On Thu, 5 Jan 2017 11:03:31 +1000, Adrian Jansen <adrian_at_qq.vv.net
On 4/01/2017 1:06 PM, bill.sloman_at_ieee.org wrote:
Interesting article on the "tragedy of the commons" and what kind of international CO2 emission regulation system might work.
As usual in engineering-type problems, the devil is in the fine detail, and this article goes deep enough to be interesting.
Here is my take on a way to improve CO2 recycling, and cut the total
fossil fuel input:
There are 3 main systems where we use energy.
Ground transport, cars, trucks, etc
Air transport, airplanes
Fixed base ( non - nuclear ) power stations, the electricity supply.
These are roughly equal in size, and contribute about the same both to
total energy and total co2 production.
So some significant reduction in co2 generation from any one of these
would help reduce co2 emissions globally.
Ground transport mostly uses liquid fuel, oil derived, and its pretty
efficient in terms of energy use, but cannot easily store or cycle the
co2 produced. The extra work to do that would kill the efficiency and
raise the cost of transport very significantly.
There is the possibility though to replace fuel burning with
battery/electric systems, at least for short haul. And battery
technology is still improving. But that places an even heavier load on
power stations, to generate the electricity required. And the total
efficiency drops, so the fossil fuel input and co2 output from the base
stations goes up significantly.
Air transport is similar to ground, but the energy density required,
and the recycling problem, is even higher. I really doubt there is much
room to change there. Best would be just to limit air transport to some
acceptable level, to limit the total load.
But fixed base power stations have a unique possibility to be improved.
We have plenty of energy available from the sun, pv, heat, wind, etc.
What we dont have is a good cheap, efficient way of storing it for use
when no sun, eg night, cloudy day, etc. Electric batteries at the size,
energy density and lifetime we need are only just barely possible for
small installations. The chemistry puts a hard limit on the energy
density, and we are already pretty much at that limit. Safety
considerations are also an issue with more exotic chemistry.
So instead we burn fossil fuel, and throw the co2 into the atmosphere.
2 effects from that, we lose the non renewable fossil fuel, and we add
co2 to the atmosphere. Imho the first of these is more important than
the second, since eventually we will run out of fuel. That will fix the
second problem too.
There is a lot of work being done on carbon capture, after burning the
fuel, but almost all on permanently storing the carbon in some
inaccessible place, so it wont end up in the atmosphere. But that means
we have to dig up more fossil fuel, and cope with the mess that makes,
as well as finding a place to store the co2. Both of these are really
So far all the proposals I have seen for carbon capture suffer from
serious efficiency problems. If you burn fossil fuel, and use a
significant part of the energy processing the carbon into permanent
storable form, you dont get enough energy left over to run civilisation.
Thats a dead end. As well nobody seems to take account of the fact that
co2 is roughly 3 times the mass of the original carbon ( as coal ). So
if you dig up and burn 1 million tons of coal, and capture all the co2,
you get 3 million tons of co2. Coal has density roughly 2.0, CO2 as
liquid under pressure has density 1.1. So the 3 million tons of C02 has
volume roughly 6 x the volume of coal mined. Where are you going to put
it ? It sure wont fit in the hole you got the coal from.
But there may be a better way. Hydrocarbon fuel (chxx, eg diesel) is an
ideal energy store, with a very high energy density, much higher than
any electric battery. Wikipedia gives energy density of lithium
rechargable battery at around 1.8 Mj/kg. Diesel is around 48. So why
not convert co2 to chxx using the energy in sunlight, the hydrogen of
course we can get from water, of which we have plenty, and even that is
recyclable, if it matters, using a suitable process. But only enough to
create a reservoir of fuel to use at night, and over a couple of weeks,
to allow for weather events. Recapture the co2 in a fully closed cycle,
and use the energy from the sun both as primary source, and to convert
the co2 back to chxx. Then the chxx becomes the energy store, much
easier to handle using existing technology than big electric batteries.
So the whole system is still driven by solar energy, whether as pv or
heat, depending on what is needed both to run civilisation, and the
chxx-co2 cycle is purely an energy store, using well known technology,
tanks, pumps, gas turbines, etc to do the storage and conversion. The
only piece missing is the co2 to chxx chemical process. That process
has already been done, at least to make methanol, which can either be
used directly, or processed further into chxx.
All we need now is the will and the planning to convert our major ground
based power systems over to this form of generation. At least the
technology for each part is already available, we just have to rearrange
the components into the correct configuration.
Extraordinarily long-winded "solution". Disposing of all leftists
would be easier, more fun, and more efficient reduction of energy
While that also sounds interesting, word is that the Saudis only have 5 years of oil left.