All: Sam says:
"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." Pleasant to think so, but what these ideas need is a real calculation, experiments and field trials. At least attempt the calculation, as Stuart and Ihave done (building on the 3 earlier papers dating from 2001). We must all build support for lab and local experiments and then field trials, by first doing the hard homework. Governments are lethargic. Getting smart use of carbon waste is going to be a long haul, despite the accelerating climate problem. So let's do the at-home work now, and publicize the results, however they work out -- CROPS, biochar, whatever. But ocean sequestration we can do now. Gregory Benford -----Original Message----- From: Stuart Strand <[email protected]> To: [email protected] <[email protected]>; geoengineering <[email protected]> Sent: Wed, 4 Feb 2009 9:06 am Subject: [geo] Re: Crop residue ocean permanent sequestration 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; - red ucing 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=2 0where 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 >>> =0 A>>> 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 -~----------~----~----~----~------~----~------~--~---
