In the long run, I think the only reliable way to store carbon is to set up
carbon sequestration forests and then plant and cut these and place the wood
mass in old mines, coal or gravel pits. Though, I can't see how coal-fired
power stations could sequester economically carbon this way. I think it is very
efficient in locking carbon away, but costly.
Wood can be also stored almost indefinitely in deep waters and there are many
areas in Arctic where some lakes could be made to act as carbon sequestration
log warehouses
I think crop residue and hay harvesting is 'too easy way out' here, although
water logged peat bogs do store carbon, something similar would have to take
place. On the other hand, melting permafrost (i.e. warmer future climate) will
intensify decay and placing hay or crop residue to water-logged, or burying hay
in permafrost, do not work in future if the climate is much warmer. Otherwise,
hay-burial in permafrost would be an attractive option.
In my mind this leaves good storages for carbon-sequestration logging such as
the sea, lakes and man made coal and gravel pits where the logged wood can be
put safely to salt carbon dioxide away from the athmosphere.
Someone should make estimates how much this kind of forestry would cost by
doing it where it could be done cheapest. May be initially, by just cutting off
trees and planting new ones. Later when best sites have been done away, sites
that require planting and fertilisation would be looked at.
Initially, the idea of carbon sequestration logging would be just to get as
much carbon salted away as cheaply as possible, perhaps also making this as
some sort of employment generation social programme.
So, lets go boys for the old gravel pits and seasides...
Rgs,
Albert> Date: Wed, 4 Feb 2009 15:57:35 +0000> Subject: [geo] Re: CROPS paper>
From: [email protected]> To: [email protected]> CC:
[email protected]; [email protected]; [email protected]> >
> I already suggested methane recovery. Methane from landfills is a> rather
unreliable technology, and involves significant leakage. You> can accelerate
production with a 'flushing bioreactor' design, where> water is pumped through.
However, bearing in mind the fill would be> 100pc crop residue, the landfill
(plus all the complex layering and> piping) would just collapse in a big wet
mess - belching out huge> amounts of methane into the air as it did.> > Far
better to use anaerobic digestion if you wish to recover methane.> You can then
use this methane for grid gas. I don't know if you use> natural gas (methane)
in the US but in Europe it's piped to most> buildings for heating and cooking.>
> A> > 2009/2/4 Alvia Gaskill <[email protected]>:> > Stuart and I also
discussed the possibility of disposing of the crop residue> > in abandoned coal
mines. At the time you said you were concerned about> > oxidation there and if
the environment were anoxic, conversion to methane.> > KABOOM! I proposed coal
mines, since they would not involve ocean disposal> > (obvious) and might be
closer to the fields.> >> > The issue of oxidation time is, I believe, not
trivial. While it would be> > desirable to have the carbon gone forever, as in
the case of deep ocean> > disposal, a storage time of 100 years would be
attractive as well. If one> > believes that major technological advances are
going to be made in the areas> > of renewable energy and also in air capture of
carbon dioxide within the> > next 100 years, then placing the residue in an
environment where it would> > slowly decay might be acceptable also. The carbon
credits could then be> > priced and prorated to reflect storage lifetimes.> >>
> Example: a ton of unbaled wheat straw will completely oxidize to CO2 in a> >
field in 3 months (my estimate). The same ton baled up next to the field> >
will last for 5 years (another made up estimate just for the purpose of> >
comparison). Storage in an arid environment might extend the lifetime to 25> >
years. As for the methane issue, why not cover some of the crop residue and> >
collect the methane for use as fuel for transportation of the residue to> >
deep ocean or other disposal locations? This would not require any complex> >
technology as this is how methane is collected from municipal waste> >
landfills. Methane from landfills is a proven use of stranded energy and> >
could be applied to crop residue disposal as well. If the methane cannot be> >
directly used to provide fuel for transportation of the crop residue, it> >
could be sold and the funds generated used to purchase diesel fuel. The> > cost
of diesel fuel appears to be the single greatest cost of the CROPS> > strategy
and reducing that cost with stranded energy generated by the> > process seems
like a win win plan.> >> >> > ----- Original Message ----- From: "Stuart
Strand"> > <[email protected]>> > To: "Andrew Lockley"
<[email protected]>> > Cc: <[email protected]>; "geoengineering"
<[email protected]>> > Sent: Tuesday, February 03, 2009 7:22 PM>
> Subject: [geo] Re: CROPS paper> >> >> >> > I thought I explained the
methanogenesis issue pretty well previously and I> > don't understand your
reasoning in the first paragraph below. The> > oceanographers I have talked to
agree generally with my analysis, so I think> > I'll leave it at that.> >> >
Temporary storage of crop residues in the river basin is a good idea.> >
Probably at local depots, away from flood prone areas.> >> > = Stuart => >> >>
> It methanogenesis starts, it can fairly quickly undo a lot of your> > work.
Even if it doesn't directly reach the atmos. any effect on> > partial pressure
may affect exchange with the atmos and thus raise> > methane concentrations in
the atmos. Even if the methane is oxidised,> > all that CO2 is eventually going
to cause you problems.> >> > Open storage in the desert should be possible.
Here in England we> > have massive warehouse-sized towers of straw bales. They
take ages to> > rot, even in our rainy weather. Fire is the biggest problem.>
>> > As regards carbon content, it's not readily available for various> >
different kinds of straw, husk, cob etc that you might be dumping. I> > assume
it varies between plants?> >> > The purpose of pyrolysing to char is to reduce
bulk, enhance> > consistency and reduce bioavailability. I wasn't intending to
use it> > as an energy recovery process. Surely a few hundred kgs of char> >
powder is easier to handle and sequester than a ton of damp straw?> >> > A> >>
> 2009/2/3 Stuart Strand <[email protected]>:> >>> >> 1. Significant
methane production seems unlikely, but it may be possible> >> in deep
deposition sites. Anaerobic metabolism in ocean sediments is> >> dominated by
sulfate as the electron acceptor, not CO2, as in freshwaters.> >> We expect
crop residue mineralization under anaerobic conditions inside the> >> bale to
be slow, so sulfate in surrounding waters would have time to diffuse> >> into
the bales. But if the bales are stacked too deep sulfate will be> >> exhausted
and methanogenesis will start. If methane is produced it will not> >> be as
bubbles (which could penetrate the thermocline), but as dissolved> >> methane,
due to the pressure. Dissolved methane will be oxidized as it> >> diffuses up
through the sediment and the water column where aerobic and> >> anaerobic
methane oxidation occurs (the latter coupled with sulfate> >> reduction). So
methane from the crop residues is unlikely to reach the> >> atmosphere.> >>> >>
The above is our working hypothesis, but this is a question that must be> >>
answered with experiments in situ, which would also provide data to estimate>
>> parameters needed for modeling and design.> >>> >> 2 and 3. I am working on
comparisons to pyrolysis now and I have> >> discussed first impressions
previously on this group.> >>> >> 4. readily available info, Andrew> >>> >> 5.
see above> >>> >> 6. C Lossy. Andrew, biomass is a poor energy source, whether
you make> >> methane, ethanol or biochar from it.> >>> >> 7. Not as safe as the
ocean I would judge. But it is something we could> >> do temporarily, while
ocean research and the expected political wrangling on> >> CROPS is done. But
transportation costs to and from deserts and the> >> landfilling operations to
try to keep moisture would be costly and CO2> >> productive.> >>> >>> >>> >> =
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 Andrew Lockley> >> Sent: Tuesday, February 03, 2009 3:05 AM> >> To:
[email protected]; geoengineering> >> Subject: [geo] CROPS paper> >>> >>> >>
I've read through your paper in detail and I note the following. (I> >> may
have missed some things of course)> >>> >> 1) You don't discuss anaerobic
decomposition to methane in the ocean.> >> Is it a risk? Outgassing may be
immediate or by clathrate> >> destabilisation.> >> 2) You don't discuss
pyrolysing the waste to char before sequestration.> >> 3) You consider burying
the waste, but you do not consider creating> >> biochar and burying that to
create terra preta> >> 4) You reject the idea of burning crop residues and
using CCS, but do> >> not provide a quantitative analysis of the carbon content
of biomass> >> by % compared to other fuels, so it cannot be determined
whether> >> burning is relatively more efficient than for other fuels.> >> 5)
You do not directly consider the production of char by pyrolysis> >> then
onward transport of the fuel to be burned in sites suitable for> >> CCS. It may
be that thermal and industrial inefficiencies preclude> >> this, but this
cannot be assumed. Further, char is likely to be> >> compatible with existing
coal plant, when raw crop waste is not.> >> 6) You do not consider anaerobic
digestion of the crop waste to make> >> methane gas for power generation or
large-vehicle transport fuel.> >> This technology is used extensively in the UK
for food waste, albeit> >> on an emergent scale.> >> 7) You do not consider the
alternative of storage of waste in the> >> desert. If transported by rail to
the desert, crop waste could dry> >> naturally and then be sealed with plastic
in bales. This is an> >> obvious alternative destination for the waste.> >>> >>
A> >>> >> >> >>> >> > >> >> >
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