Drax Power Station - Electricity Generation

Electricity Generation

Coal is fed into one of thirty coal bunkers, each with a capacity of 1,000 tonnes of coal. Each bunker feeds two of the station's sixty pulverisers, each of which can crush 36 tonnes of coal an hour. The station has six Babcock Power boilers, each weighing 4,000 tonnes. The powdered coal from ten pulverizers is blasted into each boiler through burners, which are ignited by propane. In 2003 the original burners were replaced by low nitrogen oxide burners. Each of the six boilers feed steam to a steam turbine set. Each steam turbine consists of one high pressure (HP) turbine, one intermediate pressure (IP) turbine and three low pressure (LP) turbines. The HP turbines generate at 140 megawatts (MW). Exhaust steam from them is fed back to the boiler and reheated, then fed to the 250 MW IP turbines and finally passes through the 90 MW LP turbines. This gives each generating set a generating capacity of 660 MW, and with six generating sets, the station has a total capacity of 3,960 MW. Each of the generating units is equipped with the Advanced Plant Management System (APMS), a system developed by RWE npower and Thales, and implemented by Capula.

The station also has six gas turbines installed. These standby turbines provide backup for breakdowns, or shut downs in the National Grid. Their annual output is generally low, generating 75 MW. and three of the units have been mothballed and are out of operation, but they could be refurbished. Emissions from these units are released through the stations second, smaller chimney, to the south of the main stack.

Between 2007 and 2012 all the power stations high and low pressure turbines were replaced by Siemens according to a £100 million replacement program.