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Medway Power Station

Coordinates: 51°26′23″N 0°41′24″E / 51.43972°N 0.69000°E / 51.43972; 0.69000
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Medway power station
Map
CountryEngland
LocationIsle of Grain
Coordinates51°26′23″N 0°41′24″E / 51.43972°N 0.69000°E / 51.43972; 0.69000
StatusOperating
Construction began1992
Commission date1995
Owner(s)Medway Power Limited
Thermal power station
Primary fuelNatural gas
Secondary fuelFuel oil
Turbine technologyGas fired gas turbines, Heat recovery steam generators and steam turbine
Site area11 acre
Site elevationAbove 200 year storm tide
Chimneys2 (65 metre)
Cooling towers0
Cooling sourceAbstracted from, and returned to, River Medway
Power generation
Units operational2 x 228 MW
Make and modelGE 9FA
Nameplate capacity660 MW
External links
Websitewww.ssethermal.com/flexible-generation/operational/medway/
CommonsRelated media on Commons

Medway Power Station is a 735 megawatts gas-fired combined cycle gas turbine (CCGT) power station on the Isle of Grain in Kent adjacent to the River Medway, about 44 miles east of London. It started to supply electricity to the national grid in 1995.

History

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Medway Power Limited (MPL) was incorporated in September 1990.[1] It is a joint venture company originally comprising Arlington, Virginia-based AES Corporation (trading as AES Electric) (25%) and the RECs SEEBOARD (37.5%) and Southern Electric (37.5%) (became SSE in 1998).[2] In April 1992 MPL awarded a design, procurement and construction contract to a consortium of Europower Development Ltd and TVB Power Ltd. The contract called for a turnkey 660 MW combined cycle electricity generating plant, deliverable by 1 August 1995.[2]

The station was built by Marubeni (Japanese), Tarmac and Kansas City-based Black & Veatch. The station is run by Scottish & Southern Energy under the name Medway Power Ltd. It was commissioned in 1995, being . In June 2002, American Electric Power (AEP) sold its SEEBOARD company to eDF, giving eDF 37.5% of the power station. SSE bought the plant from AES and eDF Energy for £242m on 3 October 2003. It is near (west of) to the Grain Power Station and next to the Thamesport.

The Site

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The station is on an 11 acre (4.45 ha) site, above the 200 year flood plain.[2] There is a requirement that the noise at the perimeter must not exceed 65 dBA. The three turbines are contained within an acoustic enclosure in a containment building. The two exhaust stacks are 65 m tall. Stack emissions are limited to 45 ppm NOx. Cooling water is abstracted from the Medway and chlorinated. Water discharges are monitored and treated prior to discharge.[2]

Specification

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Medway power station is a CCGT-type power station that runs on natural gas. It has two General Electric Frame 9 (9001F) gas turbines.[3] The exhaust gas from these reaches two Nooter Eriksen heat recovery steam generators.[4] The steam from these powers one General Electric steam turbine.

Main plant

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The operating parameters of the main generating plant are as follows.[2]

Medway power station main plant specifications
Parameter Value
Combustion turbine generators (CGT)
Manufacturer General Electric
Model MS9001FA
Type Advanced Aero Engine
Number of 2
Combustion chambers 18
Firing temperature 1,288°C
CGT output 228 MW at 11°C
CGT heat rate 10,180 kJ/kWh
CGT efficiency 35%
Steam turbine generator (STG)
Manufacturer Nooter/Ericsen
Type Natural circulation, triple pressure, reheat type HRSG
Number of 2
Exhaust gases Vented to 65 m high steel stacks at 113°C
STG output 247 MW
STG heat rate 7,934 kJ/kWh
STG efficiency 88.7% HP isentropic, 91.8% IP/LP isentropic
Net output available 682 MW
Net heat rate 6,800 kJ/kWh
Net plant efficiency 53%
Generators
Manufacturer GE
Model GE 324S
Rating 291 MVA / 15,000 V at 0.85 power factor
Type Hydrogen cooled


During a major upgrade project in 2012 the power station benefitted from the GE DLN 2.6 install as well as an upgrade to the excitation and turbine control system. Currently the power station operates as a two-shifting plant with approximately 20MW of black start capacity.

Ancillary plant

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Specification of the ancillary plant is as shown in the table.[2]

Medway power station ancillary plant specifications
Parameter Value
Step up transformers
Rating 290 MVA at 15 kV/420 kV
Manufacturer GEC-Alsthom
Number 3
Ancillary supply Two 20 MVA transformers for auxiliary services
Cooling plant
Manufacturer Hamon
Type Open wet mechanical cooling tower
Construction 12 cell mechanical ventilation
Flowrate 612,000 litres per minute
Design condition 11°C, 80% humidity
Heat rejection 1.614 × 109 kJ/h heat rejection
Condenser
Manufacturer Senlor Thermal
Type Surface condenser
Condensing rate 655,000 kg/h using cooling water at 21°C
Back pressure main steam 41 mm Hg A on steam turbine at 538°C at 97 barA
Back pressure reheat 335°C at 28 barA for hot reheat; 260°C at 6.7 barA
Demineraliser
Manufacturer Glegg
Type Two train two bed
Capacity 4,670 l/min (maximum NOx control

water injection when running on fuel oil)

Feed water deaerator
Operating pressure 150 mm Hg A
Water storage tank
Fuel gas heater
Manufacturer Graham/Crane
Type Water-to-gas heat exchanger
Number 2
Temperature rise 27°C to 150°C
Auxiliary cooling
Manufacturer Allfa-Laval
Type Plate heat exchangers
Number 3
Service Cool auxiliary cooling loop; turbine lube oil;

Generator coolers

Metallurgy Titanium for saline cooling water
Lube oil
Reservoir 30,280 l (8,000 gals)
Equipment Pumps; filters; heat exchangers
Fuel oil
Equipment Dual filters; 3 x 50 % pumps; 2 x atomising air compressors
Control system
Manufacturer Bailey
Type Distributed control and information system (DCIS)
Facilities Operator interface with turbines; control outputs to generators;

Operator control functions; Control of equipment and process parameters

See also

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References

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  1. ^ "Medway Power Limited". Retrieved 2 November 2023.
  2. ^ a b c d e f Leis, Darrell M.; Boss, Michael J.; Melsert, Matthew P. (June 1994). "Medway: A High-efficiency combined cycle power plant design". American Society of Mechanical Engineers, ASME, 1994 International Gas Turbine and Aeroengine Congress and Exposition, June 13–16, 1994. The Hague, Netherlands.
  3. ^ "Products & Services". Gepower.com. Retrieved 15 May 2012.
  4. ^ "Nooter/Eriksen". www.ne.com. Retrieved 9 June 2021.
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