Littlebrook Power Station
Encyclopedia
Littlebrook Power Station refers to a series of four oil and coal-fired power stations
Fossil fuel power plant
A fossil-fuel power station is a power station that burns fossil fuels such as coal, natural gas or petroleum to produce electricity. Central station fossil-fuel power plants are designed on a large scale for continuous operation...

 situated on the south bank of the River Thames
River Thames
The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

, next to the Queen Elizabeth 2 Bridge and the Dartford Tunnel in Dartford
Dartford
Dartford is the principal town in the borough of Dartford. It is situated in the northwest corner of Kent, England, east south-east of central London....

, Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...

.

Littlebrook A

The first power station on the site was the coal-fired
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 Littlebrook A Power Station, built by the Kent Electric Power Company in the early 1930s. It was opened in 1939. Coal was initially brought to the station by rail
Rail transport
Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...

, until a riverside pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...

 was completed. The station was later converted to burn oil, and remained in use until it closed in 1973.

Littlebrook B

The construction of Littlebrook B Power Station was delayed by the Second World War, and came into use between 1949 and 1950. Like the A Station, it originally burned coal, but was later converted to burn oil instead. It had a capacity of 120MW and remained in use until 1975.

Littlebrook C

Littlebrook C Power Station was opened between 1952 and 1956 by the Central Electricity Board
Central Electricity Board
The United Kingdom Central Electricity Board was set up under The Electricity Act 1926 to standardise the nation's electricity supply. At that time, the industry consisted of more than 600 electricity supply companies and local authority undertakings, and different areas operated at different...

, and had a total generating capacity output of 240MW. Like the two earlier plants, it was originally coal-fired, but was converted burn fuel oil by 1958. The station continued operating until it was replaced by the D Station in 1981.

Littlebrook D

Littlebrook D is an oil-fired power station and was built by the nationalised Central Electricity Generating Board. The station was built by the Cleveland Bridge Company
Cleveland Bridge & Engineering Company
The Cleveland Bridge & Engineering Company is a renowned bridge building and structural engineering company based in Darlington, England. It has been involved in many major projects including the Victoria Falls Bridge and the Humber Bridge.-History:...

 with construction starting in 1976. The first unit commissioning underway by 1981. The 1980s still saw a potential threat from the Cold War and as such the CEGB designed Littlebrook D as a robust station with high plant redundancy meaning that the station would form a pivotal role should disaster have struck the city of London. At this time, London was still dependant on several smaller generating stations within the city itself. Due to the flexibility of the oil fired boilers, a cold unit can be synchronised onto the grid within 4 hours and the increased ability to rapidly increase or decrease load forms a significant part of what makes the station attractive on a commercial basis. Five 110,000 tonne fuel oil storage tanks are used to store the heavy fuel oil for the main units and this fuel is delivered to the site by tankers mooring at one of the sites two jetties on the River Thames.

Originally built with three operational units having a design rating of 660MW MCR (Maximum Continuous Rating), this was increased to 685MW during commissioning with practically no additional engineering works required which is testament to the robust design standards rigorously upheld by the CEGB. This total generating capacity of 1,370 MW (1,475 MW including open cycle gas turbines - see below) is enough power to meet the needs of over 2 million people. Unit 3 has been held in "long term reserve" for a number of years now, mainly due to the wear and tear the boiler experienced during the UK miners strike 1984 to 1985
UK miners' strike (1984–1985)
The UK miners' strike was a major industrial action affecting the British coal industry. It was a defining moment in British industrial relations, and its defeat significantly weakened the British trades union movement...

 where oil fired stations were run aggressively while the base load coal stations were struggling to obtain fuel. The remaining two units are still fully operational, having undergone massive refurbishment investment in recent years to increase their efficiency and further improve the quality of emissions from the 215 m (705.4 ft) tall chimney
Flue gas stack
A flue-gas stack is a type of chimney, a vertical pipe, channel or similar structure through which combustion product gases called flue gases are exhausted to the outside air. Flue gases are produced when coal, oil, natural gas, wood or any other fuel is combusted in an industrial furnace, a power...

, which is the fourth tallest chimney in the UK. Recent investment includes the addition of an electrostatic precipitator
Electrostatic precipitator
An electrostatic precipitator , or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas using the force of an induced electrostatic charge...

 to remove any particulates present in the flue gas before it leaves the chimney and the unit control is currently being upgraded to a modern PLC (Programmable Logic Controller
Programmable logic controller
A programmable logic controller or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and machines...

) based system.

Although the running regime of the Littlebrook D site has changed significantly since it was built, it still forms a critical strategic component to the UK grid system. The site is one of a number of stations throughout the UK with black-start capabilities, meaning that it is able to start generating without an external power supply - the station would be one of the first to start generating should the UK ever experience a partial or complete blackout. Littlebrook D played a vital role in restoring power supplies to the South East of England in the days following the storm force winds of October 1987. The black-start capability is facilitated by the presence of three open cycle gas turbines (OCGTs) each capable of generating 35MW which is sufficient to operate the station auxiliary equipment and allow a main unit to be started. Each OCGT set incorporates two Rolls-Royce Olympus
Rolls-Royce Olympus
The Rolls-Royce Olympus was one of the world's first two-spool axial-flow turbojet aircraft engines, originally developed and produced by Bristol Aero Engines. First running in 1950, its initial use was as the powerplant of the Avro Vulcan V Bomber...

 jet engines which are industrial derivatives of those that were used on the Concorde aircraft. As well as providing black-start supplies to the station, the fact that they can synchronise and ramp up to full load in under five minutes means they are used to generate at the request of National Grid Company (who operate the UK electricity grid system) to deal with short term peaks in demand. Such peaks typically arise during the winter months where evening demand is higher due to lighting and heating requirements. A further facility provided to the National Grid Company by the OCGTs is one of system protection. They will start automatically should the system frequency (50.0Hz in the UK) fall to 49.6Hz which would indicate that the supply from generation is not sufficient to meet the demand. The National Grid Company are obliged to ensure that there is enough operating reserve
Operating reserve
In electricity networks, the operating reserve is the generating capacity available to the system operator within a short interval of time to meet demand in case a generator goes down or there is another disruption to the supply...

 available at all times and as such, low frequency events are rare and will only arise where a substantial loss of generation has occurred.

A modification has been made to one of the units which allows for alternative fuel trials. Several have been trialled at the Littlebrook D site as part of ongoing research into generating energy from more sustainable fuel sources. At present, the current owners of the station have decided that Littlebrook is to "opt-out" under the Large Combustion Plant Directive http://www.defra.gov.uk/environment/airquality/eu-int/eu-directives/lcpd/, an EU directive aiming to deal with air pollutants created by the combustion of fossil fuels. This essentially means that Littlebrook D will cease to generate after 2015 in its current configuration.

After privatisation in 1991, the station was owned by National Power
National Power
- History :National Power was formed following the privatisation of the UK electricity market in 1990. In England and Wales the Central Electricity Generating Board, which was responsible for the generation and transmission of electricity was split into three generating companies Powergen, National...

, and later by its subsidivision Innogy. The station is currently owned by RWE nPower which is owned by the German utility company, RWE.

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