Fuel cells produce electricity and heat by combining a fuel and oxygen in an electrochemical process. In principle, a fuel cell operates like a battery except that the fuel and the oxidant are stored externally. Oxygen is usually taken directly from the 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 do not run down or require recharging as long as fuel is supplied.
Fuel cells can be made in a huge range of sizes. However, the electrical power produced by a fuel cell is only a few tens or hundreds of Watts, so lots of fuel cells are usually put together in a so-called “stack” to provide a larger power output. They can be used to produce quite small amounts of electric power, for devices such as portable computers or radio transmitters, right up to very high powers for electric power stations.
There are several different types of fuel cell, but generally they share these similar characteristics:
- They are very efficient
- They produce very low emissions
- They have no moving parts, so there is less to go wrong with them
- They can be much quieter than conventional alternatives
While their environmental benefits are clear, to become a widely used “mainstream” energy option, fuel cells will need to prove themselves in terms of cost and reliability. It is generally thought, though, that fuel cells will have a growing role over the coming years. Fuel cells could become the preferred means of power generation in the future, driving our cars and buses and lighting our cities.
Contacts
Energy Saving Trust Advice Centre for London
Telephone: 0800 512012
E-mail: advice@est-london.org.uk
Website: www.energysavingtrust.org.uk/london