[Timgt5]

Following the historic move by Honda, General motors is loaning out a small group of Hydrogen Fuel Cell Powered Vehicles to real people in the DC area. Read more:

http://news.yahoo.com/s/ap/20080827/...akers_hydrogen

Hydrogen cars are going to be the critical step forward to ending our reliance on fossil fuels and a cleaner more carbon-free environment

TJ

[pachyderm]

Where do they refuel?

Hydrogen is dangerous stuff. It burns like crazy. But then, I suppose so does gasoline...

[Timgt5]

Good questions:

1) Special Equipped Hydrogen Fuel dispensers are set up in both the Washington DC area and in and around Los Angelos CA. One of the qualifications for getting one of these cars is that the individual had to live within 20 miles or less of one of these facilities. One of the reasons that GM, Honda and BMW have embarked on these pilot programs is to help convince the government to invest in the necessary infrastructure to support hydogen cars

2) In it's gaseous state Hydrogen is very volitile. In the fuel cell cars however Hydrogen is kept in its liquid state at very low temperatures. Both GM and Honda have built in a number of redundant systems to keep their respective cars safe in the event of a collision( reinforced tanks, additional structure and cooling systems) The cars are no more likely to catch fire than a standard ICE vehicle.

TJ

[pachyderm]

> In it's gaseous state Hydrogen is very volitile. In the fuel cell cars however Hydrogen is kept in its liquid state at very low temperatures.

Notice that you have used it's and its for exactly the same purpose. This message courtesy of the grammar curmudgeon.

The liquid hydrogen becomes gaseous when it warms, in which case it is highly dangerous (if there is any oxidizer in the neighborhood). And since liquid hydrogen has to be kept very cold compared to our ordinary surroundings, its warming is very easy.

[Timgt5]

Honda has addressed the flamibility issue on their page regarding Hydogen fuel cells.

The following on the Clarity's web site addresses those concern specifically. It is likely that GM engineers used similar ideas in thier vehicle as well:

Hydrogen Safety
Sensors are located throughout the vehicle to provide a warning in the unlikely event of a hydrogen leak. Should such a leak occur, the ventilation system is activated and an automatic system closes the main cut-off valves on the hydrogen tank or supply lines as necessary. The high-voltage lines are electrically isolated. Sensors provide a warning in case of grounding. In the event of a collision, high-voltage contactors shut down the source power line. Repeated flood and fire testing have confirmed a very high level of safety and reliability.

Refueling Safety
Honda has taken safety precautions with regard to refueling safety. To prevent reverse flow from the tank, the hydrogen filler inlet has an integrated check valve. The fuel intake mechanism is also designed to prevent contamination by other gases or the connection of nozzles designed for hydrogen stored at incompatible pressure levels.

No system is perfect but there is no evidence these cars pose any greater danger to the public than any standard ICE car.

Now, you can stop being a luddite-just kidding-

TJ

[pachyderm]

Do you know how they keep the hydrogen cold? What if a car is sitting for a long time without being driven? Liquid hydrogen will boil at -252 degrees Celcius. Wikipedia says "Typically it will evaporate at a rate of 1% per day." That is with insulated containers.