Hydrogen Fuel Cells For Cars

[Vincero dOro]

Hydrogen is shocking explosive and is a real pain to handle - it's not something that you would ever want in your house.

 

 

Did you know unleaded pump petrol has twice the explosive force of hydrogen?

 

We keep our car in the garage. It is far safer than keeping it in the living room.

[Vague_Boy]

The main problem with hydrogen at the moment is that it takes more energy to produce than is obtained from the Hydrogen as a fuel.

 

It's important to realize that hydrogen is not a fuel source; it's an energy carrier. Hydrogen does not exist freely in the universe; it's always bound to something else. So it takes an investment of energy to free hydrogen from its existing arrangement and make it available as a stored fuel.

 

1. Suppose we generate the hydrogen by the electrolysis of water. First we must "rectify" the grid's AC electricity into DC, at a cost of about 2% to 3% of the energy contained in the hydrogen.

 

2. Now we can electrolyze the water, but that process is only about 70% efficient, so we lose another 30% there.

 

3. Now we have hydrogen gas, but it takes up a lot of space. We could compress it to around 10,000 psi to make it fit in a reasonably sized tank, which costs another 15%. But even then, it would only have about one-fifth of the energy density of gasoline, and the pressurized tank needed to store it is very heavy, large and expensive. So if we wanted to use it in a vehicle, we would have to liquefy the hydrogen by cooling it down to about -253°C and keep it in a pressurized, insulated container instead. This process would cost another 30% to 40% of the energy in the hydrogen.

 

4. We lose some more during storage because hydrogen boils off above -253°C, so it's very difficult to keep it from escaping its container. In vehicles, about 3% to 4% of the hydrogen boils off every day. And at least 10% of the hydrogen will boil off during delivery and storage.

 

5. Then we burn the hydrogen in a vehicle's fuel cell at an efficiency of about 50% (for a proton membrane fuel cell stack).

 

6. And finally, we lose another 10% of the energy that makes it to the electric motors driving the wheels, because they are only about 90% efficient.

 

7. In the end, about 80% of the original energy generated in order to produce the hydrogen is lost, for an EROI of 0.25. Since it doesn't pay to have an energy regime with an EROI of less than one, hydrogen cars seems a permanent improbability.

 

LINK

 

So you would expend 1 unit of energy to get 0.25 of a unit back.

 

If anyone thinks this makes sense, please PM me, I am more than willing to sell you £25 (for the price of a mere £100). Bargain!!!!

 

 

There are other problems with using Hydrogen to power cars, mainly to do with storage and distribution:

 

A final problem with the concept of a "hydrogen economy" is that we'd essentially need a whole new infrastructure for it, from "wells to wheels." Nothing in our current energy infrastructure is compatible with hydrogen.

 

A major reason for that is that it's the smallest element, so it wants to escape from just about anything you use to contain it. Tanks, pipes, valves, and fittings all along the way leak constantly. For another, it's highly reactive, and makes metal brittle and prone to leakage. The storage and transport losses can be considerably worse than in the above example.

 

LINK

 

 

As James Howard Kunstler puts it in The Long Emergency:

 

The extremely low density of hydrogen, given its low atomic weight, means that it takes up a lot of space. In automobiles it has to be compressed and stored in high-pressure tanks. The “fuel” tank would take up most of the space in the car. Compressing the gas takes a lot of energy in itself—an additional cost. To make a hydrogen fuel cell car with the same range as today’s gasoline-powered car, with comparable passenger room, would require storing the hydrogen at 10,000 pounds per square inch (psi), which is ultrahigh pressure. This can be done, using ultrastrong carbon fibers to reinforce the tanks. Such a tank might even survive a high-speed crash. The question is whether the more delicate plumbing connections from the tank would survive. If not, hydrogen under extremely high pressure would escape rapidly. Hydrogen is extremely flammable. Hydrogen-and-air mixtures combust over a wide range of concentrations from 4 percent to 75 percent, and will be detonated by very low energy inputs less than one-tenth the energy needed to ignite air and gasoline. Because hydrogen produces considerable heat at decompression, it could self-ignite in a crash as the gas rushed out of a tank through broken valves.

 

Kunstler, James Howard (2006-04-01). The Long Emergency (Kindle Locations 1977-1985). PGW - A. Kindle Edition.

 

Oh the humanity.

 

 

Further on he states:

 

Hydrogen presents two other problems for storage tanks. One is that it diffuses easily. That is, it leaks. Due to its extremely low atomic weight, it can escape through very small openings. It is very hard to contain. Hydrogen is also extremely corrosive. It likes to combine with other elements and compounds. The interior of the storage tanks, the pipe connections, the valves, and the seals would all be subject to much more rapid disintegration than is the case with gases such as methane.

 

Kunstler, James Howard (2006-04-01). The Long Emergency (Kindle Locations 1986-1989). PGW - A. Kindle Edition.

 

Distribution of the Hydrogen would be a problem. Our current gas pipe system is incompatible due to the extremely low atomic weight of Hydrogen compared to natural gas.

 

And distribution in tankers?

 

A mid-size filling station on any frequented freeway easily sells 25 tons of fuel each day. This fuel can be delivered by one 40-ton gasoline truck. But it would need 21 hydrogen trucks to deliver the same amount of energy to the station, i.e., to provide fuel for the same number of cars per day. Efficient fuel cell vehicles would change this number somewhat but not considerably. The transfer of pressurized hydrogen from the truck to the filling station takes much more time than draining gasoline from the tanker into an underground storage tank. The filling station may have to close operations during some hours of the day for safety reasons. Today about one in 100 trucks is a gasoline or diesel tanker. For hydrogen distributed by road one may see 120 trucks, 21 [of which] or 17 percent of them transport hydrogen. One out of six accidents involving trucks would involve a hydrogen truck. This scenario is unacceptable for political and social reasons.

 

Ulf Bossel and Baldur Eliasson, “Energy and the Hydrogen Economy,” EVWorld (http://evworld.com), January 2003.

 

LINK

 

 

To those simple folk who still think that cars can be run on water:

 

This is the classic problem of energy economics: energy returned over energy invested (ERoEI). It applies in one way or another to all categories of fuel and every procedure for getting and using them, and it comes back to a basic law both of physics and metaphysics: You can’t get something for nothing.

 

Kunstler, James Howard (2006-04-01). The Long Emergency (Kindle Locations 1882-1884). PGW - A. Kindle Edition.

 

Don't blame the oil cartels, blame the laws of thermodynamics!

 

Science. It can be a bugger at times.

[Resident]

The hydrogen fuel cell car exists and is at the stage where it could be mass-produced. It has been since 2007. Honda built the FCX Clarity.

 

However I find it mighty strange that nothing has been mentioned about it in the 6 years since. There are rumours that the oil giants clubbed together and are paying Honda to kept it from production (honda also designed the filling station equipment)

[Obelix]

Did you know unleaded pump petrol has twice the explosive force of hydrogen?

 

We keep our car in the garage. It is far safer than keeping it in the living room.

 

How volatile is petrol compared to hydrogen? What's the explosive concentration range for petrol vs hydrogen, and most importantly what's the E(a) value?

[geared]

The hydrogen fuel cell car exists and is at the stage where it could be mass-produced. It has been since 2007. Honda built the FCX Clarity.

 

However I find it mighty strange that nothing has been mentioned about it in the 6 years since. There are rumours that the oil giants clubbed together and are paying Honda to kept it from production (honda also designed the filling station equipment)

 

or maybe the numbers still don't work out and it'd cost far more to produce, ship and store the hydrogen than it would to run a car on petrol.

 

Just because one company can make a working prototype doesn't mean it can mass produce it for sensible money and the average joe can buy and run it.

[Vague_Boy]

But looking on E-Bay, I see a Pure Hydrogen Gas Generator for sale for less than £600, and I would imagine, having one of these stored away at home and connecting it up to the filler cap on your new fuel cell car; would do away with ever having to buy any fuel ever again?

 

Green Source HydroKit9 Hydrogen Generator uses electricity from your vehicle’s battery to create hydrogen from water while you drive. The hydrogen is then fed into the engine delivering a cleaner, more efficient combustion.

 

This is a world of difference from a Hydrogen powered vehicle.

[le-joker]

Why is this posted in Sheffield Discussions?

 

Might be `cos I live at Gleadless ?

[Phanerothyme]

or maybe the numbers still don't work out and it'd cost far more to produce, ship and store the hydrogen than it would to run a car on petrol.

 

Just because one company can make a working prototype doesn't mean it can mass produce it for sensible money and the average joe can buy and run it.

 

The simplest solution, it seems to me, is to use renewable energy (deep tidal/solar/wind/hydro etc) to synthesise petroleum distillates out of thin air.

 

In terms of energy storage efficiency I reckon large, dense hydrocarbons outstrip batteries, flywheels, pump storage and thermal storage by significant margins, when you consider the whole cycle generation - storage - release.

 

These can then be used to power electricity generation using the existing infrastructure of powerstations, with excess capacity being diverted into fuel synthesis.

 

A dramatic drop in energy consumption would need to be engineered by compelling manufacturers to develop low watt alternatives to lighting (already well under way), cooling, heating, etc, combined with research money carrots for promising avenues of investigation and development.

 

And keep our fingers crossed for ITER.

[alchresearch]

In The New Scientist this week its all about using ammonia.

[geared]

The simplest solution, it seems to me, is to use renewable energy (deep tidal/solar/wind/hydro etc) to synthesise petroleum distillates out of thin air.

 

Couldn't agree more, there's no where near enough hydro production going on - or money being pumped in for research.

 

The government seems hell-bent on sticking up those god awful wind-turbines, which never ever produce the amount of energy they claim.

 

I think the only reason they do it is because it's such a massive striking object it make it look like something good is being done.