Why isn't hydrogen fuel more optimistic?

[Singular Intellect]

First off, I'll admit to not being excessively versed or knowledgeable on this subject.

But I do have a few questions and comments:

Hydrogen, in my limited estimation, seems like the most abundant and useful replacement fuel for oil. From what I've read here and there, it seems we do have the technology and capability to start making hydrogen our core fuel dependency for our society, and that technology is getting better all the time.

So why aren't we?

I understand we have a massive infrastructure that's built upon oil systems and it'll take time to change over.

But why isn't hydrogen being more hyped up as the alternative fuel source? We have so much of it available we probably couldn't use it all up even if we actually tried to.

If we dedicated other renewable energy sources like geothermal plants, wind power, ocean wave power, solar power, dams and other examples to producing hydrogen fuel, surely we could establish a self sustaining hyrogen fuel economy and society that would last an incredibly long time with virtually no worries about quanitity available?

Or am I missing some key element or thinking here?

EDIT: Moved~GR

[Singular Intellect]

Son of a...!

I meant to put this in SLAM, so if it's better suited there I'd be much obliged if the moderator fired away.

[aerius]

We have almost endless hydrogen, the problem is it isn't free hydrogen, it's bound up with other elements, and except for hydrocarbons we can't separate it out and make it useful without using up a ton of energy.

See this thread. To convert all our cars to hydrogen for example, we'd actually have to double our energy consumption, it would take about 450 nuclear generating stations to provide the energy for making the hydrogen needed to do the same amount of work as our current gasoline engines.

[Sea Skimmer]

It’s pretty simple, hydrogen is not a net energy source as oil is, it is simply a way to readily transport energy which must come from other sources. Hydrogen is useful because we can make it from any source of electricity, but it does not solve any other part of the energy economy equation. Hydrogen also has some major practical limitations, since right now the only decent way to transport it is in 3000-5000psi storage tanks.

Until we have those sources of renewable and alternative fuel (nuclear for example isn’t renewable but it gives us a damn long time to think up other ideas) it doesn’t make sense to make a vast investment in today’s still immature hydrogen technology (a liquid/solid storage system for example may be available in a few years). It really would be a blunder to go all out for hydrogen right now, and that’s also true of a lot of other alternative energy technology. The world simply hasn’t cared for long enough yet to fully develop them.

The estimated cost of establishing a hydrogen distribution infrastructure for cars and trucks BTW, is about 300 billion dollars. This however does not include the costs of building the hydrogen production facilities or investing in energy sources to power them. The true cost of establishing a US hydrogen economy is easily several trillion dollars. That’s of course still well within reason for a nation with a GDP of 13 trillion, and a federal budget of about 2.6 trillion, when spread over a decade or so. Course, everything hinges on long term political planning, and we’ve already seen the shit that comes out of trying to pass even a mere 20 billion dollar energy bill.

[kinnison]

Hydrogen might be viable for transmitting energy without spending much money, simply because the infrastructure is already there (gas pipelines).

It might need some money spending because hydrogen leaks more easily than any other gas, so this change wouldn't be free. It would also require changes to gas-burning equipment, because the ideal volumetric ratio for burning is very different from that for natural gas. In addition, something would probably have to be done in the way of additives. Why? Simple - a hydrogen flame is virtually invisible and therefore accidents could happen.

That's the bad stuff. Advantages; hydrogen is not going to kill people the way gas does every year, by incomplete burning causing generation of carbon monoxide. And of course burning hydrogen creates no CO2.

But as it isn't a fuel, you have to get the energy to make it from somewhere!

As for hydrogen as an automotive fuel - forget it. IMHO it would be much better to develop a liquid fuel, possibly methanol, as an energy storage medium for transport. Methanol, and probably other fuels as well, can be created by processes that absorb energy; so again you have to find a source of the energy required.

Methanol fuel cells are in fact very close to being practical - as far as I know low-power units, for such uses as running laptops and mobile phones, are already in production in small numbers. The advantage of fuel cells is much greater efficiency - thermodynamic considerations (theoretical limits on heat engines for example) aren't as important. Also, if you have an electric vehicle then you can include a storage battery and by doing this use regenerative braking, which saves even more energy especially in city traffic.

In such a case, hydrogen would probably be generated in large quantities as a process gas, and used on site - which already happens, on a very large scale, in the bulk chemicals industry.

Finally, a blue-sky thought; hydrogen may be a viable fuel, in very small quantities indeed and even if it's combined with something else - probably in combination with boron-11, as a fusion fuel. Dr. Bussard's experiments on electrostatic-confinement fusion look like being successful, and the advantage of this would be much smaller generating units. Perhaps not for cars - but probably for very heavy trucks, locomotives, ships and aircraft. And no radiation either - the proton/boron-11 reaction produces no neutrons.

[Zixinus]

Here's my take:

First off, hydrogen is called "boom-gas" in my language. Here's why:
The reason hydrogen is cool in regards of energy, is that with oxygen, it creates one of the most powerful chemical reactions known. For the same reason, it is also high-energy chemistry, which in common language is, explosive.

Now riding a container of boom-gas under your butt is not that favourable. Gasoline isn't that safe either, but hydrogen is VERY reactive and it reacts very suddenly. Hence the name boom-gas. For this reason containment in tricky and non-trivial.

Second, hydrogen is a gas at room temperature, while gasoline is liquid. Hydrogen has the most potential energy with oxygen per kilogram, but not per cubic meter (I think). Meaning that you can store more gasoline in a one liter tank then hydrogen.
This means hydrogen is far less dense.

Add to the fact that the hydrogen atom is the smallest atom there is (well, in a practical case, molecule), meaning that it can leak trough the smallest cracks and leaks.

Third, you can take oil and the energy required for getting oil is fairly small as it occurs naturally. Hydrogen, unless you live on a gas giant or a sun, doesn't. It's bound by various molecules, water being the most common case on Earth. This is a strong bound that you need to invest significant amount of energy to brake and get the hydrogen.

Then you have it, you have to contain it and finally use it. Fuel cell technology, another little gizmo from NASA (or I think it's from NASA, I've never confirmed), does that.

As you can see, hydrogen doesn't produce energy. In fact, it losses energy if you do electrolysis, as the gained oxygen is already free to get.

For this reason, hydrogen is an ENERGY STORAGE, not energy PRODUCER. It's essentially a battery. Switching to it would massively increase our electric consumption as a whole, even with the high-performance electric cars have.

Switching to hydrogen to get away from oil is not impossible despite all of this. The technology to do it however, is just not ready for practical and economical usage.

Fun: We already make hydrogen rockets: I recall that the third stage of the Saturn-5 is hydrogen-oxygen rocket, the space shuttle second stage is also a hydrogen-oxygen rocket. But these rockets store hydrogen by CRYOGENIC means. That means that they cool hydrogen down until it's liquid, allowing easy control and good storage density-wise. The temperature that low is enough to make AIR LIQUID.

So, yeah the the technology is just not ready yet.

[Zixinus]

(sorry for double-post but there was a post while I was writing my own)

Finally, a blue-sky thought; hydrogen may be a viable fuel, in very small quantities indeed and even if it's combined with something else - probably in combination with boron-11, as a fusion fuel. Dr. Bussard's experiments on electrostatic-confinement fusion look like being successful, and the advantage of this would be much smaller generating units. Perhaps not for cars - but probably for very heavy trucks, locomotives, ships and aircraft. And no radiation either - the proton/boron-11 reaction produces no neutrons.

Making a Polywell (Bussard fusor) mobile is not easy and current concepts basically disallow anything smaller then a cruiser or 747 as a mobile unit. You will not only need the reactor: you will also need all the equipment it requires, and you will need shielding. Side reactions of p-b11 does produce radiation: gamma radiation. I'm not sure, but neutron production is also possible (I'm not secure about p-b11 side reactions, would a nuclear physicist help me out here?).

A Polywell machine will require liquid nitrogen cooling, vacuum pumps and a strong vacuum structure as well as a series of other things to get it working. You would need four trucks, not one. And those trucks better be big.

POPS system and the like may improve this, but mobile Polywells is really the futurure's song. Heck, p-b11 Polywells are a the future's song. Most advocates are confident that it would work just fine and easy, but I'm sceptical of this so-called ease.

[aerius]

Hydrogen might be viable for transmitting energy without spending much money, simply because the infrastructure is already there (gas pipelines).

Bzzzt! No. There's a wonderful thing known as hydrogen embrittlement, run hydrogen through existing natural gas pipelines and they'll all crack and fail in short order. You'll have to build an entire new pipeline system.

It might need some money spending because hydrogen leaks more easily than any other gas, so this change wouldn't be free. It would also require changes to gas-burning equipment, because the ideal volumetric ratio for burning is very different from that for natural gas. In addition, something would probably have to be done in the way of additives. Why? Simple - a hydrogen flame is virtually invisible and therefore accidents could happen.

You have no idea what you're talking about do you? Hydrogen burns at a much higher temperature than natural gas, existing equipment can't be used, burners, boilers, feed systems, everything will have to be swapped out. It's not a matter of switching a couple parts, you'll have to replace the entire system.

As for hydrogen as an automotive fuel - forget it. IMHO it would be much better to develop a liquid fuel, possibly methanol, as an energy storage medium for transport. Methanol, and probably other fuels as well, can be created by processes that absorb energy; so again you have to find a source of the energy required.

So where are all these fuels coming from again?

Methanol fuel cells are in fact very close to being practical - as far as I know low-power units, for such uses as running laptops and mobile phones, are already in production in small numbers. The advantage of fuel cells is much greater efficiency - thermodynamic considerations (theoretical limits on heat engines for example) aren't as important. Also, if you have an electric vehicle then you can include a storage battery and by doing this use regenerative braking, which saves even more energy especially in city traffic.

Here's a hint dumbass, other than BMW, we don't burn hydrogen in cars, we use it fuel cells which generate electricity to run the car. Also, hydrogen fuel cells are a lot more efficient than methanol ones, in fact current methanol fuel cells are only as efficient as a conventional internal combustion engine at best. The maximum projected efficiency is around 40%, which can be matched by a good diesel engine.

[kinnison]

Zixinus:

Sure, the reaction produces gamma rays - but gammas can be shielded against and, most important, don't make the reactor radioactive. I confess that I don't know the proportion of the reaction energy that goes into the 3 alpha particles also produced (although doubtless I could find out) - but whatever that proportion is, it's a heck of a lot easier to make use of it than the energy in high energy neutrons, because alpha particles are charged. For the side-reaction neutrons, maybe use a paraffin wax blanket?

As for the size of the machinery - well, computers were once the size of a house, and 10-horsepower steam engines often weighed several tons. Everything always gets smaller.

aerius:

You get the energy from anywhere that it will come from; SPS, tidal, ocean thermal and geothermal come to mind. As for methanol fuel cells being less efficient; well maybe - I don't claim to be an expert. But I'd rather have a tank of methanol attached to my car than a tank of highly compressed and highly explosive gas or cryogenic liquid. In addition, AFAIK methanol is easier to purify and the cells are more difficult to poison. If you're really desperate and you're right about methanol fuel cell efficiency, use a Stirling engine perhaps, or even an IC engine. After all, if you haven't made any greenhouse gas creating the energy to make the methanol, who cares? Direct energy input into the planet's energy cycles isn't a problem - yet.

Fuel equipment replacement? Hmmm... didn't most of the world do just that when we changed over from coal gas?

[Starglider]

As for the size of the machinery - well, computers were once the size of a house, and 10-horsepower steam engines often weighed several tons. Everything always gets smaller.

This is a broken analogy. Computers got smaller firstly because a brand new physical property was discovered, and secondly because it took time to develop the tooling capable of mass producing very small structures in sillicon (a process which is still ongoing). Steam engines got smaller largely due to materials enhancements (being able to take higher temperatures and pressures), specifically new alloys becoming available, with some improvement due to a better understanding of heat engine physics.

Fusion reactor size is constrained by hard and fairly well understood physical limits. For better confinement you need stronger magnetic fields and that's limited by the saturation current/field density of the superconductors used. We might eventually be able to improve it with advanced nanostructured materials that allow us to create stronger fields, but unlike computing or steam engines. We'd need a radically novel concept to make minature fusion reactors possible, probably some sort of cold fusion or direct-impact minature accelerators that reliably avoid side reactions. In other words it's not beyond the realms of possibility but there's no strong reason to believe that minature fusion reactors are possilble.

[Starglider]

We might eventually be able to improve it with advanced nanostructured materials that allow us to create stronger fields, but unlike computing or steam engines.

Gah, edited in preview and accidentally chopped some stuff out. 'Unlike computing or steam engines, the physics does not scale down to arbitrarily small limits, nor is there any strong reason to believe that such designs are possible'.

[kinnison]

Starglider, I don't claim to be an expert - but it looks as if even first-generation IEC fusion reactors will be much smaller than any magnetic-confinement ones. Maybe an IEC reactor will be the size of a large room; power tokamaks will likely be the size of a ten-story building - if they ever work at all.

Even room-sized equipment would bring in applications impossible for a tokamak - such as powering locomotives, ships and perhaps individual office buildings. I imagine that the Woolworth Building could accommodate a 30-foot cube?

As for how small the things can be made - well, we'll have to wait and see, but I find it hard to imagine that it's impossible to make them any smaller at all. Your comment about magnetic field density is true but irrelevant - IEC fusion doesn't use magnets at all IIRC.

And finally - with a not-very-difficult design change, the designer of the prospective fusion reactor says, on his own website, that it shouldn't be too hard to turn an IEC fusor into a reaction engine. In other words, a fusion rocket - which gives us the Solar System.

Dr Bussard wants $200 million for research - about 8 hours of Mr. Bush's adventure in the desert. I think that sort of money is worth gambling, given the potential rewards.

[Zixinus]

Sure, the reaction produces gamma rays - but gammas can be shielded against and, most important, don't make the reactor radioactive.

True, but there will be enough gamma rays for a Polywell that has self-sustaining size will be significant enough that you don't want to go near it.

For the side-reaction neutrons, maybe use a paraffin wax blanket?

Boron blanket actually. Boron is the best neutron-killer material there is.

As for the size of the machinery - well, computers were once the size of a house, and 10-horsepower steam engines often weighed several tons. Everything always gets smaller.

Not Polywell reactors, at least not in the foreseeable future. And you don't get the point: a power-generating Polywell isn't just the reactor; it is also a series of other machinery that must be also cared for and portable. Future Polywells will use superconductors, that means cryogenic equipment must be used. First generation Polywell machines will used liquid nitrogen-cooled copper.
Might fit on a rocket, a big enough sea vessel and perhaps a 747. Not on a truck though, or anything of similar size. And personally, I don't want a Polywell-powered cars zooming on the streets.

As for how small the things can be made - well, we'll have to wait and see, but I find it hard to imagine that it's impossible to make them any smaller at all. Your comment about magnetic field density is true but irrelevant - IEC fusion doesn't use magnets at all IIRC.

IEC doesn't in general, but Polywell does: the electrons are confined by magnetic fields.


Regardless, the size of a Polywell machine IS set in stone, stone of physics specifically. There are losses in the Polywell machine that can only be overcome by making it bigger. Make it too small and the machine will choke on losses.
Not to mention engineering problems like shielding, cooling, structure, etc.


Here are some papers regarding fusion-powered rocket engines done by EMC2:

http://tinyurl.com/273g2s
http://tinyurl.com/2huubw
http://tinyurl.com/yup9m3

[Zixinus]

That said, kinnison has a point: any Polywell device is going to be smaller then anything the MagConf crowd has to throw at it. I recall that the vacuum chamber of a a Polywell reactor isn't going to be much bigger then a fission reactor.

[Sea Skimmer]

Stuff defiantly doesn’t always get smaller, sure we gained the ability to make smaller steam engines for example, but the main use of the technology was to build ever bigger ones putting out even more power. Just look at a 1900 steam locomotive, and then look at one from 1940, the 1900 model will practically fit inside the boiler of the latter one. The main improvement in wind turbine technology to make another example, has been to build way bigger turbines. The newest 5 megawatt models dwarf the Statue of Liberty, while 100 years ago a windmill that was five stories tall would have been big.

The size of the reactor is only part of the size of a fusion plant anyway, same story for fission plants. A nuclear reactor pressure vessel might only be about 40x40ft installed at a plant covering several acres.