I suspect the proper role of biochar is to use waste materials, rather than to use forests, and improve agricultural soils.
My brother, a forestry engineer, looked into the commercial prospects of waste-to-energy of urban/suburban/exurban tree and shrub wastes a few years ago, including coking them, using the gases driven off by the process for the fuel needed for the process. It was quite cost-effective and a net carbon sequestor. While is was enough to power small towns, it isn't really enough to make a dent in the carbon emissions of the coal-fired power plant industry. David Schnare On Tue, Apr 14, 2009 at 9:54 PM, Ken Caldeira < [email protected]> wrote: > Folks, > > I think biochar suffers from the same fate as most biomass options. > > Because of the low efficiency with which ecosystems convert sunlight to > reduced carbon and because only a fraction of this reduced carbon will be > converted to biochar, biochar options are unlikely to be able to offset more > than 1 W of fossil-fuel CO2 emissions per square meter of land area. My > post-doc has done some calculations indicating that this estimate might be a > factor of 5 too small (taking into account other inputs and inefficiencies). > > We in the United States each use about 10 kW of energy, so this would be on > the order of a hectare per person at the higher efficiency, 5 hectares at > the lower efficiency. > > For 7 billion people at 2 kW, this is 1.4 x 10^13 m2, or roughly 10% of > land area on Earth at the higher efficiency -- roughly the amount of land > already devoted to agriculture -- or half the land area on Earth if my > post-doc is right about the lower efficiency. > > So, this is another one of those things that could be good to do where > appropriate, but is not likely to be a major player in the grand scheme of > things. > > Best, > > Ken > > ___________________________________________________ > Ken Caldeira > > Carnegie Institution Dept of Global Ecology > 260 Panama Street, Stanford, CA 94305 USA > > [email protected]; [email protected] > http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab > +1 650 704 7212; fax: +1 650 462 5968 > > > > > On Tue, Apr 14, 2009 at 6:24 PM, dsw_s <[email protected]> wrote: > >> >> I don't get the impression that the anti-biochar pdf is very >> credible. For example, it suggests that there's basically no degraded >> land in the world, that could be improved with biochar. It's a big >> world. There's a lot of not-so-degraded land, and a lot of degraded >> land. It wouldn't surprise me if the loudest claims over the last >> couple decades were grossly exaggerated as to how much biological >> productivity was being lost as vast areas of the Amazon got clear-cut, >> eroded, and turned into quasi-desert. But to dismiss biochar out of >> hand for lack of land to improve with it (even if it works, which they >> reject, and even if it's affordable, which they reject, and so on) >> just sounds as though they're looking for anything that would >> invalidate biochar and then reasoning backward to the putative facts. >> It may be that the improvable acreage is enough only for X gigatons of >> carbon to have any benefit, with X too small to be a big part of the >> overall picture. It would still be able to generate legitimate carbon >> credits up to that point. >> >> On Apr 14, 9:58 am, Ray Taylor <[email protected]> wrote: >> > I thought we should rename this biochar for the sake of the archive. >> > >> > Does biochar hold water significantly better than the organic matter >> > it was made from? Especially if the latter was used as mulch? >> > >> > [See YouTube "Greening the Desert" - clip from permaculture >> > institute of Australia] >> > >> > Thank you all for bringing biochar to my attention. I like the >> > fact that (for Africa) it can be locally produced in low-tech kilns. >> > >> > I'd be interested to know if there is a site which replies to the >> > following limitations/drawbacks: >> > >> > http://www.biofuelwatch.org.uk/docs/biocharbriefing.pdf >> > >> > Raywww.globalcoolers.net <http://raywww.globalcoolers.net/> >> > >> > On Apr 14, 3:20 am, David Schnare <[email protected]> wrote: >> > >> > > My Center is doing a major report on putting carbon back into the soil >> as >> > > the means to developing two kinds of market mechanisms for farmers, >> > > nutrients and carbon. I'll keep the group informed as we prepare our >> > > materials, but just to give you a heads up, this is no silver bullet >> (for >> > > carbon). Biochar is better than crop detritus (no till farming), but >> both >> > > lose carbon due to microbial action (CO2 emissions). However, both do >> a >> > > terrific job creating a substrate for water. They take high clay >> soils and >> > > turn them into an organic sponge, holding nutrients in the ground, >> attached >> > > to the invested carbon. >> > >> > > David Schnare. >> > >> > > On Mon, Apr 13, 2009 at 10:03 PM, dsw_s <[email protected]> wrote: >> > >> > > > Wow, that sounds very promising, although we'll have to see about >> the >> > > > economics. >> > >> > > > I hadn't heard (or hadn't absorbed) that the biochar was to come >> from >> > > > a pyrolysis process that makes oil and gas, so there's more >> > > > hydrocarbon and less just-plain-carbon than there would be in >> charcoal >> > > > from burning in open air. I don't know how stable regular charcoal >> is >> > > > either, although it sounds as though it's much more stable than I >> had >> > > > thought. I would certainly expect biochar or ordinary charcoal to >> > > > improve water retention (at least in most soils), and one of the >> > > > references in the Wikipedia biochar article says it does (without >> > > > saying for what kinds of soil, as far as I saw). >> > >> > > > I hope we study soil ecology before doing it on a very large scale, >> > > > though. >> > >> > > > On Apr 12, 5:18 am, Andrew Lockley <[email protected]> >> wrote: >> > > > > Biochar is highly stable in soils, and lasts centuries-millennia >> as Terra >> > > > > Preta. >> > > > >> http://en.wikipedia.org/wiki/Biocharhttp://en.wikipedia.org/wiki/Terr... >> > > > > I understand it also bulks up the soil, trapping '3rd party' >> carbon. >> > >> > > > > I am unsure whether this either affects the hydrological >> properties of >> > > > the >> > > > > soil, or promotes forest regrowth. If either were the case, it >> could >> > > > have >> > > > > the cloud-inducing effects discussed. This effect could be highly >> > > > > significant and I hope someone expert can consider it. >> > >> > > > > A >> > >> > > > > 2009/4/12 dsw_s <[email protected]> >> > >> > > > > > But wouldn't the carbon in the biochar get returned to the >> atmosphere >> > > > > > fairly quickly if it were used that way? >> > >> > > > > > On Apr 11, 6:24 pm, Andrew Lockley <[email protected]> >> wrote: >> > > > > > > It would be very interesting to see if biochar has a similar >> effect. >> > > > If >> > > > > > > biochar could lock up carbon in soils, thicken soils, preserve >> and >> > > > spread >> > > > > > > forests and brighten clouds it would have benefits that could >> > > > reasonably >> > > > > > be >> > > > > > > described as 'ginormous'. >> > > > > > > I'd be interested to know if anyone in this group could >> explore these >> > > > > > > effects and potentially look at doing a paper or a model run >> on them. >> > >> > > > > > > A >> > >> > > > > > > 2009/4/10 dsw_s <[email protected]> >> > >> > > > > > > > That sounds a lot like how I imagine geoengineering can >> work. A >> > > > > > > > suggestion I've made is that materials like expanded >> vermiculite >> > > > and >> > > > > > > > perlite (basically rock popcorn) could be used to increase >> water >> > > > > > > > retention in soil for both agricultural and climatic >> benefit. The >> > > > > > > > climate benefit includes CO2 removal by weathering, but the >> > > > > > > > distribution could also be chosen to optimize cloud >> patterns. >> > >> > > > > > > > On Apr 9, 11:50 am, Ray Taylor <[email protected]> >> wrote: >> > > > > > > > > Hello all, >> > >> > > > > > > > > I've been in consultation with a range of land-atmosphere >> > > > > > > > > and cloud meteorologists, looking at scope for increasing >> > > > > > > > > stratus and cumulo-nimbus over land in regions identified >> > > > > > > > > in GLACE (nasa). >> > >> > > > > > > > > Literature review available atwww.globalcoolers.net >> > >> > > > > > > > > Focus is on West Africa and rainwater harvesting, >> > > > > > > > > pilot studies plus 4 continents alliance-building. >> > >> > > > > > > > > Anyone interested in collaborating? >> > >> > > > > > > > > Ray Taylor >> > >> > > > > > > > > ray [at] andy-taylor.org >> > >> > > -- >> > > David W. Schnare >> > > Center for Environmental Stewardship >> > >> > >> >> > > > > -- David W. Schnare Center for Environmental Stewardship --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
