawns and evaporation from things like air conditioners. Obviously, not all evaporation is bad - after a certain point, those losses return as rain. But what people fail to account for is the reality that most rain is intercepted and reevaporated long before it reaches the ground, let alone recharges the groundwater. And the static level in some of our municipal supply wells has been dropping as much as 12' per year as a result of the drought conditions. My concern is that we are still deluding ourselves and one another in this discussion - not that the proposed switchover of our transportation fleets to ethanol is a fundamentally bad idea, for the same reasons that I believe biodiesel or battery-based hybrids as currently promoted and practiced are a bad idea. Because just like those movements, it is still just another palliative, because we are still merely rearranging the deck chairs on the Titanic, rather than addressing the issues in front of us. The discipline of I/O modeling offers a great tool for exposing knowledge gaps and showstoppers and it appears to me that we are assiduously avoiding its teachings. It is pretty clear that lots of people are going to make lots of money promoting this technology. But that does not mean that ethanol - at any price - is a necessary step on the path to where we want to go. You’ve got to contrast this statement about 100 MPG plug-in hybrids: "Since they’re usually plugged in at night, when electricity rates are lowest, advocates estimate that it costs less than $1 per gallon to replenish a plug-in hybrid. If gasoline costs $3 a gallon, driving most gasoline cars costs roughly 8 to 20 cents per mile, CalCars estimates. The cost of a plug-in hybrid for local travel and commuting drops to 2 to 4 cents per mile, the group says" with this for the same day's NYT: Still, despite most power grids having run at or near record demand this past week, most power failures in the country this summer have come from problems with the distribution system, not with the supply. Local utilities typically learn of problem transformers and cables only as they fail, said Stan Johnson, who monitors power grid trends for the council. “It does raise some very serious questions that need to be answered, if we are putting sufficient money in upgrading the distribution system,' Mr. Johnson said. But Mr. Martinez said the utility had been keeping pace with repairing and replacing equipment and called this heat wave, with its severity and length, a particularly unusual strain. I spent the first half of the '90's as a water planner, and the second half of the '90's doing tech-transfer for federal labs, and I've been watching the evolution of this discussion pretty diligently for the past few years. My core concern is that most of the papers coming out of the Federal Labs appear to be rah-rahs for corn growers that totally ignore both the reality that the water involved is a finite resource for which competition is fierce and increasing and the caloric cost of pumping it. For example: http://www.ncga.com/public_policy/PDF/03_28_05ArgonneNatlLabEthanolStudy.pdf The paper I've referenced at least shows the range of values used by different analysts, including David Pimentel, and the inputs considered. Changing from corn to switchgrass is an improvement, but we need to get serious about this and quantify it. Another fascinating paper that tangents this discussion is : Multiscale Integrated Analysis of Social Metabolism, from Mario Giampietro. On a related subject, for the past couple of years I have been passing out the round number that the nameplate horsepower of one year's production of infernal combustion engines in the US is damned near equal to the total installed electrical generating capacity in the US - that is the sum of the nukes, gas-fired, coal-fired and hydro power plants. That means that during rush-hour, when all the cars are out, there is probably more energy spent moving the cars than ALL of the stuff that is happening because of electrical power. All the motors big and small, the radio and tv transmitters, the lights, the computers, the tv sets, the space heaters, the steel furnaces, the works ... Joe Breskin, Port Townsend |