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Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

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Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#61

Post by waps »

toomuchtodo wrote: post #59
JanezStupar wrote: post #52

Earlier quoted context omitted.

One possible solution is renewable energy. All current renewable energy sources have one big flaw. They produce energy when the circumstances are right, not when required. Beacause of this they cause issues in the energy grid. If we could build water cracking facilities at the right scale with the right characteristics, that could help offset the efficiency/cost issues. And on the issue of high pressure fire bombs, g…

>Edit: On the topic of fire bombs. I have today learned that one would not want Hydrogen tank in his vehicle. Everyone comes to this conclusion when you realize how deadly compressed hydrogen is compared to liquid petroleum. Nothing like being burned by fire you can't see.

Given how quickly an explosive shock wave travels through hydrogen, I doubt anyone near the car would be alive long enough to even register a mild temperature increase when the tank blows up.

Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#62

Post by saalweachter »

mchannon wrote: post #57
saalweachter wrote: post #30

Earlier quoted context omitted.

Oil is a net positive on the energy, even with the energy cost to refine it. Generating hydrogen from water is a net negative on the energy, guaranteed, by thermodynamics. Unless we start stealing it from an extra-planetary source, it is best to think of hydrogen as a battery, not a fuel.

Oil is not a net positive on the energy; gasoline consumes more in electricity during the refining process than it contains; it's just in a much more useful form.

That is a fascinating claim. I've just spent twenty minutes or so trying to track down the origin and veracity of it.

As near as I can tell, that is a corruption of the claim "you can drive an electric car further on the electricity which goes into refining a gallon of gas than you can a car on the same gallon of gas".

Specifically, the numbers I saw people quoting were that it took between 3 and 7.5 kWh of electricity to refine a gallon of gas, and that an electric vehicle could drive 30-50 miles on that amount of electricity.

However, a gallon of gasoline contains far more than 7.5 kWh: approximately 37.8 kWh. So gasoline is still a net positive on energy, even after refining.

Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#63

Post by mchannon »

saalweachter wrote: post #62
mchannon wrote: post #57

Earlier quoted context omitted.

Oil is not a net positive on the energy; gasoline consumes more in electricity during the refining process than it contains; it's just in a much more useful form.

That is a fascinating claim. I've just spent twenty minutes or so trying to track down the origin and veracity of it. As near as I can tell, that is a corruption of the claim "you can drive an electric car further on the electricity which goes into refining a gallon of gas than you can a car on the same gallon of gas". Specifically, the numbers I saw people quoting were that it took between 3 and 7.5 kWh of electrici…

Thanks for saving me the trouble of tracking down sources.

The claim was inartfully stated at best. However, it all ends up going back to your definition of "net positive". I read "net positive" as getting more out than you put in during the refining process. Neither gasoline nor hydrogen from water is a net positive by this basis.

If you extend the "net positive" test to the extraction and refining process, then you have to include the process to make the electricity for hydrogen-from-water or it's not a fair comparison. I can't dig up electricity. In this case both processes are net positives if the comparison is even.

Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#64

Post by saalweachter »

mchannon wrote: post #63
saalweachter wrote: post #62

Earlier quoted context omitted.

That is a fascinating claim. I've just spent twenty minutes or so trying to track down the origin and veracity of it. As near as I can tell, that is a corruption of the claim "you can drive an electric car further on the electricity which goes into refining a gallon of gas than you can a car on the same gallon of gas". Specifically, the numbers I saw people quoting were that it took between 3 and 7.5 kWh of electrici…

Thanks for saving me the trouble of tracking down sources. The claim was inartfully stated at best. However, it all ends up going back to your definition of "net positive". I read "net positive" as getting more out than you put in during the refining process. Neither gasoline nor hydrogen from water is a net positive by this basis. If you extend the "net positive" test to the extraction and refining process, then you…

I wouldn't go that far.

First, to be honest, I don't trust the initial claim. I couldn't find a source for the 3.5 to 7 kWh figure, and their are a lot of ways it could be wrong or misleading. Firstly, you don't refine gasoline in a vacuum; when you refine a barrel of oil, you get roughly 45 gallons of refined petroleum products, including about 19 gallons of gasoline. Are they assigning the full cost to the gasoline, dividing it by volume, or by energy cost? And 3.5 vs 7.5 is a full factor of two. What is the average cost?

Even taking the energy cost as gospel, it still tells you a heckuva lot more about the vehicles than the fuel. ICEs peak at about 30% efficiency, so you ought to be able to apply a solid 12 kWh from a gallon of gas to making cars go. If the fifty miles you can push a particular electric car on 7.5 kWh is more than your typical car, that's hardly the fuel's fault. And indeed: the current record for fuel efficiency is 209 mpg.

So it's duplicitous to say that electricity is more efficient for running cars than gasoline, or claim gasoline is somehow energy negative. We get so much energy from gasoline we can be extraordinarily wasteful in how we use it.

Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#65

Post by tezza »

frezik wrote: post #40
Xylakant wrote: post #34

Earlier quoted context omitted.

That pumped water requires a lot of space up there, so viable spots are fairly limited. It also is fairly difficult to transport compared to hydrogen.

If we're talking about the US, we have tons of open space. Really, tons. Americans don't appreciate just how much open space is in this country. If it's really a concern, it can be done with water towers rather than a conveniently-placed hill. As for transport, that's what a power grid is for. Transporting hydrogen loses more efficiency than transmission losses. Batteries are way ahead on every objective measure, and…

I'm afraid the physics just don't work out for Hydro.

See the Hydro section of Sustainable Energy - without the hot air by David JC MacKay:

http://www.withouthotair.com/c8/page_55.shtml

Even though the land mass of the US is larger than the UK, it's hard to see hydro being more than MacKay's 2kW per day per person...

That's two 40W light bulbs left on all day.

Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#66

Post by tocomment »

Has anyone looked into running the fuel cell in reverse to recharge it? I remember seeing a demo at a fair where it was a sealed fuel cell and it could go from h2 02 to water and then run it in reverse to recreate the o2 and h2.

If that's feasible it could simply be a new type of battery, no?

Re: Elon Musk Calls Hydrogen Fuel Cell Cars ‘Bullshit’

#67

Post by frezik »

tezza wrote: post #65
frezik wrote: post #40

Earlier quoted context omitted.

If we're talking about the US, we have tons of open space. Really, tons. Americans don't appreciate just how much open space is in this country. If it's really a concern, it can be done with water towers rather than a conveniently-placed hill. As for transport, that's what a power grid is for. Transporting hydrogen loses more efficiency than transmission losses. Batteries are way ahead on every objective measure, and…

I'm afraid the physics just don't work out for Hydro. See the Hydro section of Sustainable Energy - without the hot air by David JC MacKay: http://www.withouthotair.com/c8/page_55.shtml Even though the land mass of the US is larger than the UK, it's hard to see hydro being more than MacKay's 2kW per day per person... That's two 40W light bulbs left on all day.

That's not the same thing. In a standard hydroelectric dam, you need an existing river to create electricity.

The goal of pumped storage isn't to create new electricity, but to store large amounts of unused baseload power. This can be done with a standard hydroelectric dam by pumping the water back up into the lake behind the dam, but it can also be an entirely artificial reservoir.

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