Fun facts, kinda OT, for the bored Options

[lapuwali]

1 US gallon of gasoline contains 104,000 BTUs of energy.
1hp = 2,540 BTU/hour of energy consumption.

A typical car requires about 9hp to cruise at 60mph, given aero loads and rolling resistance from tires.

So, if engines were 100% efficient at extracting energy from gasoline, you'd get 273 mpg at 60mph in a typical car. Since most cars actually get less than 30mpg, most engines are extracting roughly 10% of the energy in the gas and applying those to actually propelling the car. Most of the energy is being thrown out as waste heat directly out of the exhaust, or in heating up the coolant, the engine itself, the gearbox, and the tires.

btw, hydrogen has 180,000 BTU/US gal, so if a liquid H2 fuelled engine were produced that only had the same efficiency as a 27mpg gasoline engine, you'll see 45mpg typically.

Pure ethanol has only 70,000 BTU/US gal, for only 18mpg. E85 would bring this up to 20mpg. Britt noted E85 where he lived was $2.10/gal v. $2.58/gal for gasoline, meaning E85 costs 81% as much, but only takes you 74% as far...

Now, as for the efficiency of a Mr. Fusion powered car...

[lapuwali]

QUOTE (Cap'n Krusty @ Aug 23 2005, 06:22 PM)

And to the cost of the Hydrogen, add the cost of making the fuel, in terms of energy consumed, which is substantially higher, I've read, than the energy it provides. Can you say "net loss"? The Cap'n

I agree, but that's not what H2 is or should be about. I have no idea what it costs (in energy terms) to refine and deliver gas, either, but I'll bet it's pretty remarkable. Hydrogen and gasoline aren't "energy sources" but "energy storage mechanisms". You can oxidize either one to release energy in a mobile application, like a car, relatively easily. In terms of energy density per unit mass, they have it all over electricity using any electric storage technology we have now, and electricity is also a "net loss" form of energy storage.

The only *real* forms of energy available are solar, nuclear, and geothermal. Geothermal's not going to work in a car for obvious reasons. Nuclear's not going to work until someone devises a Mr. Fusion. Solar on the car doesn't work for sheer energy delivery v. area issues. So, you have to tap one of these sources, store the energy in some medium, and use it to power the car. Oil is solar power that's been stored over millions of years. Hydrogen is all around us (the most abundant element in the universe by far), but not in a convenient form, and it's that conversion that costs. The big difference is that the oil cycle takes millions of years, whereas the hydrogen cycle takes no time at all. Emissions from a hydrogen IC engine are water and nitrogen oxides. With a catalyst, they're water, N2, and O2. H2 is currently made in bulk from natural gas, but CAN be made from water and enough electricity (which can be generated by one of the "real" power sources). Once we got going using hydrogen directly as a fuel, we'd never run out of it, for all practical purposes, no matter how much we used (again, up to practical limits).

Hydrogen could be "refined" from seawater using shoreline wave-power electricity generation stations, making delivery to much of the California population rather simple. Cutting out the drilling and oil tanker steps would reduce the costs (both in dollars and energy spent) quite dramatically.

There are lots of other problems with using hydrogen as a fuel (storage on the car, for one), but if this really is the way things are going, I'm optimistic. The IC-powered car could remain a fixture in daily life. Without this, I'm sure that within my lifetime, the only place you'd hear a V12 would be at at the Monterey Historics or similar events.