Modern life depends on electricity. Virtually every home in Britain is connected to the public electricity supply, though that has been achieved only since the Second World War. In 1920 the supply industry had under a million customers in England and Wales. The figure reached 10 million by 1945 and 15 million by 1960. Now there are 21 million, and they use about two hundred thousand million units of electricity per year. Of this consumption 36 per cent is used at home, 38 per cent in industry, 22 per cent in commerce, and the remaining 4 per cent in such diverse applications as farming, transport and street lighting. Of the domestic electricity, 21 per cent is used for space heating, 18 per cent for water heating, 11 per cent for cooking and 17 per cent for freezing and refrigeration. Everything else, including lighting, comes out of the remaining 33 per cent.
At first electricity was only for the well-to-do. The major expansion came during the 1920s and 1930s, and during that period the average consumption per household fell, reflecting the fact that new consumers used electricity mainly for lighting, and not much for other purposes. The range of domestic electrical appliances with which we are familiar today have in fact been available almost from the beginning. Catalogues of the 1890s include electric cookers, kettles, saucepans, irons and fires. Early electric fires used carbon filament lamps as the heating member because there was no metal (except platinum) which could be heated to red heat in air without oxidizing. A great advance came in 1906 with the alloy nichrome, a mixture of nickel and chromium. This does not oxidize when red hot, and most electric fires since that date have used nichrome wire elements on fireclay supports. Storage heaters for room heating were introduced on a small scale in the 1930s. In the 1960s the Electricity Council conducted research to improve their design, seeking longer heat retention, and modern storage heaters are much smaller than their earlier counterparts.
Motorized appliances generally came later than lighting and heating, though an electric table fan was on sale by 1891. The first electric vacuum cleaner was made in 1904. Early electric washing machines had a motor fixed underneath the tub. Usually there was a mangle fitted on top (spin driers came later) and a gearbox that permitted the user to couple the motor either to the agitator in the tub or to the mangle. Food mixers and refrigerators came after the First World War, though they were rare until the 1950s. Electric space heating and refrigerators have changed house design. Before the mid-1930s it was normal to have a fireplace in every bedroom, and into the 1950s every house was built with a larder. Many modern houses have no fireplace, except possibly one in the living-room for effect. Larders have become obsolete since it is assumed that food which might go bad will be kept in the refrigerator.
Lighting has also progressed. The carbon filament lamps that were such a wonder in the 1880s and 1890s encouraged the gas industry to develop the mantle, and for a time gas lighting undoubtedly had the edge over electricity. The electric lighting industry sought a better filament material. Three metals seemed promising: osmium, tantalum and tungsten. Osmium filament lamps were on sale from 1899, but since 1909 all metal filament lamps have used tungsten. Carbon lamps continued to be made for some years since they were cheaper in first cost, but the metal filament lamps were more efficient, giving cheaper light when the cost of electricity was taken into account. The latest development in high-power filament lamps is the inclusion of a halogen gas (usually bromine or iodine). This reacts chemically with tungsten that evaporates from the filament and is deposited on the glass. The resulting tungsten halide is a gas which decomposes close to the hot filament, depositing the tungsten back on to the filament. Such lamps can be run at a higher temperature and are therefore more efficient.
Various gas discharge lamps were made in the 1890s, and neon lamps were introduced about 1910. The widespread use of both mercury and sodium discharge lamps dates from the 1930s. The low pressure sodium lamp, with its extremely monochromatic yellow light, has been popular for street lighting because it is the most efficient of all. Since the early 1970s, however, the high pressure sodium lamp has been taking over. It is almost as efficient, and although its light has a yellow-pink tinge its colour rendering ability is fairly good.
Fluorescent lamps, developed in Britain just before the Second World War, have an efficiency in between that of filament lamps and discharge lamps. A low pressure mercury discharge within them produces ultra-violet light which acts on the fluorescent coating of the tube to give visible light. The choice of phosphor determines the colour and the efficiency of the lamp, and they are widely used in commercial applications. One great advantage of electricity is its easy controllability, and with timeswitches, thermostats and semi-conductor dimmers that is even more true than before. Other technologies have done much for mankind: electricity has put virtually unlimited power at the disposal of all.