Comment by spodek | Hacker News Reader

Comment by spodek | Hacker News Reader

Capturing carbon is a valuable step, but only as part of a process that net removes it from the atmosphere. This project doesn't seem to have that goal.

> "China's new CCS project will remove CO2 from two coal gasification (syngas) plants and re-inject the gas into previously exhausted oil fields."

> "CCS "is an important set of technologies for reducing emissions from fossil fuel use, while enabling important resources such as coal to continue to contribute to energy security and economic objectives.""

They aren't net taking CO2 out of the atmosphere. They're using it to pump more oil out of the ground and using it to argue to burn more coal. The CO2 in the ground won't likely stay there forever but much of it will seep back into the atmosphere.

> "the world's first commercial carbon capture and storage (CCS) plant opened in Zurich, Switzerland with the goal of selling compressed CO2 gas to industry, basically re-purposing the gas."

The Switzerland plant isn't taking CO2 out of the atmosphere either.

The article doesn't mention how much energy the plant uses to capture the carbon. If not powered by renewables, the process itself may not even be carbon neutral.

Let's hope others find ways to sequester the carbon, and maybe this step may help that process, but I don't see it offering much hope.

Meanwhile, almost no efforts put into changing people's behavior to reduce their emissions.

> Capturing carbon is a valuable step, but only as part of a process that net removes it from the atmosphere.

The IPCC, the IEA, and a boatload of scientists disagree. We cannot prevent catastrophic global warming without doing the type of CCS you describe as useless. Sure, we also want to be doing stuff that's net carbon negative, but that's a long way into the future.

And CCS from power generation is only one aspect. CCS from cement plants, steel furnaces etc. is another thing we need - those processes will inherently emit large amounts of CO2 even if electric power is 100% renewable.

Finally, when it comes to capture from air, I think stuff like "biomass -> syngas -> water shift -> separation of CO2 captured and stored, H2 produced for energy" is much more likely to be successful, because you can make it net CO2 negative and it produces something valuable as a byproduct. Capture from air is a whole 'nother matter, starting from a very low CO2 partial pressure and thus very inefficient.

(I work in CCS, happy to answer questions.)

How effective is carbon capture? Are we talking 30% less carbon? 99% less carbon? somewhere in the middle?

How much cost does it add to a typical coal plant? How does that compare to new solar installations?

Is carbon capture tech renewable? I.e. does it depend on some finite chemical material?

Is carbon capture feasible in smaller scales? E.g. can we stick a carbon capture system on a car?

> How effective is carbon capture? Are we talking 30% less carbon? 99% less carbon? somewhere in the middle?

Usually this is something you can tune to optimize your total system and the cost of capture. But typical requirements are >90% CO2 captured, often you see >95% or even 99%.

> How much cost does it add to a typical coal plant? How does that compare to new solar installations?

IIRC the target for something like a coal plant is getting below $100 total cost per ton of CO2 captured, transported and stored. Usually that's calculated summing up CAPEX paid down over some time span, plus OPEX, plus the price you pay someone else for taking the CO2 and storing it. To put that into perspective, if you pass this cost directly on to the consumer, it would correspond to almost doubling the price of electricity. Usually some form of government subsidy accounts for this price increase.

> Is carbon capture tech renewable? I.e. does it depend on some finite chemical material?

Depends very much on the tech. Broadly, we can split into four categories: solvent-based, adsorbent-based, membrane-based and liquefaction-based. E.g. for membranes for H2/CO2 separation, palladium is a key ingredient, which is hardly renewable (but we're not exactly running out tomorrow).

> Is carbon capture feasible in smaller scales? E.g. can we stick a carbon capture system on a car?

On a car? No. I've heard it discussed for diesel locomotives, anything smaller than that your CAPEX and OPEX are so high it makes much more sense to either go electric, or do "pre-combustion" capture, such as converting natural gas into CO2/H2 in a big plant and separating out CO2 while distributing H2 for use in cars.

> Sure, we also want to be doing stuff that's net carbon negative, but that's a long way into the future.

Isn't refusing emitted carbon (net negative) the entire point? That wouldn't be an "also" then, and newfangled ideas that don't give such a result are nothing to be excited about.

Seems to me capturing from the air is a wholly separate matter, whereas capturing at the source (i.e. power plant) should be the focus.

I guess "net negative" can be interpreted different ways. I was thinking of "net negative" to mean "capturing CO2 that's already been emitted", as opposed to "capturing CO2 before it is emitted in the future".

I agree any CCS scheme must be "net negative" in the sense that it doesn't produce more CO2 than it captures. But all the technologies in the pipeline today fulfill this.

> The CO2 in the ground won't likely stay there forever but much of it will seep back into the atmosphere.

That's really not the case. The injected CO2 is under such pressure that it stays liquid. We don't worry about massive oil seepage from kilometers underground, and studies have shown we don't have to worry about CO2 either: https://hub.globalccsinstitute.com/sites/default/files/publi...

E.g.: " The CO2 being injected should be in a “dense phase,” which means that it is put under pressure (compressed) until it turns from a gas into a kind of liquid. Because liquids take up much less space than gases, when large amounts of CO2 are injected, less space will be needed underground if the CO2 is in liquid form. It will mix more easily with water and other compounds, helping to secure the CO2 underground. The storage location must be deep enough in the earth that the pressures of the multiple layers of rock above the storage site keep the CO2 in this dense phase, to help it stay in the secure storage location, and not rise up like a gas. It is possible for CO2 to be injected as a gas, but the storage location would have to have a higher storage capacity since a gas takes up more space than a liquid. • Containment: A storage site must also have a layer of dense, impenetrable rock above it (called caprock) to stop any upward movement of CO2. There is often more than one such layer above the target storage formation that offers protection to keep the CO2 in the storage site. "

And: " The oil reservoirs studied in the WMP are about 1500 meters deep, which is deep enough so that the CO2 remains like a liquid. The reservoirs are made of limestone and a similar rock-type called dolostone. Both rocks contain lots of pore space where the oil has been trapped for millions of years. "

The technical word for "kind of a liquid" is supercritical. See e.g.

https://en.wikipedia.org/wiki/Supercritical_fluid#Phase_diag...

> We don't worry about massive oil seepage from kilometers underground

I dunno, I sure hear a lot of hand-wringing over fracking and the water supply.

Almost no effort? I consider this inflamatory!

Half of the consumables today are virtual products - movies, software, services. A gaming youth living in his room with his parents lives a life, that previous generations would have seen fit to a monk. Shareeconomys boom, removing the empty car from the lanes, electric cars simplify and reduce the many parts once used to make a car. All this, and you call that nothing, and dream about reshaping the human- this damned old project that is as much a bug, as the bugs encountered when "reeducating, reshaping" humans. Go and buy two books "The Rise and Fall of Communism" and literally any comment on literally any democratic constitution and why it was built that way. And then put them on the end of two pistons and get them into your head.

Reshaping human behaviour is hard. Like really hard. Like they vote for Trump, if you only ramp down hard. And the problem is not only with the shapeshiftresistant, but also with the "We-should-Shift-Them"-Smurfs, who - very much resist not there tendency to go full totalitarian the moment the hardness of the task becomes obvious.

Sorry for this, but this comment is here in a thousand shapes and forms, day in and day out, and it rarely replaced with something worth reading after an attempt to educate.

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