From: everything-list@googlegroups.com
[mailto:everything-list@googlegroups.com] On Behalf Of LizR
Sent: Thursday, November 14, 2013 12:26 AM
To: everything-list@googlegroups.com
Subject: Re: Global warming silliness

 

On 14 November 2013 20:24, Chris de Morsella <cdemorse...@yahoo.com> wrote:

 

From:  <mailto:everything-list@googlegroups.com>
everything-list@googlegroups.com [mailto:
<mailto:everything-list@googlegroups.com> everything-list@googlegroups.com]
On Behalf Of LizR
Sent: Wednesday, November 13, 2013 7:29 PM


To: everything-list@googlegroups.com
Subject: Re: Global warming silliness

 

On 14 November 2013 16:25, Chris de Morsella <cdemorse...@yahoo.com> wrote:

 

And to have the depth and breadth of understanding of the climatic systems
both atmospheric and oceanic to be able to say with a high degree of
certainty that there won't be unintended consequences that emerge out of the
geo-engineering intervention (especially if it is difficult to reverse). I
say this because as history shows we -- as a species (or culture perhaps) --
often fail to first understand before we act... there is quite a bit of
precedent.

>> Yes of course. It would be preferable to stabilise the climate in its
current benign state, which has allowed us to develop agriculture and
civilisation, by simply (!) removing CO2 from the air.

 

That's not removing it - it is recycling the energy carriers (the hydrogen
and the carbon) into new hydrocarbons (requiring other systems and taking
more by some factor energy to re-generate the hydrocarbon chains that are
the liquid fuel. Certainly preferable to just burning more fossil carbon,
but it is not removing carbon from the biosphere (it is returned as soon as
the fuel is burnt). 

 

"That's not removing it" is a non sequiteur in answer to me saying we should
remove it. I think we should, if possible, remove some of the CO2 from the
atmosphere. Whether removing it is removing it I will leave it to others to
judge.

>> Were you perhaps responding to my next comment, which you've left buried
down below for some reason? The one where I say we should remove CO2 from
the air and combine it with water (and sunlight) to make petrol?

That is what I was responding to Liz - synthesizing hydrocarbons in some
chemical process from CO2 and water + copious amounts of needed energy in
order to reduce both the CO2 and H2O - would return CO2 into the biosphere
as soon as the fuel was burnt. It is rec-cycling carbon through the
biosphere; not removing it. IMO - I am not certain that this is the best use
of the energy inputs that would be required in order to synthesize the
hydrocarbon from CO2 + H2O. Why not just use the energy directly. Remember
no process is 100% efficient so more energy is going to go in to making the
fuel by a substantial factor than will ever be extracted from that fuel by
burning it - transforming it into heat and then finally useful work. An ICE
engine - a very efficient one operates at around 20-25% efficiency - and
that is a modern efficient ICE. Do the math. Lets say it takes 200% the
energy in inputs to produce one energy unit of synthesized fuel - even if by
burning it you could turn it into 100% work the efficiency would still be
50%. Now multiply the 50% by the efficiency of an ICE engine and you are
getting in a good case about 10% maybe at the very best 15% of the energy
you are putting into to this artificial hydrocarbon fuel system.

Why not just use the energy directly? Sometimes there can be other factors
that make it make sense to produce a liquid fuel even though it takes far
more energy to produce it than can ever be extracted from it as useful work.
For example, liquid fuels are essential for aviation for example - because
of their power density; some energy is of low quality - for example wind
energy (or nuclear or other big thermal electric power plant) that is being
generated at 3:30 am. So there is an argument for doing so, but it is a for
niche reasons.

 

>>If so - yes, I realise that removing CO2 from the air and converting it to
petrol is recycling it. Obviously. I'm not a complete idiot. The point is
that doing that would be a short term solution that would make the economy
more carbon neutral and wouldn't require creating huge amounts of new
infrastructure. It isn't intended to be a universal panacea, merely a
suggestion - a highly hypothetical one at this moment - for how we can use
solar power to reduce the amount of stuff we're digging up and burning.

 

It would require a whole new infrastructure - the infrastructure to
synthesize the liquid fuels from CO2 gas + water. The massive energy
production infrastructure required in order to supply these huge refineries
with their energy inputs. Etc.



(Unless of course we can remove more CO2 from the air than we burn, in which
case we might even have "negative emissions". But this is all, if you'll
forgive the pun, a pipe dream at present).

 

What if we discover that we need to sequester large numbers of gigatons of
CO2 in a near term horizon?

 

>>We do. How would you suggest we go about it? At the moment we're mainly
using the oceans, which is bad news for anything that lives there.

 

That is a tough problem. It is far better to not dump it in the atmosphere
to begin with. The has been talk about deep geologic sequestration - pumping
CO2 into deep porous geologic formations that are covered by cap rock. They
are doing this in Canada as part of a tertiary recovery effort in some oil
or gas field up there. I covered that story a few years ago. Local farmers
were starting to complain that CO2 gas was ex-filtrating up from where it
was supposed to be sequestered - so I am not certain geologic sequestration
will work. It has been proposed to turn it into CO2 ice then essentially
bomb the ocean depths with it. Some suggest that under the immense pressure
and pretty low temperature of the sea floor mud that it would remain
sequestered down there for a long time. Re-growing old growth forests
(perhaps). Low grade peridot minerals of which some areas have a good
accessible supply also can chemically absorb CO2.

But - it is a tough problem. Much easier to not put it into the biosphere in
the first place where it becomes dispersed and hard to re-capture. So called
clean coal basically is attempting to do something like this - taking a
significant energy and capital hit in order to sequester the CO2;  never
seen any of these systems actually work - but am reporting them as I have
heard them porposed.

 

Chris

 

(And preferably turning it plus water into petrol... but I am starting to
sound like a stuck record.)

 

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