Economy 7

Economy 7 is the name of a differential tariff provided by United Kingdom electricity suppliers that uses base load generation to provide cheap off-peak electricity during the night.

Houses using the Economy 7 tariff require a special electricity meter which provides two different readings - one for electricity used during the day, priced higher, and the other for the night, priced lower. The night (off-peak) period lasts for a total of seven hours, hence the name; however it may or may not be a continuous period, as it may alternate between the two prices during the night.

The first mention of Economy 7 is in 1978: "A new off-peak tariff known as the 'Economy 7' tariff was introduced in October [1978]. It featured a seven-hour night rate some 20 per cent cheaper than most night-time tariffs, made possible by economies in the night-time operation of the system." In more recent years the difference between day and night rates has become much larger, with typically over 50% reduction (though dependent on the supplier). Choice of the Economy 7 tariff results in either or both of an increased standing (fixed) charge or increased daytime rate. (Also known as "White Meter", mainly in Scotland, with appropriately white-cased meters.)