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A comment on Tim O'Reilly: Stop throwing sheep, do something worthy. Parent comment

Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DabAsteroid on Friday September 19, 2008 @09:26PM (#309648)
Have you looked at this?:

http://en.wikipedia.org/wiki/Energy_density#Energy_density_i...

                            Energy density    Energy density 
                            by mass (MJ/kg)  by volume (MJ/L)

  Gasoline                       46.9              34.6 
  Lithium ion battery             0.72              1.9 
  Lead acid battery               0.11              0.17 
  Compressed air in fiber-wound
  bottle at 200 bar (at 24°C)     0.1               0.1 
  compressed air in steel bottle 
  at 200 bar (at 24°C)            0.04              0.1
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Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DaniFong on Saturday September 20, 2008 @02:02AM (#309764)
Yes, we have. We're not intending to use 200 bar air, and we have to aim at a substantially more efficient vehicle, and even then we need a much larger tank than normal.

But compared to batteries they're very, very cheap. We think we can hit the range required, and that's what really matters.

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Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DabAsteroid on Saturday September 20, 2008 @03:32AM (#309797)
There are 700-bar tanks. What are you aiming for?

and we have to aim at a substantially more efficient vehicle

Against which car models (once you are done marketing the scooter) are you intending for your car to compete? Camry/Accord?

But compared to batteries they're very, very cheap.

What tank-prices are you figuring? $4,000?

http://www.google.com/search?q=hydrogen+car+tank+costs

[ Parent | on HN ]
Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DaniFong on Saturday September 20, 2008 @02:10PM (#309992)
We'd scale from 300 to 700 bar as the market allows. In the Asian market, for example, range and bulk is less of an issue than cost.

We're actually aiming at creating a scooter first, and other vehicles later.

The hydrogen tanks are much more sophisticated than we need. In particular they require a plastic liner (because hydrogen is so damned small). We just need carbon fiber wound tanks. These are manufactured to a higher precision but are not fundamentally different from 300 bar tanks which are fairly cheap (ie: you can buy single quantities of 9 L tanks for $500 - $600).

It's only a guess, but we think we can keep the tank price for a scooter below $1000, and for a car, below $3000. This is dependent on carbon fiber prices, and how efficient we can make the engine and drivetrain.

The important thing is that we can expect prices to improve handsomely while t goes to infinity, whereas batteries have had a lot of the manufacturing improvements that they're going to get.

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Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DabAsteroid on Saturday September 20, 2008 @12:57PM (#309957)
This is interesting:

http://www.google.com/search?q=%22modern+car%22+%22million+p...

... a modern car involves as many as 30000 component parts

In light of the fact that in a modern car there are about 2000–3000 galvanised parts

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Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DaniFong on Saturday September 20, 2008 @02:13PM (#309996)
Modern cars are quite complicated devices, even if the median vehicle contains no technical innovation at all. This is one reason we're doing a scooter first.
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Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DabAsteroid on Saturday September 20, 2008 @06:35AM (#309852)
But compared to batteries they're very, very cheap.

Lead-acid batteries can do something that air-tanks might not do as well: provide ballast.

http://www.google.com/search?q=commuter+cars+ballasted+paten...

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Re:Tim O'Reilly: Stop throwing sheep, do something worthy by DaniFong on Saturday September 20, 2008 @02:12PM (#309994)
Empirically, when you improve the weight of a car by a factor of 10% it improves the fuel usage by a factor of nearly 8%. Ballast is an expensive way to get stability.
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