Fuelling Controversy [Irish Times]

STaN

Hydrogen could become the world's car fuel of choice, but how could the most common element of all also be come the most common fuel in you tank?

In the old days smart young graduates were encouraged to get into the plastics. Today it is hydrogen, the fuel of the future.

All of the world's leading motor manufacturers are studying hydrogen-powerd cars and have prototypes whizzing around the test tracks. They don't burn the hydrogen however, they use it in a chemical reaction to produce electicity.

The technology behind the new hydrogen cards is based on a device known as a fuel cell. These take oxygen and combine it with any of the variety of hydrogen energy sources to produce electiricty, heat and water.

Of course, if you choose a fuel cell car you are actually choosing an electric car. The fuel cells are used to produce electricity and then this is used to drive electic motors, with many designs and prototypes with an individual motor on each wheel.

Fuell cells represent the Promised Land for motor manufacturers with an enviromental conscience. If the hydrogen gas is used, then the only thing coming down the exhaust pipe is pure, drinkable water.

Fuell cells have a long and distinguished history. They provided electricity and of course fresh water on board Apollo and the Gemini manned spacecraft and the space shuttle. They were chosen for the electiricty generation in preference to radioactive sources, which were considered too dangerous.

More recently fuel cells are powering road vehicles. Late last year Honda and Toyota became the first to lease environmentally friendly fuel cell cars, making four available to the Japanese government.

The great drawback to the fuel cell approach, however, is cost. The Japanese lease arrangements are about 40 times higher than a conventional lease.

Then there is the inherent risk of carrying around pressurised gases as a fuel source. Hydrogen burns both powerfully and quickly if exposed to a live flame or ember. The ill-fated Hindenburg Zepplin which crashed and burned in the later 1930s was filled with hydrogen gas. Even so, the environmental advantages of a hydrogen car are encouraging motor manufacturers to find engineering answers to these problems.

Some of the difficulties can be overcome quite easily, depending on the hydrogen source you choose. Pure hydrogen gas is but one source.

Hydrogen is also a constituent of the whiskey some like to sip, and raw alcohol used to sterilise surfaces. It is found in natural gas, petrol, coal and dozens of the exotic chemicals formulated to operate many different types of fule cells currently under study.

Any of these hydrogen sources could be used, but there is an immediate trade-off depending on your choice. The further you get from the pure hydrogen the greater the emission problem, of other more complex compounds.

This variety of sources is causing something of a transatlantic schism when it comes to choosing your hydrogen. Hydrogen does not occur naturally as a gas, it has to be taken from something else, for example by splitting a water molecule or breaking off a hydrocarbon such as methane. One way or the other it takes energy to free the hydrogen and here is where the great divide occurs. The EU, which recently announced a €2.1 billion hydrogen energy research programme, favours the use of renewable energy to derive hydrogen.

The US, which has its own €1 billion hydrogen plan, is pushing the idea of taking hydrogen from fossil fuels.

One very clean method of getting hydrogen is using electric current to split water molecules. If done using electricity from a fossil fuels or nuclear power, it would cost $15 oto $18 per gigajoule of hydrogen energy. Of done using solar cell electricity, a completely renewable source, it would cost $25 to $50 per gigajoule.

The US alternative is much cheaper, but less environmentally friendly. Hydrogen taken directly from coal, gas or oil would cost between $1 and $5 per gigajoule. If you used natual gas and then spent extra money to sequester the carbon dioxde emissions, it would still only costs $8 to $10 per gigajoule.

STaN

Originally posted by STaN
The great drawback to the fuel cell approach, however, is cost. The Japanese lease arrangements are about 40 times higher than a conventional lease.

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One very clean method of getting hydrogen is using electric current to split water molecules. If done using electricity from a fossil fuels or nuclear power, it would cost $15 oto $18 per gigajoule of hydrogen energy. Of done using solar cell electricity, a completely renewable source, it would cost $25 to $50 per gigajoule.

The US alternative is much cheaper, but less environmentally friendly. Hydrogen taken directly from coal, gas or oil would cost between $1 and $5 per gigajoule. If you used natual gas and then spent extra money to sequester the carbon dioxde emissions, it would still only costs $8 to $10 per gigajoule.

I didnt not understand the bit about the lease. Does it mean it costs 40 times as much to rent a car like this?

Also, i assume a gigajoule is a quantity of hydrogen needed to produce a gigajoule? What would this translate to relatively in normal running costs?

Thorbar

A gigajoule is the work it takes to move a 1000 kgs the distance of 1 km.

Barry

drrnwbb

http://www.wired.com/wired/archive/11.04/hydrogen.html

also an article on the subject in this months wired.

dw