Synthetic fuel

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The NYT reports on an interesting concept, making synthetic fuel from atmospheric CO2:
Scientists there say they have developed a way to produce truly carbon-neutral fuel and useful organic chemicals at large scale using water and carbon dioxide removed from the air as raw materials. There are plenty of schemes brewing to capture carbon dioxide, both directly from the atmosphere and from the stacks of power plants. All of them, for the moment, are costly or hard to envision at the billion-tons-a-year scale that would be needed to blunt the buildup of carbon dioxide in the atmosphere coming mainly from fuel burning.

UPDATE: 2/13, 5 p.m.: This plan has a minor hurdle, too; the electricity for driving the chemical processes, according to a white paper describing the overarching concept, would come from nuclear power. The proposal says it'd be worth it to have a payoff of steady, secure streams of methanol and gasoline with no carbon added to the atmosphere (and a price for gasoline at the pump of perhaps $4.60 a gallon -- comparable to petroleum-based fuels as oil becomes harder to find).

So, I don't know if this particular plan makes sense, but there's an important underlying concept here: gasoline (any fossil fuel, for that matter) serves two purposes: it's both a source of stored energy that we can extract and an energy transportation medium. From a physics perspective, energy is energy, but since batteries have a fairly low storage capacity and you don't want to tow a power line behind your car, chemical fuels are pretty much the only game in town. That's why people are interested in hydrogen power, since it's plausible that you can synthesize it from common materials (e.g., water) by application of energy. Hydrogen's not an energy source in itself, but it's at least a plausible carrier.

Unfortunately, it's not really that plausible a carrier. The problem is that it's not really compatible with our current storage and distribution infrastructure. On the other hand, if you had some way to efficiently synthesize liquid fuels that were compatible with the existing infrastructure, then you could synthesize it centrally without changing anything else. Moreover, this would give you flexibility to use any energy production mechanism that was convenient or practical (wind, solar, nuclear, etc.)

Based on this article, I can't tell if this method actually is practical and of course it doesn't solve the problem of aggregate energy supply. However, a practical version of something like this would allow you to separate the fuel problem from the energy problem, which seems like a good first step.

5 Comments

The basic technology dates back to WWII: Fischer/Troph (sp, sorry) synthesis.

If you can get Carbon Monoxide (CO) and water, you can mix them in the right amounts to get hydrocarbon and oxygen.

So its "Hey, if we capture CO2, and can dump a LOT of energy into it, we can strip off one oxygen and make CO". The problem is "enough energy" is "alot", so you need a nuclear power plant.

Also, we'd need to be building the nuclear power plants NOW, and they take years to build in sensible countries, and can't be built here in the US.


Hearing that $4.60 number fills me with hope for a few reasons.

1. It tells me that they're not obviously over-promising by saying that they can compete with current prices. (It may still be bunk, since I don't know enough about chemistry to evaluate all their claims.)

2. It implies a price cap within about 50% of where we currently are.

Other technologies may be better, but this is a pretty-good upper-bound on the problem.

The basic technology dates back to WWII: Fischer/Troph (sp, sorry) synthesis.

If you can get Carbon Monoxide (CO) and water, you can mix them in the right amounts to get hydrocarbon and oxygen.

So its "Hey, if we capture CO2, and can dump a LOT of energy into it, we can strip off one oxygen and make CO". The problem is "enough energy" is "alot", so you need a nuclear power plant.



Sure. Like I said, this is just using the fuel as an energy transport system. You still need to put all of the energy of the original fuel into the system and then some because the synthetic route is inefficient. The question is how efficient we can make it. But if you can make it reasonably efficient, then it lets you try to solve the problems separately.



Also, we'd need to be building the nuclear power plants NOW, and they take years to build in sensible countries, and can't be built here in the US.


Well, we could build them in Iraq, right? I'm sure that would be totally safe!

Nah, mexico.

If I was the mexican government, I'd be investing $10B/year to build nuclear power plants, because regardless of what one thinks of global warming, peak oil is probably happening, and if you have a lot of nuclear power, you can do solid->liquid conversion on any organic crap (waste paper etc), as well as gas->liquid with CO2 extraction.

Remittances to Mexico form some $23 Billion a year, or about 2% of their GDP.

It's clearly a growth industry and I assume they're working hard to ramp that number up as fast as possible. Nuclear energy would just be a distraction.

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