The issue with algae fuels in the past has been cost competitiveness with fossil fuels. Processing the algae to make usable diesel is labor intensive. If you're just going to bury the algae, though, that might be doable for the cost of a carbon credit. But you still have to feed the algae.
Carbon Sequestration
- Thread starter Vlip
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The issue with algae fuels in the past has been cost competitiveness with fossil fuels. Processing the algae to make usable diesel is labor intensive. If you're just going to bury the algae, though, that might be doable for the cost of a carbon credit. But you still have to feed the algae.
And you got to make sure nothing metabolizes it into escaping methane. Although given that methane has most hydrogen per carbon, if you burn that methane for power you should still have a lot of carbon left in the ground...
I mean if the worst case is carbon neutral oil that's not so bad, I just don't know that it would be competitive as an energy source. Maybe for something like aviation where it's extremely difficult to get the needed energy density any other way.
With algae I believe if properly processed you get triglycerides, which have only C, H, and a little bit of O. Everything else can be recovered and fed back to the next generation of algae.
Much of the energy cost comes from having to separate the oils from the water sufficiently to avoid problems in engines, and it seems like that could be abbreviated or skipped. I believe triglycerides are insoluble in water so possibly it would be enough to allow them to separate by density. Loss of some amount of water to the process shouldn't matter much, especially if it's seawater.
The project I posted a while back was focused solely on sequestration. Upwelling, nutrient-rich ocean water is pumped into pools on a stretch of land where a local algae species is bred. The algae are then extracted from the water and dried before being buried in dry soul, which limits decomposition. The water returned to the ocean may have lost the nutrients, but the process reduces the acidity of the water which is a net plus.
Of course the same idea could also be used to produce algae food crops rather than for sequestration.
Algae are actually a really rich source of oils, it's better in many ways than other crops we grow for biodiesel! Purely speaking economically, algae are a better choice than almost anything else. Bioengineered strains have up to 60% by dry weight in oil and require less post-processing than oil crops - those tend to peter out at around 25-30% by weight (and require freshwater, fertilizers, relatively high fossil fuel investment, etc.)
But as is often the case, biodiesel by and large isn't made for environmental or efficiency reasons, it's a political thing. It gives farmers something to do, farmers who otherwise would be producing surplus stuff and driving down market prices. It's also an energy independence thing spurred on by the first oil crisis.
As such, a lot of biofuel endeavors are highly subsidized and an integral part of the economy competing with actual solutions for climate change. That hinders the investment into and development of things like algae-based oil production. Which as it looks now is one of only 2 viable ways to decarbonize aviation and part of global shipping.
Yeah, that's one of those areas that I was following from my armchair for a while, and got despondent with the apparent lack of progress. Have there been some recent developments in algae for fuels in the last couple of years? From what I can tell there are some promising lab developments but not much more.
Last I checked, the most promising development was with strains of algae that actually exude oil, raising the possibility that the oil could be separated from the algae without killing it. But those strains were relatively slow growing, and they couldn't find a way to "milk" the algae that was cost effective--it had to be rinsed in some kind of fairly exotic solvent.
The other issue with farming algae that I noticed was the difficulty of preventing other algaes from invading your algae ponds. Weeding your garden is one thing, picking bad algae out of the good algae is something else. So now instead of plastic-lined pits or raceway ponds, you're looking at growing algae in sealed reactors, with all the pumps and plumbing that entails.
The other issue with farming algae that I noticed was the difficulty of preventing other algaes from invading your algae ponds. Weeding your garden is one thing, picking bad algae out of the good algae is something else. So now instead of plastic-lined pits or raceway ponds, you're looking at growing algae in sealed reactors, with all the pumps and plumbing that entails.
This is one upside for using it for carbon sequestration though. You may not have to extract the oil to immobilize the carbon for a useful amount of time. Using it as fuel requires purity sufficient to work in engines, but for sequestration you only need it to be in a state where it won't decompose anaerobically releasing methane. Just evaporating the water leaving a salty oily brine may be sufficient. That can then be disposed of in salt domes or old oil wells or some other suitable location.
As noted before, the "bury carbon in the ground" method I like is biochar - preferably mixed with livestock waste (manure, urine) and used as a soil amendment in areas where it will improve soil fertility. After it's mixed into soil, re-extraction to burn as fuel is unlikely to ever be cost effective.
https://www.globalcarbonproject.org...limits to negative CO2 emissions.NatureCC.pdf
The technologies exist and many of them are feasible and rather affordable. The challenge is that the ones which are most feasible also require considerable land use, which is typically more politics constrained than just manufacturing more widgets.
Economically speaking it's not a big deal. The level of coordination, however, is probably similar to what's required to build a spaceport in every major city.
In the Guardian today was an article "Fossil fuel producers must be forced to ‘take back’ carbon, say scientists," an idea I had never hear of before. I'd imagine some of the more advanced thinking activists already have been down this path, but at least the paper cited has the Oxford imprimatur. But, as Prof. Barnhart in the "TDTESS" (1951) says, "we scientists are often ignored or misunderstood," so it is hard to tell what if any impact this might have against mighty petrol who, I would hazard, might not want to trade in this market at all and scoff at the idea as unrealistic.
Hello, I'd like to talk more about this subject.
I did some calculations a few months ago and I think ultra chilled non-frozen water can be a carbon sink? something like for a 1000 square foot house, ten gallons of very chilled water could capture enough CO2 to reduce CO2 levels by half. Theoretically and it likely would be a very loud contraption.
I did some calculations a few months ago and I think ultra chilled non-frozen water can be a carbon sink? something like for a 1000 square foot house, ten gallons of very chilled water could capture enough CO2 to reduce CO2 levels by half. Theoretically and it likely would be a very loud contraption.
You're going to have to come with more than that to necro a thread like this. What do you propose to do?
Put a quadrillion bottles of ginger ale into storage and never open them?
I'm unsure if this is the best place to post this. The subject isn't a specific carbon sequestration method, but rather research (note: abstract only; non-public) that might help in their development.
From phys.org: Permafrost study finds abrupt thaw accelerates soil phosphorus cycling, offsetting carbon release
From the article:
Presumably, this means that it may be possible to develop strategies for what plants might be most beneficial to grow as permafrost thaws in response to climate change.
From phys.org: Permafrost study finds abrupt thaw accelerates soil phosphorus cycling, offsetting carbon release
From the article:
Presumably, this means that it may be possible to develop strategies for what plants might be most beneficial to grow as permafrost thaws in response to climate change.
I don't think there's any possibility we'll be able to sequester enough carbon to offset fossil fuel burning, let alone that plus permafrost thawing.
We're going to need to do something different. The goal is to cool the planet to something consistent with MOST species surviving.
They won't all.
We're going to need to do something different. The goal is to cool the planet to something consistent with MOST species surviving.
They won't all.