A brown utilitarian structure with a substantial chimney, Lerwick Power Station is located in Gremista, 1¼ miles (2 km) northwest of Lerwick town centre and is the principal source of electrical energy for Shetland. Opened on 27th May 1953 and now owned and operated by the Perth-based utility company Scottish and Southern Energy plc (SSE), the station is diesel-fuelled and generates a total of 66 MW of power. Designed by Alexander Cattanach (1895 - 1977) for the North of Scotland Hydro Electric Board with six generator sets, two 8 MW French Pielstick engines were added in 1983 as demand increased and a further Finnish 12 MW Wartsila engine was commissioned in 1994. A waste-heat recovery system produces super-heated steam which runs a 2.1 MW turbine. Two standby gas turbine generator units, each with a capacity of 5 MW, were installed to augment peak output.
The station is expensive to run and has struggled to meet peak demands for power. However, wind turbines are beginning to play an important part in Shetland's energy mix, despite these giving rise to problems of power stability. This has led to SSE installing a controversial 1 MW sodium-sulphur battery in a building adjacent to the power station, at a cost of £3.3 million, to smooth the load and help deal with peak demand. SSE is committed to developing three new wind turbines at Rova Head, each rated at 2.3 MW. At off-peak times these will supply a large immersion heater, which warms a thermal storage tank, that allows the District Heating Boiler Station to meet peak loads more effectively.
