Hydrogen as fuel

Fuel cells are an efficient way of obtaining electricity from combustible fuels.

You've confused the terminology. A fuel cell consumes hydrogen (H2) and oxygen (O2) to produce electricity and water. The opposite device, an electrolyser (electrolysis unit), is used to "generate Hydrogen for use as fuel." An electrolyser drives the reverse of the fuel cell reaction, consuming electricity to produce H2 and O2 from water. Fuel cells are very expensive and the subject of research to drive down cost and improve efficiency. Electrolysis units are cheap and can be made by any garage tinkerer or third grade science teacher.

An electrolysis unit splits water into H2 and O2. The energy value of the resulting H2 is generally about 60% of the energy that does the splitting. For this reason, it is cheaper to generate hydrogen from methane, (already a high energy fuel) in a process called reforming. This process is used for more than 90% of all the commercially produced H2.

A "fuel cell" is the reverse of an electrolysis unit: it takes in H2 and O2 and produces water and electrical energy (the electrical energy being the useful part). Typically, very expensive materials are required to build an efficient, durable fuel cell. Fuel cell cars are essentially electric cars, and usually include batteries to store energy from the fuel cell for use during peak demand -- typically the fuel cell cannot produce electricity at a rate adequate for good acceleration.

The confusion in terminology has been promoted mainly by scam artists who sell electrolysis units to ostensibly improve fuel efficiency in cars. (Dennis Lee sells the HAFC -- Hydro Assist Fuel Cell -- at about $1000 each, which is not a fuel cell, but instead a simple electrolyser which any garage experimenter can make for $10.) The term "fuel cell" sounds high tech, because it is the technology used in the incredibly expensive* prototypes auto manufacturers have made to demonstrate the idea of running cars on stored hydrogen. I suppose that Lee hopes that the confusion in terminology will make people think his units are valuable.

* Here is a one watt fuel cell for $124.95. To replace an average car engine of 100,000 watts, you could use 100,000 of these (for $12,495,000.00) and a 100,000 watt electric motor!

Guest,

"roadside vendors who generate Hydrogen in a small cylinder to inflate the ballons."

I think you mean helium. I would think that filling balloons with hydrogen for use by children would be dangerous enough to be illegal.

Gases in cylinders are not generated in them, they are simply filled from another source.

Mike

Thanks all for responding and educating me.