New Hydrogen Storage Technique

pwp writes to mention that researchers at the University of New Brunswick are reporting they have found a new method of storing hydrogen gas. The new method is able to condense hydrogen gas into a usable solid under mild conditions. "Hydrogen gas is typically stored under pressure in large metal cylinders, approximately four feet high. These cylinders are heavy and expensive to transport. Since they are under pressure, they also pose a safety hazard. 'We've reached a milestone with our ability to condense hydrogen into a usable solid,' said Dr. McGrady. 'The next step is to produce a safe, compact storage system for the compound that is both lightweight and affordable.' The research is expected to produce reversible hydrogen storage materials that can be processed into a powder for use in limitless commercial applications."

Comments

I want more.

[PrinceAshitaka]

This article has absolutly vague information on what research they are doing. Storing hydrogen as a solid, apparetly as a powder? What would be interesting is to see how much energy is lost in the chemical reactions of reacting hydrogen with whatever they react it with and then changing it back into hydrogen gas. I would also like to see how this compares to the energy required to compress hydrogen as it is currently done. This is what will determine this technologies usefulness in reality.

Only nine percent hydrogen by weight is success? How much fuel will it waste in transportation if there is nine times as much "pakaging" material as there is hydrogen. Yes the currently used hydrogen cylinders are heavy, but I do not believe they weigh nine times as much as they can carry.

Re:I want more.

[[Mobius]]

They bind it with aluminum to create a stable hydrogen/aluminum powder.

At least, that's what a local news report mentioned a few days back.

Re:I want more.

[Sockatume]

Of course, the real problem isn't just hydrogen density, the thermodynamics and kinetics of hydrogen uptake and release are important too. You want it to fall off in a nice controlled manner with very little energy: on the order of thermal energies so you can use waste heat from the fuel cell, or a simple heater, to get the hydrogen off. Likewise you want to be able to recharge it with hydrogen quickly and with small energy requirements. Many really great hydrogen storage solutions have run into problems at this end of the problem and need metal catalysts, which increases the weight and cost. Frankly, practical hydrogen fuel vehicles are still a couple of decades off. It's going to be cool, though. At the gas station, you won't have to go to the pumps, you'll just haul your "empties" out and swap them for reloaded cartridges. If you wanted to take extra fuel with you for a cross-country trip, you could just buy some spares. More expensive than jerry cans, but easier to swap in and out. Of course there's no particular reason for Audi's hydrogen cartridges to be same shape as BMW's, which could get "interesting".

Re:I want more.

[drinkypoo]

No, it's a quarter as energy dense, and half as energy efficient (since hydrogen fuel cells + electric enginess have so much better efficiency than ICEs). Still, that's not problematic; doubling the mass of 15 gallons of gasoline is only 48 kg extra, and you don't have to haul around that big hunk of steel we call an internal combustion engine. ;)

But that leaves open the question of regenerative braking. A great deal of the efficiency bonus of EVs and HEVs (PHEV or no) is that they do regenerative braking. You can't effectively use a fuel cell for this without an intermediate storage medium, which currently means batteries (as we've been waiting for supercapacitors to get good price:performance for many years now.)

If you have to add batteries in to store the power from regenerative braking until you can accomplish electrolysis of water, then you have inefficiency and weight to deal with. And you probably won't be able to store it in this solid form, which I suspect won't be a very portable process (although I am willing to be proven wrong.) So you'd lose out on one of the major benefits of using an electric vehicle.

Re:I want more.

[Sockatume]

That works fine for compressed or liquefied hydrogen, and maybe some physisorption methods. Chemically stored hydrogen (which seems to be the most promising) would probably require that the cartridge was regenerated by the manufacturer. I think it'll be like milk deliveries: buy new stuff and return the empty bottles.

Re:I want more.

[cupofjoe]

I agree that it would appear they could be talking about Alane (AlH3), which has a theoretical weight-density of about 10% hydrogen. Yes, 10% is good...but as folks in the hydrogen storage community would be quick to tell you, it's not unusual. For example, Lithium Borohydride (LiBH4) has a theoretical weight-density of almost 18.5% hydrogen! The key is simply to bind hydrogen with light elements in a stable configuration, right?

Wrong. That's not even the tip of the iceberg.

The real problem, as any hydride person would correctly point out, is not "theoretical storage fraction"; rather, it's REVERSIBLE storage fraction. It doesn't really matter, in the long run, if you can store 18%, or even 25% hydrogen by weight in a substance if the following are true:

1. it takes a LOT of energy to put it in (theormodynamically unfavorable hydrogenation reaction)
2. you can only get out a small fraction of what you put in under favorable conditions (non-reversibility)
3. the reaction doesn't move very quickly (unfavorable kinetics)

With these limitations, you face a severe energy penalty for trying to use the material as a hydrogen carrier, mostly because it's one-way. The keys to an inexpensive, efficient solid-state hydrogen storage material combine high storage fraction with a high level of reversibility: why bother using a material if you have to ship it back to the "refinery" when the hydrogen has been depleted? As an example, let me use the typical automotvie application to illustrate. (I know that TFA - which doesn't really say ANYthing, natch - doesn't explicitly state that their "revolutionary" material is for automotive applications, but that's where all the money is coming from these days.)

What I want to do is expose the dehydrogenated powder (it's usually a powder) to hydrogen gas at about 1 atmosphere (~15 psi), remove some heat of reaction (for later use, naturally) and go on with my business. Preferably at a "hydrogen filling station", whatever that ends up looking like. Oh, and refueling shouldn't take more than about 5 minutes. And once the tank is full, I should be able to drive 300 miles without filling up again.

Right now, there is NO material known on Earth that can fulfill these requirements and still be designed into a car.

The astute reader will notice immediately that I'm leaving out what might be the single-most crucial design driver: SAFETY. I don't know if everyone's been keeping up, but alane (and the alanate hydrides in general) are ROCKET FUELS. Personally, I don't want to drive around with 20kg of solid rocket fuel in my car's gas tank. In this case, safety will absolutely drive eventual adoption, even trumping reversible storage fraction.

For example, sodium alanate (NaAlH4) has a theoretical storage fraction of 5.6%, and the reversible fraction is starting to approach 4-5%, which is a very, very good track record. However, when it sees water (which it might, in a car accident) it EXPLODES. Well, deflagrates, but you get the point.

(rant on)

Don't get me wrong. I'm all about solid-state H2 storage, and the "H2 economy" in general, whatever that happens to be. I'm even a "real" materials engineer, working with hydrides. But I'm also all about reality, and hopefully trying to "drop the veil" of proprietary information wherever possible. We're working as a team, people. So, to the press folks at UNB: write better articles, publish some papers, or both.

(rant off)

-joe.

Re:I want more.

[drinkypoo]

Oh, fine, you talked me into it. Let's say you want the charge from 110km/h (30.5 m/s) in a 600kg vehicle. That's a kinetic energy of 0.5 * 600 * 30.5^2 = 280 kJ. Let's say that you can recover 250kJ of that. That's ~70 watt hours. A little over 1kg worth of NiMH batteries. Not a big deal, wouldn't you say?

Now, give me enough hardware to do that thirty times as I drive from one corner of SF to another, and take into account the maximum practical charge and discharge rates. Also take into account the weight of the hardware needed for charge/discharge control. Obviously the regenerative braking power can come out of the batteries to drive the car forward, to some degree.

It may very well be feasible, but there's a WHOLE lot more than just the batteries themselves to consider.

Re:I want more.

[Rei]

Okay, new calculation time, then :)

NiMH batteries have a specific power around 200 W/kg. Let's say we're talking about 1.5kg. 70 Wh would indeed take too long to be useful, at 14 minutes for discharge. However, with such small weights, why go with batteries? Just with what's on the market right now (which is a literal order of magnitude behind the next gen), and you're looking at ~6 Wh/kg and ~2kW/kg. ~70Wh => ~12kg. Not a big deal. And for discharge rate? 24 kW, discharging 70 Wh => 10.5 seconds for your 110km/h 0km/h velocity change. Sounds about right. So, your solution is a 12kg ultracapacitor. Heck, call it 15kg for some leeway.

Re:I want more.

[Rei]

Let's see, a quick search reveals a supercapacitor price of $2.50/Wh, so 2.5 * 70 = $175. Hardly breaking the bank there. Cooling, charge controller, etc -- I'm not sure how many different ways that I can point out that we're not exactly dealing with a lot of energy here. I could do the calculations, but why bother? It's obviously not going to cost much. Most of the cabling you need anyways (to run to the engine(s) from the fuel cell. You're just splicing a new power source into that line.

Re:this can not work!

[PrinceAshitaka]

While they do not say directly in the article, the artcile does have hints that thier method of turning hydrogen solid is to react it with something. This will form a powerder at room temperature. The thing is they only have six percent of this powder is hydrogen so there is alot of dead weight to haul around so little H2. Also this method of a reversible reaction will use up energy. It is yet to be seen if this is more or less than the energy required to compress a similar volume of hydrogen.

Sweet

[inviolet]

Assuming the energy needed to perform the condensation is not lossy, this technique is going to be da bomb. :)

Haha. But seriously, this is what the "hydrogen economy" needs. You could even grind the powder fine enough to be a slough, and 'pump' that into your vehicle's fuel tank.

When George Bush first proposed hydrogen as the solution to our fossil-fuel habit, everyone mocked him for failing to understand that hydrogen is just a storage medium, rather than an energy source. I suspect he knew that all along... but since most Americans don't know it, he persuaded them to (at least in principle) buy in to the idea.

Once there is enough interest in hydrogen, the "hydrogen economy" will indeed take off (e.g. today's breakthrough), and at that time we will be groping for a way to produce hydrogen in bulk. The optimal way to produce bulk hydrogen is of course a nuclear reactor. And so by this (alas necessarily) indirect route will Americans come to accept ubiquitous nuclear power. And that is exactly what Bush wanted (or at least should have wanted) all along.

Weight isn't the problem, it's volume

[Ryan C.]

But yes, even 9% is better than curent gas storage, which is much less than 5% hydrogen by weight. The DOE target for 2010 is 6%. And even then you'd be about five times the volume using compressed gas for a given amout of hydrogen.

It's not actually solid hydrogen, it's chemical.

[Sockatume]

Unsurprisingly it's not the formation of solid dihydrogen as you might expect from the amazingly poorly written press release. Like almost everyone else they're working on chemical hydrogen storage, whereby hydrogen-rich compounds are used to store and release hydrogen gas. The remainder are working on physical dihydrogen storage (carbon nanotubes etc).

I present you: The Wheel (TM)

[Lars T.]

Powder metal hydride hydrogen generator

Abstract A system for generating hydrogen gas for use in a fuel cell includes a powder metal hydride source, a water source, a mixing device and a catalytic hydrogen generating chamber. A method of generating hydrogen for use in a fuel cell includes the steps of: providing a source of dry metal hydride fuel; providing a source of steam; providing a mixing/reaction chamber connected to the source of dry metal hydride fuel and to the source of steam; operating the mixing/reaction chamber to transport the dry metal hydride fuel from its source to a byproduct receptacle and feeding steam into the mixing/reaction chamber such that the steam reacts with the dry metal hydride fuel to produce hydrogen gas and a dry metal powder byproduct; removing the dry metal powder byproduct from the mixing/reaction chamber; and extracting the hydrogen gas from the mixing/reaction chamber.

Filed: August 28, 2003; Granted: February 20, 2007

Oh well, it's something else completely, I guess.

If you'd settle for 2% then check this one

[ahfoo]

Home power has a cool PDF that describes how to create your own metal hydride based system. What's cool about their plans is they use bulk materials direct from the manufacturers and then show you how to prime your own system in a home lab if you're so inclined. I'd love to try it.

  Seems I read there was a similar system that is used in one version of the hydrogen powered car prototypes and they say they can get a hundred miles per tank on tanks about the size of a scuba tank.

Re:I want more. (How about a H2 hybrid car)

[ArmchairAstronomer]

Nothing that new here.

Energy Conversion Devices has two stock Prius vehicles modified to run on Hydrogen instead of gasoline tooling around Detroit and LA. The hydorgen is stored as a Nickel Hydride (solid). Right now they can travel about 200 miles on a "tank" of hydrogen.

More info on the web site. http://www.ovonic-hydrogen.com/home/home.htm

It's also been on CNBC.
http://release.theplatform.com/content.select?pid= XOfv_P9SrRHQUdfpqH_nadnlA-YvYzDd&Token=-Q0QvZVYzaU gzNXFHUWxSeG5NMzByN0cx-TEY0SXF4R1NpSmNzVUE5R0xVL3I zOXRI-VFR6UWR2eUdlYjE1UTMxMQ==

And the Car Connection. http://www.thecarconnection.com/Auto_News/Green_Ca r_News/TCC_Drives_A_Hydrogen_Prius.S196.A11951.htm l

I'll bite.

[horos2c]

Ok, lets just assume that this is a real breakthrough, and that we can safely and cheaply:

        * manufacture said compound (AlH3)
        * store said compound
        * use said compound with high efficiency in fuel vehicles

After all, its volumetric density is fair (I calculate it at .15 kg/L hydrogen * 120 MJ/kg or 5 kwh / liter versus 9.7 kwh /liter for gasoline) and with the extra efficiency boost it IS energy competitive.

My question is - where are we going to get the aluminum? This would require a MASSIVE production spike in aluminum - to provide a replacement for the ~ 400 million metric tons of gasoline that the US alone uses.

(source: http://www.energy.ca.gov/gasoline/statistics/gasol ine_consumption_country.php
)

Right now, the amount of aluminum we produce globally per year is about 20 times lower - 23.8 million metric tons yearly to be exact (source: http://www.world-aluminum.org/stats/formServer.asp ?form=1) and aluminum production is very energy intensive (I calculate it as being 6 times *higher* - at 30 kilowatt hours /liter - than the hydrogen is meant to store. That becomes 90 kilowatt hours / liter considering that most of the energy used in aluminum production is electric)

So the only realistic way of doing this would be to recycle the aluminum and 'rehydrate it'. And there would be a hefty price premium on the creation of the fuel ($12 / gallon at current aluminum prices, which would probably go up dramatically if this took off)

Overall then this is a mixed bag. The infrastructure costs would be substantial in creating the distribution network for the fuel, both for hydrating and recycling the fuel containers, and the energy cost would be horrific in making the aluminum.

At 30 kilowatt hours / liter, and 700 grams CO2/ kilowatt hour (if the energy making the aluminum was coal), this corresponds to 19000 grams C02 / liter of fuel, versus the 2000 grams CO2 / kilowatt hour that you get by simply burning the gasoline to go! The aluminum had better be VERY recyclable.

I'm skeptical. It'd be cool if it works, but we'll see.

Ed