Coventry power stations

The original plant at Coventry (Sandy Lane) power station comprised horizontal engines coupled by ropes to Fowler dynamos. In 1898 the generating capacity was 350 kW and the maximum load was 126 kW.[4]

During the First World War new plant was installed to meet growing demand for electricity. Coventry was a major armaments centre and there was a three-fold increase generating capability during the war.[2] By 1923 the generating plant at Coventry comprised:[5]

• Coal-fired boilers generating up to 440,000 lb/h (55.4 kg/s) of steam, this was supplied to:
• Generators:
  • 2 × 600 kW reciprocating engines driving alternators
  • 4 × 300 kW steam turbo-alternators
  • 2 × 600 kW steam turbo-alternators

These machines gave a total generating capacity of 25,200 kW of alternating current.[5]

A variety of electricity supplies were available to consumers:

• 2-phase, 50 Hz AC at 6,600, 2,000 and 200 Volts.

A new power station at Longford / Hawkesbury Junction was sanctioned in August 1926 and was commissioned in October 1928.

The main contractors for the works were British Thomson-Houston Company of Rugby. Sub-contractors included Cleveland Bridge & Engineering Company, Wilson Lovatt, Stirling Boiler Company, and Pirelli-General Cable work.[6]

The engine room and boiler house were constructed on mass concrete foundations. The buildings were steel framed with infill of brick and artificial stone. The coal handling equipment was capable of handling 50 tons an hour from the canal or from the railway sidings.[6]

The station was officially opened on 31 October 1928.[6]

The initial configuration of plant was:[3]

• Boilers:
  • 6 × Stirling tri-drum boilers with chain grate stokers, each producing 50,000 lb/h (6.3 kg/s) of steam, steam conditions were 325 psi and superheat to 700°F (22.4 bar, 371°C), steam was supplied to:
• Turbo-alternators:
  • 2 × British Thomson-Houston 19.25 MW turbo-alternators, generating at 6.6 kV
• Cooling towers:
  • 4 × hyperbolic cooling towers each with a capacity of 600,000 gallons per hour (0.76 m³/s), make up water was drawn from the adjacent Oxford Canal.[3]

Coal was delivered by barge from the canal, and via a siding off the Coventry to Nuneaton railway line.[7]

These extensions to the power station comprised:[3]

• Boilers:
  • 4 × John Thompson tri-drum boilers with chain grate stokers, each producing 150,000 lb/h (18.9 kg/s) of steam, steam conditions were 325 psi and superheat to 720°F (22.4 bar, 382°C), steam was supplied to:
• Turbo-alternators:
  • 2 × British Thomson-Houston 30.75 MW turbo-alternators, 3,000 rpm generating at 33 kV.
• Cooling towers:
  • 2 × hyperbolic cooling towers each with a capacity of 1.5 million gallons per hour (1.89 m³/s), arranged in a lozenge plan with the 1928 towers.[8]

This extension comprised:[3]

• Boilers:
  • 2 × John Thompson tri-drum boilers with chain grate stokers, each producing 150,000 lb/h (18.9 kg/s) of steam, steam conditions were 325 psi and superheat to 720°F (22.4 bar, 382°C), steam was supplied to:
• Turbo-alternator:
  • 1 × British Thomson-Houston 30.75 MW turbo-alternator, 3,000 rpm generating at 33 kV
• Cooling tower:
  • 1 × hyperbolic cooling tower with a capacity of 1.5 million gallons per hour (1.89 m³/s).[3]

The operating data for the period 1921–23 is summarised in the table:[5]

The data shows the general growth of demand and use of electricity.

Under the terms of the Electricity (Supply) Act 1926[9] the Central Electricity Board (CEB) was established in 1926.[10] The CEB identified high efficiency ‘selected’ power stations that would supply electricity most effectively; Coventry was designated a selected station. The CEB also constructed the National Grid (1927–33) to connect power stations within a region.[10]

Coventry (Longford) power station operating data in 1946, just prior to nationalisation, was as follows:[11]

The British electricity supply industry was nationalised in 1948 under the provisions of the Electricity Act 1947.[12] The Coventry electricity undertaking was abolished, ownership of Coventry power station was vested in the British Electricity Authority, and subsequently the Central Electricity Authority and the Central Electricity Generating Board (CEGB).[10]

At the same time the electricity distribution and sales responsibilities of the Coventry electricity undertaking were transferred to the East Midlands Electricity Board (EMEB).

Operating data for the period 1954–72 is shown in the table:[3][13][14]

The data demonstrates the declining usage, capacity and supply over the period 1954–72.