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Thread: Beware of Hydrogen
09-29-2006 07:12 AM #1
Beware of Hydrogen
Honda is getting a lot of publicity lately on a fuel cell & battery hydrogen fueled car. At first glance it may seem like a good thing but I have questions.
How safe is the 350 atmosphere storage tank? Isn't that about 5000 psi? And what happens in a closed garage if it leaks? Isn't hydrogen odor free and combustible with almost any amount of air?
The two least cost ways to mass produce hydrogen that are proven seem to be electrolysis of water with nuclear power or reduction of water with Carbon Monoxide from partially burned coal. Aside from all the toxic Carbon Monoxide as an intermediate from the coal process, what happens to all the Carbon Dioxide from the process conclusion? Do we really think it can be sequestered for thousands of years by pumping down failing Saudi oil wells?
09-30-2006 02:20 AM #2
Beware of Hydrogen
You are quite right in your concerns. Hydrogen is probably a no-starter for several reasons.
I wouldn't worry about the storage tanks. One can always make them extremely strong. It's just that they get really heavy when you make them strong, to the point that they are prohibitive. The reality is that real, road-worthy vehicles will have small tanks with lower pressure and only get around a hundred miles of range on a tankful. A good example is the hydrogen powered Priuses that the city of Santa Monica, CA has that only get about 70 miles of range.
Hydrogen leaks are a problem, just like natural gas is. I'm sure that agents will have to be added to provide odor like it is with natural gas so someone can detect it. Sensors will be necessary to detect significant amounts of hydrogen leakage. Remember that as the smallest element, hydrogen actually will leak from anything. All one can do is to slow it down.
The only cost effective way to get hydrogen is by stripping it from natural gas. This is wasteful of the natural gas and it definitely leaves the carbon problem that you mention. My question is: why not just use the natural gas as it is?
Don't worry though. None of the auto manufacturers have any real plans to ever produce hydrogen cars. They are just an expensive ruse (funded by the US government for $1.5 billion) to delay having to change their status quo. In the '90's, they thought that battery electric vehicles (BEV's) would hold off the pressure but unfortunately, all the research money invested in BEV's (and cellphones/laptop computers) solved the few remaining issues (capacity, battery life, and charging time) so they had to put up the hydrogen smokescreen.
10-03-2006 08:16 AM #3
Beware of Hydrogen
I for one would like to see hydgrogen-powered vehicles. The sooner the better. I'm not an expert here, but I do know a lot about combustion.
Hydrogen is extremely light. If the H2 tank is punctured the gas will blow out very quickly and disperse just as quickly. It won't pool and burn like a liquid fuel will. Chances are you'll be safer. Although H2's flammability limits are wide, chances are the gas will disperse before it ignites. Even though you have fuel and air, you still need an ignition source to get it to burn.
Hydrogen "spills" won't pollute the ground or ground water.
When burning, since there is no carbon involved, the hydrogen fire does not emit nearly as much radiative energy as a liquid fuel, wood, etc. One would have to be very close to the fire to get burned. The DOE tested a fire on two vehicles caused by H2 and gasoline. The H2 fire was out in around a minute (I think) while the gasoline fire started the whole vehicle on fire.
A tank designed to hold H2 at 5000 (or 10,000?) psig is going to withstand a crash much better than a typical gasoline tank.
As for producing H2, the nuclear salesman seems to be knocking on the door....yet again. Nuclear power is so expensive that, if govt subsidies were removed, it would fail in the economic market place. I think a more elegant--and economically viable--solution is to use solar (and wind) power to make H2 through hydrolysis. That way the natural water/wind/solar cycle can be used fuel our future.
It would also make much more sense to have distributed H2 sources than one large nuclear target (I mean, plant) producing a lot of H2--not a good solution in my book.
The other method you mention is really trying to make liquid fuel from coal (or natural gas) using the Fischer-Tropsch (FT) process. Hydrogen is a by-product of this process as well as CO2. The FT proponents are trying to sell this as an environmentally friendly process because they say they will sequester the CO2 and make H2 for fuel cells. Also, and this is the kicker, FT fuels make much fewer particulates--which is a good thing. UNfortunately, they don't tell you that the process is only economically viable at about $60-80/barrel of oil, which just guarantees you would get $3.00/gal FT fuel, and sequestering CO2 will be expensive.
People that propose these types of solutions are the old, stodgy supply-siders. There is much more to be gained by reducing demand, that by increasing supply.
The more people that buy high-mileage cars, the less there would be a need for these plants at all!!
In my opinion, the best solution is to start making all our processes, i.e., cars, trucks, homes, buildings, appliances, etc. much more energy efficient. That saves money, pollution, health-care costs, etc. Once the products are very efficient, then putting a H2 fuel cell in them will be much easier.
03-31-2008 09:41 AM #4
I just found this forum,
I just found this forum, seems like the replies are few and far between, but I want to put in my $.02 One CAN convert his present car into a "hybrid" very simply and at low cost...under $300.00 by building a hydrogen generator that only produces HHO as needed and supplements the petroleum product you are currently burning. This has the benefit of increasing gas mileage and reducing the tail pipe emissions. Check out www.oupower.com and see what the gear heads are doing. I am in the starting stages of building a HHO gen. for my '93 Corolla. If it performs as expected I will increase my mileage from it's present 32 M.P.G. to at least 40 M.P.G. possibly higher.
05-12-2008 11:18 PM #5
I must take issue with the
I must take issue with the Hydrogen-bashing on this site. There are a couple of incorrect assumptions used here that I would like to address.
First is what I would call the "fuel cell assumption"--that is that hydrogen will automatically be utilized in some sort of fuel cell arrangement. There is actually a much better way to use hydrogen as a fuel which would be in a hydrogen-hybrid configuration. In this set-up compressed hydrogen would fuel a small gas-turbine engine connected to a generator which would charge a battery/supercapacitator pack.
The advantages of this set-up are numerous. Hydrogen is an excellent fuel for gas turbine engines which in turn are very well suited to turning a generator at a constant rpm. The battery/capacitator array acts as a buffer and provides electrical energy to power electric drive motors located in the wheels of the vehicle. This is all off-the-shelf technology that could be developed very quickly with the proper motivation and incentives.
The second incorrect assumption is that of "centralized production/distribution". It is understandable since this has been the model for previous energy sources but hydrogen represents a brand new paradigm. It need not--in fact should not--be produced in large centralized facilities and then distributed outward by truck or pipeline as is the case with gasoline or natural gas. Right now several scandanavian countries are looking at on-site micro-production of hydrogen. This eliminates the need for large production facilities and a distribution network. There are really only two things you need to produce hydrogen--electricity and water. Micro hydrogen generation stations can be located anywhere you have access to the power grid and water supply. An owner of a hydrogen-hybrid vehicle could have a hydrogen micro-generator in their garage. Just about every fuel station in the country could also be the site for a hydrogen microgenerator. Obviously government incentives and mandates would have to be involved to get this infrastructure in place but there is a precedent in the gradual phase-out of leaded gasoline from fuel stations back in the 1970's/80's
The final incorrect assumption is that regarding the "safety factor". Hydrogen is by no means any more dangerous than any other fuel. In fact careful examination of the evidence shows just the opposite. Hydrogen is a much safer and forgiving fuel than what we have grown accustomed to using.
Due to it's low density hydrogen gas does not pool in potentially explosive pockets--such as gasoline vapor. In contrast hydrogen wants to escape to the upper atmosphere. With proper venting the safety issues surrounding hydrogen should be minimal.