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.
