The Hydrogen Myth

http://www.slideshare.net/stephenfleming/the-hydrogen-myth-presentation

by TriinT • 17 years ago

72 37 17 years ago

slideshare.net

Shakescode• 17 years ago

A 38 page powerpoint presentation. Very illuminating. Who knew such things as:

Liquid hydrogen leaks can be ignited by the static spark set off by the leak itself?

Hydrogen flames are not visible (see slide 16: hydrogen refinery would look same when on fire as when not.

Compressed H2 gas or Liq H2 have only about 15% or 30% of the energy-per-gallon as gasoline.

And on and on... Sure casts doubt on feasibility of H2 as a medium for energy storage.

TriinT2• 17 years ago

Indeed. I found the following amusing:

"There is actually more hydrogen in a liter of gasoline (116 grams) than there is in a liter of pure liquid hydrogen (71 grams)!"

But the coolest of all is that hydrogen flames are invisible! Hydrogen flames are so energetic that they emit UV radiation! I remember when I was in grade school and tried electrolysis at home. I managed to collect some hydrogen in a test tube, and I ignited it with a match. I heard a loud bang, but no flame. Sound, but no light. That was fascinating.

nazgulnarsil• 17 years ago

so what youre telling me is that setting someone on fire with hydrogen is the perfect crime.

endtwist• 17 years ago

Or methanol (under the right circumstances): "Pure alcohols burn with a nearly invisible flame in daylight." (http://www.energyquest.ca.gov/transportation/alcohols.html)

Which was done in (yeah, I know) an episode of CSI:Miami: http://csimiami.wetpaint.com/page/207:Grand+Prix

Though, of course, hydrogen is far more exciting.

jws• 17 years ago

hydrogen refinery would look same when on fire as when not. - except for the heat wave distortion, plumes of smoke from burning paint, drooping steel gangways, showers of electrical sparks from the shorting electrical system, and workers leaping from the upper levels.

potatolicious3• 17 years ago

And if the fuel in a hydrogen car decided to burn, everyone in its vicinity will find out in a real hurry - a fire that looks different is still a fire.

Though his point is valid - hydrogen will burn extremely quickly, we used to do these as demonstrations in school. Where a pool of gasoline will burn over a period of time, a tank full of hydrogen will burn almost instantaneously to disastrous effect - forget about rescue, the only sort of "rescue" will be body retrieval of whatever is left.

dryicerx• 17 years ago

I completely agree with the content in this sideshow, except I think he left out a important part of the H2 discussion.

H2 is a complicated/inefficient/explosive way to move energy, but it's very clean (as a energy transfer medium). At the moment, the way H2 is generated is very unclean (using Methane, or using the power from coal and other dirty power sources).

But if the origin of the energy is totally clean (hydroelectric, wind, solar), you can use that energy to break water down, then transfer that hydrogen in to the vehicle. Breaking down water is not so efficient, but it's still clean. I think this is the ideal (maybe dreamlike) goal of the H2 Camp.

TriinT2• 17 years ago

"But if the origin of the energy is clean (hydroelectric, wind, solar), you can use that to break water down and then transfer that energy to the car."

Using electrolysis, right? How pure must the water be? One can't use seawater, as that would produce HCl instead of H2, right? Desalination consumes a lot of power, but it may be an option if enough hydroelectric / wind / solar power is generated.

I wonder if one could use the water stored in the ice caps for electrolysis. An enormous source of relatively pure water could perhaps be an economical and scalable source of H2. Just speculating.

Retric2• 17 years ago

It's not that bad; a little math suggests people would still use more water for flushing the toilet than transportation over the average day.

Energy density of 1 kilogram of hydrogen = ~1 US gallon of gas. A gallon of water has ~2/(2+16) * 3.8kg =0.4 kg.

So ~2.4 gallons of water + (ton of energy) ~= 1 gallon of gas.

PS: Bulk fresh water still tends to run at thousandths of a cent per gallon in most areas. But, 14 kilowatt hours desalinates 1000 gallons of seawater so 14 watts per gallon which is a tiny fraction of the energy needed to split water into hydrogen and oxygen.

lutorm• 17 years ago

Given the low density, it's questionable to me whether it's better to use electricity to make hydrogen and put it in a tank compared to just putting it in a battery in a car. Bypasses the production losses and the low ICE efficiency.

potatolicious3• 17 years ago

I agree with you entirely - converting clean electricity into a finicky form of transport seems ill-advised. That being said, battery technology has a long way to go before being able to power a car entirely.

For one thing, energy density needs to improvement by an order of magnitude to make mass application useful, and the average lifetime of the battery I would say would have to increase 2-3x. Batteries are expensive to manufacture and the ecological impact of disposal is also extremely high - better to make longer-lasting batteries than cheap crap.

nihilocrat• 17 years ago

I'm confused about something he says in slide 22: "Solar and wind power are rounding errors"

Is he saying that they are currently just very limited compared to other energy generation methods in use, or that they're completely unviable?

designtofly• 17 years ago

He means that solar and wind power (and other renewable energy sources) represent only a tiny fraction of power generation in the US. Therefore, using them as a justification for the "clean" generation of hydrogen just doesn't make the case.

He is right that they are indeed "rounding errors." The DOE's own data shows that "Wood, black liquor, other wood waste, biogenic municipal solid waste, landfill gas, sludge waste, agriculture byproducts, other biomass, geothermal, solar thermal, photovoltaic energy, and wind" contributed to only 3% of total energy production in the US in 2008. [1]

[1] http://www.eia.doe.gov/cneaf/electricity/epm/table1_1.html

stephenfleming3• 17 years ago

Precisely. (Thank you for chiming in. I'm the author of the presentation in question, and am completely surprised to find it here on Hacker News nearly two years after publication!)

potatolicious3• 17 years ago

I can't speak for the author - but there is some evidence that, to produce our power needs via wind/tidal means on a large scale (i.e. an appreciable portion of total production) would cause as of yet hard to predict ecological impact. You sap the energy out of your tide and wind and bad juju will happen to your environment.

rjurney• 17 years ago

Stay away from my waves!

jcl• 17 years ago

"Hard to predict" is an understatement. For all we know, extracting energy from wind and waves could counter the recent perceived increase in hurricanes and tropical storms, or it could restore weather patterns to what they were prior to deforestation.

wglb3• 17 years ago

This is what Don Lancaster at http://www.tinaja.com/h2gas01.asp has been saying for a long time. One quote "Please also note that because of the staggering loss of exergy, use of electrolysis for bulk hydrogen apps is a really, really dumb thing to do. It is the equivalent of exchanging two US dollars for one Mexican peso."

physcab2• 17 years ago

One thing I can't stand about the hydrogen debate is how people link it to "fuel cells are bad." Solid Oxide fuel cells happen to be quite economical and successful by using other fuels like propane and gasoline. There are disadvantages with every energy technology, but the trick is using them in the right combination that makes the most sense. No need for unproductive flame wars.

And the quotes from "smart people" are ridiculous. Wow, you quoted someone else (and most likely out of context) to make your point stronger. Good for you. Do you want a cookie?

stephenfleming3• 17 years ago

Nope, got plenty of Oreos, right here.

Other people may have looked at the unfavorable characteristics and conclude "fuel cells are bad." That would be sloppy and stupid.

My message would be that "HYDROGEN fuel cells are bad, especially for automotive use." I like fuel cells in general; my employer has some great work going on with methanol fuel cells.

As far as the quotes being out of context... you've got Google, right there in your toolbar. Look 'em up.

physcab2• 17 years ago

I have no problem with your content (with the exception that you failed to mention which technologies COULD be commercialized rather easily). I believe you gave all accurate information. I just didn't like your presentation.

So some critiques, if I may:

1) Slide 2 - Why? I know you're trying to demonstrate your credibility, but this just seems like bragging. Who cares if you achieved highest honors.

2) Slides 2,6,9,13,14,15,19,22,28,29,37 - waaaaay too verbose. If you came to give a seminar at my school, I would have been drawing stick figures by now. Brevity is key.

3) I still stand by my criticism of your quotes. They add absolutely nothing to your presentation. What are they supposed to accomplish? And I assumed you were giving this talk in front of a group of people...so which toolbar are you referring to...the one on my iphone?

Tichy• 17 years ago

"The first and second law of Thermodynamics:

1. You can't win

2. You can't even break even"

wglb3• 17 years ago

And doesn't the third translate to "3. You can't get out of the game"?

eru• 17 years ago

And the zeroth?

drawkbox• 17 years ago

I want a nuclear car: http://en.wikipedia.org/wiki/Ford_Nucleon

The Hydrogen Myth

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