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TimW

On 04/01/17 17:32, wrote:
On Wednesday, 4 January 2017 14:21:13 UTC, TimW wrote:
On 04/01/17 13:33, tabbypurr wrote:
On Wednesday, 4 January 2017 11:55:06 UTC, TimW wrote:
On 04/01/17 02:56, tabbypurr wrote:
On Wednesday, 4 January 2017 00:12:19 UTC, TimW wrote:
On 03/01/17 23:03, tabbypurr wrote:
[...]

Carbon capture has never made any sense even at the most basic level. But if it can rake in subsidies...

How could it not make sense?
I understand a method and technology has been elusive, but itmakes sense
at a basic level to take CO2 out of the atmosphere, no?
TW

Energy generation requires turning C into CO2 to generate heat. Going from CO2 back to any less oxidised form is merely reversing the process. It's like taking 2 steps forward then one back, you make less progress. And since the step back costs money and is not entirely efficient, the whole process ends up using more energy per kWh out, producing more CO2 per kWh out, and costing more. It just fails to make any sense.

This is the first time I have heard anyone suggest that 'Carbon Capture'
should involve converting CO2 to pure Carbon.

I didn't say back to C, I said back to any less oxidised form.
okay, I didn't read carefully enough.

It would be an idiocy, but
I don't think it is any more than a straw man. I thought it was about
pumping CO2 underground into old mines or natural rock formations in
which you hoped it would stay put.

That's a hopeless approach, quite unrealistic. And achieves worse than nothing. The percentage of CO2 output one can bury is tiny, and guess what's required to do it... producing more CO2 to drive pumps etc. And of course putting it there temporarily does't achieve anything.

Taking CO2 out of the atmosphere temporarily may even be worthwhile.
Meanwhile plants continue to take CO2 out of the atmosphere and they use
up energy to do so and somehow that doesn't make the whole process
pointless. It doesn't matter if it consumes energy, there's plenty of
that, what matters is that you don't get it from fossil fuels.

You've missed the point entirely.

I think you have missed the point, by saying (correctly) that it would
cost energy to convert CO2 back to some less oxidised form. We aren't
talking about making energy here, we are talking about reducing
atmospheric CO2 so as long as the energy is not from a source which
produces CO2 it isn't pointless.

You of course sit in your armchair saying it'll never work, but you
don't really know. Iron ships - they will never float because you can't
make a ship leak proof, and flying! What an outlandish idea - god would
have given us wings.

It's the old unimaginative conservative attitude - nothing will ever
change, the poor will always be poor, people are selfish, money is the
only thing worth caring about, we can't stop the world from burning
blah blah...

TW

No, that has nothing to do with our difference. The difference is an understanding of basic engineering.

I don't claim to have any detailed understanding of how carbon capture
and storage might work. I somehow doubt that anyone here does, but just
saying 'I don't see how you could put it underground so it will never
work' is not demonstrating a knowledge of basic engineering, it's just
being a naysayer.

TW