Magnox’s largest nuclear power station will be shut down at the end of December after 44 years.
The Welsh ‘Wylfa’ site generated almost 232TWh of electricity – enough to power around 1.1 million homes a year.
The plant was initially due to shut down in 2010 but continued to generate for another five years.
Magnox added: “Wylfa’s extra five years of generating life has resulted in an estimated £785 million additional revenue for the UK taxpayer.”
Last year regulators extended the plant’s life to this month.