Duncan, Repeating what others have already said, kudos on your report, which represents a great first step toward a systematic comparison of competing CDR technologies/NETs. One of your main policy conclusions is that NETs should be excluded from carbon markets due to the possible (probable?) effects of offsets. If carbon markets are off the table, how else do you propose to achieve large-scale deployment of these various technologies?
Josh Horton joshuahorton...@gmail.com http://geoengineeringpolitics.blogspot.com/ On Sep 28, 11:49 pm, Ning Zeng <z...@atmos.umd.edu> wrote: > Ron: > > At this stage, I'm not sure how meaningful it is to say which method > is better. One should be particularly careful with inferring which is > better based on single criteirion comparison. So I thought Duncan's > analysis is nice in trying to look at many aspects simultaneously. We > should also look at factors/constraints that could 'kill' an idea, > though this has its own danger of taking something off the table by > subjective choice. My feeling is that ultimately many of these > methods, or some aspects of them will be useful and each will have its > own niche depending on the local circumstances.. > > Another thing is of course that, we need to know more how these > technologies work in the real world by a lot more research and demo > projects. > > Best! > -Ning Zeng > > On Sep 28, 2:16 pm, rongretlar...@comcast.net wrote: > > > > > Duncan, Ning, list: > > > I wholeheartedly support the idea of sequestering through forestry > > products. The analysis of them is straightforward. But the potential is > > obviously quite limited compared to the GtC/yr values in your (Duncan's) > > recent report. So this seems like a good opportunity to ask Duncan what the > > criteria should be for evaluating different NET (CDR) options. I hope > > others will answer the following methodology questions as well. > > > 2. Dr. Zeng obviously feels that ground burial is better (being cheaper as > > a NET (Negative Emissions Technology) and more widely applicable) than the > > BECCS approach which I believe Duncan has favored in his report. Duncan's > > likely reasoning: BECCS uses the same (tree) resource both for > > carbon-neutral replacement of fossil fuels at electrical power plants and > > then captures almost as much in a carbon-negative placement of the > > resulting CO2 deep underground. Presumably Duncan (maybe most on this list) > > would say that the large gain in carbon neutrality (with monetary income to > > offset part of the sequestration costs) more than balances the small (?) > > loss in carbon negativity. But is there a more specific definition of > > "better" here? How would Dr. Zeng rebut the argument that we need biomass > > for its energy content? Does it include questions about the eventual > > success of CCS? > > > 3. I think almost the same questions would be asked by those favoring ocean > > burial of biomass. I presume that ocean or pit burial are roughly > > equivalent - and the preference would be based on location (and resulting > > cost differences). But both have foregone the carbon-neutral energy > > contribution. Nevertheless, I can understand both the pit and ocean burial > > proponents' concerns, as they are focusing on NET (carbon negativity). I > > hope Duncan can first address this narrow issue of combining > > carbon-neutrality and carbon-negativity; in discussing and comparing NETs, > > should carbon-neutral benefits be part of the dialog and/or exactly how > > should they be balanced? > > > 4. But along comes Biochar - and it further confuses the debate by saying > > that other criteria should also prevail besides the neutral (Energy) - and > > negative carbon issue above. Biochar is almost as good as BECCS on both > > carbon-negativty and carbon-neutrality (much of biomass energy value is in > > the hydrogen content which both capture, and BECCS has some energy losses > > in capture). But overall, Biochar proponents can agree that BECCS is > > superficially able to impact more CO2 than can Biochar. But I say > > superficially because Biochar out-year benefits seem to have a chance of > > overcoming the first-year advantages of both BECCS and burial. Many of > > those are spelled out by Duncan, but they do not seem to have made their > > way into the numerical computation on either carbon neutral or carbon > > negative sides of the ledger. > > > 5. I will send more on this to Duncan (others please let me know if they > > want to see this), but I think it likely that most readers will know that > > anthropogenic Amazonian Terra Preta soils (not mentioned by Duncan) are > > today several times more productive than the poor parent soils from which > > they were constructed. Increased Ag production may be replaced in some > > already excellent soils by a halving of fertilizer needs. Nitrous Oxide, > > methane, and nutrient capture are other carbon-equivalent out-year > > continuing benefits that do not appear in Duncan's analyses - some with > > long term offsetting dollar income values. The question for Duncan, Dr. > > Zeng and others on this list are whether these out-year CO2-climate > > benefits of Biochar should be included ? Or should all NET computations > > have the same (one year) time regime. > > > 6. Second, whether non-CO2-related, but clear economic benefits (like > > increased multi-year crop yield and increased multi-year farmer income) > > should somehow enter into the dialog. For many in the Biochar research > > arena this is their main focus; NETs (carbon-negativity) are a distant > > second in their thinking. Increased soil productivity might obviate the > > need for carbon credits entirely (as was the case for the Amazonian Indians > > centuries ago.) This is somewhat like saying that it is important for BECCS > > proponents that there is an income from (carbon-neutral) electricity sales, > > but in this final NET (carbon-negativity) question, I am going one step > > further - carbon-neutrality is not involved. > > > 7. It is my impression that Duncan has not included these last two issues > > when calculating a Biochar price in the curves of his Figures 5 and 7. > > Surprisingly, Biochar also doesn't appear in the economics of Table 10 - > > maybe because of these analytical hurdles. I have other questions on the > > potential magnitude of the Biochar resource, which I think should be larger > > than the other biomass options, but that is a different topic I will raise > > separately with Duncan. > > > 8. Despite my questioning here, I think Duncan has done a better job than > > anyone else of comparing the NET options. I am only trying to make clear > > the process, and the assumptions for his second edition. If carbon-neutral > > (energy), out-year, and non-CO2 topics are to be either included or > > excluded from NET analyses, I feel it should be made clear why. > > > Thoughts? Ron > > > ----- Original Message ----- > > From: "Ning Zeng" <z...@atmos.umd.edu> > > To: "geoengineering" <geoengineering@googlegroups.com> > > Sent: Wednesday, September 28, 2011 7:21:48 AM > > Subject: [geo] Re: New report(s) on carbon dioxide removal > > > Talking about wood products for carbon sequestration, I don't know if > > you have seen this report from the Wilderness Society, perhaps the > > most in-depth I've seen? -Ning > > >http://wilderness.org/files/Wood-Products-and-Carbon-Storage.pdf > > > On Sep 27, 7:55 am, Duncan McLaren <duncan.p.mcla...@gmail.com> wrote: > > > Thanks for your feedback. It's great to see more detailed work > > > ongoing, and I look forward to reading your paper. Hopefully I will > > > get the chance to use it to update my report. > > > > I agree that sustainable forestry has a role in a package of NETs, but > > > whether WHS is the best option for some or all of the accumulated > > > carbon is an open question for me still. Comentators above have argued > > > for BECCS and biochar. Personally I have a soft spot for timber use in > > > construction (even if the store is relatively shortlived). > > > > I agree that there are environmental impacts from most if not all > > > NETs, and hadn't intended to imply that forestry-related approaches > > > were particularly bad, simply to highlight that current forestry > > > techniques are not always sustainable (or ethical for that matter), > > > and expanding conventional approaches to plantation forestry, for > > > example, could be counterproductive, even in carbon terms. > > > > Best wishes > > > Duncan > > > > On Sep 25, 4:37 pm, Ning Zeng <z...@atmos.umd.edu> wrote: > > > > > Hello Duncan: > > > > > I enjoyed reading through your very nice analysis of NETs over the > > > > weekend. I agree with Oliver Tickell's comment that we need > > > > "knowledge, not conjecture". I have been researching on the "wood > > > > burial" idea which has even less research compared to many others. > > > > > We have a paper that is in review at Climatic Change, which brings > > > > more information on wood burial's (we now call it Wood Harvest and > > > > Storage or WHS) harvest potential, and more information is on the way > > > > on cost and storage and other practical considerations. The abstract > > > > of the paper is below. It is relevant to some key factors you > > > > discussed in your report, including: > > > > > 1. We use GtC, while you use GtCO2, so that the estimate of Zeng > > > > (2008) of 10 GtC potential is really 37 GtC/y. However, that is just a > > > > theoretical potential based on coarse wood production rate of all > > > > world's forests. In this new paper (Zeng et al. 2011), we consider > > > > many practical constraints including land use and conservation needs, > > > > and we arrive at a range of 1-3 GtC/y (4-10 GtCO2/y). > > > > > 2. This new paper also shows the area of forest needed in order to > > > > accomplish these sequestration goals. At our low value of 1GtC/y, it > > > > requires 800 Mha forest land with a (modest) harvest intensity of 1 tC/ > > > > ha/y, a much lower rate than typically assumed bioenergy crop harvest > > > > rate. The amount of biomass (2Gt dry biomass) involved is equivalent > > > > to the current worldwide forest harvest. So this is definitely not > > > > business-as-usual, but a leap for forestry. > > > > > 3. The cost estimate of Zeng (2008) of $14/tCO2 was based on cost of > > > > harvesting. If including storage (mostly in situ around harvest > > > > landing site to minimize transportation cost), it will probably double > > > > to $30/tCO2. Adding other unforseen cost, bearing in mind the > > > > observation that real-world implementation often tends to be more > > > > expensive, I'd wave my hand (before realistic demo project) to put > > > > the cost at about $50/tCO2. I think this is actually what you used in > > > > the cost/potential plot (Fig. 7). > > > > > 4. I > > ... > > read more »- Hide quoted text - > > - Show quoted text - -- 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. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
