Unit 4 was put into operation in 1967. In 1995 this block was retrofitted with a fluidized bed furnace . According to E.ON, this is the largest fluidized bed furnace in the world. Due to stricter environmental regulations, the unit should have been taken out of service by January 1, 2016 at the latest. That is why E.On commissioned the plant construction company Doosan in 2013 to convert Block 4 into a block fired with biomass (wood) with an electrical output of 150 MW. The fluidized bed furnace was modified and the steam turbine revised. The conversion is intended to Template: future / in 5 yearsextend the service life of the power plant unit until 2034 . It is the largest biomass plant in France; in normal operation it requires 855,000 tons of wood per year. Critics fear overexploitation of the regional forests. The test operation started in February 2016, in January 2017 the start of regular operation was assumed to be imminent, but without specifying a specific date. On June 8, 2017, the Marseille administrative court withdrew the facility's operating license due to an inadequate environmental impact assessment. Uniper appealed against it.
