A fire at Tilbury Power Station has seen around 100 firefighters called to the scene to fight the 'severe' blaze.
Essex County Fire & Rescue Service said firefighters were called to Tilbury Power Station at about 7.46am, with 15 fire engines and three aerial ladder platforms, used to reach higher places, sent to the scene.
A spokesman, who described the blaze as "severe", said the officer in charge had reported that the fire is in a wood pellet hopper containing 2,100 tonnes of machinery.
Opened in 1969, Tilbury previously operated as a coal-fired power station but has been converted to generate power from 100% sustainable biomass until its scheduled closure at the end of 2015.
Biomass plants burn wood pellets, generally made from compacted sawdust or other wastes from sawmilling and other manufactured wood products.
A spokesman for RWE npower, which owns the power station, said: "A fire broke out at 7.45am this morning in a fuel storage area at Tilbury power station.
"The health and safety of our employees is our absolute priority and all have been accounted for.
"The fire brigade and police are currently on site. We will issue more details when they become available."
CORRECTION: An earlier version of this article incorrectly labelled one of the pictures as Tilbury Fire Station instead of Tilbury Power Station