4 ms·

I’ve been sending the same math to people who’ve been getting excited about this. It’s premature. Even just trying to remove our annual emission would take 7% o

by erentz 8y ago

I’ve been sending the same math to people who’ve been getting excited about this. It’s premature. Even just trying to remove our annual emission would take 7% of our global GDP. This needs to come down in cost 20x to be a viable solution to our problem. And that’s just going by cost, not looking at the logistical aspects. For example the plant pictured captures 1 million tonnes annually. So we would require 37,000 of those giant plants to capture our annual emissions. We haven’t explored how much energy would be required to do that and where we would get it from. The plant shown uses gas, a polluting power source oddly, and a very cheap energy cost figure in its calculations. Presumably we’d want to use solar. And thus half the efficiency of that plant. So double the number required to 74 thousand. Everyone getting excited that this is a solutions has gotten ahead of the science and logistics. We’re far from being there.

DennisP 8y ago
Nuclear seems like a better option than solar. Assuming capital cost is a major factor, you'd want the carbon removal plant to run all the time, not shut down at night. Constant load is perfect for nuclear.
- TangoTrotFox 8y ago
  There are countless ways to store energy: hydrogen, artificial hydroeletric, batteries, etc. Solar energy is practically unlimited. Nuclear still requires fuel, and it's a very limited resource unless you start considering things like extracting fuel from the ocean where costs just skyrocket. And it's likely that our global energy usage will skyrocket in the future for a variety of reasons. The first level is that many places are still undeveloped and have not yet hit their 'China' phase. But beyond that we can also just do some really cool sci-fi soundings things if we massively ramped up our energy production. Fossil fuels, and fuels in general, were never really fit for these sort of ideas - but solar certainly is. This [1] article goes into detail on the remaining nuclear material. Keep in mind that this is at current consumption rates. Energy usage rates are going to increase in the future, and right now only 4% of global energy production is nuclear. In other words, you can shave orders of magnitudes off the numbers they give in that article to give a ballpark for how long nuclear would last. It's just not a great fit for the longterm future. [1] - https://www.scientificamerican.com/article/how-long-will-global-uranium-deposits-last/ https://www.scientificamerican.com/article/how-long-will-glo...
  - 08-15 8y ago
    Scientific American is flat out wrong, compare[1]. (Someone who states that "a breeder creates more fuel than it consumes" has to be wrong about many things.) Common rocks contain about 13ppm uranium and thorium, which gives them a 50x higher energy density than coal[2]. We will never run out of rocks. As a bonus, if we actually "burn the rocks", we end up with a lot of sand to be spread on fields, which counters soil erosion, serves as fertilizer, and captures CO2 through accelerated weathering. In other words, solar power uses land, nuclear power restores land. [1] - http://www.nuclearfaq.ca/cnf_sectionG.htm#uranium_supply http://www.nuclearfaq.ca/cnf_sectionG.htm#uranium_supply [2] - http://energyfromthorium.com/cubic-meter/ http://energyfromthorium.com/cubic-meter/
    - TangoTrotFox 8y ago
      It's a misleading, but technically accurate marketing point for breeders. More specifically it's fissile material, which is converted from larger amounts of fertile material used in the reactor. There's no violation of conservation principles, just some fast talk. Read your own links - as at least the first mentions this. The second link is junk. The average distribution of elements in the Earth's crust does not mean each every and every chunk of earth contains exactly that distribution. And while many types of rocks do contain trace amounts of uranium, it's nowhere near 13 ppm. Though so far as I can see even that site didn't state that.
      - 08-15 8y ago
        > It's a misleading, but technically accurate marketing point for breeders That's the point, it's not technically accurate. A breeder makes more fissile material than it consumes. Fissile material is the fuel in light water reactors, but breeders use a different, more abundant fuel. I know that, you know that, and we both know that we both know that. But inaccuracies like this lead to the likes of Helen Caldicott dismissing the whole technology with a sneer such as "a breeder that magically makes more fuel than it consumes". > trace amounts of uranium, it's nowhere near 13 ppm It's about 13ppm uranium and thorium, in fact about 10ppm thorium and 2-4ppm uranium. And while energyfromthorium doesn't state these numbers explicitly, it clearly uses them in the energy density calculations. > does not mean each every and every chunk of earth contains exactly that distribution So "burning the rocks" will never work, because there are a few rocks that don't burn? It works even better, because some rocks burn better, e.g. Conway Granites at 56ppm thorium.
- delecti 8y ago
  Or to take it a step further, massively build up Nuclear to match daytime peak (give or take some renewables) and then use carbon sequestration as the load on the grid at night time instead of batteries (or other sorts of storage).

by erentz 8y ago

DennisP 8y ago

Nuclear seems like a better option than solar. Assuming capital cost is a major factor, you'd want the carbon removal plant to run all the time, not shut down at night. Constant load is perfect for nuclear.

TangoTrotFox 8y ago
There are countless ways to store energy: hydrogen, artificial hydroeletric, batteries, etc. Solar energy is practically unlimited. Nuclear still requires fuel, and it's a very limited resource unless you start considering things like extracting fuel from the ocean where costs just skyrocket. And it's likely that our global energy usage will skyrocket in the future for a variety of reasons. The first level is that many places are still undeveloped and have not yet hit their 'China' phase. But beyond that we can also just do some really cool sci-fi soundings things if we massively ramped up our energy production. Fossil fuels, and fuels in general, were never really fit for these sort of ideas - but solar certainly is. This [1] article goes into detail on the remaining nuclear material. Keep in mind that this is at current consumption rates. Energy usage rates are going to increase in the future, and right now only 4% of global energy production is nuclear. In other words, you can shave orders of magnitudes off the numbers they give in that article to give a ballpark for how long nuclear would last. It's just not a great fit for the longterm future. [1] - https://www.scientificamerican.com/article/how-long-will-global-uranium-deposits-last/ https://www.scientificamerican.com/article/how-long-will-glo...
- 08-15 8y ago
  Scientific American is flat out wrong, compare[1]. (Someone who states that "a breeder creates more fuel than it consumes" has to be wrong about many things.) Common rocks contain about 13ppm uranium and thorium, which gives them a 50x higher energy density than coal[2]. We will never run out of rocks. As a bonus, if we actually "burn the rocks", we end up with a lot of sand to be spread on fields, which counters soil erosion, serves as fertilizer, and captures CO2 through accelerated weathering. In other words, solar power uses land, nuclear power restores land. [1] - http://www.nuclearfaq.ca/cnf_sectionG.htm#uranium_supply http://www.nuclearfaq.ca/cnf_sectionG.htm#uranium_supply [2] - http://energyfromthorium.com/cubic-meter/ http://energyfromthorium.com/cubic-meter/
  - TangoTrotFox 8y ago
    It's a misleading, but technically accurate marketing point for breeders. More specifically it's fissile material, which is converted from larger amounts of fertile material used in the reactor. There's no violation of conservation principles, just some fast talk. Read your own links - as at least the first mentions this. The second link is junk. The average distribution of elements in the Earth's crust does not mean each every and every chunk of earth contains exactly that distribution. And while many types of rocks do contain trace amounts of uranium, it's nowhere near 13 ppm. Though so far as I can see even that site didn't state that.
    - 08-15 8y ago
      > It's a misleading, but technically accurate marketing point for breeders That's the point, it's not technically accurate. A breeder makes more fissile material than it consumes. Fissile material is the fuel in light water reactors, but breeders use a different, more abundant fuel. I know that, you know that, and we both know that we both know that. But inaccuracies like this lead to the likes of Helen Caldicott dismissing the whole technology with a sneer such as "a breeder that magically makes more fuel than it consumes". > trace amounts of uranium, it's nowhere near 13 ppm It's about 13ppm uranium and thorium, in fact about 10ppm thorium and 2-4ppm uranium. And while energyfromthorium doesn't state these numbers explicitly, it clearly uses them in the energy density calculations. > does not mean each every and every chunk of earth contains exactly that distribution So "burning the rocks" will never work, because there are a few rocks that don't burn? It works even better, because some rocks burn better, e.g. Conway Granites at 56ppm thorium.
delecti 8y ago
Or to take it a step further, massively build up Nuclear to match daytime peak (give or take some renewables) and then use carbon sequestration as the load on the grid at night time instead of batteries (or other sorts of storage).