Drax, the UK’s largest power station is situated in North Yorkshire, dwarfing the neighbouring village it is named after. It is situated on the River Ouse between Selby and Goole and has a generating capacity of 3,960 megawatts (MW). Drax was the third power station in the area to be commissioned by the Central Electricity Generating Board (CEGB) following the discovery of the Selby Coalfield, the first being an expansion of Ferrybridge (2,000MW Ferrybridge ‘C’) and the second was a new 2,000MW station at Eggborough. The power station was built in two phases – the first phase comprised three units and began operation in 1973. The second phase of construction was completed in 1986, making Drax the last major coal-fired power station to be built in the UK.
Drax was initially conceived as the largest power station in the UK, at 3,000MW. The capacity was expanded further when the CEGB saw this as a good opportunity to install their first 660MW turbogenerator sets and the plans were revised to almost 4 gigawatts.
The turbine hall is around a quarter of a mile long (400m) and the chimney is the tallest industrial chimney in the UK at 259 metres high. The twelve natural draught cooling towers are 114 metres high and arranged in two groups of six to the north and south of the station.
Buildings and Plant Detail
Decarbonisation – Conversion to Biomass
Drax began testing the firing of biomass in 2004, when it converted one boiler to co-fire biomass along with coal. In 2012 Drax announced plans to convert three of its six units to full-firing with biomass. Following this conversion the first unit came online in June 2013, the second in 2014 and the third unit in 2016. One further unit was converted to fire biomass in 2018. Drax now supplies up to 12 percent of the UK’s renewable energy through its four biomass-only boilers.
Construction and Infrastructure
A conversion to biomass on such a large scale is a huge undertaking, and is in fact the largest decarbonisation project in Europe. One of the biggest challenges is the logistics behind sourcing the fuel. The biomass is acquired from sustainable forests in North America, where waste products are collected up and processed to create pellets suitable for feeding into the power station. The pellets are then transported by road and rail to Louisiana where they are transferred to 50,000 tonne barges to be brought to the UK. The final leg of the journey takes place by rail after which the wood pellets arrive at Drax and are housed in huge biomass storage domes. Unlike coal, which can be stored outside and open to the elements, biomass needs to be kept dry. The four purpose built domes can each hold 75,000 tonnes of biomass in a controlled atmosphere.
The overall aim of converting to full-firing of biomass is to reduce the carbon emissions. Drax was the UK’s sole largest emitter of carbon, and although carbon is still released from burning wood chips, it is carbon that has recently been absorbed while the wood was growing in the forest. As the forest is replanted, further carbon is absorbed from the atmosphere to, in theory, create a carbon-neutral process. The preparation of the biomass releases a small amount of carbon, and oil burnt to transport the biomass from North America to the UK further adds to the emissions. Even after these factors are taking into account, the carbon emissions from the three converted units at Drax have been reduced by 80%.
The move away from coal isn’t stopping at the conversion of three units to biomass. Drax aims to become free of coal by 2025 and has laid out plans to convert its remaining two coal-fired units to run on gas. The project will see the construction of two combined cycle gas turbine generators, the waste heat from which will be used to generate steam for two of the existing steam turbines. The gas turbines and two converted steam turbines will generate more electricity than the current total station output, while also lowering emissions.
Drax Image Gallery
Visit the plant detail pages above to view more images from each area of the power plant