Hydrogen and the Honda "Clarity"

[Ted C]

This is what I don't understand about hydrogen cars. It may seem like a basic and stupid question, but I am wondering about future aggregate effects.

First off, while it may seem strange to ask, where does hydrogen come from? I know it is one of, if not the, most basic elements but I'm wondering where/how does it get made for fuel in cars?

It would most likely be separated from water via hydrolysis, using electrical power. A hydrogen fuel cell is basically a glorified battery, using a chemical process to generate electricity from the reaction of hydrogen and oxygen.

Of course, if your electrical power source is a coal-burning power plant, your hydrogen fuel cell becomes even more polluting than a gas engine.

The emissions are water-- doesn't that mean that water molecules are bonded with hydrogen, and then released? So we have to use more water to create fuel, right? Now technically, the Earth doesn't "lose" water, there's not really a water "shortage" but there are problems with distribution. Water is in various pools (oceans, rivers, etc), in vapor, in animals' bodies, but it seems there's never enough where we need it to counter droughts. Agriculture soaks up a lot of the stuff. Now we're going to put it in our cars on the same scale we use gasoline?

Isn't that going to be troublesome?

Probably not. If water for the system can be made from sea water, then it's not a drain on the supply of fresh water needed for human consumption and agriculture. In any case, there shouldn't be a huge percentage of the water supply tied up in fuel cells at any given time. They'll be constantly releasing water back into the environment.

[Stile]

Of course until we get more electrolysis plants up, the primary means of getting hydrogen will be from Natural Gas. Which means that we are still using Fossil Fuels anyway.

[CmdrWilkens]

Hydrogen-powered engines DO require oxygen. Combining oxygen with the hydrogen is what makes the magic happen.

Clarifying a little bit fuel cells in space applications tend to carry liquid oxygen to combine with the hydrogen. So you don't need an atmosphere but you do need a source of oxygen.

Hydrogen is a boondoggle. Go electric. I always find it funny how people talk about hydrogen efficiency and cleanliness when they're turning water via electricity into hydrogen then back into water for electricity, rather than use electricity to... fill a power cell.

I don't know what the numebrs look like but it probably comes down to energy density. Until we can build a battery that does this better than hydrogen then the choice is obvious.

[Questor]

I have few related questions:

Is the electrolysis performed at the fueling station on an as needed basis or does the station have to store liquid hydrogen?

Do the cars?

If so, how will we ramp up production, as fueling station owners would lose money for every day the hydrogen is not sold?

[aerius]

Hydrogen is a boondoggle. Go electric. I always find it funny how people talk about hydrogen efficiency and cleanliness when they're turning water via electricity into hydrogen then back into water for electricity, rather than use electricity to... fill a power cell.

I don't know what the numebrs look like but it probably comes down to energy density. Until we can build a battery that does this better than hydrogen then the choice is obvious.

I did a back of the envelope calculation in this thread, going to hydrogen would take over 6 times as much energy as using electricity to charge batteries.

[Darth Wong]

Hydrogen is a boondoggle. Go electric. I always find it funny how people talk about hydrogen efficiency and cleanliness when they're turning water via electricity into hydrogen then back into water for electricity, rather than use electricity to... fill a power cell.

I don't know what the numebrs look like but it probably comes down to energy density. Until we can build a battery that does this better than hydrogen then the choice is obvious.

I did a back of the envelope calculation in this thread, going to hydrogen would take over 6 times as much energy as using electricity to charge batteries.

I don't see the relevant calculation. All I see is a reference to a Car and Driver article. The biggest problem with hydrogen is the impracticality of transporting it. However, it could work for certain types of installations, such as farmers who have an on-site windmill and who locally charge hydrogen tanks and fuel cells for their on-site vehicles. Some installations along those lines are already running.

[FireNexus]

Couldn't existing natural gas infrastructure be used for hydrogen, once we have the nukes up to make it (off-peak, of course)?

[Ted C]

I have few related questions:

Is the electrolysis performed at the fueling station on an as needed basis or does the station have to store liquid hydrogen?

I believe that a Discovery Channel show on future cars said that there's an experiment underway in Scandinavia (either Norway or Sweden, I'm not sure which) with fuel stations that use solar power to make hydrogen on site. Using solar power is probably not very scalable, but the idea of making the hydrogen at the point of sale seems feasible.

Do the cars?

No. The cells have to be filled with hydrogen at a fueling station. The car would need another source of power to create fuel. You may be thinking of the "HHO" systems that use power from a car's alternator to create hydrogen and oxygen from water, and then feed them into the fuel system of a gasoline engine to improve fuel efficiency. I still don't have any reliable reports on how well those work.

If so, how will we ramp up production, as fueling station owners would lose money for every day the hydrogen is not sold?

Fuel stations that provide hydrogen will naturally increase in number as the number of hydrogen fuel cell vehicles increases. A minimum number of fuel stations will be needed to provide the basic infrastructure for the introduction of the cars, though, and those might need to be supported by some kind of subsidy until the demand grows enough to make them self-supporting.

[CaptainChewbacca]

Couldn't existing natural gas infrastructure be used for hydrogen, once we have the nukes up to make it (off-peak, of course)?

It would require about as much money to modify gas infrastructure for hydrogen as it would to just build a new hydrogen infrastructure.

[Mange]

I have few related questions:

Is the electrolysis performed at the fueling station on an as needed basis or does the station have to store liquid hydrogen?

I believe that a Discovery Channel show on future cars said that there's an experiment underway in Scandinavia (either Norway or Sweden, I'm not sure which) with fuel stations that use solar power to make hydrogen on site. Using solar power is probably not very scalable, but the idea of making the hydrogen at the point of sale seems feasible.

Are you quite sure? It's definitely not Sweden, but another Nordic country, Iceland, is known as the "hydrogen economy" and the hydrogen is produced through electrolysis (and Iceland has the cleanest energy production there is).

[Ted C]

Are you quite sure? It's definitely not Sweden, but another Nordic country, Iceland, is known as the "hydrogen economy" and the hydrogen is produced through electrolysis (and Iceland has the cleanest energy production there is).

I wasn't exactly taking notes, but I don't think it was Iceland. If you're sure it's not Sweden, it could have been Norway or Finland.

It was in FutureCar: The Fuel, as best I can recall.

[Hawkwings]

I'm pretty sure it was Iceland. They were talking about how Reykjavik is heated by geothermal, and how they use that power to make hydrogen from water.

[Surlethe]

One objection I've heard to hydrogen as a power source is that it's not practical in an internal combustion engine: the hydrogen+oxygen to water reaction decreases the number of particles present, so the temperature of the mix has to increase much more than in a gasoline reaction, which (by breaking apart the carbon chains) creates more molecules, automatically creating pressure to push the piston.

[Mange]

Are you quite sure? It's definitely not Sweden, but another Nordic country, Iceland, is known as the "hydrogen economy" and the hydrogen is produced through electrolysis (and Iceland has the cleanest energy production there is).

I wasn't exactly taking notes, but I don't think it was Iceland. If you're sure it's not Sweden, it could have been Norway or Finland.

It was in FutureCar: The Fuel, as best I can recall.

Yes, I'm sure it's not Sweden. There's only one hydrogen fueling station here which opened in 2003 and Norway has two fueling stations (the electrolysis is water-powered). There's also an experimental facility in Denmark where the electrolysis is wind-powered (but that's not a fueling station). With the case of Iceland, the goal is that the entire transport system will be based on hydrogen in 2050.

[The Big I]

One objection I've heard to hydrogen as a power source is that it's not practical in an internal combustion engine: the hydrogen+oxygen to water reaction decreases the number of particles present, so the temperature of the mix has to increase much more than in a gasoline reaction, which (by breaking apart the carbon chains) creates more molecules, automatically creating pressure to push the piston.

But the what wil the next couple of generation hydrogen vehicle be like if they become popular and mass produced???

[Lancer]

One objection I've heard to hydrogen as a power source is that it's not practical in an internal combustion engine: the hydrogen+oxygen to water reaction decreases the number of particles present, so the temperature of the mix has to increase much more than in a gasoline reaction, which (by breaking apart the carbon chains) creates more molecules, automatically creating pressure to push the piston.

But the what wil the next couple of generation hydrogen vehicle be like if they become popular and mass produced???

Who said that hydrogen fuel had to power an ICE? Pretty much every mention of hydrogen fuel that I've heard recently has been in the context of fuel cells powering electric motors.

[Admiral Valdemar]

We already use hydrogen from natural gas, it's the only real source we have for industrial scale today anyway.

Hydrogen as a fuel source for cars is problematic. Firstly, fuel-cell stacks are hideously expensive, requiring platinum which with present designs, couldn't accommodate everyone and their car today. Also, the biggest deposits exist in South Africa, that bastion of stability.

Next, there is the infrastructure, which simply cannot carry H2. At all. That is easily trillions globally for everything from underground tanks at forecourts to national distribution lines.

When that's sorted, you still have to find a way of storing H2 without it being an explosion risk or seeping out somewhere. Tanks don't work, the gas will escape even if cryogenic and leave you with half a tank after a week and a more brittle one at that thanks to the passing through. You've got the potential of those nano-storage units and metal hydrides etc., though they are far from commercially possible.

It would just be simpler to work on better batteries or capacitors/flywheels than to switch to something which is half-assed and not even fully backed by Big Auto any more.

[Singular Intellect]

It would just be simpler to work on better batteries or capacitors/flywheels than to switch to something which is half-assed and not even fully backed by Big Auto any more.

Can we have realistic expectations of battery powered vehicles being competitive or even surpassing their gas powered counterparts?

Every time I hear electric vehicle, I think of battery powered toy cars that have juice for awhile, but then die rather quickly with pitiful performance for the last half of the battery life.

[Admiral Valdemar]

Can we have realistic expectations of battery powered vehicles being competitive or even surpassing their gas powered counterparts?

Every time I hear electric vehicle, I think of battery powered toy cars that have juice for awhile, but then die rather quickly with pitiful performance for the last half of the battery life.

We've had ones that could replace 90% of Europe's commuter vehicles today with ease. The only major issues are batteries being nasty to make and also requiring replacing every few years. Many of these problems are down to economies of scale, though technical issues could be dealt with using different approaches e.g. the aforementioned supercapacitors and superflywheels that overcome the hurdles of traditional chemical power cells.

For HGVs, we can use bio-fuels or fossil energy still, or until they find better electrical systems to power them. I'm quite fond of the ammonia fuel-cell, actually. Forget hydrogen or methanol. This technology was proven in the '60s and fuel-cells have been around well over a century, which shows you just how powerful Big Oil lobbying can be.

[CmdrWilkens]

Hydrogen is a boondoggle. Go electric. I always find it funny how people talk about hydrogen efficiency and cleanliness when they're turning water via electricity into hydrogen then back into water for electricity, rather than use electricity to... fill a power cell.

I don't know what the numebrs look like but it probably comes down to energy density. Until we can build a battery that does this better than hydrogen then the choice is obvious.

I did a back of the envelope calculation in this thread, going to hydrogen would take over 6 times as much energy as using electricity to charge batteries.

Okay that's not really the point I'm making. My point is that while just putting the electricity directly into the car is more efficient in terms of total energy expended it creates a lot of problems in terms of energy availability. Hydrogen is much better in terms of storing energy by weight AND by volume than a battery which makes it a better choice for a power source over traditional batteries even leaving aside the materials used and their relative environmental effects.

Here is a bit of google-fu that yields somewhere in the neighborhood of 530 Wh/l for hydrogen and around 300 Wh/l for NiMH batteries Now I will note this is a REALLY back of the envelope.

When you design the car you are basically replacing the gas tank...well that gas tank takes up a certain amount of space and has a certain amount of weight (which in turn affects all of your performance variables). A purely battery operated car charged from power lines is going to be the most efficient user of power BUT it won't be able to carry as much energy in abslute, by weight, and by volume terms when compared with hydrogen. Put this way if you have to design a car which needs to be able to travel 200miles before refueling how much hydrogen do you need versus how many batteries? Of those two solutions hydrogen occupies less space and takes less weight which within the constraints of designing a car for private use is hugely important.

[Lancer]

AV, ammonia fuel cells are still hydrogen fuel cells. The only difference is is how the hydrogen is stored (NH3 as opposed to LH2 or an alcohol) before being cracked into H2 and fed into the fuel cell.

[Admiral Valdemar]

AV, ammonia fuel cells are still hydrogen fuel cells. The only difference is is how the hydrogen is stored (NH3 as opposed to LH2 or an alcohol) before being cracked into H2 and fed into the fuel cell.

Which still produces electricity like a battery. I'm aware of their workings, the difference is the fuel which is by far the most important part of this. How the reaction goes is irrelevant because pure H2 requires far more be done to install and has many technical drawbacks to go with.

[Keevan_Colton]

I think some people need to be reminded of the problem with hydrogen and storage. Hydrogen by itself is small...the smallest atom going in fact...and also the one with the weakest repulsion from other atoms. Part of the problem is making materials that hydrogen wont just pass through....and then building an entire infrastructure out of them. Bonding it with a nitrogen atom into ammonia makes for a bigger molecule that behaves closer to natural gas etc in terms of what materials it can penetrate and what will contain it.

Basically the problem with hydrogen is what's referred to in the whiskey industry as "the Angel's share" the loss to the environment.

[Admiral Valdemar]

Which is precisely why I suggest ammonia instead. The sourcing and storing of this material is a piece of piss next to hydrogen, even if the end result is a fuel-cell utilising the same electro-chemistry.

[Sikon]

Any gasoline engine can theoretically be adapted to use hydrogen fuel and provide the various benefits offered by the gas in the type of vehicles we're already driving.

It's worth revisiting BMW's experiments with hydrogen as a fuel for internal combustion engines - a project that has been going on for many years now. The Bavarian automaker is so convinced of the viability of hydrogen that it's into its fifth generation test sedan using that fuel. In fact, BMW has made a serious commitment to the future of hydrogen as a vehicle fuel and is claiming that its small fleet of hydrogen-fuelled sedans are the first such vehicles in series production in the world.

I once rode from downtown Munich to the city's airport (a lengthy trip) in a fourth generation BMW 750hL and even "filled up" at a hydrogen service station located right on the airport property. It was an interesting experience, but a common enough routine at Munich airport where many of the vehicles used around the facility, including apron buses, are hydrogen-fuelled.

BMW has been operating 7-Series hydrogen-powered sedans on a daily basis in both Munich and Hanover. When running on hydrogen, the 750hL 12-cylinder engine develops 204 horsepower, tops 100 km/h in 9.6-seconds and is capable of a top speed of 226 km/h. The car's 140-litre cryogenic hydrogen tank gives the fully-equipped luxury car a range of 350 km. The cars are "dual fuel" units capable of being run on gasoline when needed. After all, you won't find a hydrogen filling station on every street corner just yet.



The latest BMW hydrogen car is the 745h, which uses a 4.4-litre V-8. The only major modifications to make the big BMW's engine run on hydrogen involve the intake ports, which have additional injector valves for hydrogen. The engines come off the same production line as other BMW powerplants and are installed in the vehicle using the same assembly techniques. BMW has also produced a concept Mini powered by hydrogen.

BMW says that its hydrogen vehicles are just as safe as gasoline-fuelled cars. The hydrogen is stored in a double-walled steel tank behind the rear seat back - resulting in some loss of trunk space. The fuel is "cryogenic," or in an ultra low-temperature condition of minus 253 deg C. Safety has been assured by numerous crash tests. BMW points out that even in a very severe nose-to-tail collision in which the colliding vehicle reaches the hydrogen tank, the double-walled tank would not leak. Even in the severest possible crash, which would probably involve little chance of occupant survival, the hydrogen cannot explode, according to BMW. [...]



At Munich airport's unique filling station, hydrogen is produced right on the premises in a facility comprising just a couple of small shipping container-sized buildings. The hydrogen is dispensed automatically using a robot arm which reaches out in response to inserting a credit card and probes for the filler location. It even lifts and replaces the "gas cap" flap.

The downside to all this is cost, though it should be borne in mind that if hydrogen was in wider use, the price per litre could drop dramatically. At the Munich airport filling station last time I checked, hydrogen costs close to 80-cents a litre and the energy density in the fuel by volume is a quarter that of gasoline [due to 11 times lesser density for LH2, although it gives 3 times the energy per unit mass]. You need four litres of hydrogen to travel the same distance you would in a gasoline-powered vehicle on one litre.

From here.