Lots Road Power Station Visit

David St George

On arriving at the station, I was reminded of Ronnie Barker in "Porridge". There is a massive gate with a small door inset and on ringing the bell I was admitted and after stating who I was, I was shown (or escorted!) into a small guard house where I had to give all possible details and fill in a form. I was then given a pass 'to be worn at all times whilst on the premises'.

After a short while a very pleasant gentleman appeared and I was shown up two flights of stairs to an immaculate 'chemi lab' which my guide explained was a very necessary part of the station. (He was a chemist by profession.) From this pristine atmosphere I was escorted through a long passage to the heart of the station. Here things were very different, noisy and dirty! Looking down into the generator hall was like looking into a large cathedral with the alternators lined up neatly in a row. Lots Road Power Station provides, together with Greenwich power station, the motive force of the London Underground.

There is an ancient rumbling lift which took us to various stages including the boilers (gas fired) and the switch room. From the roof I can see Chelsea's football ground and a large distance up and down the Thames. The land between the King's Road and Chelsea Creek had been occupied by a riverside garden and a house built in 1745 and later enlarged for Viscount Cremorne. In 1832 the grounds became the Cremorne Stadium but were closed in 1877. A pair of wrought iron gates from the gardens is now displayed to the public in a garden at the eastern end of Lots Road.

When the District Railway acquired the power station site in 1902/3 the houses on the north side of Lots Road had already been built. In 1901 James R. Chapman, chief engineer to the MDET Co. who had come from America with Yerkes, invited tenders for the supply and installation of plant at Lots Road. The Westinghouse Electric Manufacturing Co. of Pittsburgh was invited to tender for four 7000 HP compound engines and The British Westinghouse Co. for four 5,000 kW, 11,000 volt, 25 Herz alternators.

Westinghouse offered either a four cylinder, double compound engine, as specified, or a three cylinder, vertical compound engine which was similar to engines in use in various stations in the U.S. Alternatively, they offered a tandem steam turbine for which an improvement in steam consumption of 6.66% compared with the conpound engine was claimed. The prices quoted for four units were:- Four 4-cylinder, couble compound engines (not including crankshafts which were to be purchased separately): 135,480 Four 3-cylinder, compound engines (including crankshafts): 148,920 Four steam turbines: 127,080

A letter of intent to purchase four steam turbines with four alternators for 152,000 was issued in August 1901. This was subject to the result of arbitration on the dispute with the Metropolitan Railway, over the system of electrification to be adopted jointly for the Circle Line, being in favour of the use of direct current, as opposed to the GANZ three-phase overhead conductor system. The decision in favour of the D.C. system was given in December 1901, after a Board of Trade tribunal had heard evidence on the two systems on twelve days in October and November. However the capacity of the generating station would have to be increased to 40,000Kwts. To provide for the requirements of the three tube railways beside the District Railway.

The contract was therefore placed for eight steam turbine alternators each having a nominal output of 5,500 kW and operating at 1,000 RPM to give a frequency of 33.3 Hz (as compared with 5,000 Kw and 25 Hz originally specified).

Construction work began in 1902 and involved sinking some 220 concrete piers to provide the foundations for the steel structure. The timber bank on the north side of Chelsea Creek was replaced with a brick wall and the walls of the main building were also constructed in brickwork, supported by the steel frame. The building was 453 ft long, 175 ft wide and 140 ft high to the apex of the boiler house roof and was surmounted by four brick chimneys 275 ft high. The structural steelwork was ordered from Germany so the dimensions were in millimetres - 60 years before the British civil engineering industry adopted the metric system.

The first plant to be installed in its permanent position was a 35 ton electric travelling crane built by Jessop & Appleby of Leicester. This could move on rails across the west end of the site between the creek and Lots Road and was used for deliveries of materials or heavy components from either barges or carts. It remained in position near the Lots Rood wall until the west yard was cleared for the second modernisation programme in 1963. During construction site power for lights and for driving the cranes and air compressors was obtained from one of the dynamos intended for supplying excitation current to the alternators. This was driven by a 175 HP vertical compound engine and was erected in a temporary house in the west yard. There is no record of an architect for the building which is massive, especially when seen against the three-storey houses. The coal elevator at the east end of the building, together with the four chimneys, gives rise to a comparison with an elephant lying on its back.

The boiler house contained the 64 Babcock and Wilcox WIF Land type boilers on two floors, supported directly on the steel framework of the building, with space for a further 16 units. The boilers were arranged in two facing rows on each floor. Eight boilers were grouped to supply steam to each turbine. There was also a pump to raise water from a 450 ft well. The boilers would provide some 16,000 lb of steam per hour at a pressure of 200 lbs/sq in and a temperature of 500F. The ash hoppers under each boiler were discharged into hopper wagons on a narrow gauge railway track in the basement. These were hauled to the west yard by a battery powered locomotive where the ashes could be loaded into a barge moored in the Creek or carted away by road. The artist James McNeil Whistler protested that it would completely ruin the view of Chelsea Reach painted by Turner. In 1907 the UER Co. was prosecuted by the Chelsea Borough Council for causing a nuisance by allowing black smoke to issue from the chimneys. The prosecution claimed that the company had improved conditions for railway travellers by removing the smoke from the tunnels but, by other means, were discharging it over the citizens of Battersea and Chelsea. After seven days in Court, between July and November, the Company was acquitted and awarded costs of 300 guineas.

The turbine house structure included three galleries on the north side and originally across the east end. These were occupied by the 11,000 volt switch gear and bus-bars, the control panels, voltage regulators, auxiliary transformers and low voltage switch gear and the control panels for the excitation sets. The high voltage switch gear was supplied by BTH and was a cellular pattern with manually operated switches to isolate the oil circuit breakers which were operated by small 125 volt d.c. motors supplied by the station battery. From the feeder isolating switches, the feeder cables were run down to the basement to a block of 64 ducts that were laid through the streets to Earls Court station, from where the cables ran alongside the railway to 24 sub-stations.

The turbine house was equipped with two 18 ton overhead travelling cranes which still carry the name plate of Herbert Morris & Bastert Ltd, Empress Works, Loughborough. During the 1914-1918 war the firm dropped the Germanic-sounding name 'Bastert' from its title and continued as Herbert Morris Ltd. The generating sets were erected on large pier foundations built up from the basement level. The Westinghouse turbines were a single cylinder, double flow design which was claimed to eliminate end thrust and the need for a balance piston. The main bearings were spherical, each weighing 8 tons and had cooling water jackets and the couplings to the alternator spindles were a flexible claw design to allow for some misalignment. Oil was supplied to all bearings from a central oil cooling and filtering plant with the coolers below low tide level in the basement of the building overlooking the barge dock. Water for cooling the condensers and the oil plant was drawn from the river through two 66 inch pipes and a connection to the oil coolers was also provided from the barge dock for emergency use at low tides. The excitation current for the alternators was provided by four 125 volt d.c. 125 kW generators driven by vertical compound steam engines, which also provided a central battery and station auxiliaries. The turbine exhaust was discharged to vertical condensers, provided with automatic relief valves, which appears to have been a common occurrence due to the failures of the various auxiliary pumps! The condensers were installed in the central pit between the two rows of turbines.

Cooling water was supplied and discharged through the two 66 inch pipes running the full length of the turbine house below the sub-basement floor, arranged so that any build up of silt in the delivery pipe could be cleared by reversing the flow. The circulating system was syphonic, with a vacuum pump to prime the system and a circulating pump on each unit.

Two machines were first run during November 1904 but it was January 1905 before one was taking load. Only four sets were available when the first supplies for the public railway service were given in June 1905 although a fifth set became available in July. The last of the eight units was in service in May 1906. Numerous problems arose with vibration and erratic governing, with failures of the automatic stop valves, the circulating water pump drives and the vacuum pumps. Turbine blades were stripped on 18 occasions during the two years to January 1907 and several alternators required repairs to either the rotor or the mains wiring. There were also problems with cooling the alternators and with noise complaints from neighbouring houses. In January, February and March 1905 - before commercial operation had started - Yerkes was complaining to Geo. Westinghouse that he was receiving threats of legal action from owners of the neighbouring properties because of the noise and vibration. On the 10th March 1905 Westinghouse replied that "every possible effort will be made to hasten forward the needed changes. No one however is better aware than you are, how much time is consumed in England in doing even ordinary work". In November 1905, "formal notification of nuisance was received from the Chelsea Authorities" and on the first of January, 1906, a complaint was received from the LC.C. about vibration at the Ashburnham School on the opposite side of Lots Road.

Alterations to the enclosures of the alternators were made in 1906 with satisfactory results on both temperatures and noise, although there was still doubt about the machines meeting the specified 50% overload.

Trial running of two electric trains with different traction control equipment and motors had started in March 1903 between Ealing and South Harrow, using an electricity supply from a temporary power station plant at Alperton. The service was opened to the public on June 23rd 1903 between Mill Hill Park (now Action Town) and Park Royal for the Royal Agricultural Show, being extended to South Harrow on June 28th 1903. A trial run was made eastwards from Mill Hill Park in the early hours of the 20th January, 1905 presumably using power from Lots Road, but had to be abandoned because there was insufficient clearance for the new rolling stock to pass some stations!

The first through trip from Mill Hill Park to Bow Road and back was made on the 28th March 1905. On the 13th June 1905 a public service was operated from South Acton through Mill Hill Park to Hounslow and from that date the District Railway began to depend on the output from Lots Road. Steam locomotives continued on the Inner Circle until 23rd September and almost all steam trains were withdrawn from the District Railway by 5th November 1905.

Westinghouse continued to repair and modify the plant in the attempt to obtain more reliable operation.

A contract with C.A. Parsons & Co., dated 31st December 1908, provided for the installation of four steam turbines to drive four of the existing alternators, with the resulting sets having a rating of 6,000 kW. A Second contract followed for four further units and all the Westinghouse turbines had been replaced by 1910. The contract price for each turbine was 8,100, which may be compared with the original Westinghouse tender price of 31,000, although this had been reduced in subsequent negotiations. The load on the generating station increased as the tube lines were opened. The Baker St and Waterloo Railway was opened on March 10th 1906 between Baker Street and Kennington Road and was extended to Elephant and Castle on August 5th 1906 and to Edgware Road during 1907. The traffic did not grow as quickly as had been hoped and Chapman stated in January 1907 that only three 5,500 kW machines out of eight were required to meet the load of the District, the Bakerloo and the initial service level on the Piccadilly. However, the high rate of failures on both turbines and generators seriously reduced the spare plant capacity available. Replacement of the Westinghouse turbines by the larger Parsons machines in 1909/1910 was necessary to improve this position. The Central London Railway which had its own power station at Wood Lane, Shepherds Bush, was also taken over in 1913 but the transfer of this load to Lots Road could not be undertaken until later. The long awaited increase in railway traffic levels came during the 1914/1918 war. By 1919 the load on Lots Road was nearly 18%zzz of that of 1914. The original high-voltage switch gear has been installed in 1905 for a plant capacity of 50,000 kW and the increase to over 100,000 kW would have raised the fault capacity seriously beyond the safe level. The bus bars were replaced with conductors of larger cross section and new cell work, with bus junction switches to divide them into five sections and a new section of bus bars was installed to form a ring.

New group feeder switches with the higher rating were installed as an initial improvement to avoid clearing a cable fault on the old circuit breakers, but when a cable fault did occur, this made it impossible to discriminate between the feeders in a group. New feeder switches were provided later which also required the feeder bus bar cells to be rebuilt to accommodate the larger switches. Generator reactors were also provided to limit the fault level. A new control room was built over the offices at the east end of the turbine house, but to obtain the necessary width an unsightly steel structure was placed outside the east elevation. The old control board on the gallery projecting over the turbine hall was considered to be too exposed. The 1927 report includes the under-statement that "In the event of trouble in the station, the operator and board are exposed to flying fragments of broken machinery and to the escape of steam. These in addition to the noise and confusion below him are likely to distract the operator's mind from his work"! Installation of the larger turbines at the west end of the turbine house had required improvement of the circulating water system and a new tunnel, 93 inches in diameter, was constructed forming a loop under the creek connecting the ends of the existing twin 66 inch pipes to a new intake. By 1928, four 15,000 kW sets were in service and replacement of six of the remaining 6,000 kW sets continued.

Subsequently, the first two 15,000 kW turbines were replaced after which all the sets were rated at 18,750 kW. On completion of the reconstruction programme, the station had 40 boilers and 10 turbo-alternators. The general strike of 1926, when the power station was manned by naval personnel, had drawn attention to the risk of the underground associated with its independent power supply system at a non-standard frequency. The extensions to Morden and Cockfosters had already been supplied from public supply undertakings at 50Hz. After the formation of the London Passenger Transport Board in 1933, the need to co-ordinate the separate power supply systems of the constituent undertakings was recognised and it was decided that the standard supply frequency of 50Hz should be eventually adopted.

The 1939/1940 New Works programme included the first stages of modernisation at Greenwich and Neasden Generating Stations, and the provision of a link between Lots Road and Neasden by connecting transformers installed at both stations with 22,000 volt cables. These cables were laid along the West London Extension Railway from Lots Road to West Brompton, the via Earls Court and the Circle and Metropolitan lines. When it became necessary to take precautions against air attack, they were also turned in at a new switch house and control centre at the northern corner of the triangular junction of the District and Circle lines between Earls Court and Gloucester Road and High Street Kensington known as Cromwell's Curve. Here another group of transformers reduced the voltage to 11,000. Thus the bus bars at Cromwell Curve could be fed from either Lots Road or Neasden which were also connected. The 11,000 volt feeders from Lots Road to substations in the central and eastern areas which passed close by, were also connected to the Cromwell Curve switchgear so that they could be fed from either power station if necessary.

At Lots Road, the windows of the turbine house, overlooking the road were bricked up and the decorative roof light in the new Control Room was protected by a concrete rood. Steel shutters were provided for some other windows but elsewhere all lights were removed and the staff carried out their duties by the light from hand-held torches.

The area under the concrete coal bunker was designated a an air raid shelter for staff other than the plant operators, but after the first few weeks of false alarms they decided to remain in the main building during raids. Apart from numerous incendiary bombs there was only one direct hit on the station, although there were many in the surrounding streets. A bomb was also reported to have fallen in the Creek and a splash of mud was found on the south wall. There was no damage and the bomb was never found although civil engineering work has taken place in the area subsequently. As happened elsewhere, women were recruited to the staff as Fitter's Mates and Cleaners, including boiler cleaner! But it seems that the only woman on the Operations Staff was a control room assistant. The shift pattern for Operations Staff of 8 hour shifts was disrupted when air raids during the evenings delayed or prevented staff arriving, in which case the afternoon shift had to work a double shift of 16 hours and then perhaps be ready to report again the following day. A revised rota of 12 hour shifts was tried but eventually a regular pattern of 8 and 16 hour shifts was adopted to avoid travelling during raids.

It had been assumed in the various reports on the proposals for modernisation that Lots Road would continue to be coal fired, but in the meantime the use of heavy fuel oil in power stations had been developed to provide an economic alternative. This had the advantage of not requiring such complex and costly fuel handling plant, which would have been very difficult to accommodate on such a congested site. Work started at Lots Road in 1963 at the west end of the site.

The ash disposal system was reconstructed so the ash could be flushed into the concrete sump which had been the bottom of the coal storage tank at the west end. A new coal elevator from the wagon tipper on the south side of the creek along the south side of the concrete bunker and across the creek at a high level to reach the boiler house bunkers at the east end. The concrete bunkers had 48 separate hoppers and 16 of them were emptied of coal to allow oil storage tanks to be constructed inside them. The ash handing plant and the annexe to the boiler house were demolished to clear the west yard for the contractors' access to the main building and for construction of the new Circulating Water Pump-house and the Switch-house. Two turbo-alternators at the west end of the turbine house were removed and two groups of switch-gears were released by transferring feeds to other groups. Thus the station was completely west of the western chimneys and corrugated steel screens were erected so that the plant to the west of that line could continue to operate. In the west yard, the walls of the West Pump house were formed in bored concrete piles before the earth was removed and the internal structure constructed.

The 83 inch circulating water tunnel was plugged at its inlet to the river and was exposed at the bottom of an excavation in the west yard, where a three-way connection was formed in concrete for the pump suction main to the pump house. The superstructure is a steel-framed building with sheet metal cladding over brick walls. The top floor houses the main 22,000 volt switch gear, 3,300 volt switchgear for the station auxiliary supplies and the Electrical Control Room. Cable shafts from the floor below lead to the turbine house for the main cables from the generators and to the boiler house for the cables to 3,300 volt switchgear for each unit. Four House Transformers for the 3,300 volt system are accommodated in the south side of the building. The 22,000 volt switchgear was energised initially from Greenwich through new cables to provide supplies for commissioning the new plant and new 22,000 volt cables were installed from Lots Road to new switchgear at Cromwell Curve and onwards to Coburg Street (near Euston) in preparation for the changeover from the old 33.3 Hz distribution system.

The first boiler and turbine were commissioned in July 1965. This was the first Membrane Wall boiler to be commissioned in this country, the second boiler and turbine followed shortly. Many of the substations fed from Lots Road at 33.3 Hz had been prepared for the change of frequency by diverting one of a pair of high voltage feeders to Cromwell Curve or Coburg Street so that part of the load could be transferred to the 50 Hz system almost immediately, followed by a phased programme to build up the load on Lots Road within the 30 MW firm capacity. As the load on the 33.3 Hz system was reduced, four of the old turbines and 16 boilers could be taken out of service and dismantled to enable work to start on the foundations and structures for two further boilers and turbines, followed immediately by the fifth and sixth units.

Deliveries of coal by rail ceased in 1965 and the storage in the coal bunker was reduced to release further sections for installation of oil tanks. During this period, temporary gantries were erected outside the north and south walls of the building, about 20 ft above the road level, to enables staff to move between the two operational sections of the station while construction work was in process in the centre. The 33 Hz plant was finally taken out of service at the end of 1967 for dismantling, resulting in the space at the east end of the station containing no main plant. The south east chimney was lined with fire-brick but the north-east and north-west chimneys were no longer required and were taken down to below the roof level.

Completion of the Lots Road modernisation programme in 1969 resulted in the power system being supplied from two sources independent of the National Grid for the Underground sections and from a bulk supply on the grid at Neasden for the surface section, in accordance with the recommendations of the 1960 report. But the steam plant at Greenwich was over thirty years old (except for one turbo-alternator installed in 1951) and was becoming both unreliable and costly to operate and maintain. The decision was taken to replace it with eight gas turbine generators driven by Rolls Royce Avon gas turbines which would be more economical than steam plant of similar capacity on both installation and running costs. The eight gas turbine units were commissioned between 1970 and 1972. The use of gas reduced the maintenance costs of the boilers because there is no need for cleaning, but it was found shortly after the conversion that the additional moisture in the flue gases had attacked the mortar of the chimneys to such an extent that the upper third of each had to be taken down and re-built during 1978 and 1979.

The boilers at Lots Road had been designed to burn heavy fuel oil with a sulphur content not exceeding 1% to limit the emission of sulphur dioxide. This was relatively cheap at that time as the quantity of H.F.O. produced by the oil industry was linked to the demand for petrol and diesel fuel rather than to the market for fuel oil. Natural gas from the newly discovered North Sea gas field was made available in 1974, initially at Greenwich but shortly afterwards at Lots Road. Financial approval was obtained from the GLC which had been given control of London Transport from 1970, to convert both stations for dual fuel operation, justified by savings in fuel and maintenance costs. At Lots Road, a supply main was installed from the Fulham gas storage plant to a pressure regulating and metering station on the south side of the Creek. On each boiler, Babcock and Wilcox had installed gas burners around each oil burner, with control valves and a gas control system linked to the original boiler control system. Conversion of each boiler was undertaken while it was out of service for periodic survey and overhaul and the work was completed in 1977. The use of gas reduced the maintenance costs of the boilers because there is no need for cleaning but it was found shortly after the conversion that the additional moisture in the flue gases had attacked the mortar of the chimneys to such an extent that the upper third of each had to be taken down and rebuilt during 1978 and 1979.

By 1980, the power supply system was again under review. Experience had shown that, although it would operate in parallel with the larger machines at Lots Road, the Greenwich plant was not able to supply the traction load by itself because it could not respond to the rapid fluctuation in demand. Its value as a second source of supply was therefore in doubt. The cost of electricity generated at Lots Road was found to be higher than that purchased from the Central Electricity Generating Board, while the cost of the small proportion generated at Greenwich was very much higher, reflecting higher fuel cost and very low utilisation of the plant. The prospect of heavy capital expenditure becoming necessary for replacement of the Lots Road plant in ten years time was also a serious problem for the organisation when investment was already being restricted by government limitations on public borrowing. The value of independent generation was no longer accepted, given the improvements in technology, in plant availability and inter-connection which had been introduced on the National Grid since the previous study twenty years before.

A Future Power Supplies project was drawn up which envisaged three dedicated Bulk Supply Points from the National Grid, any two of which would be capable of meeting the full load of the system and a last-resort emergency supply from the Greenwich gas turbines to feed essential lighting, ventilation pumps and communications. Two new intakes, in addition to the existing intake at Neasden, would be provided at Mandell Street, near Aldgate and at Lots Road, where connections to the existing distribution system could be made. As the mains supplies would no longer be independent of the public supply, emergency lighting supplies in the deep-level section would be supported by batteries. Approval in principle was given by the Department of Transport in September 1985 although detailed consideration by the Railway Inspectorate of the security of supply and the emergency lighting proposals was still outstanding.

Construction of the Mansell Street supply point and alterations to the 22,000 volt distribution system were well in hand when the Government announced its policy of de-nationalisation of the electricity supply industry.

The prospect arose of using the two sites for modern generating stations to feed into the local public supply network as well as continuing to supply the Underground. Further work on the Future Power Supplies project was suspended and in 1990, a separate company known as Metropower Ltd, was set up jointly by London Underground Ltd with Scottish Power plc and Veba Kraftwerke Ruhr AG, an experienced operator of private power plants in Germany. This was to develop the proposal and eventually to build and operate new plant on the sites as a licensed private generator in the re-organised supply industry, as well as continuing to provide a secure supply for the Underground. London Underground's equity share was to be the provision of the sites and the existing buildings and plant, while the others would find the capital for re-equipping with gas fired combined-cycle gas and steam turbines. Each station would have an installed capacity of 350,000kW as compared with the existing capacities of 180,000kW at Lots Road and 117,600kW at Greenwich.

As detailed investigation of the proposals continued, the difficulties became more apparent. There was concern over the atmospheric pollution associated with the larger quantity and temperature of the cooling water to be discharged into the river. The need to hold plant in reserve to meet the requirements of the Underground in case of a failure of the public supply network reduced the potential for commercial sales in an industry which was already aiming to improve efficiency by reducing spare capacity. The cost of the new installations on the congested town-centre sites was high compared with the larger installations being planned outside London, and a local planning enquiry into the proposals for Greenwich focused opposition on atmospheric pollution, noise and disturbance during contribution. Eventually, the increased cost of fuel and lack of interest from the Regional Electricity Companies in purchasing supplies generated near to the load centre, rather than at larger remote stations, caused the project to be shelved.

Work on the Future Power Supplies project recommenced in 1992 on construction of the Lots Road intake and on planning the station and tunnel emergency lighting systems. It was envisaged that Lots Road would be closed in 1997 after completion of the schemes for emergency lighting and the refurbishment of five of the Greenwich gas-turbine units. But in March 1995 the department of Transport decided that private sector finance must be sought for these projects. At June 1995, the resulting delay to completion cannot be predicted and so the eventual closure of Lots Road is as indefinite as it has been ever since the Future Power Supply project was approved in 1985.

The Creek where warm water is exuded from the station is full of fish and the herons and other birds have a ready supply. The water for cooling is taken from a large filter structure protruding from midstream. I was very impressed with the control room with its switchboards and Apple computers. It is such a contrast with the grime down below in the boiler house.


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Last updated by Julie Atkinson for David StGeorge   06-Dec-2002