Plant in 1923

In 1923 the generating plant at the Llanelly power station comprised:^[5]

• Coal-fired boilers generating up to 76,000 lb/h (9.58 kg/s) of steam which was supplied to:
• Generators:^[5]
  • 1 × 500 kW reciprocating engine with DC generator
  • 1 × 750 kW steam turbo-alternator AC
  • 1 × 2,000 kW steam turbo-alternator AC
  • 1 × 3,000 kW steam turbo-alternator AC

These machines gave a total generating capacity of 6,250 kW comprising 5,750 kW of alternating current (AC) plus 500 kW of direct current (DC).^[5]

Electricity supplies to consumers were:

• 12,400 & 6,600 Volts, 3-phase, 50 Hz AC
• 500 & 250 Volts DC
• 500 V DC Traction current^[5]

Plant in 1923–28

New plant was commissioned and installed at the Llanelly power station from 1923 to 1928. This comprised:^[6]

• Boilers:
  • 2 × 40,000 lb/h (5.04 kg/s) boiler, steam conditions 265 psi and 700 °F (18.3 bar, 371 °C)
  • 2 × 60,000 lb/h (7.5 kg/s) boilers, steam conditions as above
  • 4 × 20,000 lb/h (2.52 kg/s) boilers, steam conditions as above

The boilers were manufactured by Babcock & Wilcox and Yarrow and supplied steam to:

• Generators:^[6]
  • 1 × 5 MW British Thomson-Houston turbo-alternator, generating at 6.6 kV
  • 1 × 7.5 MW British Thomson-Houston turbo-alternator, generating at 6.6 kV
  • 1 × 12.5 MW British Thomson-Houston turbo-alternator, generating at 6.6 kV

The station was supplied with coal via a siding off the nearby dock railway line.^[4]

Condenser cooling water was drawn from the sea.^[6]

Operating data 1921–23

The electricity supply and consumption data for the period 1921–23 was:^[5]

The electricity loads on the system were:^[5]

Revenue from sales of current (in 1923) was £69,818; the surplus of revenue over expenses (1923) was £32,186.^[5]

The Corporation tramways ceased operating in September 1932.

The supply of electric current in the inter-war period was as follows:^[8]

Operating data 1946

Llanelly power station operating data for 1946 was:^[9]

The British electricity supply industry was nationalised in 1948 under the provisions of the Electricity Act 1947 (10 & 11 Geo. 6 c. 54).^[10] The Llanelly and District Electric Supply Company Limited was dissolved, ownership of Llanelly power station was vested in the British Electricity Authority, and subsequently the Central Electricity Authority and the Central Electricity Generating Board (CEGB).^[11] At the same time the electricity distribution and sales responsibilities of the Llanelly Electric Supply Company were transferred to the South Wales Electricity Board (SWEB).

Operating data 1954–67

Between 1964 and 1966 the boilers were converted to oil-firing.^[12][13] Operating data for the period 1954–67 was as follows.^[6][14][12]

The output from the station in MWh is shown on the graph.

Graphs are unavailable due to technical issues. There is more info on Phabricator and on MediaWiki.org.