Comment by jerf | Hacker News Reader

Comment by jerf | Hacker News Reader

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They aren't sexy and few people talk about them, but if you do an engineering and economic analysis, some form of carbon-neutral liquid fuel is still very much on the table as a reasonably long-term energy transport solution. The characteristics of liquid hydrocarbon fuel are pretty good in most ways, which is why we still use them. For instance, have you ever worked the math on the amount of energy being moved when you pump ten gallons of gas in one minute and converted that back to Watts? There isn't an immediately obvious replacement for them that actually works as well. If the problems of the particular way we obtain them can be solved, then it's worth it to continue to figure out how to use them more efficiently.

And while 20 years ago you might have thought it would "just be easier" to switch away entirely to something like electric vehicles, research on that front has not proceeded as satisfactorily as would have been nice (batteries, oh batteries, why can't you just be an order of magnitude better?), and "fix the problems that liquid hydrocarbons have" has started to look less like a stupid idea.

Actually, I said fuel cell because of these reasons. H2 isn't nearly as energy dense as diesel. We've already had fuel cells that use diesel for a while:

Penn State Develops Fuel Cell for Diesel (2001):

http://www.sciencedaily.com/releases/2001/09/010905072008.ht...

Fuel cells don't seem to have quite gotten to practical yet, and large-scale usage last I knew is still problematic due to requiring more rare-earth metals than we actually have access to on planet Earth. Like pure electric, they seem stuck on "frustratingly close".

Even worse is that you need a continuing supply of them because of "poisoning" of the catalyst by contaminants in the fuel or oxidizer. Despite decades of research, they have reduced but not eliminated the problem. Also, if you use atmospheric oxygen as the oxidizer, it makes the problem worse since it is even harder to reduce its contaminants.

Someone familiar with the technology claimed to me, that in 5 years the super-capacitor batteries will be in widespread production and their prices will start dropping.

(I have no way to evaluate the accuracy of his prediction.)

What about changing out the whole battery? (You no more own a battery but you rent one from the gas station.) The infrastructure is hard to build, it's not easy to standardize in a future proof way (The same battery or at least very few different models of battery have to fit every car and they should be replaceable within minutes in some automatable way.) but I still think that the idea is very appealing.

From what I can see, it might be practical if the infrastructure already existed. The question is how we get from here to there. And it's not just the stations themselves, but the question of how we get that much electricity in there. But it at least might work; electrical recharging stations that people try to use seem impossible to me.

I suppose I should show the math, so someone could correct me if it's off. This source [1] puts the number of Joules in a gallon of gas at 130,000,000. Let's take a slow gas pump and assume five gallons in a minute. That's 4.3 megawatts [2]. For one car at a time. You can fiddle with that number if you're willing to be brutal on how far the electric car can travel or if you think people will stop every 50 miles for a 30 minute electricity topup, but no matter how you slice it you're going to need a major electrical network upgrade. I think this is a good idea anyhow, but in a country that would rather buy bread and circuses than bridges I'm not sure how it's going to happen.

[1]: http://www.evworld.com/library/energy_numbers.pdf

[2]: http://www.google.com/search?q=(1.3*10**8)+joules+per+30+sec...

> What about changing out the whole battery? (You no more own a battery but you rent one from the gas station.)

People already steal copper wires and screw up our infrastructure that way. I honestly can't imagine a world in which greedy idiots don't screw everyone over given how expensive those batteries are and that makes me sad.

If you are doing it right I can see very few scenarios for screwing the system — not more than exist now when it comes to, say, manipulating the odometer.

Such systems must already allow you to keep the battery as long as you want and to use it as often as you want (for as long as you have a contract), they must allow you to charge yourself, otherwise they wouldn't make all that much sense. The idea is that you don't have to change batteries for daily commutes or short trips (you charge at night), only for longer trips. (This is something that works much better in densely populated countries with little sprawl — the US might not be a very good candidate. I think Israel is trying out such a system in some way, its smallness makes it ideal.)

It's like a flat rate, some drive little, some drive more, but just because the battery is rented doesn't mean that driving behavior will change all that much. There is only so much you can drive and charge.

I also think that it would be somewhat involved to sell the battery on the black market. You have to at least get a replacement battery before your contract is up, so where's the advantage in selling your old battery on the black market? You might be able to profit a little, but you would also need scale, you need know how (how to manipulate the data those batteries would no doubt be collecting) and you need to be able to hide from the police. Nothing unheard of, but also no show-stopper. (People already do this with odometers and hardly anyone cares.)

This is the exact approach that Better Place is using, starting in "island" economies. The idea being that most times you can just trickle-charge, but if you need distance, you stop by a battery station and it's swapped out robotically, in about the same time it takes to fill a gas tank.

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