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Comment by dojomouse | Hacker News Reader

It's highly recyclable. Aluminium oxide (the result of the reaction in the battery) is one of the feedstocks for industrial aluminium smelting. Recyclable isn't necessarily the same as 'efficient' or 'a good idea' though. It's energy intensive (haven't checked the efficiency of 'recharging'), and additionally has, as a byproduct, massive amounts of CO2 even before considering CO2 emitted in generating the electricity required for the smelting process.

I can't see how that a single use battery like this (which also needs swap infrastructure) has any net advantage over the rechargable swappable packs + fast chargers as Tesla use.

Maybe it could have applications in aerospace where existing lithium ion cells don't have sufficient energy density to even come close to a viable solution. But you'd want to compare it to other 'single use' options like synfuel.

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This particular smelter uses hydroelectric power, mentioned in the article.

The power source is immaterial. Industrial-scale smelting produces CO2 at the point of production.

http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process

Moot point, unfortunately. Hydropower displaces fossil energy if the nearby energy markets are halfway deregulated and efficient.

Unless you're Iceland, with more geothermal and hydro than you know wat to do wit, and too far away from civilization. One of the largest aluminum exporters in the world.

Though you might want to read here: http://www.cpcml.ca/Tmld2013/D43129.htm for a bit of background on the price paid for such electricity.

The communists are against them? Fucking go Alcoa, I say!

Maybe if the aluminum could be packaged as a liquid or a gel, it could be pumped in and out like gas.

Something that requires 1,221 F (660.3 C) doesn't seem like something you would want to sit on or pump without serious protection.

Slurry, not molten. This (aluminium powder suspended in a liquid) was considered as a rocket fuel at one point.

Russian super-sonic solid fuel anti-ship missiles burn aluminum based fuel in their ramjet engines :)

The Space Shuttle solid rocket boosters were basically just oxidiser and aluminium powder.

Just use aluminum powder or prills. Bonus you get a huge surface area so the reactions happen fast.

and just dump the alumina result out the tailpipe - its just ceramic dust. And refill with new powder. So it becomes very much like the process of gasoline fueling.

I thought ceramic dust was toxic, at least in the large quantities a fleet of cars would produce? Is that not the case?

Well, its non-reactive (doesn't break down with low or high ph). But I don't know otherwise.

A little Googling shows lots of problems with clay dust (toxins for coloring etc) but nothing about actual fired ceramic dust. For clay it seems to depend upon the particle size in large part. So some control there might help alleviate the risk.

It's energy intensive (haven't checked the efficiency of 'recharging'), and additionally has, as a byproduct, massive amounts of CO2 even before considering CO2 emitted in generating the electricity required for the smelting process.

Aw come on! I'd rather see thinking two or more steps ahead from the HN crowd. If the CO2 emitted from the battery's materials came from the atmosphere in the first place, this will be a closed cycle and won't increase global CO2 levels. Supply the power to recycle the aluminum and charge the battery from renewable sources, and you're good.

The thing that might sink this is simply the sheer amount of energy needed. There is nothing inherently carbon intensive about it, though.

>If the CO2 emitted from the battery's materials came from the atmosphere in the first place, this will be a closed cycle and won't increase global CO2 levels.

The carbon emissions of aluminum smelting come from the carbon electrodes in the electrolytic cell-- you're essentially burning them to pull the oxygen atoms off the aluminum oxide molecule.

http://en.wikipedia.org/wiki/Aluminium_smelting

Carbon electrodes used in industrial processes are generally formed from processed coal and mineral graphite: the fossiliest of the fossil fuels. You could theoretically produce synthetic bulk carbon from atmospheric CO2 using the Bosch process, (http://en.wikipedia.org/wiki/Bosch_reaction) at incredible cost per kilogram of carbon produced, which would then directly increase the cost per kilogram of aluminum smelted.

Carbon electrodes used in industrial processes are generally formed from processed coal and mineral graphite: the fossiliest of the fossil fuels.

Again, there's no fundamental reason why this must be the case.

You could theoretically produce synthetic bulk carbon from atmospheric CO2 using the Bosch process, (http://en.wikipedia.org/wiki/Bosch_reaction) at incredible cost per kilogram of carbon produced, which would then directly increase the cost per kilogram of aluminum smelted.

Yes, but this is like saying that because our present economic/industrial configuration is the way it is, there's no escape from emitting carbon, which is simply circular logic. Or, maybe you do understand the implication, which is that the only way out is for us to make energy much cheaper across the board.

It's more like saying 'if you're looking at a new solution you better account for every step of the process, including costs and losses, and compare to viable alternatives, before deciding it's a good thing.

The logic isn't circular. Rather, you're conflating multiple independent processes. Even if we did have a commercially viable way to capture atmospheric co2 and turn it back into carbon that still doesn't mean we should then burn the carbon to make batteries. We could also bury it, and use normal rechargeable batteries.

It's more like saying 'if you're looking at a new solution you better account for every step of the process...The logic isn't circular.

In the general context of whether we can get ourselves out of carbon dioxide pollution, it is, and this happens again and again. If we assume that the current truism of our industrial society -- that you almost can't do anything without a carbon footprint -- is somehow true for all time is a vastly convoluted circular logic.

You will also note that the "two positions" above are actually the same position. The big caveat is the massive power use in recycling. We just interpret that in two different ways. "Not viable because it's not viable in our present economic infrastructure" is a position that's clearly false in the historical record. Unless you're being specific to the short term only, using that to justify a position is just obfuscated circular logic.

Uhh... I disagree. Firstly, I don't see the circle in the following:

- SolutionX puts lots of CO2 into the atmosphere compared to alternatives, and would be extremely uneconomic if we included in the cost/unitSolutionX the cost required to extract that CO2 from the atmosphere again.

- Lots of CO2 in the atmosphere is bad

-> SolutionX is either bad because it's uneconomic, or bad because it leads to lots of CO2 in the atmosphere.

-> We shouldn't use SolutionX until some factors change such that SolutionX is better than alternatives, rather than worse.

That's linear reasoning. If you want to change one of the underlying assumptions, namely that it's expensive to capture CO2 (and convert it back to carbon in this case... where at least the CO2 is coming from a concentrated point which reduces the cost of the process) then it's still linear reasoning with a slightly different result.

For it to become circular there would have to be some step where we said "If we had SolutionX it would be cheap and easy to get CO2 from the atmosphere and turn it back into carbon, but we don't have SolutionX because the methods of getting CO2 from the atmosphere without SolutionX are expensive so SolutionX is dirty".

That, interestingly, was used and is used as an argument against solar cells (e.g. solar cells made on power grids consume energy that may have a large CO2 loading). But it's easily revealed as bullshit through the use of EROEI (Energy returned on energy invested) accounting, and it's easy to show how 'SolutionX' (solar in this case) makes itself clean over time.

How is that the case with this aluminium fuel cell concept? Any advances in energy generation and CO2 capture are probably going to happen independently of aluminium fuel cell production. There's certainly plenty of incentive for both already, the aluminium fuel cells won't create a new market.

In conclusion, you're right that an aluminium based energy storage cycle would be more attractive if we had vast quantities of cheap and clean energy and low emission method of capturing CO2 and turning it into carbon. But.... 1. We have neither of those things 2. So for now an aluminium energy storage cycle is probably unattractive for most applications 3. If we did have both of those things it would totally change the economics of all sorts of other solutions, so you'd need to recalculate those as well before doing any comparisons between aluminium fuel cells and (e.g.) synthetic gasoline.

Uhh... I disagree. Firstly, I don't see the circle in the following

Having made this realization, then coming back to see this hunk of text written absent it sort of seals the deal as far as you being one of these particular kinds of circular thinkers. Namely, I 'll note that you're seemingly going on with the assumption that the Bosch process is the only way we could possibly get carbon out of the atmosphere on industrial scales. Left as an exercise.

Not at all. I'm pointing out that whatever process you assume to get carbon out of the atmosphere, you should plug the inputs and outputs of that process into your calculation.

Speaking of circular processes though... does this one look familiar?

a) Angrily and dismissively state flawed views

b) Have flaws in views pointed out

c) goto a)

Of course it's not purely circular as with every iteration there's more anger and less substance. But whatever.

Not at all. I'm pointing out that whatever process you assume to get carbon out of the atmosphere

Yeah, you don't know what it is, do you?

you should plug the inputs and outputs of that process into your calculation.

It's powered by the sun and all of the carbon gets pulled out of the atmosphere by nanomachines. As the mass of carbon used for the reaction is only 1/10th the mass of aluminum produced, the mass of the carbon needed for the current world production of aluminum would constitute a fraction of a percent of the world's total current agricultural output. Some additional energy would be needed to carbonize the material, but this fuel could be drawn from the same feedstock, and still amount to a fraction of a percent of the world's agricultural output.

a-c

Not at all. My position is that there is a kind of commenter who thinks themselves "smart" for being able to recite facts about the current world, but can't see when they are applying the facts in ways that show they can't think a few steps ahead from first principles. Instead they rigidly apply the current situation and present it in arguments as if they had actually refuted something. Any escalation is merely due to the level of annoyance from repeatedly missed hints.

The same sort of "logic" you present could be used in the Napoleonic era to "prove" that aluminum smelting would forever be impossible. (And you probably don't recognize the trap inherent in that one, or the other two traps above.)

Oh, of course. Nanomachines.

So basically we should celebrate this contemporary not-really-an-innovation because some future speculative innovation might make it useful... and ignore the fact that it's much more likely that the future speculative innovation would make it entirely redundant. I love it that your future sees us pulling CO2 directly from the atmosphere with nanomachines, but still driving around in cars that run on blocks of aluminium taken from aluminium oxide through smelting.

If I use your logic then I can just say "There's no issue with everyone running their cars on diesel". After all, one day we'll have nanomachines which can pull the soot, sulphur dioxide, CO2 and water vapour from the atmosphere and convert it all back into diesel again for a squeaky clean closed loop system running off the clean energy technology I have also implemented at massive scale.

I don't know why we're even bothering with clean diesel. Or any pollution controls at all for that matter. Nanomachines will sort that right out!

How're they coming along by the way? Oh, they're not ready? In the meantime then we should probably stick with assessing merit based on near term available technology, rather than saying "this thing is great, because I will solve all the things you don't like about it with my nanotech magic wand which I'm sure I'll have access to on a suitable timeframe".

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