

Aluminum doped with titanium was able to catalyze hydrogen

Mercedes-Benz B-Class hydrogen fuel cell vehicle 

Other researchers have been studying composite materials for storing hydrogen.

Source: Eurekalert

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RE: Hmmm
By Aikouka on 11/1/2011 3:02:53 PM , Rating: 2
I thought I heard something about the energy required to perform hydrolysis didn't make it that practical. Can anyone chime in on this?

RE: Hmmm
By Gurthang on 11/1/2011 3:09:11 PM , Rating: 2
It depends on the application. I beleive most hydrogen is made from syngas or other chemical techniques. Rather than from cracking water.

RE: Hmmm
By bah12 on 11/1/2011 4:22:17 PM , Rating: 2
Correct the vast majority of it is from syngas (usually from natural gas or methane), so contrary to popular belief it is NOT a green fuel (as it stands today at least).

RE: Hmmm
By Solandri on 11/1/2011 8:42:11 PM , Rating: 5
Yeah, if you make a big chart of all naturally occurring hydrocarbons, and sort it by most hydrogen atoms vs. least volume at room temperature, guess what you find at the top? Diesel, gasoline, and kerosene, with alcohols not far behind. We've basically come full circle. Petroleum-based fuels were deemed bad, and pure hydrogen was suggested as an alternative. But pure hydrogen has massive problems with storage and volumetric energy density. If you then look at hydrogen compounds with high energy density and which store easily, you find that the best candidates are... petroleum-based fuels.

If there's going to be a green hydrocarbon-based fuel, it's most likely going to be biofuels. Photosynthesis is basically hydrolysis. Plants take H2O, combine it with energy from sunlight and CO2 to separate out the hydrogen atom to create O2 and sugars (CH2O)n. Those sugars can then be decomposed into alcohols (Cn H2n+1 OH) and hydrocarbons (Cn H2n+2). Instead of building all sorts of fancy equipment and burning electricity to split hydrogen from water, why not just grow a bunch of plants to do it for you?

The one area of hydrogen fuel research which may pan out is using fuel cells instead of an internal combustion engine. The ICE is limited by thermodynamics to about 35%-40% efficiency in something the size of a car (that is, 40% of the energy in the fuel spins the engine, 60% gets converted into waste heat). Fuel cells have exceeded 90% efficiency in the lab, with more practical versions hitting about 60%-70%. But as for hydrogen as a fuel, I don't see it becoming green unless we either massively expand either our biofuel capacity (cheap fuels for hydrogen fuel cells) or our nuclear capacity (cheap electricity for hydrolysis).

RE: Hmmm
By Paj on 11/2/2011 8:54:19 AM , Rating: 2
Thanks for that - very informative.

RE: Hmmm
By m51 on 11/2/2011 11:56:15 AM , Rating: 2
There are a number of flies in the ointment when it comes to Hydrogen fuel cells that are constantly glossed over. The hype tends to exceed the reality.

1) Storage and transportation of hydrogen. The best viable storage mechanism is compressed gas in high pressure cylinders. Compressing the hydrogen cost you about 12% of the embodied energy in the hydrogen. However the density is still so low that it would take 20 tanker trucks of hydrogen to transport the same amount of effective fuel as 1 tanker of gasoline. This increases the cost of the fuel. Even pumping gaseous hydrogen in pipelines is surprising energy intensive because of the very low density and can consume a significant amount of the embodied energy.
Liquifying isn't really an economical option because it takes 30% of the embodied energy in the hydrogen to liquify it and then you also have cryogenic boil-off issues. Storage by adsorption in solid materials (eg Paladium) is an interesting phenomenon but all the materials that can adsorb a significant amount of Hydrogen also bind quite strongly to it and it takes a significant amount of energy to release the hydrogen. Again you lose too much efficiency. Also the storage density is low.

2) Cost of hydrogen production - Currently almost all commercial hydrogen is derived from steam reformation with Natural gas. This is fairly efficient at around 80%, but converting natural gas to hydrogen and running it in a fuel cell is still less efficient well to wheels than a diesel hybrid car. If you want to get away from fossil fuel sources of hydrogen things get a whole lot worse. If you try to do electrolysis of water it's only around 50% efficient, however after you add in the extra required steps of drying the gas and compressing it and all the other details actual Hydrogen electrolysis systems for generating vehicle fuel consume about 75-80 Kwh per kilogram of H2 produced. In an automotive fuel cell you can recover only about 16 Kwh from that kilo of hydrogen. This is only a 20% system efficiency,and again it negatively effects the fuel cost. Battery powered cars on the other hand can achieve about 90+% efficiency. Batteries of course have their own problems in costs, weight, and longevity.

3) Fuel cell efficiency quotes are often misleading. 90% Laboratory efficiency numbers have almost no relation to real world numbers for an automotive fuel cell because they are achieved at incredibly low current densities. You have to run much higher current densities for an actual fuel cell that has the weight and size constraints needed to fit in a car. Actual efficiencies are more on the order of 50-55%.

4) Expensive. Currently the catalyst of choice is platinum. It achieves the highest efficiencies. Much effort has been put into finding cost effective alternatives and there are some but they all perform significantly less efficiently that platinum. All the top end efficiency numbers you see are with platinum catalysts.

5)Catalyst poisoning. The source of oxygen to run the fuel cell comes from the air, unfortunately there are a number of sulfur and nitrogen compounds in the air also that poison the catalyst and degrade the capacity and efficiency of the fuel cell. This vulnerability is an additional headache.

6)Infrastructure - or lack of. To build up a wide scale hydrogen fuel delivery infrastructure will cost into the Trillions of dollars. You have a chicken and egg problem, Fuel cell cars and a widespread fueling infrastructure to fuel them, we have neither and can't afford to build them.

If you include all the losses from well to wheels, even though IC engines only have about 30-40% efficiencies, the much lower losses in the rest of the fuel chain mean that fuel cells are actually less efficient over all.

Fuel cells still have a broad appeal though probably because the paradigm of a 'gas' tank and fueling up at a station like we do now with gas is something we are already comfortable with. Fuel cells are in reality just another form of a Battery. The difference being that if you double the size of the 'gas' tank in a battery powered car you double the cost, doubling the size of the tank in a fuel cell vehicle is much less costly. The basic problem though is that production and delivery of Hydrogen is just too expensive and is constrained by physics from significant improvement.

As for Biofuels, I find it very disturbing that nobody addresses the problem that our fresh water supplies are already maxed out. There is no fresh water to supply the enormous requirements that growing biofuels on a significant scale would require. Nor is soil erosion losses addressed. To achieve economical yields per acre requires intensive tilling and soil loss rates at 1 inch per 10-20 years. Topsoil replacement rates are around 1 inch in 500 years. It's sacrificing our future farm land for fuel, it's not sustainable.
If you go with covered aquaculture your infrastructure costs go up and you might as well go with solar panels. The only viable biofuels growth areas seem to be the oceans.
/rant off

RE: Hmmm
By JediJeb on 11/2/2011 5:29:42 PM , Rating: 2

I'm not sure about the fresh water supply being maxed out. Maybe in certain areas but not everywhere. You could simply build offshore structures out past the point where the Mississippi River empties into the Gulf of Mexico, then pump fresh water from the river, through the biofuel growing platform with the excess going into the Gulf, it would still end up at the same place only take a different course.

Also if you are using algae for the biofuel production then there shouldn't be any problem with topsoil erosion, since that type of facility can be placed anywhere, on an offshore platform, on rocky less fertile ground, or even on rooftops of industrial plants. If you place an algae biofuel plant on top of a building you would shade the building by capturing the sunlight used to produce the fuel which would lower the energy needed to cool the building. It will take a little creative thinking but overall I believe biofuels can be made to work without too large an impact on the environment.

RE: Hmmm
I agree, algae is looking really good right about now.

RE: Hmmm
By m51 on 11/2/2011 9:15:06 PM , Rating: 2
The problem lies in the sheer scale of biofuel production needed. Energy capture and storage by plants is very low in efficiency. Coupled with the enormous fuel requirements we have dictates fresh water requirements far beyond any available supply. I agree that algae has probably the best potential of the biofuels and that seawater based algae may be the only potentially workable direction for biofuel production.

Unfortunately with conversion efficiencies so low, area requirements so large, and the energy and materials costs to harvest and economically extract from such a low density energy source the problems are formidable.

There are many alternative energy sources that are technically feasible, but very few of those are economically feasible, and even fewer can be accommodated within our sustainable resource limits. Any workable solution must meet all three requirements. Biofuels may supply a small percentage of the energy puzzle, but it currently doesn't look to good at large scales.

It's a difficult problem with no clear winning answers, and anybody who tells you there is a clear solution is just ignorant of the over all picture. The clear answers evaporate before you when you look into the details.

RE: Hmmm

RE: Hmmm
By werfu on 11/1/2011 3:16:44 PM , Rating: 3
Newer aloy enable low power hydrogen production. There's also a new solar panel based on photosynthesis that can produce hydrogen.

RE: Hmmm
By Quadrillity on 11/1/2011 5:01:25 PM , Rating: 2
There are literally hundreds of different methods to split/harvest hydrogen. Algae farming is one of the most promising.

On a side not, the article mentions that the storage of hydrogen is very dangerous; but that's not necessarily true. That was one of the first problems they fixed. If I'm not mistaken, storing hydrogen is as safe, if not safer, than gasoline.

I really hope to see the world using hydrogen for commuter transport in no less than 50 years. It's pretty much the perfect technology.

RE: Hmmm
By Aikouka on 11/1/2011 5:13:10 PM , Rating: 2
Thank you (and everyone else) for the information on methods for harvesting hydrogen. :)

I've always had a bit of fondness toward hydrogen, because of how the entire reaction is very cyclic (I think that's an accurate word...). I think it'd be interesting if the day came when we could fill our car with water, it separates the hydrogen, uses it for the reaction, and the byproduct of the reaction (water) goes back in the fuel tank. Of course this isn't going to be perpetual, and I have no idea when such a thing would be feasible, but it is an interesting concept. :)

RE: Hmmm
By Quadrillity on 11/1/2011 5:24:23 PM , Rating: 1
Actually, the only hindrance right now is a lack of development. What little they have worked on it (and I mean in terms of total, world wide collaborative research) has yielded very promising breakthroughs.

But, the single largest obstacle right now is invested interest in oil based transportation. Hydrogen would be so much of a good thing that it would devastate our economies (sounds stupid, but it's true). Think of how many jobs would be instantly lost if the only moving parts of a vehicle were the electric drive-train? Cars would probably cost a LOT less too.

I'm starting to sound a little bit like a hippy now, so I'll stop while I'm ahead :D

RE: Hmmm
By Kurz on 11/2/2011 9:52:37 AM , Rating: 2
It wont devastate anything... since the money and focus of our economy will just shift since now we have a more efficient system. If anything our economy will improve and more people (especially the poor) will have access to more energy.

Though I will argue that Hydrogen is currently less efficient what we have currently. It only will become more efficient when it can compete price wise with Oil. Hence why we have a system based on money, it makes it easy to tell when technology has progress far enough for it to replace what we currently been using.

RE: Hmmm

RE: Hmmm


RE: Hmmm


RE: Hmmm
Being cyclical is not enough.

The pollution alone would favor the HFC.

RE: Hmmm
EV's have a more promising future than HFC.

RE: Hmmm


RE: Hmmm
By mars2k on 11/3/2011 4:48:02 PM , Rating: 2
Electrolysis is not the only way to separate Hydrogen and Oxygen from water. There are also chemical and thermal processes along with photosynthetic processes using algae or bacteria.
There is lots of research on catalysts used in the electrolytic process to bring down the cost. Further if your goal is only to lower carbon emissions the source of the electricity would be important. Wind, Solar, Geothermal or Nuclear sourced power could provide enough electricity without producing CO2 as a byproduct.
Hydrogen has a lot going for it.


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