The current term “clean coal” is obviously BS, but is it possible either now or in the future, but just uneconomic?
It is an immense resource if we could extract the energy of coal in a clean way.
There exist “high efficiency low emissions” (HELE) coal stations, but that moniker is only true in relation to conventional coal stations. They’re still some of the dirtiest generation we have. From the experience of the ones we have in Australia, they appear to be more unreliable in hot weather than older coal plants too - I believe probably because they would operate at higher temperature/pressures to improve efficiency.
*Citation not handy but easily googleable.
Filtration is good enough that it could technically capture everything.
Technically you could plant enough trees to capture all the CO2 as well.
The energy required to make all the filters and plant and maintain all the trees might be greater than the energy produced by coal though, and that is the issue.
No they don't. They need to be harvested and used for timber products, where the carbon can stay locked in for decades or longer. The land can then be replanted for more carbon removal.
Ideally you would use trees to make engineered wood products that replace steel and concrete, the production of which also release large amounts of CO2.
https://psmag.com/environment/young-trees-suck-up-more-carbo...
'Tropical rainforests, the revered "lungs of the planet," were once thought to take the cake when it comes to carbon sequestration. But a new study adds to a growing body of evidence that other types of forest may actually be better at sucking CO2 out of the atmosphere. Specifically it finds that young temperate forests may be more effective carbon sinks than are old rainforests.'
Imagine if nuclear reactors were allowed to dump waste in air/river.
The buildings have stacks.
I'd suggest calculating the volume of gas produced by the combustion of 3750 MTOe of coal, the amount presently extracted and consumed annually.[1]
It is significant.
1. https://www.bp.com/en/global/corporate/energy-economics/stat... https://www.bp.com/en/global/corporate/energy-economics/stat... https://www.bp.com/content/dam/bp/business-sites/en/global/c...
> In the United Kingdom, spent fuel is reprocessed at the Sellafield facility in Cumbria on the North West coast of England. Waste generated at the site comprises a wide range of radionuclides including radiocarbon (14C) which is disposed of in various forms including highly soluble inorganic carbon within the low level liquid radioactive effluent, via pipelines into the Irish Sea. This 14C is rapidly incorporated into the dissolved inorganic carbon (DIC) reservoir and marine calcifying organisms, e.g. molluscs, readily utilise DIC for shell formation.
https://www.sciencedirect.com/science/article/pii/S0265931X1...
https://phys.org/news/2019-05-iceland-carbon-dioxide-cleaner...
Capture it and convert it to fuel https://phys.org/news/2018-10-catalyst-door-carbon-dioxide-c...
Capture it and convert it to plastics https://phys.org/news/2018-11-co2-ingredients-fuel-plastics-...
etc...
I personally believe that in addition to pricing carbon governments are going to have to self fund massive sequestration projects as well to avoid catastrophic change.
The best way to sequester carbon is to turn it into coal or oil and bury it deep underground where it will remain for hundreds of millions of years.
It's insane to dig up coal and oil, burn it for energy, then spend MORE energy capturing all that CO2, converting it back into a long-term storage formfactor, and burying it again.
Much simpler to leave the coal/oil buried and get your energy from other sources.
Carbon sequestration makes way less sense than simply not digging up the carbon and burning it in the first place.
This is false. There are several tests of capture underway, where it's working at least within other parameters. [1]
As for economic viability, that may or may not come with scale and integration.
The bigger question is obviously the long term implications of storing CO2 (i.e. will it leak) etc..
"It's insane to dig up coal and oil, burn it for energy, then spend MORE energy capturing all that CO"
No, if sequestration can be viable, it would be 'insane' to ignore it.
If it increased the cost of burning natural gas by 2x, it'd still be cheaper than anything else.
It'd be irresponsible to ignore possible vectors of innovation.
Why would you build solar equipment with unreliable output at 7 cents kww instead a reliable natural gas / sequestered operation with 3 cents kwh?
"Much simpler to leave the coal/oil buried and get your energy from other sources."
There is no plan to going to get all of our energy needs from wind and solar, so I don't know what you mean by 'simpler'.
Carbon fuels are by far our best source of power, if we can capture CO2 efficiently, than we should.
The apparent 'anti sequestration' attitude that seems to prevailing here in HN is naive.
[1] https://www.reuters.com/article/us-japan-carbon-storage/japa...
I wish people who'd down vote my comment would reply if there is a factual error or misrepresentation of some kind on my part.
"The reasons that CCS is expected to cause such power price increases are several. Firstly, the increased energy requirements of capturing and compressing CO 2 significantly raises the operating costs of CCS-equipped power plants. In addition, there are added investment and capital costs. The process would increase the fuel requirement of a plant with CCS by about 25% for a coal-fired plant"
This is on top of the new reality that building solar and wind is cheaper than the cost to just operate existing coal plants [1], and therefore far cheaper than building new coal plants or retrofitting old coal plants with expensive (both CapEx and OpEx) CCS systems.
1. https://www.forbes.com/sites/energyinnovation/2018/12/03/plu...
"[The C02 sequestration process steals] up to 30% of the energy produced by a coal-fired power plant, reducing its efficiency and raising its electricity price. Second-generation facilities capture and reuse waste heat, among other things, but their costs are still too high, Brickett says."
a) Solar was 'not feasible' only 10 years ago, with more innovation and otherwise more expensive prices, it's feasible in some scenarios. There's no reason we can't innovate along other vectors. If the operating costs of solar can be reduced, surely they can with carbon fuel plants as well.
b) My point was specifically regarding burning any carbon fuel, not just coal. Natural Gas is by far the cheapest way to make electricity (depending on how you amortize Hydro I think), so 'Carbon Sequestration' would be a massive opportunity. Why would we ignore it?
c) A '30% cost increase' is actually pretty small considering most other alternatives and issues. In fact, that's good news because most energy schemes are not remotely feasible - if some clean energy scheme were only '30% away from being competitive' we'd be celebrating. If we could save the planet merely by raising electricity costs by 30% that would probably be a viable plan, globally.
d) There are places that exist 'outside the US' - like Canada, where way up north there isn't nearly as much sunlight, and the days are exceedingly short in winter, and this changes the nature of the electricity equation quite a lot and it's not actually feasible, and neither is wind in many places.
e) Carbon fuels burn in a predictable manner, which has all sorts of utility beyond the simple price. Something you can plan for is considerably more valuable than something that's inherently variable, so much so that in many cases the 'variable power' has little utility.
Particularly given there's tons of carbon fuels in the ground, I don't see why people would be against sequestration as long as it actually works.
Nobody is against anyone trying, but people are entitled to their doubts. If there were significant potential in CCS, investment dollars would respond accordingly. So far the results haven't gotten anywhere near the value proposition offered by renewables, especially in OpEx. Maybe that will change, maybe it won't.