The electricity system in Great Britain relies on a combination of “baseload” power – from stable generators such as nuclear and biomass plants – and “intermittent” sources, such as wind and solar farms that need the right weather conditions to feed energy into the grid. National Grid also imports energy from overseas, through subsea cables known as interconnectors that link to France, Belgium, Norway and the Netherlands. They allow companies to trade excess power, such as renewable energy created by the sun, wind and water, between different countries. By 2030 it is hoped that 90% of the energy imported by interconnectors will be from zero carbon energy sources.
The technology behind Great Britain’s power generation has evolved significantly over the last century. The first integrated national grid in the world was formed in 1935 linking seven regions of the UK. In the aftermath of industrialisation, coal provided the vast majority of power, before oil began to play an increasingly important part in the 1950s. In 1956, the world’s first commercial nuclear reactor, Calder Hall 1 at Windscale (later Sellafield), was opened by Queen Elizabeth II. Coal use fell significantly in the 1990s while the use of combined cycle gas turbines grew. Now a combination of gas, wind, nuclear and biomass provide the bulk of Great Britain’s energy, with smaller sources such as solar and hydroelectric power also used. From October 2024, coal will no longer be used to generate electricity.
Energy generation data is fetched from the Balancing Mechanism Reporting Service public feed, provided by Elexon – which runs the wholesale energy market – and is updated every five minutes.
Elexon’s data does not include embedded energy, which is unmetered and therefore invisible to Great Britain’s National Grid. Embedded energy comprises all solar energy and wind energy generated from non-metered turbines. To account for these figures we use embedded energy estimates from the National Grid electricity system operator, which are published every 30 minutes.
Import figures refer to the net flow of electricity from the interconnectors with Europe and with Northern Ireland. A positive value represents import into the GB transmission system, while a negative value represents an export.
Hydro figures combine renewable run-of-the-river hydropower and pumped storage.
Biomass figures include Elexon’s “other” category, which comprises coal-to-biomass conversions and biomass combined heat and power plants.