Module B1 Study Book - the Graduate School of the Environment

transmission lines. It was completed in 1934, standardized on 50-cycle AC,
with only 140 stations from the original 438 still operating. Generation costs
fell by 24%: a triumph of central planning!
With nationalization in 1947, the private and municipal electricity undertakings
were amalgamated into Area Electricity Boards, and 240 volts AC was chosen
as the ‘standard’ UK distribution. From 1957 onwards the state-owned Central
Electricity Generating Board (CEGB) both owned and coordinated electricity
generation in England and Wales.
Scale
The centralization process led to the development of larger generating units
with higher efficiencies and lower staffing costs. Battersea power station in
London, when it was commissioned in 1934 contained a 105 MW steam
turbine and generator, then the largest set in Europe. By the 1970s single
turbine generator sets of over 600 MW were being used in the UK, and over
1000 MW in the US.
There were exceptions like Battersea, but, generally, new stations were
concentrated near the coal fields, a trend later also driven by pollution
legislation. A 1 GW coal-fired power station requires about 10 000 tonnes of
coal [ten large, slow, train-loads] a day to keep it going: they also needed to
be kept as far away as possible from the rest of the rail network. Most of the
country’s electricity was ‘coal by wire’.
With rising size of station, there was also increasing steam temperatures and
pressures and therefore rising generation efficiency. Coal-fired stations in
England and Wales increased their average efficiencies from about 17% in
1932 to 27% in 1960 and to 36% in 2000, after which it has flattened out.
New fuels
Falling oil prices in the 1950’s and 60’s prompted plans for new oil-fired
power stations. Unfortunately, the first ones came on stream shortly before
the oil price rose dramatically. One, enormous, station at Grain in the Thames
estuary was never fully completed and remains virtually unused today.
Civil nuclear power began in 1956 with Calder Hall station, Chapelcross in
1959, and then nine more Magnox stations were commissioned between
1962 and 1971. Later stations were Advanced Gas Cooled (AGR) reactors
and Pressurized Water Reactors (PWR)
Natural gas was little used in UK power stations until the ‘dash for gas’ of the
1990s.
Transmission and distribution
Britain was fortunate that power generation on the grid was standardized so
early. Building the system of pylons, cables, transformers, etc, was slow, partly
because of the planning laws, but by 1933 4800 km of 132 kV transmission
lines had been built. One of the biggest benefits was that, with the greater
flexibility of operation, a failure in one station did not mean black out. On the
Lecture: Britains Power System 87