Andrew and list cc Greg and Michael
See inserts below.
On Sep 18, 2014, at 2:21 AM, Andrew Lockley <[email protected]> wrote:
> All CDR schemes that reduce carbon before sequestration sacrifice the energy
> available from it.
>
[RWL1: I will restrict my response to biochar, which I believe does
not fit the "All" of this sentence. First, biochar is receiving almost all of
its intellectual progress now for soil, not sequestration, reasons. There is
no conflict between these; improving soil comes at no expense to
sequestration. Yes one can get more energy output from biomass combustion than
pyrolysis - but only if you stop the analysis in the first year. Reports of
increased bacteria and fungus as well as increased above ground productivity
fill biochar technical papers these days (a rate of about one per day). My
guess is that pyrolysis beats combustion (BECCS) within 2-4 years based on both
sequestration and energy terms. Unfortunately, I know of no CDR comparison
that has included these out-year benefits. Biochar will always lose in both
energy and sequestration comparisons if soil improvement issues are ignored.
> While we still burn carbon fuels this doesn't make sense, as you have to
> input energy to reduce the carbon (unless you use photosynthesis) ,
>
[RWL2: Biochar always uses photosynthesis - and of course the free
nature of solar energy is the key to biochar's favorable economics.
> and sacrifice the energy available from oxidizing the resulting fuel, as well
> as lose all the process costs and energy involved in incidental materials
> handling and preparation.
>
[RWL3: Yes, one can make char and ignore the roughly half of the
available energy. And that is happening right now. But it is not with those
conversion approaches seen as most promising (see www.coolplanet.org for a
liquid fuel example with plentiful funding and exuberance about the char - the
part that provides carbon negativity.) Better yet is that BECCS economics
assumes huge facilities that do not allow combined heat and power. And BECCS
seems likely to follow CCS with coal, not precede or accompany it. And the
requisite geology is not everywhere, while soil problems are.
Process and energy costs (even transportation costs) have not appeared
large in the LCAs I have read. Biomass energy density is as good as many coals
(because of lower ash content) - about 18 GJ/tonne.
> Sequestration of oxidized carbon is fundamentally more efficient.
>
[RWL4: Not understood. BECCS takes a 30-40% hit over combustion -
same as why we are seeing reluctance to CCS. When viewed over 30 or 100 year
time period, biochar comes out way on top. Proof is in today/s land
productivity (factor of 3-4 X) of the terra preta soils of the Amazon -
untouched for 500 + years.
> If we really want to reduce it, releasing it from storage slowly whilst
> creating biochar slowly would seem a more sensible approach than the
> suggested scheme, and doesn't require a large technological infrastructure.
>
[RWL5: Also not understood; does "it from storage" refer to stored
biomass or stored CO2? I presume "suggested scheme" is that of Michael Hayes;
please clarify. Doing anything slowly sounds like a sure way to increase costs.
The technological infrastructure is tiny for all forms of biochar
production I have seen proposed - including Michael's. Even the Cool Planet
refineries are tiny - and projected to have lower drop-in fuel costs than those
starting with fossil fuels. Villages of a few thousand people are projected to
be enough with transportation distance under 20-25 km (much larger for BECCS).
So virtually every square meter of earth is available to provide both inputs
and receive inputs from any biochar operation. There are economies of mass
production as well as of size in the sequestration business. You are assuming
something about biochar operation size I have never seen in print.
Ron
> A
>
> On 18 Sep 2014 03:54, "Ronal W. Larson" <[email protected]> wrote:
> List cc Greg and Michael:
>
> 1. This note relates to Michael's submission (geoengineering category)
> to MIT at http://climatecolab.org/plans/-/plans/contestId/1300209/planId/3710
> . I just
<snip as not being pertinent to Andrew's comments, except for
my mentioning biochar a few times.>
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