Geo list, Andrew, David, Marty etal? The third international biochar conference in 4 years, sponsored by IBI (www.biochar-international.org) ended today in Rio de Janeiro. In the next several days, 50 of us will be on the Amazon near Manaus - looking at the several-thousand year old Terra Preta sites that give us quite significant evidence that the modern version (Biochar) has a potential much greater than either of the biomass options (burial, combustion, and BECS) being discussed in this thread. Can anyone explain to me why this thread has been ignoring Biochar? (This question being asked for a second time.)
I t is my impression that the popular literature on bio-sequestration is maybe 90% about Biochar - not the options being compared below. This conference (not the first this year) had about 200 papers. How many were presented this year on burial, co-firing, BECS, etc.? The papers here that were comparative should be available on the above web site within weeks. Without having them myself right now, I can not give specific comparative results, but I can assure the geo list, that this conference would not have conceded anything when viewed from an overall societal perspective. Yes one can get more energy or more sequestration - but those should not be the only metrics (given that there are more problems out there to consider.) Ron ----- Mensagem original ----- De: "Andrew Lockley" <and...@andrewlockley.com> Para: ke...@ucalgary.ca Cc: geoengineering@googlegroups.com Enviadas: Quarta-feira, 15 de Setembro de 2010 12:36:58 Assunto: Re: [geo] Carbon sequestration workshop Sep 9-10, Heinz Center, Washington DC Regardless of the debate about carbon efficiencies, there are of course further dimensions to the issue of crop waste. The waste contains a wide variety of chemicals, including macro and micronutrients for plants, which have the capacity to affect yield and nutritional value of crops in subsequent years. These elements may need to be replaced artificially if the waste is not returned to the soil. Therefore, you need to calculate the impact of any fertilisation of soil which needs to be done in lieu of the application of the crop waste to soil. Not only is there the carbon cost of manufacturing the fertilizers, but there's also some direct climate impacts from fertilizer application. Nitrogenous fertilizers especially have a significant climate impact. Furthermore, the fibrous nature of the crop waste affects soil composition, and the physical shielding of the soil from wind and rain helps to reduce erosion. This affects silt in runoff, aeolian dust, river mouth sequestration of soil organic fraction, marine food chains, etc. It's very dangerous to make climate-impact pronouncements when such factors have not been properly considered, as it can end up with a situation where predictions are far adrift from the real-world impacts. We all need to make sure that we don't get too dogmatic about our own perspectives on this issue, as in all likelihood the great majority of them will be proved wrong to some extent by later analysis and experimentation. A On 15 September 2010 15:29, David Keith < ke...@ucalgary.ca > wrote: Marty, Thanks for this gracious response. Sometimes, not often, I miss being back in physics. Cheers, D From: Marty Hoffert [mailto: marty.hoff...@nyu.edu ] Sent: Wednesday, September 15, 2010 7:11 AM To: David Keith Cc: z...@atmos.umd.edu ; geoengineering@googlegroups.com ; James Rhodes Subject: Re: [geo] Carbon sequestration workshop Sep 9-10, Heinz Center, Washington DC I agree with David that whether to bury or to burn depends on details like whether you can burn the biomass AND bury its CO2, and whether you are looking at methane or coal as the alternate fuel for generating electricity. A big problem is that we have too few pilot plants measuring actual performance versus idealized limits in parameter space. This is a problem for all alternate energy sources. People get into huge arguments over these numbers and come to different conclusions about a technology's viability. I like to think we engineer/applied physics types are ethically compelled to abandon our beautiful theories in the face of ugly facts -- something our social science colleagues aren't quite as obsessed about. The reason I circulated that paper from climatic change was to stimulate quantitative discussion & if it did I'm happy. Marty Hoffert Sent from my iPhone On Sep 14, 2010, at 8:42 PM, David Keith < ke...@ucalgary.ca > wrote: Andrew et al A few comments on this thread. Ning Zeng has it right, statements that burying beats burning in all (or even most) cases are not supported by the evidence. This is a case with the details and circumstances matter. If you have wet waste near the Mississippi and the alternative is combustion of the waste in a purpose-built biomass to electricity facility (which will be small, inefficient, and of high capital costs) then burial wins. If you have somewhat dry waste near a coal-fired power plant then cofiring wins. Marty said "fundamentally" it's better to bury them burn. Marty is smart guy. We both have the curse or blessing of physics as a background. But I have to say I am mystified how anyone can make any kind of fundamental claim that either burial or burning is better. I don't see any evidence for that claim in the paper. Stuart said: "All of these arguments were answered last year when the paper came out, but apparently you did not digest them then, so I will repeat, briefly. Burning biomass for electricity or making ethanol avoids fossil fuel carbon emissions = 30% of the starting biomass carbon. Biomass is a poor fuel, better to bury it. Please read the paper. Or is there something about 3>1 that you don’t understand?" I don't think the problem is our failure to understand that 3>1, nor do I think that this style of rhetoric helps settle arguments on complicated topics. In this particular case, the 30% depends on a set of assumptions, which in some cases might be true, in some cases burial is better than burning. However in other cases (many) they're not true. When you do the economic analysis in $/tC terms and finds that things that are easy breeze by matter. Example: capital costs. If you have to build a purpose built biomass facility than the capital cost will be well north of 2000 $/kWe and it may look big compared to the equivalent cost of building the infrastructure to do the burial. If, you're talking about retrofitting for cofiring then the capex looks 5X smaller. Utilization of capital also matters, biomass is a variable resource. One advantage of cofiring is that the capital is used all the time, if there's no biomass you just use the coal. Where is dedicated biomass systems must stand idle when there's not much biomass, when you calculate dollars per ton you have less utilization per unit capital and prices go up. Here's some of our papers that address these points: 47. David W. Keith and James S. Rhodes (2002). Bury, burn or both: A two-for-one deal on biomass carbon and energy. Climatic Change, 54: 375-377. This paper was invited with the paper Marty referred to because that Steve Schneider was concerned that the burial paper seem too much like advocacy, and wanted to hear another point of view. 95. James S. Rhodes and David W. Keith. (2008). Biomass with Capture: Negative Emissions Within social and Environmental Constraints. Climatic Change , 87 : 321-328. A more general overview of various pathways to negative emissions. 64. Allen L. Robinson, James S. Rhodes and David W. Keith (2003). Assessment of Potential Carbon Dioxide Reductions due to Biomass-Coal Cofiring in the United States. Environmental Science and Technology , 37 : 5081-5089. This paper was an attempt to quantify the potential of cofiring by doing a state-by-state match of biomass resources and coal-fired power. There are obvious limitations to this analysis, but it will least it was an attempt to go beyond gross national averages. It also contains a review of the status cofire technology by Allen Robinson a colleague at CMU who is a combustion expert. N.B., this paper has an error in one of the axis labels of the final figure. Jamie: if you're reading please double check that we have a corrected version up. 126. Jamie Rhodes and David Keith (2009). Biomass co-utilization with unconventional fossil fuels to advance energy security and climate policy. National Commission on Energy Policy Finally, things look different again when you consider gasification pathways to co-processing. Here the disadvantage of wet biomass is less important. This is a report we wrote more recently summarizing these options for a major Washington think tank. All of these papers are available for free download at http://people.ucalgary.ca/~keith/Other%20Energy.html . To sum up, I am not claiming that burial is foolish. It's a good idea that make sense under some circumstances. I am claiming that statements to the effect that burial is fundamentally or obviously better is advocacy not analysis. Yours, David -----Original Message----- From: geoengineering@googlegroups.com [mailto: geoengineering@googlegroups.com ] On Behalf Of Ning Zeng Sent: Monday, September 13, 2010 6:40 AM To: geoengineering Subject: Re: [geo] Carbon sequestration workshop Sep 9-10, Heinz Center, Washington DC Dear Andrew and all: The question of bury or burn is an important one that is far from resolved. One point emphasized by several people involved in implementing climate mitigation strategies at the Heinz Center workshop last week is that in general, there are many other competitions with biomass use as the total supply is limited by available land. For example, two that are being strongly promoted at this moment are long-term product use of wood by the forestry community, and biochar by soil scientists+, in addition to burning for energy. CO2 storage in geological formations are not yet practical at large-scale, so one can not assume so (and yet most stabilization scenarios count a few wedges on that!). At the end it will all come to the economics vs carbon/energy benefit, and most likely each method will find its niche depending on the local circumstances and carbon price. Plenty of research and real projects will have to be carried out before we know how much, where and when for which method. cheers, -Ning On Sep 12, 9:11 pm, Andrew Lockley < and...@andrewlockley.com > wrote: > An interesting paper, but one which nonetheless does not consider the > possibilities offered by Biomass Energy with Carbon Capture & Storage. > If you can float crop waste down the Mississipi for sinking, you can > float it down in dry bags for burning. > > Typically, CCS knocks about 20% of the energy output of a power plant > (from memory). So, it still looks like it's worth burning the crop > waste to recover the energy, then sequestering the CO2. (Although the > 20% may rise if the carbon efficiency of the generation process is > lower for crop waste). > > Further, the paper's comparison with natural gas isn't terribly > helpful, as it's a particularly scarce fossil fuel. Coal would make a > more realistic comparison, in the long term - dramatically reducing the > benefit claimed. > > One further point is that sequestering CO2 rather than crop waste > doesn't carry any risk of clathrate formation. > > Perhaps someone could do me the courtesy of pointing out any flaws in > my analysis? > > A > > On 12 September 2010 21:55, Marty Hoffert < marty.hoff...@nyu.edu > wrote: > > > Maybe the attached paper will help: An early approach explaining > > why, fundamentally, it's better to bury crop residue biomass than to > > burn it for energy. > > > Marty Hoffert > > Professor Emeritus of Physics > > Andre and Bella Meyer Hall of Physics > > 4 Washington Place > > New York University > > New York, NY 10003-6621 > > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com . 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