In the 20th century, power stations along the River Trent were the backbone of the UK's electricity supply. They ran with a remarkable thermal efficiency 24 hours a day, burning locally mined coal, transported from the colleries in merry-go-round trains that could be loaded and unloaded without stopping.
Today the local mines have all closed and the the few surviving power stations operate for a few hours a day to supply peak load in winter. Friday 21 April 2017 was the first coal-free day in the history of electric power generation in the UK and it is expected that by 2025 there will be no more electricity from coal in the UK.
This heritage day will look at the history of electricity generation in the Trent Valley, from the first small scale local plants of the 1880s to the CEGB giants of the 1960s.
Organised by Derbyshire Archaeological Society and held on Saturday, 19th May 2018 in Long Eaton.
The conference programme:
09:30 Registration and coffee
10:00 The Early years of electricity generation
10:40 Long Eaton's municipal electricity supply
11:15 Trent Valley power stations of the CEGB
11:45 Merry-go-Round coal trains
13:15 The heritage of post-war power generation
13:45 EMIAC Business Meeting
14:00 Walk through Long Eaton Lace Factories Conservation Area and along the Erewash Canal looking at the Long Eaton electricity generating station buildings and the factories that were its first consumers.
There will be a stop for tea in one of the old lace factory buildings.
16:30 Close of conference.
Image courtesy of Ian Mitchell.
As with any new technology the early generating machines took many forms offering a variety of outputs and by 1852 electric street lamps using carbon rods were being reported as offering a better light than the gas lamps. Incandescent lamps were still a curiosity and it wasn't until 1881 that Sir Joseph Swan demonstrated the first commercial use of these new lamps at the Savoy Theatre.
By the end of the century the concept of long-distance transmission of electricity with a single generating station supplying a large area had been borne. Locations close to coalfields, such as Colwick, Trowell, Ilkeston and Newbold, were considered for a generating station to supply London. Those early stations had the choice: to supply AC or DC voltage, selection of voltage and, if AC, then frequency of supply. In London alone there were 70 generating stations supplying 80 supply authorities with 24 different voltages and 14 frequencies!
In 1925 the government sought to standardise the supply industry and to create a high voltage grid system. The Electricty (Supply) Act was passed in 1926. Starting in 1928, the newly formed Central Electricity Board created the first synchronized AC grid operating at 132 kV and 50 Hz. Work was completed in 1933 and by 1938 the new 'regional grids' were opearting as a single national grid.
Plans for Long Eaton's municipal electricity supply were first aired in 1882. By the end of the century it had been decided to use coal from Ilkeston delivered by boat on the Erewash Canal. Four boilers provided steam to four steam engines, ranging in power from 200 hp to 800 hp, to drive four DC generators operating at 440 volts and 220 volts. By the end of its first year of operation in 1903, it was supplying 215 consumers as the lace factories replaced their steam engines with electric motors.
In c.1914 batteries were installed to supply private homes and street lighting on a Sunday when the factories were closed and generation was stopped. Although the plant shut down in 1938, the batteries remained in use until 1946. The site is still used as a sub-station.
A new gas-powered generating station has been built, and commissioned (2018), on the site of a former gas works.
For economic reasons, power stations need to be located relatively close their fuel supply; they also need copious volumes of cooling water. The Trent valley is/has been home to a number of power stations: Rugeley, Drakelow, Willington, Castle Donnington, Wilford, West Burton, Cottam and Ratcliffe-on-Soar. Immediately post war, turbines were rated at 30 MW; this figure doubled during the 1950s. New power station designs in the 1960s required 500 MW turbine-generators.
A few facts about the Ratcliffe plant, one of the three still in operation: Its coal stockpile is 1 million tonnes with 812 tonnes being burnt every hour when operating at full capacity. The coal is burnt as fine powder in the 50 ft high Babcock & Wilcox boilers producing steam at a temperature of 568°C and pressure of 165 bar (2,400 psi) to power the four multi-stage turbines, each driving a water-cooled generator at 3,000 rpm. The eight 375 feet-high cooling towers handle 48 million gallons of water per hour. The thermal efficiency of the station at 35-40% is close to the theoretical maximum.
The power station has a number of by-products: some 90,000 tonnes of ash per annum collected from the furnaces is used to make concrete blocks; 48,000 tons of fly-ash collected from the smoke stack is used for road construction. The flue gas is passed through a desulphurisation plant to remove sulphur dioxide [source of acid rain], which is then combined with limestone to produce some 480,000 tonnes p.a. of gypsum used in the plaster board industry. NOx emissions are minimised using a Selective Catalytic Reduction process whereby ammonia is injected directly into the flue gas. Whilst there has been much talk of carbon capture processes for reducing the amount of carbon dioxide emitted, none has been demonstrated. The desire to reduce CO2 emissions has reduced the number of operational coal-fired power stations which have been replaced by gas-fired units and renewable sources.
Before the war a relatively small amount (~6½%) of the mined coal was sent to power stations. Battersea power station, London, the most modern in the UK, received its coal in wooden railway wagons of between 10- and 13-tons capacity. These were emptied by hand using wheelbarrows.
Post-war developments in power station design required ever-larger quantities of coal; in 1961 some 30 million tons were transported to power stations with a forecast of 76 million tons required for 1966. An almost constant supply of coal was required; indeed, the Beeching Report advocated the use what we now call Merry-go-round (MGR) trains.
New hopper wagons of 32-ton capacity were ordered in 1964 and the MGR system trialled at the newly-commissioned West Burton power station in 1966. This 2,000 MW plant required up to 5 million tons of coal per year. By the end of 1966 some 900 wagons were carrying 53,000 tons a week to four power stations.
As the wagons travelled slowly (½ mph) over a coal bunker at the power station, the bottom doors were opened to discharge their load. A train consisted of typically 30-35 wagons. Later new bogie hopper wagons of 75-ton capacity capable of travelling at 60 mph when loaded were introduced.
Consider first some of the power generation plant built during the inter-war years; the cathedral-like structure of Battersea, the use of glass cladding at Barking and the huge brick-built Bankside.
Under the Electricity Act 1957, the newly formed CEGB had to consider the environmental surrounds of any new structure built. For example Chapel Cross with its open structure and light-weight coloured cladding, the siting of Trawsfynydd and the colouring of Ironbridge’s cooling towers to match the local red-coloured soil.
Since all coal-fired power stations are due to be closed by 2025, Historic England has started a programme of recording current plants and making provision for available archive material. This raises a number of questions: Should any plant be listed; how do we protect any structure and if so how much should be protected?
Unfortunately, the archives for Rugeley power station have been lost as the station changed hands.
Notwithstanding the architectural and/or technical merits of any building, it is very unlikely that any power station will receive listed status.
The following websites provide additional background to the papers presented:
- Long Eaton Heritage Initiative - www.erewash.gov.uk/media/files
/Leisure%20and%20Culture /Leisure_downloads_and_pdfs /A5_Booklet_ THI_Guided_Walk.pdf
- Nottingham University - www.nottingham.ac.uk
/manuscriptsand specialcollections /documents/exhibitions /librarydisplay/lace.pdf
- Long Eaton archive - www.long-eaton.com/lace.asp
Please note: Although checked at the time of writing, NIAG cannot be held responsible for the validity of these links or the integrity of these sites.
Images courtesy of Terry and Jane Waterfield taken during the visit.