If we had cheap, unlimited source of energy would it be viable to actively remove CO2 from atmosphere on a large scale?
I read a book a month ago or so (wish I could recall the title) that pointed out that while this is certain technically possible as a way of dealing with climate change, it is prohibitively expensive using today’s technology. It would cost $30 trillion or more, or some figure like that.
If we had some magical cheap, unlimited source of energy we wouldn’t be producing much CO2 in the first place. We would use that magical cheap and unlimited source of energy in place of most of our fossil fuels. That would drastically reduce the amount of CO2 you’d need to scrub from the atmosphere.
This is exactly what plants do: they take cheap, unlimited solar energy and pull CO2 from the atmosphere to make biomass. I’m not presenting that fact to be a smartass: biosequestration is being promoted as a real tool for deliberately reducing atmospheric CO2 levels.
There are companies working right now trying to develop cost-effective direct carbon capture. (Sucking CO2 out of the atmosphere.) Probably the most promising one right now is Carbon Engineering which has Bill Gates (and several oil companies) among its investors. They use big giant fans and a proprietary chemical process to remove CO2 from the air and turn it into calcium carbonate. Then the carbonate is heated to release the CO2 into a controlled collection mechanism.
It does take a lot of energy. And there’s still the matter of what you do with the CO2 once you have it.
Their prototype plant does appear to work, though, and they are working on scaling it up to a full-size demonstration plant.
This.
Also, if course it’s possible to remove CO2 from the atmosphere, but even with cheap unlimited energy, it will still be expensive, and there is no financial incentive for anyone to make that investment.
There are a huge number of technologies which could be used to solve the climate change problem–the question is which are the most cost effective. Sucking CO2 out of the atmosphere is certainly one of the technologies being researched. At currently cost levels it is not cost effective. Currently wind, solar and energy efficiency measures are the most cost effective and are where massive amounts of money should now be spent–however they will only partially solve the problem–so sucking CO2 out of the atmosphere could turn out to be one of the later solutions.
If those energy sources are solar and wind then those won’t work when the sun isn’t shining and the wind isn’t blowing. And using excess solar and wind power to suck out CO2 might be more cost effective than massive electricity storage systems–batteries…
The problem is, any CO2 removed by plants will come right back into the atmosphere as soon as the plant decomposes or burns. So we need to take the plant mass and put them where they don’t decompose.
Ironically, if we stop recycling paper and put them in landfills instead, that would help. Though the amount would be negligible.
Is there a downside to biosequestration? Assuming that it’s done conscientiously, without bringing in invasive species, would it still be possible to, say, drive out desert-dwelling critters out of their habitats? Or suck too much CO2 out of the atmosphere and created a different climate problem?
Much of the surface biomass decomposes relatively quickly. But not all of it. And it depends on the plant and local environment. Root systems are more persistent. Soil and its associated organic carbon can accumulate.
The OP asks if this method is “viable”, which is a word I usually mentally add a “financially” in front of. Right now it is not. With some carbon credit/tax/something, it could be. But that depends on the details. Air is ~400 ppm CO2. More concentrated streams are cheaper to concentrate.
The better question is what couldn’t be done if we had a cheap, unlimited source of energy. That would be a very short list.
It would be nice to know more about this. We find money like this to fund other objectives. Climate change would seem to be much more important.
However, converting atmospheric CO2 into long-lived trees (that are not harvested) at least stores it for some centuries, as does using wood to build houses, furniture, and other long-term uses. Also, although burning new biomass for energy won’t reduce CO2 in the atmosphere, it at least can replace fossil fuels to some extent and reduce the amount of new CO2 entering the atmosphere.
At this point, the problem of excess CO2 in the atmosphere is so massive that all technologies for reducing it or at least slowing its increase need to be explored. Direct atmospheric capture is a new technology and at present generally too expensive as an option. However, further research may bring costs down.
DAC is hardly new. It’s just not attractive to most people building a carbon capture system today because there are plenty of easier sources to concentrate than air.
Yep. There is talk of reforestation, burying plant biomass in peat bogs, or sinking it in the ocean. These are all situations where the dead biomass would persist, resulting in some measure of enduring sequestration.
Heat would be an issue. Using energy produces heat as a waste product. It’s not a serious issue now because we only have access to a limited amount of energy. But if we had cheap unlimited energy and used it, we’d be producing unlimited heat.
You could say that the fossil fuels we’re burning now are the result of plant sequestration, but that the sequestration was only temporary, since it’s now being re-released as the dead plant matter is being burned.
But “temporary” can still be a very long time, and if we had the energy to do it, we could convert it into forms and put it in places that would last just as long as fossil fuels did.
I don’t think that active sequestration is really worth looking at right now, though. Right now, we’re burning fossil fuels and releasing CO2 to power lightbulbs etc. If we had a clean energy source that we could use to sequester carbon, it would be better to use that clean energy source to light the lightbulbs instead of using fossil fuels for that. Only once we’ve scaled up clean energy to the point where we can provide all of our lightbulb needs would it make sense to use it to sequester carbon.
If we’re digging sequestered carbon in the form of coal and burning it for energy, it makes absolutely zero sense to use energy to pull carbon out of the air and bury it in the ground. We’d be massively better off if we just skipped both steps.
The only form of carbon sequestration that makes sense is to allow forests to grow, and then prevent the burning of the wood in the forests so it doesn’t become carbon dioxide again. Active carbon sequestration is a foolish task in a world where we’re still digging up and burning millions of tons of coal every year.
So much land has been deforested and converted to other uses that you could reforest previously forested land without needing to plant trees in habitats where they formerly didn’t occur. (This said, human afforestation through irrigation or other provision of water can be detrimental to species that are adapted to non-forest conditions.)
There’s a lot of land, especially in the tropics, that has been deforested but is not currently in productive use. One option is to allow natural regeneration of secondary forests to occur, although such forests won’t have the diversity of the original primary forest.
Sucking “too much” carbon out of the air could cause global cooling, but we are so far from that level that we really don’t need to worry about it right now.