The fuel cell

Fuel cells are electrochemical devices that generate DC electricity similar to batteries. Unlike batteries they take their energy from a continuous supply of fuel, usually hydrogen. The fuel cell is not an energy storage device but may be considered as an electrochemical internal combustion engine. It is a reactor which combines hydrogen and oxygen to produce electricity, heat and water. Thus its environmental credentials are impeccable. The problem at the moment is that it is an expensive way of producing energy. Each installed kilowatt costs $3000 to $4000; whereas a combined cycle gas turbine system costs $400 per kilowatt. The reason for this cost difference is that the fuel cell uses platinum as a catalyst. However, experts think that the quantity of platinum can be cut by a factor of 5, which will bring about a significant reduction in cost. There will also be considerable reductions as mass production begins to bite. The latest prediction is that the cost should fall to between $600 and $1000 per kilowatt.

Fuel cells are efficient, clean and quiet with no moving parts and are ideal for combined heat and power application. For static cells in buildings perhaps the most promising technology is the solid oxide fuel cell which operates at around 800°C. Most fuel cells work with hydrogen. At present the most cost-effective way to obtain the hydrogen is by reforming natural gas. According to Amory Lovins 'A reformer the size of a water heater can produce enough hydrogen to serve the fuel cells in dozens of cars' (New Scientist, 25 November 2000, p. 41). In that case it will not be long before it will be possible to buy a fuel cell and reformer kit for the home which will make it independent of the grid providing heat and power much more cheaply than is possible at present. Considerable research effort is being directed into improving the efficiency and lowering the cost of fuel cells because this is the technology of the twenty-first century and huge rewards await whoever makes that breakthrough. According to David Hart of Imperial College 'If fuel cells fulfil their potential, there is no reason why they shouldn't replace almost every battery and combustion engine in the world' (New Scientist, Inside Science 'Fuelling the Future', 16 June 2001).

At present there are five versions of fuel cell technology. The proton exchange membrane system is the most straightforward and serves to explain the basic principles of the fuel cell.

Figure 13.1

Basic structure and function of the proton exchange membrane fuel cell

Figure 13.1

Basic structure and function of the proton exchange membrane fuel cell

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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