Wednesday, 1 April 2015

GREENWICH POWER STATION


GREENWICH POWER STATION – this venerable Greenwich installation is apparently due for another upgrade and Transport for London have been consulting locals on it.  Below are a three articles about it and its past –detailed descriptions from the 1970s, telling us what it was like then

FIRST – some lecture notes from Diana Rimel
Greenwich Power station (Old Woolwich Road)  This is on the site used from 1704 to 1860 for the massive Jacobean mansion of the Crowley family, who had the largest iron manufacturing business in Europe in the 17th and 18th centuries, and married into the Ashburnham family.   Land was then bought by Trinity Hospital, and presumably leased or sold to the London County Council who had horses on it (possibly for trams) here.   The power station was built (1902-10) by former LCC's Architects Department, General and Highways Sections, for the LCC tramways.  The dates are outside on the rainwater heads high up.  There are a Few remains of tram tracks left. but it is mostly simple stock brickwork on a monumental scale. The four tapering octagonal chimneys were truncated at two-thirds height, destroying the original proportions. On the riverside is a massive disused coal jetty, built to take weight of cranes. Coal ships from north-east coast came here till the 1970s, and the coal bunkers are still there.  It changed when gas turbine came in – and diesel oil was delivered by tanker. It is now part of London Underground Limited, General Division and provides emergency power to London Underground, remotely controlled from Lots Road, Chelsea.  The Building considered rather fine by industrial architecture buffs (except for the truncated chimneys). The 'Cottage' on the corner of Hoskins street was lived in by the piermaster.


Then a handout written for a 1970s Open House day:
OPEN HOUSE - Greenwich Generating Station

Welcome to Greenwich Generating Station, one of three buildings where guided tours are being arranged as London Transport's contribution to London Open House Day's 1998 programme.
Greenwich Generating Station was built on the site of an existing horse tram depot between 1902 and 1910 by the London County Council (LCC) to provide the power for its growing network of electric tramcar routes. The largest building which at that time had been erected by the LCC, the Station was opened in two stages, the northern half in May 1906, and its southern counterpart in 1910. The riverside location offered the joint advantages of direct delivery by boat of coal to fuel the boilers for the steam engines and a supply of water for condensing the steam.

The main building comprised a Boiler House with four chimneys, and an Engine Room from where current was transmitted at 6 600 volts to substations (including one on site) which supplied direct current to the trams at 550 volts. The capacity was 34 megawatts, which was sufficient to power the entire LCC tram system. The two chimneys in the first section to be opened, at the north (River Thames) end of the site, were originally 76 metres high but because the Station is almost on the Greenwich Meridian, the Royal Observatory complained that smoke from the chimneys obscured their observations. The two later chimneys at the south end of \ ... the site further from the river were built only 55 metres high, and the original taller chimneys were shortened to 55 metres during the modernisation work in the 1970s.
The development of the Station
By 1910, steam turbine technology had proved superior to the piston engines installed four years earlier, and four steam turbines were installed for the second stage opening that year. By 1922 the original engines had been removed and replaced with turbines. In 1933, the London Passenger Transport Board took over all road and Underground services in Greater London, including the power stations at Greenwich, Lots Road in Chelsea and Neasden.
 
The London Transport Conversions to oil and gas firing
In 1967 it was decided to replace the steam turbines with gas turbine plant burning oil delivered, as the coal had been, by river. The changeover from coal made possible a reduction in the staffing level by almost 90 per cent. The most visible evidence of coal firing is the 50 massive steel bunkers, each with a capacity of 270 tons, which occupy the upper part of the Boiler House. The gas turbines were modified in 1975-77 to burn either natural gas or oil, with gas as the main fuel and oil as a back-up. With post-war power stations like Bankside in Southwark already closed and being converted for other uses, London Underground's two remaining generating stations (Greenwich and Lots Road, Chelsea) are rare survivors from early this century.

The operation of the Generating Station today
All London Transport's electric vehicles (trams, trolleybuses and Underground trains) have been supplied by power generated at Greenwich during its 92-year history. Today, the role of the Station is to supplement the output of the London Underground's principal generating station at Lots Road during peak periods, and to provide emergency supply at other times if required. Full power can be delivered to the system in about three minutes.
The gas turbine plant is housed in the original Boiler House and is driven by an industrial version of the Rolls Royce "Avon" jet aircraft engine. The high temperature, high velocity exhaust gases from the Avon engine drive a power turbine which in turn drives an alternator. The operation is fully automatic, and a minimum of staff supervision is needed. The installed capacity now is 103 megawatts.

The future of Greenwich Generating Station
Negotiations were concluded last month for SEEBOARD Powerlink, a private sector consortium, to take over responsibility for London Underground's high-voltage power distribution network. It is planned that Lots Road will be de-commissioned within two years, and that part of the Greenwich plant will be refurbished and retained for emergency back-up use only. London Underground's power requirements will then be purchased from private electricity suppliers for delivery to the system via the Powerlink network.

William Edward Riley
Greenwich Generating Station was designed in consultation with the London County Council's own architect, W E Riley, and the Council used its own labour force for much of the construction work. Other buildings which Riley designed for the LCC include the Central School of Art and Crafts, Southampton Row; the Sessions House in Newington Causeway; and several large LCC housing estates notably the Old Oak Estate in Ducane Road, Hammersmith, and the Totterdown Estate (1 229 cottages) in Tooting.
The architectural design of the station

a) External features. Ocupying a 3.75 acre site next to the Trinity Almshouses, Greenwich Generating Station is, with its London Underground counterpart at Lots Road (1902-04), an early example in London of a steel-framed building. The dimensions are 114 m by 59 m, with a maximum roof height of 24 m. For non-industrial buildings, the Ritz Hotel of 1904-05 is generally considered to be London's first major steel-framed structure. The walls are of stock brick set off by Portland stone decorations, notably on the south and north elevations. The original slate roof has been replaced by corrugated sheeting, but decorated rainwater heads dated 1903 (on the north side) and 1908 (on the south side) survive. The twin-naved main block comprises the original Boiler House on the west (upstream) side and the Engine Room on the east (downstream) side. Linking the Boiler House to the river is the coaling pier separately designed and constructed by the LCC's Chief Engineer, Maurice Fitzmaurice. Attractive features are the large end windows and the tapering chimneys, although when the two north chimneys were shortened elegant decorated bands near the top were lost. The west side of the Station has been somewhat disfigured by the addition around 1927 of large concrete coal bunkers.
b) Internal features - the west nave.   The lower level of the west nave - originally the Boiler House, with 48 boilers in groups of six - is now the Gas Turbine Hall where seven units (one has been taken out of commission) generate the power output. Air is drawn in through filters on the upper floor and the exhaust passes through ducts to the chimneys. The former coal bunkers in this upper section were filled from above, originally by a bucket conveyor but later by a belt conveyor which entered the Boiler House through the north window. The coal passed by gravity through chutes to the mechanical stokers of the boilers below. The ash from the boilers was similarly removed by conveyor in the basement to bunkers under the pier from where it could be removed by barge or by road.

c) Internal features - the east nave. The east nave, now largely unused, was the former Engine Room where four steam reciprocating engines made by John Musgrave and Sons of Bolton were the last slow-speed engines to be installed in a British power station. The first steam turbines were installed in 1910 at the south end of the Engine Room, and by 1922 the remaining engines had been replaced by turbines. The walls are faced with white and brown glazed bricks, and along the roof of the Engine Room are gantries for a travelling crane.
Ancillary buildings  - On the eastern side of the main building were offices, the original control room and a substation which converted the electricity to 550 volts direct current for the trams. The control room occupied the central section at an upper level. The two- storey offices at ground floor and gallery level are panelled rooms with simple neo-Georgian fireplaces, and include an early telephone switchboard.
On the western side of the building are the 11 massive white reinforced concrete reserve coal bunkers added over the yard around 1927. Conveyors were used to transfer coal into and from these bunkers to the boilers, in the latter case on a circuitous route via the pier!

In the south east corner of the site is the former Pier Foreman's house (10 Hoskins Street) which provides a picturesque, domestic scale, contrast to the Generating Station.
The riverside structures

The Coaling Pier (1903-05) extends some 36 metres into the Thames, and is 60 m in length and 12 m in width. The pier is supported by 16 concrete-filled cast-iron Doric columns. The steel-girder superstructure of the pier originally had a timber platform on which cranes unloaded the coal (1 000 tons a day) from the colliers, initially into trucks which delivered the coal to the Station's external bunker, but subsequently on to conveyor belts which carried the coal directly to the upper levels of the Boiler House.
The area above the 1 900-ton capacity steel bunker on the riverside was converted in 1969-72 to accommodate 12 fuel-oil tanks, fed from five 112 500 gallon fuel-oil storage tanks into which the oil was pumped formerly from tanker barges and which were installed at the same period. These larger tanks are on the site of the pump house which supplied water for condensing the steam from the original engines. Now that the station is gas fired, oil deliveries are by road and the pier is not used.

The Generating Station's railway
On the quayside there are rails which passed through a gateway, now bricked up, into the site. The rails carried a 30-ton swan-necked crane which was used to unload barges. and inside the site there was a railway around the perimeter for moving heavy components.

Sources: September 1998 Greenwich Generating Station (Royal Commission on the Historical Monuments of England. 1995) Temples of Power (Gavin Stamp. 1979) J                

 
AND ANOTHER HANDOUT FROM THE 1970S

LONDON UNDERGROUND LIMITED POWER SUPPLY ENGINEER'S DEPARTMENT GREENWICH GENERATING STATION

Introduction. Greenwich Generating Station was built by the London County Council to supply the growing electric tramway system, and was opened in two stages in 1906 and 1910. The main building comprised the Boiler House, with four chimneys, and the Engine Room which, in the first stage, housed four vertical/horizontal compound reciprocating steam engines driving flywheel type alternators, operating at 6,600 volts, 25 Hz. By 1910, the superiority of steam turbines, compared with piston engines, had been realised, and four steam turbine alternators were installed for the second stage. Because the generating station is almost on the Greenwich Meridian, objections were received from the Royal Observatory that smoke from the chimneys was interfering with their sightings, so the second (southern) pair of chimneys was limited to 182 ft. in height, compared with 250 ft. for the first pair.

By 1922, the original reciprocating engines had been removed and replaced with steam turbines, and various modernisation works were carried out during the following thirty-five years, including adoption of the national frequency of 50 Hz. The L.C.C. Tramways were absorbed into the L.P.T.B. in 1933 and it was planned to generate at Greenwich the power required for the railway extensions in North-East London and for the Trolleybus system which was to replace the trams in east and south London. The programme was deferred by the War but, until the trolleybuses were scrapped in 1961, the station served both the road services and railway operations.

Following the complete modernisation of Lots Road Generating Station in 1963-68, it was decided to replace the old steam-driven plant at Greenwich by installing gas turbine generators, which enabled the staff to be reduced by nearly 90 per cent. The main requirement for Greenwich is to supplement the output of Lots Road during peak load periods and to provide a standby supply to the system as quickly as possible if required. The Greenwich sets can reach normal full load in about 3 minutes after pressing the 'Start' button, which can be done either at Lots Road or Greenwich.
Gas Turbine Alternators
Eight gas turbine alternator units were installed in the former Boiler House with two units exhausting to each of the four chimneys, but more recently one has been taken out of service. They were built by Stal-Laval Ltd. which later became part of the ASEA- Stal Group and is now in the ABB organisation. Each unit has five main components: a gas generator, a power turbine, an alternator, a transformer and an automatic control and monitoring system.

The gas generator is a Rolls Royce 'Avon' Type 1533 and is essentially an industrial version of the 'Avon' jet aircraft engine which was used in many civil and military aircraft. This comprises a 17-stage axial flow compressor, eight combustion chambers, a 3-stage turbine which drives the compressor, and a fuel control system. A transition duct channels the hot gases exhausting from the gas generator to the power turbine inlet. There is no mechanical drive between the gas generator and the power turbine.
The power turbine is of the 3-stage axial-flow design and is mechanically coupled, by a drive shaft, to the alternator. The alternator generates 3 phase, 50 Hz electric power at 11,000 volts and has a maximum continuous output of 14,700kW. . although they are normally loaded at the economic rating of 11 ,000kW. The output is fed to the 22,000 volt switchgear via the associated step-up transformer.

The run-up, loading and shut-down of the gas turbine alternators is fully automatic following the operation of a single push button, and is controlled by equipment located in the two Plant Instrument Rooms which were constructed between each pair of chimneys. Full monitoring instrumentation has been provided to facilitate minimum supervision by staff. If the gas turbine alternator malfunctions, the fault will be registered on the associated control cubicle and, if necessary, the set shuts down.

Principle of Operation of the Gas Turbine units.
Air for the gas generator is drawn through roller blind type impregnated filters situated on the upper floor of the gas turbine hall. These extract dust before the air reaches the inlet to the gas generator to reduce fouling of the compressor blades and to protect the engine from damage. The air is drawn through ducting, which contains a silencer, downwards into a sealed chamber from which it passes into the compressor inlet. The air pressure is raised about ten times before it passes into the eight combustion chambers. Fuel is forced at high pressure through the burners into the combustion chambers where it burns in the compressed air.

The 'Avon' units were originally designed to burn Light Distillate Oil (i.e. Gas Oil) but were modified from 1975 to bum either natural gas or gas oil. The oil is held in storage and service tanks with a total capacity of over 3~000 tons and so is immediately available. Gas is obtained from the British Gas (Transco) system and must be raised to a pressure of 20 Bar. before it passes through control valves to reach the burners.
The high velocity, high temperature, gas stream issuing from the combustion chambers is directed through nozzles onto the 3-stage turbine, still within the gas generator, which drives the compressor. The gases emerging from this turbine are at a lower pressure but still at a high temperature, and pass through the transition duct to the inlet to the power turbine. "

The hot gases expand through the power turbine where the energy is extracted in driving the turbine and the alternator rotor which is coupled to it. The output of the alternator is governed by the temperature of the gas stream which in turn is governed by controlling the supply of fuel to the gas generator by the automatic control system. The exhaust gases from the power turbine pass through ducting containing a silencer to one of the chimneys. Thus, the force of the gas jet, which would be used to propel an aircraft, is here utilised in driving the power turbine and alternator. The gas generator is started by a motor housed in the nose cone at the compressor inlet, powered by batteries.
Fuel system. When the gas turbines were installed, they burned gas oil which was delivered by river tanker to the pier, originally provided for coal deliveries. Storage tanks for 2,500 tons and Service tanks for a further 500 tons were provided. The oil passes through fine strainers and is held in the Service tanks to ensure the removal of any particles which could block the burners. However, since the engines were converted for dual-fuel operation (gas or oil) the quantity of oil required is so reduced that deliveries by road tankers are adequate and the pier has been taken out of use.

Gas enters the premises at a pressure of about 6 Bar. and passes to the Gas Compressor House constructed in the former Steam Turbine House. Three 4-cylinder two-stage reciprocating compressors are installed which raise the pressure to 20 Bar. A common main on the roof of the gas turbine house delivers the gas to a Gas Control cubicle adjacent to each G- T unit.
Cooling Water system. Cooling for the alternator, the transformer, the power turbine lubricating oil and the gas compressors is by a two part circulating water system. The primary system pumps water from the River Thames through heat exchangers and back to the river. The secondary system is a closed circuit; water from storage tanks on the upper floor flows by gravity through the various coolers to low-level tanks in the basement and is then pumped through the heat exchangers, where it is cooled, and returned to the storage tanks.

High Voltage Switchgear. The main switchgear is housed in a switchroom situated on the east side of the building.
The power generated by each gas turbine alternator is fed via 22,000 volt cables to individual circuit breakers. From the switchroom, the power is connected to the Underground's electrical system through cables to Lots Road, Mile End, Aldgate (Mansell St.) and Stockwell.

Office of the Generation Manager, 55, Lots Road, Chelsea, SWIO OQG JMB/Jan.97

The two handouts have pictures with them but these are not included because of the low quality of the photocopied originals and the high probability of them being copyright.

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