Energy efficiency (FR)

It is much more cost effective and less burden on the environment to use energy efficiently than to generate it. This reduces the demand on fossil fuel resources, which currently supply most of our energy needs, so enabling us to leave resources for future generations. Such actions form the basis of the sustainable use of energy.

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Our carbon footprint is a measure of how efficiently we meet our energy needs. It us generally accepted that each of us in Europe will have to reduce our footprint by 80% over the next 40 years to avoid irreversible changes in climate . In this section we consider the various options for saving energy and in the following section, options for switching from fossil fuel to renewable energy sources.

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Lighting

For more than 100 years electricity has been used for lighting lamps. The incandescent lamp, developed commercially by Thomas Edison in the 19th century, generates light by heating a thin wire of a material with a high resistance like tungsten. Only about 10% of the energy used is converted to light while the remaining energy is given off in the form of heat.

More recently florescent lamps have been developed which produce light through excitation of a gas and so are much more efficient, typically 80 – 85%. They are in general use in shops, offices and schools as they can light up large areas due to their length, typically one or two metres.

In the past 20 years, compact florescent lamps (CFL) have been developed which have folded tubes generally either elongated or spiral (Figure 1). They can be used in the same fittings as incandescent lamps and therefore can be a like for like replacement.

Figure 1: Compact florescent lamps