MadSci Network: Chemistry

Re: Does the US Gov. have technology which could produce electricity from H2o

Date: Tue May 19 16:00:47 1998
Posted By: Adrian Popa, Directors Office, Hughes Research Laboratories
Area of science: Chemistry
ID: 895167506.Ch


I believe that the technology that you have asked about is the Hydrogen - 
Oxygen fuel cells that were developed by NASA in the 1970s for use on 
the Space Transportation System (STS) commonly called the Space Shuttle. 
Extensive detailed information about the STS fuel cells can be found at the 
following NASA URL:

Each STS orbiter has three fuel cells to generate the prime electrical 
power. Each fuel cell power plant is 14 inches high, 15 inches wide and 40 
inches long and weighs 255 pounds. The voltage and current range of each is 
2 kilowatts at 32.5 volts dc, 61.5 amps, to 12 kilowatts at 27.5 volts dc, 
436 amps. Each fuel cell is capable of supplying 12 kilowatts peak and 7 
kilowatts maximum continuous power.  Each fuel cell is serviced 
between flights and reused until each accumulates 2,000 hours of on-line 

Water and electricity are the products of the chemical reaction of oxygen 
and hydrogen that takes place in the STS fuel cells. The water must be 
removed or the cells will become saturated with water, and it is stored in 
water storage tanks for use by the crew (drinking, washing  etc..)

The major problem for commercial use of the STS fuel cell is that the 
hydrogen and oxygen fuels are very explosive and they must be stored at 
very cold (cryogenic) temperatures in the liquid state to fit the fuel 
tanks within the STS vehicle. If the fuels are stored in gas form at high 
pressures and at room temperature the tanks would become extremely large.

An alternative is to use the oxygen in the air as an oxidizer and only 
store the hydrogen gas. Hydrogen powered aircraft an terrestrial vehicles 
would be very efficient and would produce mostly water and very small 
amounts of nitrogen compounds compared to today's cars and aircraft. The 
problem with this concept is that large fuel tanks of explosive hydrogen 
stored at high pressure are required to equal the range of current internal 
combustion or turbine powered vehicles. 

The city of Riverside California has several hydrogen fueled busses in 
service that use large fuel tanks filled with nickel hydride. Nickel 
hydride has the unique ability to absorb several atmospheres of hydrogen 
gas in a low pressure tank. (The chemical effect is similar to putting lots 
of sugar into a glass of water without changing the volume of the 
liquid).The busses still require a very large fuel tank the size of the bus 
frame but they are about one quarter the size of a hydrogen pressure tank 
with the same volume of fuel. I have not heard if there have been any car 
crashes into the Riverside busses yet to see what would happen to the 
released hydrogen gas.

The major automobile companies have formed consortia with the Federal 
Government to develop hybrid fueled vehicles (electric and petroleum), more 
efficient batteries and new fuel cell concepts to extend the 60 to 100 mile 
range of current electric vehicles. However, these fuel cells will 
efficiently burn conventional petroleum based fuels to generate hydrogen 
fuel. This enables the current petroleum based infrastructure to provide 
the fuel and service stations for electric vehicles.A great deal of 
research is still required to make this concept viable. 

The head of the General Motors Research Group has a paper on GM's 
experience with the EV1 electric car and the future directions 
GM is taking in this area at the following URL:

There is an interesting Web site with links to dozens of projects at large 
and small companies along with links to commentaries on many of the 
political issues involved - "If you are interested in Solar cars, Electric 
and Hybrid Vehicles, Renewable Energy, Whistleblowing, or political 
intrigue" the URL is:

At this URL both American and foreign companies are linked along with 
flywheel, solar and other alternate energy projects.

Best Regards, your Mad Scientist
Adrian Popa


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