electricity industry. As early as the 1830s the researches of Galvani, Volta, Daniell, Davy, Sturgeon, Faraday, and others had provided the scientific basis for the development of the electrical industry. The principles of electrolysis, the arc-lamp, the incandescent lamp, the electric motor, and the dynamo were understood, yet, partly due to the dominance of gas lighting, electricity was slow to reveal its potential. In the 1840s arc-lighting was used to light a few streets, and chemical batteries and copper wire were used in a rapidly expanding electric telegraph network, which had 3,700 miles of line by 1852.

Despite improvements to the dynamo, it was not until the development of a proven incandescent-filament lamp in 1878 by Swan in Britain and in 1879 by Edison in the USA that the rapid growth of public electricity supply was feasible. From the early 1880s efficient generators, mainly driven by steam power, and small lamps combined to provide the technical base for the expansion of the industry. A major improvement in generation was provided by Parsons's steam-turbine, which improved the output of power stations by greatly increasing the speed of rotation of the dynamo. In suitable locations small hydroelectric schemes were promoted, beginning in 1881 in Godalming (Surrey). Other such ventures, including a municipal scheme near Worcester, varied in size and were located as far apart as Greenock and Lynmouth.

During the 1890s the market for electricity widened and power stations were built in many cities and towns by private electricity companies or local authorities. Apart from providing light, they increasingly supplied power for street tramways, and later, in London and Glasgow, for underground railways. Bristol was the first local authority to operate an electricity supply service of any great size. Beginning in 1893 it provided both private and street lighting and soon began to compete effectively with gas. The electricity industry continued to make progress and by 1912 about 25 per cent of power used in British industry was electrical. However, foreign firms dominated, for electrical transport and factory power was mainly provided by American and German expertise.

Before the evolution of the national grid in the late 1920s, the electricity supply industry was in the hands of small stations and relatively small companies. The Electricity Supply Act of 1926 encouraged the regulation of current and greater standardization of the industry. Generating stations increased in capacity as electricity accounted for a growing proportion of power needs. Like coal-mining, the electrical industry was nationalized under the third Labour government.

Subsequently during the 1950s and 1960s, there was considerable expansion to meet industrial and domestic needs, as well as the electrification of the railways. Generation was mainly by coal or nuclear power, and there was also substantial investment in hydroelectric schemes in the Scottish Highlands. Alternative energy sources, mainly wind and tidal power, were explored, but partly on economic grounds, and partly in line with decreasing demand in the wake of the energy crisis in the 1970s, investment was limited to experimental plant. In line with the policies of the Conservative government, denationalization and privatization of both generating and supply took place in the late 1980s.

Ian Donnachie