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This is an excellent point, however even so you'd still have another problem. Let's say this all works great, and we get to the prices that make it feasible. Yo
by entee 9y ago
This is an excellent point, however even so you'd still have another problem. Let's say this all works great, and we get to the prices that make it feasible. You're still just adding one go around to the carbon cycle. The fuel you burn at the power plant once gets back converted to fuel once, then turns into CO2 that you can't recover when coming out the back of a 777.
The only way this technology gets to the point where it's net carbon neutral or negative is if it can process the highly dilute CO2 coming out of the free air efficiently rather than the highly concentrated CO2 coming out of a power plant. I have a sense that the dilute case is quite a bit more challenging to make work at scale and efficiently.
- rz2k 9y agoI suppose you could use the power generated to desalinate water, grow forests where there otherwise isn't enough water, then bury the trees before they have an opportunity to decay into the atmosphere.
- kragen 9y agoAtmospheric carbon dioxide removal via direct air capture is feasible already. The cost is small compared to the price of the fuel; estimates range from US$30–1000 per tonne. More details are at https://pubs.acs.org/doi/10.1021/acs.chemrev.6b00173 https://pubs.acs.org/doi/10.1021/acs.chemrev.6b00173
- cma 9y agoThat is a big range. One ton of Diesel is $788, but produces about 3 tons of CO2.
- mistermann 9y agoWait, burning diesel produces energy and mass?
- changoplatanero 9y agoDiesel isn't the only ingredient in the reaction. Most of the weight in co2 comes from the oxygen that is taken from the atmosphere.
- Someone 9y agoIndeed. Atomic weights are: carbon 12; oxygen 16. So the oxygen in CO2 is 32/12 = 8/3 as heavy as the carbon inside it. So, if 100% of diesel were carbon that gets burned, you would get 3.67 tons of CO2. That leaves room for incomplete combustion and for other things than carbon (hydrogen, nitrogen, sulphur, etc).
- mistermann 9y agoThanks for a reply to a sincere question rather than just downvoting.
- taneq 9y ago> You're still just adding one go around to the carbon cycle. You mean like a tree does, or corn for ethanol production, or...?
- entee 9y agoThe tree would take what you burned and bring it back down because it's working in the dilute context already. Ethanol, or other biofuels, are nominally a closed cycle because you burn what you captured then capture it again. Now it's true corn ethanol is problematic for a variety of reasons (not least of which is use of fertilizer), but the concept of carbon neutrality in biofuels is mostly sound. The tricky part is to do it at scale, and reliably.