OK, we are in agreement that most of the surface sequestration schemes are "kicking the can down the road", they are temporary. But CROPS is one kick and you have _permanent sequestration_. That is the goal of geoengineering of greenhouse gases, right?
There is an element of danger in keeping the fossil fuel carbon on the surface in contact with the atmosphere, no matter what form it is in. = Stuart = -----Original Message----- From: Alvia Gaskill [mailto:[email protected]] Sent: Thursday, February 05, 2009 10:58 AM To: Stuart Strand; [email protected]; geoengineering Subject: Re: [geo] Re: Crop residue ocean permanent sequestration 100 years may be enough if technological advances allow us to remove atmospheric CO2. Remember also that if it is 100 years for complete oxidation of the biomass, that would be 2109 for crop residue sequestered today and 2150 for crop residue sequestered in 2050. Just as we would only be able to remove carbon via crop residue sequestration one year at a time, nature will also have to operate on the same schedule, unless you can show that oxidation rates will increase in the coming decades. Admittedly, this is kicking the can down the road, but that's the whole point of geoengineering, buying time. The way nuclear waste is being handled is instructive. High level waste will remain radioactive for up to 250,000 years. There is no way we can guarantee removal of this from the biosphere for that long. Future civilizations may unwittingly dig it up, irrespective of where and how it is stored. Keeping it out of the environment for as long as practical is the best we can hope for. By 2100 or 2200 or sometime in the next millenium, it is likely that solutions other than burying it in caves or salt mines will have been found. By storing crop waste aboveground, it is also still available for use as a soil amendment if that is necessary. Very likely, crop residue sequestration will wind up being done in various ways, from aboveground storage in dry areas to landfilling to produce methane to some ocean disposal. A one-size fits all strategy probably won't work. In looking at the landfill option, I noticed that in several states, MI and MO, efforts were underway to get approval to let yard waste be sent to municipal landfills instead of separate ones as is now mostly the case. Part of the reason may be financial as waste haulers could get higher fees if the grass clippings and tree limbs were back in the mix. The stated reason is to generate more methane for energy recovery. The reason to keep yard waste out of landfills is to extend the life of the facility. The fire issue is a legitimate one. Durham County maintains a yard waste landfill, but hired a bankrupt contractor who failed to keep it aerated and allowed waste to accumulate until it spontaneously combusted during a major drought. The ensuing fire burned for several weeks, sending local residents to hospitals with respiratory problems and was finally extinguished by another outside contractor at a cost of nearly $100,000. Adding crop waste to existing landfills may be the most expedient way to capitalize on the methane option, while avoiding the problems with gas pockets Andrew mentioned. However, biocells could also be utilized. About 50% of landfill gas is methane and the rest CO2 with leakage rates varying considerably. Whatever strategy or combination of strategies are employed, complete life cycle comparisons need to be developed with respect to energy costs and GHG emissions. Stuart attempted to do this for biomass burning for energy recovery vs. cellulosic ethanol vs. CROPS. A follow on study should include all other realistic scenarios including tree planting and sequestration and consider impacts on surface albedo from the darker tree canopies vs. the barren ground that may exist there now. ----- Original Message ----- From: "Stuart Strand" <[email protected]> To: <[email protected]>; "geoengineering" <[email protected]> Sent: Thursday, February 05, 2009 12:59 PM Subject: [geo] Re: Crop residue ocean permanent sequestration > 30-40% of the crop residue must be left on the land to prevent erosion. > So removal for biochar could reach 60-70%, not 100%. > > Decadal sequestration is not enough, 100 years is not enough. 1000 years > is barely enough. > > I am not seeing much discussion of numbers here. Can you please refer me > to peer reviewed literature that in your opinion does the best estimate of > carbon flows in biochar/biomass pyrolysis? > > > = Stuart = > > Stuart E. Strand > 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 > voice 206-543-5350, fax 206-685-3836 > skype: stuartestrand > http://faculty.washington.edu/sstrand/ > > Using only muscle power, who is the fastest person in the world? > Flying start, 200 m 82.3 mph! > http://en.wikipedia.org/wiki/Sam_Whittingham > Hour http://en.wikipedia.org/wiki/Hour_record > 55 miles, upside down, backwards, and head first! > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Sam Carana > Sent: Thursday, February 05, 2009 5:23 AM > To: geoengineering > Subject: [geo] Re: Crop residue ocean permanent sequestration > > > Stuart, > > If we only looked at the percentage of carbon was kept out of the > atmosphere, then we should look at methods such as using crop residue > and other organic material to produce bricks, pavement, tiles and > similar building components. I wrote about Timbercrete in an article > on carbon-negative building at: > http://gather.com/viewArticle.jsp?articleId=281474977316789 > Timbercrete is used to build houses, garden walls, for pavement and > the like. It is made from sand and recycled timber waste, such as > sawdust or other cellulose material. It is designed to last for > generations, so for its lifetime it will store 100% of the carbon that > was removed from the atmosphere by vegetation. I suppose that, if the > building is taken down, the material could be recycled into new > Timbercrete, but by that time we may have developed even better > methods to reduce greenhouse gases. > > Anyway, my point is that this figure of 90% efficiency in keeping > carbon out of the atmosphere should not be taken as the sole measure > to assess methods. If we took such a narrow view, then the above > Timbercrete would seem superior to ocean sequestration. But again, my > point is that we should instead look at the wider picture. If we can > pyrolyze three times as much material and bury it in the form of > biochar, then that method would store a greater net amount of carbon. > > In conclusion, we should get communities to grow more vegetation and > keep as much of the carbon contained in the vegetation out of the > atmosphere for a long time, at least for decades to come. We can only > suggest methods, but what works best locally depends on the benefits > that communities each see in the various methods. Part of that bigger > picture is illustrated by the image of my article Four Cycles of a > Sustainable Economy, at: > http://gather.com/viewArticle.jsp?articleId=281474977561808 > > Don't just look at the figures for two specific methods in isolation. > We need to give it all we've got and many methods can work together > and, by complementing each other, increasing the result in terms of > reducing greenhouse gases. > > Cheers! > Sam Carana > > > > On Thu, Feb 5, 2009 at 4:06 AM, Stuart Strand <[email protected]> > wrote: >> Sam, >> >> In your first point you touch on one problem: pyrolysis is about 50% >> efficient use of crop residue carbon for sequestration. CROPS is about >> 90% efficient. Perhaps a combination of the two would be synergistic. >> >> = Stuart = >> >> Stuart E. Strand >> 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 >> voice 206-543-5350, fax 206-685-3836 >> skype: stuartestrand >> http://faculty.washington.edu/sstrand/ >> >> Using only muscle power, who is the fastest person in the world? >> Flying start, 200 m 82.3 mph! >> http://en.wikipedia.org/wiki/Sam_Whittingham >> Hour http://en.wikipedia.org/wiki/Hour_record >> 55 miles, upside down, backwards, and head first! >> >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Sam Carana >> Sent: Wednesday, February 04, 2009 6:21 AM >> To: geoengineering >> Subject: [geo] Re: Crop residue ocean permanent sequestration >> >> >> Stuart, you conclude that ocean burial was more efficient in reducing >> greenhouse gases than biochar, but you draw that conclusion by looking >> at only one small part of what is a much bigger picture. >> >> 1. As we get better in pyrolysis, it should be no problem capturing >> half of the carbon in the form of biochar. It depends partly on what >> material is pyrolyzed, but that's also the beauty of this method, i.e. >> many things can be treated this way, such as agricultural waste, >> animal manure, sawdust, etc. >> >> 2. Apart from this, biochar enriches soil, allowing more vegetation to >> grow and draw carbon dioxide from the atmosphere. This will raise the >> net effect of this method well beyond the 50%. This also goes hand in >> hand with afforestation, prevention of erosion, less emissions of >> nitrous oxide (N2O) by fertilisers, the ability to feed a growing >> world population and preservation of rainforest and water resources. >> >> 3. Thirdly, pyrolysis also produces biofuel and hydrogen. Quite >> frankly, I cannot imagine a cleaner way to power shipping than by >> means of hydrogen. If you take into account the carbon that would >> otherwise result from ships burning (a typically very polluting type >> of) oil, this alone could very well make the pyrolysis method >> worthwhile as a method to reduce greenhouse gases. >> >> Combine the above three, and the combined net effect of pyrolysis, >> biochar and hydrogen seems more efficient than ocean sequestration, >> which requires substantial transport and logistics. Similarly, the >> biofuel produced by pyrolysis could be used in transport, and perhaps >> we can even capture some of the carbon that is released in the >> process. >> >> If you look at each of these three points in isolation, there may seem >> to be better alternatives than biochar, in the sense that each such >> alternative may either seem to sequester more carbon, act as a better >> fertiliser or produce energy cheaper. But if you look at the bigger >> picture of what difference biochar could make, it is superior in all >> respects, i.e. in its capacity to reduce greenhouse gases from the >> atmosphere, as a way to enrich soil and as a way to produce energy, >> e.g. for the transport sector. >> >> For a local community there may be many reasons to welcome pyrolysis >> and biochar burial. It can deliver many local benefits, such as: >> - thinning forests, removing crop residue and getting rid of waste, >> thus reducing the risk of wildfires, pests and diseases, >> - providing renewable energy on demand, >> - enriching soil, which allows farmers to stay on their land and >> reduces slash-and-burn of further forest; >> - preventing long diseases (people can stop practices like burning cow >> dung and wood in open fires, for cooking and heating). >> People will welcome solar cookers together with pyrolysis and biochar, >> and start to plant more vegetation, rather than to breed more >> livestock (and the associated nomadic lifestyle). The fact that this >> new lifestyle also reduces greenhouse gases in many ways may not be an >> argument for them, but all the other benefits do weigh heavily. >> >> Try convincing a local community to carry their agricultural waste and >> surplus wood to the sea, for dumping into the ocean, and they will see >> no benefit in doing that. >> >> By contrast, local communities will see the benefits of less need for >> fertilisers, as this saves money and also because this means less dead >> zones in the sea and thus results in better yield of fish. So, local >> communities will welcome biochar, even if they are unaware of >> greenhouse gases. And of course, biochar and the associated change in >> lifestyle as pictured above will also reduce global warming in many >> ways, such as by: >> - reducing the use of cow dung as fuel, meaning less methane due to >> less livestock; >> - reducing the use of fossil fuel such as oil, e.g. to power ships or >> for heating; >> - reducing the use of wood and conventional charcoal for heating and >> cooking; >> - increasing vegetation growth, thus drawing larger amounts of carbon >> dioxide out of the atmosphere; >> - reducing soot, which acts as a greenhouse gas and settles on top of >> glaciers and polar ice, causing albedo change; >> - reducing CO2 and methane emissions, compared to the alternative of >> leaving much organic material to rot away; >> - reducing emissions of nitrous oxide (N2O), due to less use of >> fertilisers; >> >> Cheers! >> Sam Carana >> >> >> >> On Tue, Feb 3, 2009 at 8:28 AM, Stuart Strand <[email protected]> >> wrote: >>> >>> I am reading the biochar literature now and it is fascinating stuff. >>> But first glance reveals that pyrolysis schemes return 20-50% of the >>> total carbon originally in the biomass back to sequestration in the soil >>> (ES&T Sept 1 2007, p 5932). So already there is an efficiency problem >>> compared to CROPS which is 90% efficient. Also I am concerned about how >>> often biochar can be done on a given soil without undesirable effects on >>> agricultural soil ecology. And how permanent is charcoal in soil? >>> Amazonian terra preta still contains charcoal, but how much was lost >>> over the intervening 500 years? We would be storing biochar in soil in >>> direct contact with the atmosphere. If it decays there is no safety >>> factor as there would be in deep sediments. Safety factors and >>> redundancy are important in engineering; although geoengineering doesn't >>> seem much like any other engineering I am familiar with... >>> >>> = Stuart = >>> >>> Stuart E. Strand >>> 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 >>> voice 206-543-5350, fax 206-685-3836 >>> http://faculty.washington.edu/sstrand/ >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of Andrew Lockley >>> Sent: Monday, February 02, 2009 12:46 PM >>> To: [email protected] >>> Cc: Stuart Strand; [email protected]; >>> [email protected] >>> Subject: [geo] Re: Crop residue ocean permanent sequestration >>> >>> >>> Isn't it more efficient to pyrolyse the waste first, recovering energy >>> and reducing transport carbon? >>> >>> A >>> >>> 2009/2/2 David Schnare <[email protected]>: >>>> Stuart: >>>> >>>> I've been studying notill agriculture that relies, in major part, on >>>> building soil carbon to hold nutrients in the soil (reducing >>>> application >>>> requirements and keeping it out of streams). While a 14% sequestration >>>> (limited to only about 20 years before maxing out on sequestration >>>> potential) seems small compared to 100% if dumped into the ocean deeps, >>>> it >>>> seems to me that when used in places more than 150 miles from the >>>> ocean, it >>>> is carbon reduction efficient (based on fuels needed for transport). >>>> >>>> As such, shouldn't we be narrowing the crop waste discussion to coastal >>>> agriculture only, and give credit for soil sequestration where that's >>>> as >>>> good as is available? >>>> >>>> David Schnare >>>> >>>> On Mon, Feb 2, 2009 at 11:54 AM, Stuart Strand >>>> <[email protected]> >>>> wrote: >>>>> >>>>> By straw we are referring to the stalks of agricultural plants, wheat >>>>> stalks and corn stover. The water and nutrients were expended to grow >>>>> the >>>>> grain. Straw has a low nutrient content (C/N = ca 50/1). Presently >>>>> straw >>>>> is wasted by allowing it to decay on the soil surface (only 14% or >>>>> less of >>>>> the straw carbon is incorporated into the soil). >>>>> >>>>> >>>>> >>>>> A variety of processes are available to get energy out of crop >>>>> residues, >>>>> but they are limited by the poor specific energy of biomass. Our >>>>> focus is >>>>> how to efficiently remove Pg amounts of carbon from the atmosphere and >>>>> permanently sequester it in the least environmentally harmful manner. >>>>> >>>>> >>>>> >>>>> = Stuart = >>>>> >>>>> >>>>> >>>>> Stuart E. Strand >>>>> >>>>> 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 >>>>> >>>>> voice 206-543-5350, fax 206-685-3836 >>>>> >>>>> skype: stuartestrand >>>>> >>>>> http://faculty.washington.edu/sstrand/ >>>>> >>>>> >>>>> >>>>> Using only muscle power, who is the fastest person in the world? >>>>> >>>>> Flying start, 200 m 82.3 mph! >>>>> http://en.wikipedia.org/wiki/Sam_Whittingham >>>>> >>>>> Hour http://en.wikipedia.org/wiki/Hour_record >>>>> >>>>> 55 miles, upside down, backwards, and head first! >>>>> >>>>> >>>>> >>>>> From: [email protected] >>>>> [mailto:[email protected]] On Behalf Of >>>>> [email protected] >>>>> Sent: Wednesday, January 28, 2009 7:16 PM >>>>> To: [email protected] >>>>> Subject: [geo] Re: Crop residue ocean permanent sequestration >>>>> >>>>> >>>>> >>>>> Stuart, >>>>> >>>>> >>>>> >>>>> Why bundle and stash terrestrial straw. Growing straw requires >>>>> substantial fresh water and nutrients. You could bundle and stash >>>>> algae >>>>> instead. How about sargassum or kelp? A macro-algae can be bundled >>>>> in >>>>> large mesh "tea bags" with much of the water being squeezed out during >>>>> the >>>>> bundling process. >>>>> >>>>> >>>>> >>>>> Then, as long as you've got bundles of biomass, why not separate the >>>>> nutrients from the carbon before you stash the carbon? That way, you >>>>> can >>>>> recycle the nutrients back to the ocean surface for growing more >>>>> biomass. >>>>> High-pressure anaerobic digestion will release the carbon in two >>>>> separate >>>>> streams; one gaseous CH4, one dissolved CO2, which easily converts to >>>>> liquid >>>>> CO2 at typical ocean temperatures and pressures. >>>>> >>>>> >>>>> >>>>> Would you or others be interested in a California Energy Commission >>>>> grant >>>>> to run a few bench experiments on high-pressure anaerobic digestion? >>>>> I can >>>>> send a draft abstract. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> Mark E. Capron, PE >>>>> >>>>> Oxnard, California >>>>> >>>>> www.PODenergy.org >> >> > >> > > > > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
