Switching to H2

Intro to topic at

http://en.wikipedia.org/wiki/Hydrogen_fuel
http://www.exxonmobil.com/files/PA/Europe/Blewisfinal_Amcham.pdf

(sorry I had to use a Big Oil link, but that's where the research money is.)

I'm not at all sure where the concept of free fuel and low-cost energy comes from. The United Nuclear systems are $7kUS - $10k US. Once you've spent that, and use solar, then it's free, but you can buy a lot of gas for $10k!!

While H2 is the most abundant element in the universe, little of it is easily available at the earth's surface. The common ways to make H2 are:

Hydrolysis from water. Requires energy to make H2. You lose in the long run.

Reforming from hydrocarbons. You either put the reformer in the car and fuel it with conventional liquid hydrocarbons (adds weight ($), but can use existing distribution and refueling infrastructure)

OR

Reforming at some central location and put the H2 into the car (requires a complete rebuild of the distrbution and refueling infrastructure). $$

To get a reasonable distance out of a "tank" of H2, it must be compressed to very high pressures. Requires high pressure fuel tanks and extra safety steps in your car (see Smart Tank in your link). $$. Are YOU ready to put material in your car that self-ignites when exposed to air, if a leak develops?


The underlying concept is that, IF it was cheaper to fuel vehicles with H2 now, THEN big oil would be doing it now. They are in business to make money. Significant technology and infrastructure changes ($$$$) are necessary, but probably not insurmountable, to make H2 a common-place fuel.

http://www.exxonmobileurope.com/Europe-English/News/eu_news_questair.asp

 

I'm a Mechanical Engineer, and here's my take on it...

We do have another short-term maybe 50 to 75 year alternative. We have more crude oil in oil shale in the Rocky Mountains and up in Canada than there is in all of the Middle East, it's just harder and more expensive to get at. I see oil shale as our next real energy source. Once it takes off, the Middle East is out of the picture since we have most of it here in the US and Canada. We keep our cars as is, we get gas at the pump just like we do now, we just end up paying more per gallon.

Hydrogen is in another class of fuel, which I see much further down the road, maybe 50 years from now.

The first hurdle with most alternative fuels is the energy storage density. Batteries really stink, and are only 1/23 of gasoline (0.12/2.75=1/22.92=4.4%). That means it takes roughly 23 car batteries to equal one gallon of gas. Electric cars are out of the picture for now, since the dang things only have a range of about 90 miles on a fill up and weigh 4000 lbs because of the batteries. Compressed hydrogen has a similar problem, but liquid hydrogen is pretty close, at 2.2/2.75 = 80% the density of gasoline. Borohydride as a hydrogen source would be excellent, but nobody knows how to recycle it yet. My buddies at work have some ideas on that, but nothing solid as yet since we don't have the research dollars required.

Next, we have to figure out a way to make liquid hydrogen cheaply. Right now it costs roughly an equivalent of $7 to $10 per gallon for liquid hydrogen, and nobody wants to pay that much. Once we can get the production price down, then it can take off. I and a bunch of other guys at work have a patent on a device to make the hydrogen at high pressure, then use the pressure and a turbo-expander to liquify it cheaply. We haven't talked DOE out of any research dollars yet, so we don't know if it will work economically or not. Hydrogen is still a ways down the road.


Here's some energy storage data to chew on just in case you're curious:

Lead/Acid Batteries 0.13 kwh/liter * 90% eff.= 0.12 kwh/liter (Electric Motor Efficiency)
6000 psi Hydrogen 1.42 kwh/liter * 30% eff.= 0.43 kwh/liter (Internal Combustion Engine)
Liquid Hydrogen 2.76 kwh/liter * 30% eff.= 0.83 kwh/liter (Internal Combustion, the BMW)
CNG (3600 psi) 3.01 kwh/liter * 30% eff.= 0.90 kwh/liter (Internal Combustion Engine)
6000 psi Hydrogen 1.42 kwh/liter * 80% eff.= 1.13 kwh/liter (Fuel Cell + Electric Motor)
LNG (70 psi) 5.90 kwh/liter * 30% eff.= 1.77 kwh/liter (Internal Combustion Engine)
Liquid Hydrogen 2.76 kwh/liter * 80% eff.= 2.20 kwh/liter (Fuel Cell + Electric Motor)
Gasoline 9.17 kwh/liter * 30% eff.= 2.75 kwh/liter (Internal Combustion Engine)
Borohydride 4.58 kwh/liter * 80% eff.= 3.66 kwh/liter (Fuel Cell + Electric Motor)
Diesel 12.84 kwh/liter * 35% eff.= 4.49 kwh/liter (Internal Combustion Engine)

 

David, I appreciate your efforts here. We have to do something to wean ourselves from cheap oil. We can either:

1. Bomb Iran, or

2. Develop alternative energy sources.

The problem with hydro fuel, as I understand it, is that the plutonium necessary to make one fuel cell is very expensive. Plus, there is a safety issue also.

But guess who is big into Oxygen?

GM

Dale

 

Dr Who,

I don't think you mean plutonium is used in fuel cells. It is not. Maybe you mean polonium, which has some uses in alternative energy.

David Driver,

I think the products United Nuclear are developing have some promise, but they are expensive. Storage of hydrogen in metal hydride matricies is really the only current option I know of that's reasonable for automotive applications today. It does have storage limits however. Still, for a short distance commuter car, one could make a case for UN's technology. A fifty mile round trip and regas at home with hydrogen liberated by electrolisis works, but maybe not ecomomically.

The main problem with hydrogen is how to store it. High pressure gaseous hydrogen will leak from any container because the molecules are so small. The pressures necessary to hold a reasonable amount of energy would make the tank a pressure bomb waiting to go off, and its energy density is way to low. Liquid hydrogen requires significant refrigeration to store, but at least it has reasonable energy density. Without refrigeration, liquid hrdrogen needs to be vented, as they do on rockets.

By the way, to the best of my knowledge, hydrogen does not spontaneously combust when exposed to air. It will combust in air with the presence of a spark however. Remember the Zeplins? They were used for a while, leakage and all, but it takes a flame or spark to ignite hydrogen in the presence of oxygen where it will burn very nicely.

Bill

 

I'm not an engineer, but I stayed in a Holiday Inn last night.

It seems to me that if we switched to Diesel, and made cars smaller and lighter, with smaller engines, our 50 year supply of fuel would last for more than 100 years.

Since I have been driving in the 70's, engines have been getting bigger and more powerfull, yet speed limits go down, road congestion goes up, and speeding tickets have gotten WAY more expensive.
Smaller engines for the masses would seem like the right answer for everything.

 

This thread probably belongs in P&R, but some food for thought. Right now our fine state of Minnesota is pushing very hard on ethanol, and specifically E-85, including attempting to get a waver from EPA to allow non E-85 cars to test using it.

But consider. How do they make ethanol? By heating corn with electricity. Electricity is made primarily from coal. Coal fired power plants produce more harmful polutants than all the cars and all other sources combined. More!

Consider. It takes more BTU's to make a gallon of ethanol than the BTU's you can get back from a gallon of ethanol.

And consider also. Cars get far less MPG on ethanol than on gasoline, so its a total net loss and far higher pollutants than if we all just left well enough alone.

Now, I can understand this stuff. Why cant people with college degrees and PHD's understand this stuff?

And personally, I believe all the world oil reserves are the converted remains of oceans of methane that existed here when the world was formed, and NOT from fossil remains. There could well be enough oil underground to last another 1000 years. But now that the oil guys are putting billions in the bank thats the last thing they would ever try to prove.

 

In addition, to grow sufficient corn or a cellulosic carbon source for EToH would require significant land area. Also, now there would be competition for corn, land area, water to irrigate, etc between conventional ag industry and EtOH. The potetnial result...$20 / pound steak, $12/pound hamburger, etc.

Hydrocarbon reserves are from plants and millions of years of decomposition and pressure.

http://www.faqs.org/faqs/sci/chem-faq/part6/section-1.html

 

My mistake. Thanks for correction.

 

DavidDriver,

I think your understanding is correct. The hydrides will hold H2 safely. It's H2 in compressed gaseous form that is dangerous.

Bill

 

That is one theory, but it is far from solidly proven.


I have a question that maybe someone can answer. Why is it that when people talk about hydrogen powered cars, they always seem to mean fuel-cell hydrogen cars. The car magazines are always talking about how far off hydrogen cars are because of limitations with fuel cell technology. What is wrong with good old fashioned internal combustion engines running hydrogen? I would think that converting hydrogen directly to movement by burning it would be more efficient than first converting to to electricity in a fuel cell, then running an electric motor with it. But I don't know much about fuel cells.

The other thing that always gives me fits are these people talking about how much better the world will be when we have decent batteries so electric cars can take over the world. These people have never looked at the whole-system efficiency of the electric car. Power is generated in a coal plant someplace with losses to heat and friction. That electricity is transmitted through miles of power grid, resulting in losses. Then it is put into a battery, with losses. Then it comes out of the battery, with losses, then it goes into an electric motor and finally drives the wheels. The losses involved in moving the car one mile versus how much coal you burn (and how much pollution you created) for an electric car are astronomical. Burning gasoline in the car itself is FAR more efficient and results in considerably less pollution for each mile you drive. The only benefit with an electric car comes when you have an abundant, cheap and clean source of electricity....which we don't.

Birdman

 

we do have ways of producing clean electric. nuclear power. i lived between three plants, peach bottom. calvert cliffs and (shudder) three mile island. i'm still alive and have no new body appurtenances nor do my children. so we do have a way to accomplish unlimited cheap electricty. it's the oil companies who have made nuclear power the boogie man. they've put the fear of disaster in the general population. the only vivable answer is the electric car. hybrid and hydro power all are second stage users of electricty. battery technoloy needs goverment subsidy to develop better batteries. auto manufacturers need to embrace electromotive technology. there is already alot of this hardware around but it will take a total commitment from business and goverment to fine tune it. we need to realize we are at war and we need to bite the bullet and throw off the yoke of fossil fuels that makes us dependent on suicidal madmen. i can envision a electric car with its battery installed under the passenger compartment floor. that's a battery 6" thick and as wide and long as the cabin. when your driving and need a refill you just pull in to the service station, they flip down the rocker panel pull out the old battery and slip in the new. you may also recharge at home. too bad i'll never see it.

 

No offense to anyone, but as much as I like nuclear energy, between 9/11 and Chernoble, I really don't want to be within 20 miles of one of those things. And battery power is just such a waste I cant imagine a more backward people embracing such a thing.

First off, I dont know what school everyone else went to, but I learned in like 6th grade that anytime energy is changed from one form to another, there is a loss of energy. Generally they figured about 15% IIRC, and it matters not the source. This is why the steam locomotive went away. You burn coal to heat water into steam, then propel the engine. Boiling water is a drastic waste of heat energy and trains burned it by the ton. My granfather teamed shoveling coal into a locomotive into Wyoming and he said four guys could hardly keep up shoveling it in nonstop. I read recently that a wood fired river boat could burn 8 to 10 cords of wood a day. Real cords, not the lil fireplace ones some think of. 4 feet by 4 feet by 8 feet. Thats a lot of trees. Putt putt putt.

Our local coal burner burns one rail car of coal about every 6 minutes. 10 an hour. 240 per day. Why waste it charging batteries, making hydrogen, or making ethanol? We would burn less coal if we just went back to coal powered steam cars. Cars have one lead acid battery, and they are a toxic mess as it is now. Now we want to multiply that by 15 or 30 batteries? How long do you stand around on a trip waiting to recharge?

What we need are decent well made cars with small turbo diesel engines or super efficient gas engines and efficient transmissions. No hybrids, no ethanol, no propane, no hydrogen. This is the same crap that started back in the 70's that led to berm houses, wind generators, and solar panels when everyone was smokin hooch. We need the smart people to stop and think about all this more clearly. That and people need to power down thier lives some. We are a nation of energy hogs.

 

Q1- Why fuel cells and electric motors? The efficiency is upwards of 80% compared to combustion, which is about 30%. Hydrogen also causes some problems in a standard-valved piston engine, since it will ignite prematurely simply because the valve is hot. A rotary is a perfect match, since there are no valves and the hot exhaust part of the cycle is in a different portion of the engine block than the intake phase. BMW has a piston hydrogen combustion prototype that runs on liquid hydrogen, so it's not impossible, just difficult.

Q2- Batteries stink right now. It will take a quantum leap in battery tech before electric cars will have a useable range. Right now they seem to be limited to around 90 miles, and that's at a rather slow speed so they CAN get 90 miles out of it. As to comparing the life-cycle cost, my guess is the refining process for gasoline probably consumes as much energy as the electrical coal generation process, so they're probably about the same in the end. The big difference is pollution. It's easier to control one power plant than ten thousand cars.

 

I think everyone who believes in using electricity should read as much as they can about coal plants. The smoke stacks are upwards of 800 feet tall. The gasses going up are accelerated to high velocity, and it pushes the gasses to very high altitude, easily to 8-10,000 feet above ground level. Up there the upper level winds carry the ash particles even higher, carrying it up into the jet stream. It can remain aloft for weeks, months, and can even circumnavigate the world.

I recently became aware that coal contains a fair amount of radioactive particles including U235, Thorium, Radon, and others. This too is being "pumped" into our atmosphere along with millions of tons of C02. These are far and away the filthiest things man has ever created, yet you see no one yelling to shut them down. I would rather see more nuke plants myself, just keep them out in the boondocks.

 

I agree on the nuke power statement - but we need the right kind of power plants; Breeder Reactors. A breeder RE-BURNS the spent fuel from other types of reactors, which we currently store in pools next to our operating power plants. Instead of disposing of all that spent fuel in Yucca Mountain, we should reprocess it into breeder fuel and recycle it. Shut down Yucca Mountain and use the money to build new power plants instead. We'd be way ahead of the game that way. Japan. France, and England have a breeder or two... What's the matter with the US? We may even figure out a way to make cheap hydrogen in one of our next-generation nuke plants. Wouldn't that be an interesting twist.
Thor
www.JavelinArt.com

 

Thor,
Thanks for the clarification. I had read about the wankel engine being better for hydrogren but didn't know why. Also, I had no idea that the efficiency of fuel cells was so good. That's pretty interesting.

France, for example, generates something like 90% of its power with nuclear. I have no problem with nuclear power in general, but the radioactive waste is what bothers me. We make this radiactive waste that is dangerous for millions of years. Kinda scary. I know they have a place to store it (Yucca) but it still seems scary.

Birdman

 

That's why a Breeder reactor is the best choice for a new reactor design - Breeders re-burn the spent fuel (radioactive waste) from other types of reactors. Leaving the spent fuel in it's current form is far more dangerous because it contains a lot of Plutonium. That's what Green Peace has a problem with. However, when a Breeder is done, Lead is mostly what's left over. We won't need a Yucca Mountain facility.
Thor
www.JavelinArt.com

 

Back to H2. While hydrides can store more H2/liter than a low pressure tank, It's nowhere near the amount of liquid H2 that that same tank could hold. Suspect an order of magnitude less. So if liquid H2 gives you about 0.8 the energy density of gasoline, storing it as an hydride might only give you 0.08 the energy density. (All numbers are PFA, so may be off a tad).

As to super high energy storage batteries, there really aren't any on the horizon. The Lithium Ion batteries are pretty close to the best that's known to be feasable. Sodium-Sulfur are higher energy, but their operating temperature is way up there. If you consider it as a form of battery, a H2-02 fuel cell is about as good as we know how to do.

That leaves nuclear, solar, & biomass as the long term energy sources. Unfortunately, I think that a century or 2 from now, the 'etroleum era'will be regarded as a kind of 'golden age' that unlikely to come again.

 

Verell,
regrettably, I'm mostly a sceptic on this change, although I recognize that something has to change eventually. ONE OF THESE TIMES when they say "we only have 60 years of oil left!" it'll be true, so I do support continued research into alternative power. But I'm not sure about your final conclusion that some day in the future, those of us that have had our heads preserved will see the 20th century as any "golden age". I'm sure automotive technology will follow the trend it has with other environmental mandates; a period in which manufacturers struggle to make something salable followed by further development. I'm sure some said emissions controls would bring fast cars to an end, but we all know how much faster and cleaner cars are these days.
Unfortunately, I don't know much about the H2 revolution, except that it's currently made for industry from natural gas, but, of course, steps have to be taken to get to a new nirvana of, say, either nuclear or bio-generated H2 (some neat stuff where they use microbes that eat waste and then generate H2 as "exhaust"!)