Wednesday, March 26, 2008

Fuel cell FAQ

When was the fuel cell invented?

Fuel cells were initially demonstrated in 1839, by Sir William Grove. However, a truly workable fuel cell was not demonstrated until 1959. After use in NASA's space programme, interest in fuel cells died down somewhat until the 1990s when research and development started to lead towards greater prospects of commercialisation.

Which fuels can be used in a fuel cell?

Most fuel cells use hydrogen at the point where the electrochemical reaction takes place. This hydrogen can be chemically generated or reformed from a variety of normal fuels, including gasoline, natural gas or methanol. There is no consensus as to the single best fuel.

What types of fuel cells are there?

There are a number of types of fuel cell which are normally distinguished by the electrolyte they contain. The best-known types are alkaline, molten carbonate, phosphoric acid, proton exchange membrane and solid oxide. Direct methanol and regenerative fuel cells are also being extensively researched.

What is a fuel cell?

A fuel cell is an electrochemical device that produces electricity and heat from a fuel (often hydrogen) and oxygen. Unlike a conventional engine, it does this without burning the fuel and can therefore be more efficient and cleaner.

Can I buy a fuel cell?

In general, fuel cells are in the development phase and are not yet commercially available. Many companies are currently running field trials of alpha and beta development units and hope to be commercialising this technology from as early as this year in some cases. However, some products, such as educational fuel cells, are commercially available now, as listed in our

Why use a fuel cell?

Fuel cells have a number of advantages over other technologies for power generation. They have the potential to use less fuel than competing technologies and to emit no pollution when used. There are also many reasons why a fuel cell might be useful in specific environments, such as the high quality of electricity generated or their quiet operation.

What devices could a fuel cell power?

In principle, a fuel cell could power any device that requires electrical energy to function. This could range from a mobile phone up to a factory. Presently, the majority of attention is focussed on powering automobiles, houses and medium-sized portable electrical equipment. However, announcements have suggested that portable computers may be an early application.

How much does a fuel cell cost?

Since fuel cells are not yet fully commercialised, they are produced in small numbers. Consequently, they tend to be more expensive than they will be when selling in significant quantities. However, as technology improves, cost reduction is proceeding towards meeting challenging cost targets set by the automotive industry. People involved in the industry generally believe that this can be accomplished and that in any case, costs will continue to decrease and will be significantly lower by the end of this decade than they are now.

What is the difference between a fuel cell and a battery?

Whilst a battery chemically stores and releases electricity, a fuel cell produces energy by reacting a fuel with air. A battery will therefore run out of power and have to be recharged or disposed of. A fuel cell, however, will continue to function and produce power as long as the fuel and oxygen are supplied to it.

Is hydrogen safe?

Like any other fuel, hydrogen is potentially dangerous and is flammable. However, so are gasoline, diesel and natural gas and this has not prevented their use to power cars, alongside the correct safety features. Hydrogen even has some advantages as it is non-toxic, a definite benefit over most fuels. Use of hydrogen would therefore present new but not insurmountable safety challenges.

Why not burn hydrogen instead of using it in a fuel cell?

Hydrogen is an extremely clean-burning fuel. However, any combustion process will produce small amounts of pollutants whereas a fuel cell has the potential to emit none. In addition to this, a fuel cell can inherently be more fuel-efficient than an internal combustion engine. However, there may be applications where burning hydrogen makes sense and it is possible to imagine that hydrogen fuel cell powered cars and hydrogen internal combustion engine powered cars could run side-by-side on the roads.

Are fuel cells a renewable energy source?

Fuel cells themselves are not a power source: rather they use a fuel to produce power. If this fuel is obtained from renewable sources, then fuel cells can be an important part of the energy chain, perhaps with hydrogen being used to store intermittent energy and fuel cells converting this hydrogen back to power when required.

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