A fire has broken out at gas-fired Didcot B Power Station, according to Oxfordshire Fire and Rescue.
The blaze broke out in one of the cooling towers just after 8pm, and 60 firefighters have been sent to fight the flames.
Emergency services from Buckinghamshire Fire & Rescue Service, Thames Valley Police South and Vale and the National Police Air Service have all been called to the scene.
The power station, which has been in operation since 1997, has the ability to supply power to as many as 1m homes. Next-door coal and gas-fired Didcot A power station was shut down last year, and had its three cooling towers demolished in July.
Oxfordshire's chief fire officer Dave Etheridge told the Oxford Mail that the fire was under control and the smoke plume was not thought to pose a health risk to the public, but locals have been advised by police to go indoors and close their windows and doors.