Is this hydrogen fuel technology possible?

[W3pcq]

When hydrogen combusts it is turned into h20. H20 can be broken down into hydrogen and oxygen. NASA has been using solar panels power hydrogen generators in space for this purpose.

Say you had a vehicle that carried a water tank, a hydrogen generator a solar panel a battery and a hydrogen powered engine. You could use the solar panel to run the H. Gen. Then you could have the o2 flow into the car to breath easier.

Here is the question though. Could you run the exhaust through an air cooler and back into the water tank and reuse the hydrogen over and over again. It seems that this would work.

 

[W3pcq]

Actually a power plant may be a more useful purpose if possible because they aren't burdened by power to weight ratios.

 

[russ_watters]

Well, in that power plant, all the power would come from the solar panels, so if the sun's out it is more efficient just to use the solar panels to directly power the car. And, of course, solar panels do not generate enough power to directly power a regular car.

 

[TVP45]

Your chemistry is a little off. You would want to recombine all the hydrogen with all the oxygen. There would then be only water vapor in the exhaust.

 

[W3pcq]

Is it not possible to use some of the energy from burning the hydrogen to run the hydrogen gen while the sun is out?

Still I get your point.

 

[mgb_phys]

Actually you might decide to vent the oxygen to save the weight of the oxygen collecting equipement and storage tank - assuming you had a fuel cell whohc could use atmospheric air as the oxygen source.
You could use burning hydrogen to run the hydrogen gen. but then you couldn't use it to power the car.

It's best to think of the hydrogren fuel cell as simply a rechargeable battery.

 

[Mech_Engineer]

Is it not possible to use some of the energy from burning the hydrogen to run the hydrogen gen while the sun is out?

Still I get your point.

Now you're trying to invent an impossible machine. You can't get more energy out of burning oxygen and hydrogen than you put in separating them in the first place.

A classic perpetual machine that many people have tried to invent is one that burns hydrogen and oxygen in an internal combustion engine, and uses the power from the machine to separate water into oxygen and hydrogen. Such a device obviously defies the laws of thermodynamics...

 

[russ_watters]

Is it not possible to use some of the energy from burning the hydrogen to run the hydrogen gen while the sun is out?

Put another way, if you use some of the energy from the engine to run the hydrogen generator, some of the energy from the solar panel to move the car, and some of the energy from the solar panel to run the hydrogen generator, the net result is the same as if you left the water in the tank and used the solar panel to move the car...assuming everything was perfectly efficient.

 

[Mech_Engineer]

This post kind of reminds me of the post about Mitubishi's "MAGIC" engine that I wasn't very nice to...

https://www.physicsforums.com/showthread.php?t=182130

 

[W3pcq]

Ok. Well then how about this idea. You use hydrogen to heat your house. You keep the o2 for the hell of it and drop the extra cash. You use the solar panels to convert water to hydrogen and o2. When it is dark they shut off. Your furnace exhaust recycles the water.

 

[W3pcq]

I guess the solar panels are providing most the power, but at least you don't need batteries which are the most costly because they need to be replaced over time.

 

[W3pcq]

I guess in space it would work better because there is a constant source of high energy radiation.

 

[makethings]

Hydrogen as an energy carrier would never be a replacement for gasoline in a car for several reasons.

1) There is no abundant source of pure hydrogen on earth.
2) Making hydrogen from non-renewable sources (such as natural gas) only adds to the pollution compared to using those sources directly. As well as greater inefficiencies.
3) Our world power production from renewable sources like air and solar is miniscule compared to our reliance on coal and oil such that if we use all renewable energy to generate hydrogen through electrolosis, you will not even have anywhere close to the amount of hydrogen you need to sustain energy demand. Or not even enough hydrogen just to power all the hydrogen cars people will drive around the world.
4) If you can overcome the above problem, you still have the problem of creating pipelines to transport your hydrogen. Oil and gas pipelines are mostly made of steel and hydrogen just diffuses right through steel. There will be an enormous cost to create a new network to transport hydrogen.

 

[mgb_phys]

1) There is no abundant source of pure hydrogen on earth.

True hydrogen is a storage medium rather than a primary fuel. There is also no abundant source of pure gasoline, methane is about the only fuel you can use with little processing.

2) Making hydrogen from non-renewable sources (such as natural gas) only adds to the pollution compared to using those sources directly. As well as greater inefficiencies.

The same as electricity, it's just easier to store a kg of hydrogen than a kg of electricity.

3) Our world power production from renewable sources like air and solar is miniscule compared to our reliance on coal and oil such that if we use all renewable energy to generate hydrogen through electrolosis, you will not even have anywhere close to the amount of hydrogen you need to sustain energy demand. Or not even enough hydrogen just to power all the hydrogen cars people will drive around the world.

The internet is impossible, the availability of fibre optic links is miniscule compared to telegraph wires. If you replace all the telex transmissions with email there is not enough capacity.
If there is a market demand, and someone can money out of it, it will get built.

4) If you can overcome the above problem, you still have the problem of creating pipelines to transport your hydrogen. Oil and gas pipelines are mostly made of steel and hydrogen just diffuses right through steel. There will be an enormous cost to create a new network to transport hydrogen.

Oil and gas pipelines are mainly used to transport raw oil/gas from the production field to the nearest distribution terminal. Most transport is by sea tanker. Transporting hydrogen is about as simple as transporting LPG and rather safer.
Remember hydrogen is just a way of transporting electricity. a lot of the palces you can make renewable power (geothermal in iceland, solar in africa, hydro in n. Canada) have no local customers, make hydrogen and ship it to LA is a solution.
Even for some distant oil fields, like Alberta's oil sands, it might be cheaper to use the oil in-situ to generate hydrogen than to extract, transport and refine the oil into gasoline.

 

[makethings]

The internet is impossible, the availability of fibre optic links is miniscule compared to telegraph wires. If you replace all the telex transmissions with email there is not enough capacity.
If there is a market demand, and someone can money out of it, it will get built.


Oil and gas pipelines are mainly used to transport raw oil/gas from the production field to the nearest distribution terminal. Most transport is by sea tanker. Transporting hydrogen is about as simple as transporting LPG and rather safer.
Remember hydrogen is just a way of transporting electricity. a lot of the palces you can make renewable power (geothermal in iceland, solar in africa, hydro in n. Canada) have no local customers, make hydrogen and ship it to LA is a solution.
Even for some distant oil fields, like Alberta's oil sands, it might be cheaper to use the oil in-situ to generate hydrogen than to extract, transport and refine the oil into gasoline.

Let me give you an example as to why you cannot just change society to be dependent on hydrogen alone. There are simply limitations to what we can do.

Example taken from European Fuel Cell Forum
Frankfurt Airport (2004)
520 jet departures per day, 50 Jumbo Jets (Boeing 747)
130,000 kg of kerosene per Jumbo = 50 t of liquid hydrogen
For 50 Jumbo Jets per day:
(2,500 t LH2/day, 36,000 m3 LH2/day, need 22,500 m3 water/day)
Continuous output of eight 1-GW power plants needed
for electrolysis, liquefaction, transport, transfer of LH2!
At least 25 nuclear power plants plus the entire water consumption of
Frankfurt needed to serve all 520 jet aircrafts per day at Frankfurt Airport

Now if you don't want to go the renewable route, then by all means use reforming to get your H2. But in the end H2 will have to compete with its own energy source so it will always be expensive.

I live in Canada. And I know that the hydropower is mostly concentrated in Quebec and they do sell it but also sell locally. Solar only has 6GW of capacity but I recognize that is growing but Geothermal only constitutes 8GW of global power with little growth. And since we're talking about fuel here for vehicles, well if you want to drive 300million vehicles considering only the US alone well you would need 400GW of capacity. And that's why I am saying global power production of energy through renewables is miniscule. You would need to spend upwards up to a trillion dollars in investing into renewables like wind to get that kind of output. Sure, it is possible - but with current cost of technology, people are not interested. They would rather spend a trillion on a war instead.

You would have to show me how you could use existing infrastructure to transport hydrogen because I don't think it is simple. You have to redesign your storage tanks and even inner-city piping. Natural gas fuels my burner in my house to heat my home. So if I get a new burner to burn hydrogen, I don't think the gas company will be able to shove H2 through the pipes to reach my home. It won't work. How do you transport fuel from coast to coast, from north to south.. again pipelines won't work.

 

[mgb_phys]

You would have to show me how you could use existing infrastructure to transport hydrogen because I don't think it is simple. You have to redesign your storage tanks and even inner-city piping. Natural gas fuels my burner in my house to heat my home. So if I get a new burner to burn hydrogen, I don't think the gas company will be able to shove H2 through the pipes to reach my home. It won't work. How do you transport fuel from coast to coast, from north to south.. again pipelines won't work.

Methane is pretty unbeatable for heating/cooking in homes - which is why it is stupid to waste it burning it to generate electricity. The dash-for-gas was mainly because the way markets were deregulated it made commercial sense to build stations as quickly as possible.
Hydrogen isn't easy to transport, although in technology where there's a profit there's a way, it is easier to transport than batteries.
Quebec is lucky in that there is hydro relatively close to Montreal, the problem with most hydro is that people don't live in areas with high mountains, deep valleys, fast rivers and high rainfall. One of the most common uses of hydro is to run high energy processes like aluminium smelters so you are shipping 'power' in the form of aluminium.

Hydrogen will only compete in areas where the weight and power density of batteries is unacceptable, that is probably cars and planes. LPG is obviously much better than H2 as a primary fuel for these, but when these run out / get too expensive then H2 is currently beating batteries. Of course someone might make better cells / super capacitors.

The only real source of H2 as a primary fuel is things like abandoned coal mines, oil sands where you can reform in situ to save the cost of extraction.

I think we are both argueing the same thing - that the "replace oil with hydrogen industry" is complete snakeoil. ;-)

 

[W3pcq]

What you could do is you could make pipelines that ran seawater into areas where there are lots of wind or lots of sun and use it in conjunction with those systems to make local powerplants.

Another option would be to have each community have a station which extracted the hydrogen locally from seawater using solar panels. That way the storage and transportation issue would be solved.

The benefit is in the long term. How much water is there in the ocean. Plus burning hydrogen leaves us with no change in the atmosphere.

I know that h2 isn't ready to fill all our demands, however as oil supply's are used up we need to make some kind of huge change anyways. We are kind of planning ahead now by making fuel from plant sources. Why not start the use of h2 also and slowly work it into the system.

 

[chroot]

What you could do is you could make pipelines that ran seawater into areas where there are lots of wind or lots of sun and use it in conjunction with those systems to make local powerplants.

Why would you pipe water to the energy source, rather than wiring electricity to the water source? You're not making any sense. Piping water is enormously expensive.

Another option would be to have each community have a station which extracted the hydrogen locally from seawater using solar panels. That way the storage and transportation issue would be solved.

The main problem -- that solar energy is not an adequate solution for anything but a coffee grinder -- would not be solved.

The benefit is in the long term. How much water is there in the ocean. Plus burning hydrogen leaves us with no change in the atmosphere.

The amount of water in the ocean is irrelevant. A hydrogen infrastructure would not affect the net amount of water on the planet; at worst it would move a pretty insignificant amount of it around.

- Warren

 

[W3pcq]

My point was that moving electricity to the water source wouldn't solve the transportation issue. You still would need to transport the hydrogen all over the country.

Is it harder to pipe water than oil?

Solar panels could generate enough power to run the entire world if we built enough of them plus breakthroughs in using a wider range of the EM spectrum keep making them more powerful. My friend just hooked solar to his home and he has two panels about 2' by 4' he runs them into an inverter and the extra power charges batteries. Those two panels run his entire house including a coffee grinder.

My thoughts were that fresh water is important to cities for other reasons so we can't use that. We would need to use sea water to not interrupt the current water systems.

 

[russ_watters]

Solar panels could generate enough power to run the entire world if we built enough of them.

So could nuclear power - and at a fraction of the cost. That's the reason we're not using solar power. It's too expensive (not to mention unreliable).

 

[russ_watters]

My point was that moving electricity to the water source wouldn't solve the transportation issue. You still would need to transport the hydrogen all over the country.

Is it harder to pipe water than oil?

Since you use hydrogen as an energy carrier, not an energy source, I don't see the need to pipe it - or the water it comes from - anywhwere. Because of the difficulty in distributing the hydrogen, I think it would be best to generate it in your car or home. And why not use tapwater? We're only talking about one percent or so of your water usage - and that's only if you don't recover it (recovering it isn't just a conservation of water benefit, it is an energy efficiency benefit).

 

[chroot]

Is it harder to pipe water than oil?

No, but there's no alternative. You cannot zap oil over wires.

Solar panels could generate enough power to run the entire world if we built enough of them plus breakthroughs in using a wider range of the EM spectrum keep making them more powerful.

Sorry, but you have no idea what you're talking about. Sunlight at noon at the equator delivers about 1 kW per square meter of total energy across the entire spectrum, including IR. You do the math and figure out just how many tens of thousands of square miles of land would need to be covered with solar panels. Next, do the math and figure out how much it would cost. Next, do the math and figure out how much contamination will be caused by all the heavy metals and toxic chemicals used in (and discarded after) the manufacturing process.

My friend just hooked solar to his home and he has two panels about 2' by 4' he runs them into an inverter and the extra power charges batteries. Those two panels run his entire house including a coffee grinder.

Your friend is either lying to you, or you misunderstood him. 16 square feet of solar panels will generate about 1.4 kW of electricity, at noon, at the equator, if they're perfectly efficient. I doubt he makes any more than about 300 watts with his panels, and that's certainly not enough to run a whole house. It's barely enough to run a fridge and a couple of lights.

- Warren

 

[W3pcq]

I don't see how it is unreliable for the individual user. To make a solar powered power plant maybe theoretically, but that may be because it has not yet been considered. The difference I see is that you can't put a nuclear power plant in your back yard, and you can't charge money for free power.

 

[chroot]

I don't see how it is unreliable for the individual user. To make a solar powered power plant maybe theoretically, but that may be because it has yet been considered.

It has been considered OVER AND OVER AND OVER AGAIN. The number of proposals for thermal-solar and solar-tower plants could keep an interested reader occupied for decades.

The difference I see is that you can't put a nuclear power plant in your back yard, and you can't charge money for free power.

Free power? How on Earth can you possibly think that solar power is "free?"

- Warren

 

[W3pcq]

my bad.

 

[W3pcq]

I mean that you don't need to pay the sun for its photons.

My friend probably uses natural gas to run some appliances. Still I know that he manages to at least run his television, computer, microwave, toaster, coffee grinder, and lights on solar.

 

[W3pcq]

Still you could use solar+wind+hydro+nuclear power to help generate the h2 and then use the h2 as an oil alternative.

 

[chroot]

If your friend is only at home a few hours a day, while the panels collect sunlight during the day while he's at work, then perhaps a few appliances can be run. A microwave, for example, is only turned on for a minute or two a day. Same with the toaster and coffee grinder. If he runs his computer and TV and lights all evening, though, he'd probably go over what his panels can produce in a day. I would not believe for a minute that he's able to heat his home or run a stove off his panels. I still applaud him for trying to reduce his consumption, though.

I do support the installation of solar panels on rooftops and other "wasted" surface area, at least in situations and locales where it makes sense. On the other hand, the concept of covering an area the size of Massachusetts with solar panels (which is roughly what would be required to generate the US' electricity demand) is laughable. It would not be even remotely economically feasible, and would cause environmental damage (by their manufacture and by their robbing a significant part of the Earth's surface of sunlight) far beyond anything that anyone would consider 'green.'

As far as what solar panels can generate, look no further:

http://en.wikipedia.org/wiki/Solar_radiation

Roughly 1 kW per square meter under the best possible conditions. When you factor in periods of darkness, cloud cover, sunlight angle, efficiencies of panels and batteries etc. you'd be quite lucky to actually capture 300 watts during the daylight hours.

In truth, we have already paved over a very large part of the Earth's surface, killing everything beneath it and turning the received sunlight into unwanted waste heat (urban thermal islands, etc.). More than a third of the surface area Los Angeles county is given to cars: freeways, ramps, driveways, parking lots, parking structures, etc. It would be unbelievably cool if we could come up with some kind of durable amorphous surfacing substance that could be applied to driveways, sidewalks, lightly used roads, etc. to generate electricity, taking advantage of all the surface area we have already covered, rather than going out and seeking new land to obliterate with sprawling solar-power plants.

- Warren

 

[mgb_phys]

Unfortuntely in the case of LA you can't even do that. You have to use low albedo concrete roadways in LA because of the amount of heat that would be generated by sun on black tarmac/asphalt. If you replaced the concrete by black absorbing solar panels the city would melt!

 

[chroot]

Unfortuntely in the case of LA you can't even do that. You have to use low albedo concrete roadways in LA because of the amount of heat that would be generated by sun on black tarmac/asphalt. If you replaced the concrete by black absorbing solar panels the city would melt!

Well, hopefully a lot of the irradiance (> 50%) would be converted into electricity rather than heat. I assume the high-albedo concrete still reflects more than 50% of the irradiance, though. Good point mgb_phys...

- Warren