Tir John Power Station
Also referred to as Tir John North Power Station
After some searching for a site for a new power station, the Tir John site near Swansea docks was selected by the Swansea Corporation Electricity Board. It was relatively cheap, allowed ample room for extensions, had abundant supplies of cooling water, and had immediate access to sea, road, and rail.
Erection of the initial section of 60,000 kW. began in 1931, and the first phase was fully commissioned in 1935. C. A. Parsons supplied two 30 MW turbine-alternators.
As originally constructed, the appearance of the station was characterised by two short chimneys. It eventually had three 89m high brick chimneys, but by the start of the Second World War only two had been partly built.[1]
Engineers were Braithwaite and Co Engineers Ltd of Horseferry Road, London
Provision was made for a further 60,000 kW. set in the same building.
The station embodied two advanced features, namely, the use of pulverized anthracite duff (waste from the washing of mined coal at the colliery), and the washing of the exhaust gases to eliminate sulphur oxides and dust. Originally the station was designed for burning steam coal on mechanical stokers, but extensive experiments in the combustion of anthracite duff, a low-volatile coal (6-7 per cent of volatile matter) of high calorific value (12,500 B.Th.U. per lb.) showed that under certain conditions it could be burned satisfactorily, and the station was redesigned to suit this method of firing the boilers. The anthracite duff was pulverized in four Hardinge ball mills, complete with classifier, cyclone separator, and exhauster fan. Steam was supplied to the two 30 MW turbines at 600 psi, 825 deg. F.
The condensing water was obtained from the King's Dock and returned to the Queen's Dock, by means of low-level tunnels. The shafts at the station are 300 feet deep and at the docks 250 feet and 240 feet deep respectively, the difference in levels being due to the gradients given to the tunnels for the purposes of drainage during construction. The shafts are 14 feet in diameter and the horseshoe-shaped tunnels driven through solid rock are about 9 feet in diameter and lined with 9 inches of concrete. The intake tunnel is about 0.5 mile long and the discharge tunnel about 0.75 mile. Difficulty was experienced at the docks during the sinking of the shafts. The depth of the water-bearing strata was too great to allow the use of compressed air, so the ground had to be frozen to the necessary depth by sinking a ring of circulating pipes through which a freezing mixture was passed. The shafts were then sunk and lined and the ground allowed to thaw.
Water required to make up the losses due to evaporation in the scrubbers is drawn from the Crymlyn Bog.
Tir John was connected with the old Strand Station by means of a duplicate underground 33 kV main.
Taking advantage of the huge Llandarcy oil refinery nearby, the power station was converted to run on oil in 1967 but rising oil prices in the 1970s led to its closure just nine years later.
1967 Converted to oil burning, taking advantage of the proximity of Llandarcy oil refinery.
1976 Closed due to the high cost of fuel oil.