FUEL CELLS AND HYDROGEN PRODUCTION

1.            SCIENTIFIC AND TECHNICAL INFORMATION

1.1        Basic Principles of Fuel Cells and of Hydrogen Production

Hydrogen

The origin of the term goes back to the Greek words "hydro" and "genes" meaning "water" and "offspring". Hydrogen is a colourless, odourless, tasteless, flammable gaseous substance, the simplest member of the family of chemical elements. Though we rarely give much thought to Hydrogen, it is really quite an amazing and important element. In fact, without its special qualities there would be no life on this planet.

Examples include:

Hydrogen is by far the most abundant element in the universe, accounting for about 75 percent of the mass of all matter. It can be derived from water and when used as an energy source, it is converted back into water, so it is infinitely recyclable, as illustrated by the Hydrogen Water Cycle.

The Hydrogen Water Cycle is an attractive and simple process of water - H₂O - splitting into oxygen, which can be released into the air, and hydrogen, which is then stored as an energy source.

Hydrogen is generally considered the future energy carrier and storage medium of the next century. Though all primary energy sources can be used for the production of hydrogen, if it is produced from fossil fuels, CO₂ is emitted. This CO₂ should then be collected and stored permanently so that the production method may be considered pure. No effective method has yet been developed for storing such CO₂, and the costs involved are uncertain, therefore pure hydrogen should be produced by means of renewables or nuclear energy.

Hydrogen is not a primary energy source, but like electricity it is a secondary energy carrier, which must be produced from some primary energy source. Hydrogen and electricity are absolutely compatible energy carriers, as electricity can be used for producing hydrogen through electrolysis, while hydrogen together with oxygen (air) can produce electricity, for instance by using fuel cells.

Fuel cells

Fuel cells produce electricity and heat by combining hydrogen and oxygen in an electrochemical process. They are similar to regular batteries except that the fuel and oxidant are stored externally, enabling them to continue operating as long as the chemicals are supplied. In most applications the oxygen is taken directly from air, so only the fuel has to be stored. The ideal fuel for fuel cells is hydrogen, but other hydrogen containing fuels (such as natural gas or petrol) may be used if they are passed through a reformer, which converts them into a hydrogen rich gas.

Fuel cells have the potential to change the way of future energy use and production all over the world. Although the mass production of fuel cells is still not feasible, the expected impact on our environment is remarkable: they practically have zero emissions at the point of use, with water as the only by-product. As a result fuel cells offer a number of potential applications.

These include:

The great promise of fuel cells as a means of efficient production of electric energy from the oxidation of fuel was recognized at an early stage. Their main advantages are the following: