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Hydrogen-powered trains: Tapping the power of H20

by Katie Greenwood

Water: It’s clean. It’s cheap. It’s abundant. And it’s the not-so-new way to power trains.

No, not by steam, by hydrogen.

Hydrogen power uses hydrogen and oxygen, the 2 elements found in water, to create a powerful source of energy.

Harnessing hydrogen for fuel cells

Hydrogen trains run on a fuel cell. A fuel cell is similar to a battery in that it converts chemicals into electricity, but a battery stores all of its chemicals inside. When all the chemicals have been converted to electricity, the battery goes “dead.”

With a fuel cell, the chemicals constantly flow into the cell so it never dies. The chemicals can be replenished to keep the fuel cell running.

A fuel cell needs 2 types of chemicals, a reactant and an oxidant. In a hydrogen fuel cell, the reactant is hydrogen and the oxidant is oxygen. Hydrogen is pumped into the fuel cell, and oxygen is usually obtained from the air.

A fuel cell consists of 2 electrodes (an anode and a cathode) sandwiching an electrolyte. Oxygen passes over the cathode and hydrogen over the anode.

This generates electricity, water, and heat. The diagram on the right shows the process by which a fuel cell generates electrical energy.

Producing hydrogen from water

A limit on this technology is that there is very little pure hydrogen in the earth’s atmosphere. It exists mostly in compounds.  Hydrogen, like electricity, must be manufactured.

Hydrogen can be isolated through the electrolysis of water (or by heating natural gas). Water (H20) is a compound that has 2 atoms of hydrogen and 1 molecule of oxygen.

Electrolysis splits the water into hydrogen and oxygen by sending an electric current through the water. Through the process of electrolysis, hydrogen can be isolated into its pure form and stored for the fuel cell.

Hydrogen power in trains

In a hydrogen-powered train, hydrogen is stored in a tank that pumps it into the fuel cell as it is needed.

Some hydrogen trains also have batteries that are charged by electricity from the fuel cell when the train is not running. These are fuel-cell-hybrid vehicles.

A hydrogen train can carry a large amount of hydrogen fuel onboard, so the train doesn’t have to stop to replenish its hydrogen supply very often.

Experts agree that water is the cleanest, most efficient source of hydrogen for fuel cell trains. Of the many different ways to produce hydrogen, electrolysis of water is the cleanest and most economic process.

The future of fuel-cell rail

Right now, use of hydrogen trains is limited. (Diesel is the fuel source for most trains in the United States.) In the future, however, a national hydrogen railroad system has the potential to provide benefits to the environment and the world of transportation.

The conversion of diesel locomotives to hydrogen fuel cell technology is creating jobs in the railway industry, including jobs designing new locomotives, converting diesel locomotives to hydrogen power, and building fuel-cell rail systems.

Vehicle Projects Inc has begun a project to develop a fuel-cell freight locomotive. It is also in the early stages of developing a fuel-cell locomotive for underground coal mining that would use hydrogen from a coal mining waste product.

Learn more

Learn more about the inner workings of a fuel cell and read up-to-date news on hydrogen-powered trains.