Notes from Bob Carr — October 1992
Commissioned in 1970 the power station at Edmonton in the Lea Valley is unique to the UK in that to produce electricity it makes no use of nuclear power and burns domestic rubbish rather than fossil fuel. As GLIAS members well know this is an old idea but rubbish is not what it used to be and nowadays most dustbins contain plastics which are not as power station friendly as partially burnt coal from domestic grates which was a considerable constituent of dust cart loads before the 1960s.
Following German practice, notably that of a plant at Dusseldorf opened in 1965, rubbish is fed onto the grate of a furnace which slopes downwards and is made up of seven parallel rotating rollers which carry the rubbish onwards and downwards at the same time turning and disturbing it so near complete combustion is achieved. No fuel other than the rubbish is used and air is blown through the rollers to aid combustion. Compared with a conventional power station temperatures are low, around 1,000°C. This is insufficient to destroy tin cans for instance and these are removed afterwards from the resulting clinker by electromagnet. Ferrous scrap is a by-product of the operation at Edmonton which can be sold to steelworks.
PVC in the rubbish produces hydrochloric acid on burning which is a major problem in the boiler and the steel tubes have to be frequently renewed. The boiler itself is not unlike that at a conventional power station though smaller and temperatures and pressures are quite low by present day standards. From the boiler the products of combustion pass through an economiser and then electrostatic precipitators before emission from the main chimney. At Edmonton there are five grates each with an associated boiler.
The turbines, alternators and condensers are much as in a conventional power station though by modern standards again on the small side. Full output is only about 30 MW which is less than a fifth of that of even an old London generating station such as Battersea B. This explains why the economics of operating a plant such as this are so difficult. In 1996 new EC legislation will require the plant at Edmonton to be substantially altered and it remains to be decided whether closure or substantial investment and perhaps enlargement will ensue. Bob Carr
Burton around London
Today you will still find a branch of Burtons the Tailors (GLIAS Newsletter February 1992) in Brixton, the City, Clapham Junction, Ealing, Hendon, Holborn, Holloway, Lambeth, Lewisham, Paddington, Putney, the Strand, Stratford, at Surrey Quays, Tooting, Brent Cross, Victoria, Walthamstow, Wood Green and Woolwich, with three in the West End.
Plenty for the urban industrial archaeologist to investigate apart from the former shops. Look out for terracotta, black and white vitrolite, emerald pearl granite and of course Empire Stone. This is an architectural pre-cast concrete made by Empire Stone Ltd, a firm founded at the beginning of the century. Bob Carr
Greenwich Power Station
Earlier this year Scottish Power proposed to enlarge the generating capacity at the present LT Greenwich Power Station which is equipped with gas turbines and can supply electricity at 22kV for underground railways in central London at peak periods. Control is from the LT generating station at Lots Road.
Scottish Power proposals are to install two 123 MW combined cycle gas turbines (CCGT) driving generators; the exhaust gasses being passed through a heat recovery steam generator (HRSG) system. This would provide enough steam to drive a third 123 MW generator by means of a steam turbine, giving the new station a total capacity of 370 MW. The present LT load would be provided for from thus output.
Natural gas would be used for fuel as at present, being drawn from the British Gas plc Regional Transmission System. The gas will need to be pressurised for the gas turbines. To cover possible interruption of mains gas supply distillate fuel oil would be used as an alternative, delivered direct by ship to the Power Station's Thameside wharf. Coal was used for fuel at Greenwich until the late 1960s and surviving buildings and structures of the coal handling system would be demolished.
The present main building dates from 1902-9 and would house most of the new equipment. The existing four 56 metre high chimneys would discharge the exhaust from the HRSGs with an additional six metres being added on top to improve dispersion. Cooling water would be taken from the Thames via a new tunnel extending 70 metres from the embankment. The water is to be returned to the River via a new outfall with a rise in temperature of not more than 12°C.
Additional land to the North East would need to be acquired from Morden College, who own it. Part of Hoskins Street would be permanently closed. It is understood there have been local objections on environmental grounds. The new generating station would have a power output just over twice that of the old Battersea B station but contemporary fossil fuel power stations have an output about six times that of Battersea B. Bob Carr
Greater London news in brief
The Royal Arsenal Woolwich ceased much of its activity in 1967 and is now mostly confined to a small fragment at the extreme west end of its extensive old site. The area has been reduced from about 1,200 to 76 acres. Ministry of Defence use may finish altogether by 1995/6. Manufacturing at the Arsenal was at a peak during the First World War when many women were employed.
In 1812-16 a canal to the designs of Lt Col Pilkington was built to carry materials into the Arsenal, the southern end being filled before the Second World War. This canal is now part of Thamesmead West and what remains is known as Broadwater. The entrance lock survives in fairly good order and the swing bridge which carried a line of the Arsenal light railway across the entrance is also extant.
Thamesmead extends eastwards to Thames Water's Crossness site but not all this large area is yet redeveloped for housing. Much land is still fenced off with the public excluded and patrols by guards with dogs. The Thamesmead Town signs mean what they say! It is intended to open a public walk along the whole riverbank.
Woolwich Arsenal railway station building of 1905 has been demolished and judging from the Royal Academy Summer Exhibition its replacement is likely to be a high-tech affair. In architecture it seems high-tech rules OK at present and much by the Richard Rogers Partnership is to the fore. Just to the North West of Marylebone railway station a large new development called Marylebone Gate, between the railway tracks and Harewood Avenue, is likely to drastically alter the view northwards from the West end of the station concourse.
The northbound bore of the Blackwall Tunnel, opened in 1897, was lined with glazed tiles giving a splendid period atmosphere in recent years. Following refurbishment work the tunnel is now reminiscent of nursery interiors. Tiling may still be seen in the Rotherhithe Tunnel.
In Croydon the large red brick Victorian town hall in Katharine Street, built 1892-6, replaced the Croydon Central railway station, the railway approach to which can still be made out in the gardens to the east. Opened in January 1868 the Central Croydon railway branch never seemed exactly worthwhile, it was closed in December 1871, reopened in June 1886 and finally closed in September 1890. Rebuilding on the site still continues — a new library complex is being built at the back (south) and on top of the Town Hall, the new extension being designed by the Tibbalds/Colbourne partnership. Bob Carr
© GLIAS, 1992