Prior to the Second World War, government responsibilities for sources of power and energy were split between several government departments. After the outbreak of war, steps were taken to concentrate these responsibilities into one department. This was desirable if national priorities with regard to allocation and distribution were to be met, as difficulties over coal supplies were pronounced. The Board of Trade already administered government controls over the gas industry. In September 1941 it took over from the Ministry of War Transport those relating to electricity. The coal mining and petroleum industries were controlled by the Mines Department and the Petroleum Department respectively; both these bodies were nominally under the Board of Trade. From the autumn of 1941, fuel and power controllers co-ordinated the activities of the representatives of these Departments at regional level.
On 11 June 1942 an Order in Council transferred all functions relating to the fuel and power industries to a new Ministry of Fuel and Power (under Statutory Rules and Orders 1942 No 1132). The establishment of the Ministry and this transfer of functions was made permanent by the Ministry of Fuel and Power Act 1945. Further responsibilities relating to the control of petroleum and petroleum products were transferred from the Ministry of Supply by Order in Council on 20 March 1946.
The wartime work of the Ministry was mainly of an executive nature. It included responsibility for coal production, the allocation of solid fuel supplies, petrol rationing (which ended in 1950) and control over prices of gas, electricity and coal. The Ministry was also responsible for the health, safety and training of workers in or about mines and quarries and initiated research in these fields. It also continued to supervise the examination of colliery officials in certain grades and the testing and approval of types of mining apparatus.
Although the Minister was formally charged under the 1945 Act with a general duty of co-ordinating the development of fuel and power sources in Great Britain, little positive planning took place. Under the Coal Industry Nationalisation Act 1946, the Electricity Act 1947 and the Gas Act 1948, the Ministry acquired new responsibilities which largely involved advising and interpreting government policy to the newly created boards and other allied fuel and power industries. The Minister became responsible for the appointment and determination of tenure of the boards of the nationalised industries, was empowered to control capital investment programmes and generally to supervise schemes of research and development. The peculiar difficulties of the coal industry led to the retention of stricter controls in matters of production, pricing, modernisation, wage negotiations and recruitment. These functions were exercised partly through largely autonomous divisions within the Ministry and partly by virtue of its statutory powers in relation to the National Coal Board, the Electricity Council, the Central Electricity Generating Board and area electricity boards, the Gas Council and area gas boards.
In January 1957, the Ministry was renamed the Ministry of Power and was authorised to supervise the extended use of atomic energy for industrial purposes. The Ministry also took over functions relating to iron and steel which had been with the Board of Trade since 1955, until which time they had been discharged by the Ministry of Supply. In 1958, controls over coal distribution and pricing were abolished and the work of the Ministry was subsequently much reduced. The Nuclear Installation (Licensing and Insurance) Act 1959 added the inspection and licensing of nuclear installations to the Ministry's functions.
In 1969 the Ministry of Power was merged with the Ministry of Technology (Mintech). In 1970, Mintech, was merged with the Board of Trade to form the Department of Trade and Industry (DTI). In January 1974, a new Department of Energy was set up. With the exception of responsibilities for the iron and steel industry, this new department took over from DTI all the former functions of the Ministry of Power, which had been wound up in 1969.