Thanks Henrik fro these comments. I'm very pleased that experts in particular techniques are looking at my report. And I'm not going to be surprised if everyone feels that I haven't done justice to their particular topic.
However I must refute the implication that I have taken things 'out-of- context'. For example Biorecro's Swedish numbers for example are clearly described as such, not as globally representative. I'm sorry if you read my caveat regarding data as implying that my summary graphics and tables only included estimates from other sources. That was not intended to be my meaning. I wanted to stress that while I had made efforts and judgements to allow comparison, I remain very nervous about how valid such comparison could be, given the range of sources and assumptions. I did not, and do not want readers saying "technology A will cost x% less than technology B, so is therefore obviously preferable", especially in those cases where x is small. I think one of the main lessons in the report is that practical and sustainability constraints must drive how we plan and deploy a package of NETs, not costs per se. I welcome the chance to elaborate on why I do not accept the more optimistic cost estimates for many technologies, not just BECCS. I must stress again that the cost figures in particular should be treated with caution (and I wish other authors would do so more often with their estimates ...). However in the case of BECCS there is more material (albeit rarely with clear assumptions set out), so it was possible to come up with amended estimates which I believe are plausible. For some of the other techniques the best I could do was describe an estimated cost as 'optimistic' or 'realistic'. I think BECCS costs cited by yourself, Ecofys and others are potentially very optimistic for several reasons. Sometimes estimates in the literature are simply costs per ton CO2 captured or stored. They are therefore lower than real costs per tonne of net negative emission (NE). In other places advocates of BECCS argue that it will be cheap because it can sell energy. But I have treated it as a cost imposed on a stand-alone bioenergy system. Furthermore I could not typically identify assumptions regarding the likely future costs of CCS on fossil fuels, and learning rates on CCS and on application of CCS to bioenergy. However it would appear that most assume that CCS will become commercially viable by 2030, and thus the cost of BECCS is pretty well only the additional cost of modifying and applying the system to bioenergy. However, the future cost evolution of CCS is still highly debatable. I cite sources suggesting that current and future CCS costs estimates are likely to be underestimates, and that learning rates may be as low as zero. Even if learning rates are positive, the impatc on costs depends on deployment, which I conclude may be practically restricted by non- economic factors, again potentially raising future costs above the estimates elsewhere. Applying all these factors as far as practical to the range of costs I found in the literature (see p.43) gave me a cost range for BECCS from around $75 to over $300 per ton NE. I concluded that a range of $100-150 per ton NE was plausible and chose to use the higher figure in the summary and graphics. Of course there are a whole range of judgements wrapped up here and indeed a wide range of techniques within BECCS, so clearly a more sophisticated analysis could be undertaken. You also quibble with the TRL rating I suggest for BECCS. You have a point in comparison with wet DAC as far as BECCS on ethanol is concerned, but I'm not so sure as a general rating for BECCS. I would also note that the recent GAO Technology Assessment also rates BECCS and wet DAC as exactly the same maturity ... but they give them both a rating of just 2! Thanks again for raising these issues, and I look forward to continuing a dialogue. Best regards Duncan On Sep 22, 1:27 pm, Henrik Karlsson <[email protected]> wrote: > Hi Duncan, > > Thank you for your time and effort into this difficult field. I > believe that this report and similar initiatives are very valuable, > and must be supported. In my opinion, you have also made an important > pioneering effort into cost and potential comparisons of various NETs, > which I hope you will be able to carry on in greater detail. > Unfortunately, I do not support the methods used to process the data > in your report, which I believe have led to conclusions that are not > supported in your sources. > > I can only speak for BECCS, the area of my expertise, but I know that > some of the statements on BECCS in this report are not fsupported by > the sources available. Additionally, quotes from reports which I have > been lead author on (Karlsson 2010 and Karlsson 2011) have been > detached from their context. Swedish numbers from (Karlsson 2010) are > used in the report to represent a global context, which they are not > suitable for. Similarly, the costs from the McGlashan et al (AVOID > report) from a UK context have been used to represent a global context > regarding BECCS costs. > > I understand that Biorecro (which I represent) could according to your > argument be regarded as biased, though I believe that the IEAGHG and > Ecofys are to be considered as authorative. Their report > (http://www.eenews.net/assets/2011/08/04/document_cw_01.pdf), reviewed by a > panel of experts from four independent organizations, is the best > available source for global costs and potentials for BECCS. They state > a cost for 3.5 Gtonnes of BECCS at €50 in 2050, which has been more > than doubled to $150 in the aggregation numbers in your report, partly > based on an argument of ‘sociology of expectations’, with potential > almost halved to 2 Gtonnes (see for example the MAC curve in figure 7 > in the link). You do point out that caution should be taken with the > data and analysis in page 4, but the same section says "Most of the > data presented regarding specific NETs arises from the original > sources. Where adequate detail was available, some figures have been > recalculated to facilitate comparison, but in general the figures > reflect varying underlying assumptions." This statement gives the > impression that sources are reflected directly in the text and > figures, which is not the case. When putting these doubled costs (and > almost half of the potential) into figure 7, critical information is > lost. > > Additionally, the technological maturity of BECCS is considerably > higher than of the technologies such as DAC, yielding a much higher > confidence in the numbers. Please note that there is a full scale (300 > 000 tonnes/year, increasing to 1 000 000 in 2013) ethanol BECCS > demonstration in the US which will go into operation before November > this year. For more information, seewww.sequestration.org. This > project has had real costs for material procurement in this full scale > effort, and a number of smaller pilot forerunners, experience which is > reflected in the reports on BECCS. It also implies a higher > technological maturity of BECCS than reflected in the report under > discussion (which gives BECCS the same maturity as the DAC Wet > Calcination, TRL 4-6). > > Best regards, > Henrik Karlsson > Biorecro > > On 21 Sep, 13:11, Duncan McLaren <[email protected]> wrote: > > > > > > > > > Group members may find my assessment of negative emissions > > technologies (NETs) of interest. > > > The full report runs to about 100 pages, and can be found > > athttps://sites.google.com/site/mclarenerc/research/negative-emissions-... > > > A summary version written for Friends of the Earth (England, Wales and > > NI) will be published online later today. > > > The assessment covers a wide range of NETs, but not SRM techniques. It > > considers capacity, cost, side effects, constraints, technical > > readiness, accountability and more for about 30 options. > > > I'd be delighted to get feedback and comments. > > > regards > > Duncan -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
