Colchester power station supplied electricity to the city of Colchester, Essex, England and the surrounding area from 1900 to 1960. It was owned and operated by Colchester Corporation prior to the nationalisation of the electricity supply industry in 1948. The power station was redeveloped several times incorporating new plant.
History In 1893 Colchester Corporation applied for a provisional order under the Electric Lighting Acts to generate and supply electricity to the then town. The was granted by the Board of Trade and was confirmed by Parliament through the Electric Lighting Orders Confirmation (No. 2) Act 1893 (56 & 57 Vict. c. xxxv). The power station was built on Hythe Quay and first supplied electricity in 1900.
Equipment specification By 1923 the generating plant comprised:
Coal-fired boilers generating up to 48,000 lb/h (6.05 kg/s) of steam, these supplied steam to: Generators 1 × 150 kW reciprocating engine driving a generator 1 × 250 kW reciprocating engine driving a generator 1 × 350 kW reciprocating engine driving a generator 1 × 375 kW reciprocating engine driving a generator 1 × 500 kW reciprocating engine driving a generator 1 × 750 kW reciprocating engine driving a generator
These machines had a total generating capacity of 2,375 kW of direct current (DC) power.
Electricity supply was at 420 & 210 Volts DC.
New plant 1955 The plant in 1955 comprised:
Boilers: 4 × Vickers Spearing boilers with chain grate stokers 1 × Babcock boiler with chain grate stoker
The total evaporative capacity was 82,000 lb/h (10.3 kg/s), steam conditions were 250 psi and 650°F (17.2 bar, 343°C), steam was supplied to:
Turbo-alternators: 3 × Allen’s geared 1.25 MW turbo-alternator 1 × Allen’s geared 3.75 MW turbo-alternator
The total installed generating capacity was 7.5 MW, with an output capacity of 6 MW.
Condenser cooling water was drawn from the River Colne and was cooled in two cooling ponds of 0.45 million gallons per hour (0.57 m3/s).
Operations Operating data 1921–23 The operating data for the period 1921–23 is shown in the table: +Colchester power station operating data 1921–23Electricity UseUnitsYear192119221923Lighting and domestic useMWh570573582Public lighting useMWh192030TractionMWh448354362Power useMWh687538610Total useMWh1,7281,4851,585Load and connected loadMaximum loadkW1,3211,2701,316Total connectionskW3,2133,5153,613Load factorPer cent18.017.318.5FinancialRevenue from sales of current£–34,94435,588Surplus of revenue over expenses£–8,54514,074 Under the terms of the Electricity (Supply) Act 1926 (16 & 17 Geo. 5. c. 51) the Central Electricity Board (CEB) was established. The CEB identified high efficiency ‘selected’ power stations that would supply electricity most effectively. The CEB also constructed the national grid (1927–33) to connect power stations within a region.
Operating data 1946 Colchester power station operating data in 1946 is given below: +Colchester power station operating data in 1946YearLoad factor per centMax output load MWElectricity supplied MWhThermal efficiency per cent194618.06,1729,4999.59 The British electricity supply industry was nationalised in 1948 under the provisions of the Electricity Act 1947 (10 & 11 Geo. 6. c. 54). The Colchester electricity undertaking was abolished, ownership of Colchester power station was vested in the British Electricity Authority, and subsequently the Central Electricity Authority and the Central Electricity Generating Board (CEGB). At the same time the electricity distribution and sales responsibilities of the Colchester electricity undertaking were transferred to the Eastern Electricity Board (EEB).
Operating data 1954–58 Operating data for the period 1954–8 is shown in the table: +Colchester power station operating data, 1954–8YearRunning hoursMax output capacity MWElectricity supplied GWhThermal efficiency per cent195439061.2016.51195564562.2697.28195661062.2157.86195743761.4687.57195866362.5368.98 Colchester power station was part of the Colchester electricity supply district. This district served an area of 195 square miles and a population of 103,600 (1959). It included Colchester, West Mersea, Wivenhoe, Lexden, Winstree, Maldon, Tendering and Samford. The number of customers and the electricity sold was as follows: 195619571958Total number of consumers32,77633,52334,378No. of domestic consumers28,96729,386See belowUnits sold kWh110,612122,866139,218Domestic units sold kWh40,75344,390See below In 1958 the number of units sold to categories of consumers was as follows: Type of consumerNo. of consumersUnits sold kWhDomestic30,16948,845Commercial2,15419,890Combined premises5992,596Farms6,3096,309Industrial51760,854Public lighting15724Total34,378139,218 There were 735 miles (1183 km) of high voltage mains in the district comprising 281 miles (452 km) of underground mains and 454 miles (731 km) of overhead cables.
Closure Colchester power station was decommissioned in about 1960.Data for Colchester power station is given for 1958 in Garrett (1959), but Colchester is not on the CEGB Annual report for 1961
See also Timeline of the UK electricity supply industry List of power stations in England
References