Difficulties of interconnection, differences in AC frequencies, and the need for coal conservation by the use of large-scale plant became major issues in World War I when electricity usage nearly doubled. The Electricity (Supply) Act 1919 created a new organisation, the Electricity Commissioners, to replace the role of the Board of Trade.
A key mandate of the Commissioners was the restructuring of generation and transmission, by voluntary means, since the earlier regulatory powers had been deleted from the legislation. The first stage of the procedure for establishing Joint Electricity Authorities was the definition of a series of Electricity Districts covering parts of the country where reorganisation seemed most necessary. All the electricity undertakings were then invited to submit proposals for reorganisation schemes emphasising the technical, administrative and financial aspects of a JEA.
The South Wales Electricity District was defined in October 1920 and covered an area almost identical to the later Electricity Board (except for Eastern Monmouthshire). Proposals for reorganisation were to be submitted by November 1921. A conference was held in Cardiff in January 1923, attended by the Electricity Commissioners. An Advisory Committee was formed in May “with a view to the formulation of a scheme for submission to the Commissioners.”[23] Unlike all the other 15 Electricity Districts, no scheme was ever submitted.
The absence of any reorganisation scheme or support for a Joint Electricity Authority reflected the independence of the three large municipal undertakings, Cardiff, Newport and Swansea, and the caution of South Wales Power Co. after its earlier difficulties. All this was in contrast to North Wales where the ambitious local power company was actively promoting a large area JEA with little opposition. Any possible reorganisation in South Wales required frequency standardisation, an important provision in the Electricity (Supply) Act 1926.
Table 3 lists the statutory supply undertakings in 1925/26. Eleven local authorities had been added after 1912. Ammanford had taken over a non-statutory company and Llandrindod Wells had exercised its rights of purchase of the company undertaking. The Rhondda UD system had begun operation in 1915, the others after the war. Port Talbot was the most recent, having opened in February 1926.
Table 3 SOUTH WALES: ELECTRICITY SUPPLY UNDERTAKINGS 1925/26
Only two new companies were formed in this period. One at Aberayron, a very small system on the Cardigan coast, and the Glantawe company, an earlier non-statutory “legitimised” by Special Order in 1923.
The 36 undertakings in 1925/26 operated a variety of systems. Only seven were wholly DC and, except for Ebbw Vale (population 35,381 in 1921) were all located in small towns such as Llandilo. With an economic operating radius of 1 to 1.5 miles from the generating plant, DC was suitable only for city centres or small towns and villages. The dominant AC systems were divided by frequencies: 14 operated at 50 cycles (Hz); 11 worked at 25Hz; two places combined both these frequencies; and two (Bridgend and Monmouth) used 60Hz.
This situation of incompatible AC systems which prevented further interconnection had begun with decisions made at the turn of the century. Cardiff Corporation had selected a frequency of 50Hz for the new Roath power stations built for the tramway system opened in 1902. Large private generators such as the Powell Duffryn Steam Coal Co. and Ebbw Vale Steam, Iron and Coal Co., were also deciding to use 50Hz for their new AC operations. By 1905, 50Hz was becoming a de facto national standard.
In contrast the consulting engineers for the South Wales Electrical Power Distribution Co., Bramwell & Harris, decided on 25Hz for the Upper Boat and Cwmbran generating stations.[24] This frequency had been used for the Niagara Falls power development and was introduced to Britain for the Central London underground railway and the electrification of Glasgow tramways. As the South Wales network expanded, new local authorities and some existing companies followed with 25Hz systems.
The data for generating capacity show that only nine undertakings of the 23 with generating plant had capacities of over 1,000kW. Steam turbines were dominant in all the larger stations and varied in size from one at 18,750kW at Upper Boat to a small 500kW machine at Bridgend. A few places such as Merthyr Tydfil, Pontypridd and Rhondda were wholly served by reciprocating engines. Other types of generating technology included gas engines at Pontypool and Port Talbot.
Statistics on electricity consumption per head of population reveal major contrasts. Only four places—Cardiff, Llanelly, Newport and Swansea—exceeded 100.0kWh per person. Many small places such as Monmouth and Ogmore Valley which had had electricity for more than 20 years still languished at 17.0kWh per capita. Each place had a distinctive market profile reflecting the local economic and social geography. Two places with local authority undertakings, Swansea and Rhondda, had similar populations (around 160,000) but very different market profiles. Swansea had sales of 29.8 million kWh, with the lighting segment accounting for 15.4 percent, public lighting 1.6 percent, tramways 10.3 percent and power 72.7 percent. Rhondda, in contrast had total sales of 1.78 million kWh, divided between lighting 74.7 percent, public lighting 2.9 percent and power 22.4 percent. In Swansea the County Borough controlled all sales within its boundaries, while electricity sales in the Rhondda were divided among the Urban District Council, the tramways company, the South Wales Power Co. and some private colliery generators. Per capita consumption in Swansea was 189.3kWh but only 10.9kWh in Rhondda.
Electrification and extension of supply areas were given a new impetus following the Weir Report (1925),[25] the Electricity (Supply) Act 1926 and the formation of the Central Electricity Board in 1927. Even before the detailed regional plans for the National Grid were announced, there was a quickening of interest in the formation of new companies and applications for Special Orders. Over the next decade almost all the empty areas of the map were covered by new supply territories.
Seven new local authority undertakings were established: Risca (1926), Barry and Penybont (1928), Milford Haven (1929), Cwmbran (1930), Pontardawe (1931) and Tredegar (1935). In the company sector, the Bryammon non-statutory business was legitimised by Special Order in 1926 and the Porthcawl company began supply in 1931,
Three large companies covered the remaining “unoccupied” areas of South Wales. First, the West Gloucestershire Power Co. expanded from its power station at Lydney to serve most of eastern Monmouthshire. This expansion was authorised by a Special Order dated 13 June 1928. Then the Shropshire, Worcestershire and Staffordshire Electric Power Co. (19 December 1930) for the Abergavenny area. Electricity from the Hereford power station was switched on in the town in April/May 1932.[26] A further Special Order (13 May 1932) allowed the SWS Co. to expand in Radnor and Brecon. The West Cambrian Power Company bean as a modest non-statutory company in Fishguard during 1929. With outside capital the company was able to promote a Special Order (approved 12 July 1933) covering a wide area of South Wales. With its main base now in Haverfordwest, the company quickly absorbed the small existing suppliers in Pembroke and Carmarthen.
Municipal extension was generally inhibited by the economic depression from the late 1920s. Monmouth Corporation was unusual in transferring its electricity undertaking to a private company in 1930. Merthyr Tydfil Corporation applied to the Electricity Commissioners in November 1934 for consent to exercise its powers of purchase of the local electricity company. The Commissioners concluded that:
…if the undertaking were purchased on the terms which then applied, the revenue that could be reasonably anticipated would not be sufficient to pay the capital charges on the purchase price and that there would be a resultant deficit involving a charge on the local rates.[27]
In these circumstances, the Commissioners did not feel justified in giving their consent. Penarth Council’s application to take over the Penarth Electric Lighting Co. in 1936 was however approved by the Commissioners and came into effect on 24 March 1938.An earlier intention of transferring control to Cardiff Corporation had been dropped by this time.
Transmission lines supported by tall steel towers became the most visible effect of state intervention as they appeared in the landscape during the early 1930s. Construction of a national grid was authorised by the Electricity (Supply) Act 1926. Plans were prepared by the Electricity Commissioners and consulting engineers for implementation by the Central Electricity Board.[28] The South West England and South Wales Electricity Scheme was adopted by the CEB in June 1930, tenders were advertised, contracts made, and construction work began.
In South Wales a simple 132kv transmission line was built across the region to a western terminal at Llanelly. At Gloucester the power line connected with the other parts off the grid system and the Midlands grid scheme. The national grid was designed to link “selected” power stations. These were generally the largest and most efficient generating plants that also had some potential for expansion. Five power stations were on the selected list in 1934: Cardiff, Llanelly, Lydney, Newport and Upper Boat. Tir John, a new station at Swansea, was added later.
One expensive feature of the work in South Wales was the standardization of frequency of frequency at the Upper Boat power station, which required new or rebuilt equipment. All other customers using 25Hz also had to be converted to the new standard. The final result by 1937 was full interconnection of all AC electricity service throughout the region. Some pockets of DC continued into the 1950s.
When trading began on 1 January 1935, the grid had added a new layer to the complex of undertakings which operated the electricity supply system. The Bristol grid control office of the CEB now managed the flows of power on the transmission lines and directed the hour-to-hour operation of the selected power stations. These stations, such as the one in Cardiff, remained in the ownership and management of the Corporation but the daily operation was now directed from Bristol. The Upper Boat station worked continuously to serve the regional base load. Other selected power stations generally worked two shifts to serve the daily demand. Planning for the future became increasingly centralised, particularly from London.
Table 4 shows the situation in 1935/36 when 46 undertakings were in operation. Over the previous decade many changes had taken place. AC systems had increased while the number of DC systems had declined. Frequency standardisation was almost complete by 1936, with most of the South Wales Electric Power Company’s system converted to 50Hz. Most undertakings now drew their power requirements directly or indirectly from the grid. The most distant places still generated most of their needs: Milford Haven (100 percent), West Cambrian Power (76 percent) and Llandrindod Wells (66 percent). A few places in the core of the region continued to generate: Bridgend (81 percent), Penarth (74.2 percent) and Merthyr Tydfil (50 percent).
Table 4 SOUTH WALES: ELECTRICITY SUPPLY UNDERTAKINGS 1935/36
Generating technology emphasised economies of scale with larger units. Tir John power station in Swansea opened in late 1935 had two 30,000kW generators and Upper Boat had added a 25,000kW unit. Such machines and the larger boilers were much more economical In coal consumption. Upper Boat’s coal consumption was reduced from 2.20lbs per kilowatt hour in 1925/26 to 1.46lbs a decade later. In contrast, the old Penydarren power station of the Merthyr Tydfil company had a coal consumption rate of 6.27lbs per kWh in 1925/26. By the mid-1930s, however, the Merthyr Tydfil company derived 70 percent of its electricity generated from five small hydro-electric plants, the extravagant coal-burning station being used for peak demand.
Rationalisation of generation and interconnection of undertakings all contributed to reducing the cost of electricity. Other factors such as the growth of radio broadcasting and lower prices for small appliances helped to boost domestic electricity consumption. By 1935/36 there were ten places with per capita consumption levels above 100kWh, ranging from Newport at 476.0kWh to Gorseinon at 120.4kWh.
The growth of electrification, especially in the lighting segment, may be illustrated by the case of Swansea. Total electricity sales grew from 29.8 million kWh in 1925/26 to 61.8 million kWh in 1935/36. The lighting segment which included domestic uses expanded from 4.61m kWh to 21.17m kWh over the same period. Over the decade per capita consumption rose from 189.3kWh to 374.3kWh. Rhondda, in contrast, suffered heavily in the depression of the 1930s, losing population as the economy declined. Electricity consumption per capita increased only from 10.9kWh per capita in 1925/26 to 29.2kWh in 1935/36.
While the creation of new areas appeared to be making an even more fragmented map, much of the new development was controlled by holding companies which created a new form of integration. Table 5 and Figure 5 show the situation in 1934/5 when three organisations had a dominant position.
Table 5 SOUTH WALES: CORPORATE STRUCTURE OF ELECTRICITY HOLDING COMPANIES 1934/35
Figure 5 HOLDING COMPANIES 1934/5.
Edmundson’s Electricity Corporation had in the late 1920s been revived by US capital and began new acquisitions. By 1935 the company was the second largest in Britain. In 1929 the company had bought the Shropshire, Worcestershire and Staffordshire Electric Power Company which in turn acquired the South Wales Electrical Power Distribution Co. in 1930.
The General Electric Company was at the same time diversifying its interests into electricity distribution. Substantial investment in the new West Cambrian Power Co. changed the whole structure of southwest Wales from one of isolated non-statutory operations into an integrated unit. In the eastern part of the region, the Yorkshire Electric Power Co. acquired West Gloucestershire Power and the small Chepstow company.
Power Securities/Balfour Beatty continued to invest in the Llanelly company. British Electric Traction continued to hold the Merthyr Tydfil and Penarth companies. Only three companies—Abereyron, Ogmore Valley and Pontypool—remained outside the big groups.
Although state intervention had begun to rationalise electricity generation, the efforts of the Electricity Commissioners to reduce the very large numbers of distributors were unsuccessful. The McGowan Report published in May 1936[29] and the subsequent government proposals were strongly opposed by many sections of the electricity supply industry. A recommendation in the McGowan Report, that all undertakings with annual sales of less than 10 million kWh should be amalgamated, was particularly controversial, especially among the smaller local authorities. In South Wales, only four of the 30 local authorities –Cardiff, Neath RD, Newport and Swansea–were above this level. Thirteen local authorities had sales of less than one million kWh and objected to the idea of amalgamation with large companies. The government prepared an Outline of Proposals published in April 1937[30] but the continued opposition and more pressing issues of the time meant that reorganisation of distribution was set aside.
Table 6 lists the various undertakings that were consolidated between 1920 and 1948. Only two were local authorities. Briton Ferry became part of Neath with an amalgamation. Brecon sold its small operation to the SWS Co.
Table 6 SOUTH WALES: CONSOLIDATION OF ELECTRICITY SUPPLY BEFORE 1948.
Seven small power stations were closed between 1935/6 and 1948. The largest was at Ifor in Dowlais (5,000kW); the other stations at Brecon, Llandilo, Pencader, Port Talbot, Tregaron and Ystradgynlais all had capacities of less than 1,000kW.
The South Wales industrial economy was revived by rearmament in the later 1930s. Demand for electric power soared and all the major power stations were extended. Upper Boat installed three 30,000kW generating sets between 1939 and 1942, and a new power station at Llynfi with an initial capacity of 60,000kW was initially commissioned in 1943. Similar extension work took place at the Cardiff and Newport power stations. Private generation was also expanded at the new high explosive plants at Pembrey and Caerwent. The latter site which covered nearly 2,000 acres had three power plants.[31]
[23] Third Annual Report of the Electricity Commissioners, 1922-23 (London: HMSO, 1923,), p.11.
[24] Curiously, the same consulting engineers adopted 50Hz for the Neath power station and 60Hz at Bridgend. These two generating stations were sold to the respective local authorities in 1908. See: “District Electric Power Development,” Electrical World, vol. XLV(4), February 1905, pp.191-194.
[25] Ministry of Transport, Report of the Committee appointed to review the National Problem of the Supply of Electrical Energy (London: HMSO, 1927), 39 pp.
[26] The Engineer Vol.153, 6 May 1932, p.500.34-35
[27] Fifteenth Annual Report of the Electricity Commissioners 1934-1935 (London: HMSO, 1936), p.79.
[28] Tenth Annual Report of the Electricity Commissioners 1929-1930 (London: HMSO, 1931), p.114.
[29] Ministry of Transport, Report of the Committee on Electricity Distribution, May 1936 (London: HMSO, 1936). The report noted that there were no fewer than 635 separate authorised undertakings in Great Britain in 1934, comprising the Central Electricity Board, 3 Joint Electricity Authorities, 5 Joint Boards, 373 Local Authorities and 253 Companies and persons.
[30] Ministry of Transport, Electricity Distribution: Outline of Proposals (London: HMSO, 1937).
[31] Wayne D. Crocroft, Dangerous Energy: the archaeology of gunpowder and military explosives manufacture (Swindon: English Heritage, 2000), p.206.
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