6. History of Electricity Supply Industry

Keith ToveyН.К.Тови М.А., д-р технических наук

Energy Science Director

CRed Project

ENV-2E02 Energy Resources

2004 - 2005

• Prior to 1900 - numerous small utilities sprang up in towns and cities. Many operated on DC (Direct Current).

• Early 20th Century, Local Authorities in control of supply. – Supply switched to AC, – Some areas still had DC until after Second World War.

• In 1924 there were about 435 power stations supplying electricity.

• In 1930s, the Central Electricity Board began establishing a National Grid, initially at 33kV, then 66 kV and finally by the early 1950's, 132 kV.

• Higher voltages for transmission minimise transmission losses.

• The CEB built larger stations connected to grid

6. Early Background 1900 - 1957

• At end of War, the number of stations had dropped to 345.

• cf 240 in 1965

• 168 in 1976

• 78 in 1986

• 1947 Electricity Act (effectively Nationalisation)

• In most other countries, supply of electricity, gas etc. remained in the control of the Local Authority.

• The Act also set up the BRITISH ELECTRICITY AUTHORITY as the successor company to the CEB.

6. Early Background 1900 - 1957

• ELECTRICITY AUTHORITY as the successor company to the CEB.

• Finally in mid 1950's, the BRITISH ELECTRICITY AUTHORITY was reorganised as follows:-

• CEGB - responsible for generation and supply to the local Electricity Boards. CEGB only operated in England and WALES, and was divided into 5 regions. The CEGB operated nuclear, coal, oil, gas, and hydro stations.

• ELECTRICITY BOARDS - purchased electricity from the CEGB and distributed it to customers. There were 12 Area Boards (e.g. MANWEB, SEEBOARD etc). These Boards did not generate electricity.

• ELECTRICITY COUNCIL - This was a body covering the whole

Electricity Industry, and had a Research Centre at Capenhurst.

6. Early Background 1900 - 1957

• SCOTLAND, the organisation was different.

• SOUTH OF SCOTLAND ELECTRICITY BOARD. (essentially area covered by SCOTTISH POWER)

– Generated and supplied electricity to customers in the South of Scotland. It also operated nuclear power stations.

• NORTH OF SCOTLAND HYDRO BOARD.

– Generated electricity mostly by Hydro-electricity and supplied electricity to the North of Scotland and the outlying islands. Fossil Fired power stations were built, and the hydro component became less than 50%.

• The NSHB exchanged electricity with SSEB who in turn exchanged electricity with the CEGB.

• A low power link was also installed to link the CEGB with Electricite de France (EdF).

6. Early Background 1900 - 1957

• CEGB began installing Super-grid at voltages of 275 kV and finally 400 kV.

• Decision taken in early 1960's to build new power stations to avoid shortages of late 1950's and early 1960's.

• Sited on coal fields or on coast (Nuclear and Oil). • Electricity became National Electricity Vector•

• Consequences:-

• Less coal by rail - closure of lines in 1960's• More Grid Lines needed

– ( even today there are parts of the country which are vulnerable eg SW and SE).» Made implementation of CHP difficult.» Power stations became very » Large stations did not have nearby heat sink for CHP.

6. DEVELOPMENTS ELECTRICITY SUPPLY 1957-90

6.1. Change in Demand for Electricity

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6.1. Change in Efficiency of Generation of Electricity

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6.1. Installed Capacity

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6.1. Maximum Demand

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Typical UK Electricity Demand in Winter

2003

For an up to date indication of actual demand – consult

www.bmreports.com

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Typical UK Electricity Demand in Summer

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1st August 2002

• Electricity CANNOT be stored, and generating capacity at any instant must be closely matched to demand.

• FORECAST DEMAND AS ACCURATELY AS POSSIBLE.

• FACTORS AFFECTING DEMAND:-

Weekdays have generally similar demand pattern Weekends have a different but generally consistent demand

pattern.

Minor variations occur:-

– e.g. larger morning peak on Mondays, more spread out evening peak on Fridays.

6.2. Forecasting Demand

Weather affects demand by shifting curve upwards:-

• *Dominant factors:-

• EXTERNAL TEMPERATURE

(approx. 8% increase in heating demand per 1o C drop in temperature).

– INDUSTRIAL DEMAND (these are usually constant for a given day)

Other factors:-

• * Wind chill • * Solar gain

• - affect consumption by a few percent at most.

Seasonal factors shift evening peak to late evening as daylight hours increase.

6.2. Forecasting Demand

• MADE BY NATIONAL GRID TRANSCO

• 1) LONG TERM:- Strategic planning of requirements of period of years.

• 2) SHORT TERM:- (about 1 week ahead)

• on basis of long range weather forecasts

• 3) 24-HOUR FORECAST:- (previous afternoon)

• on basis of latest weather information.

• indirectly influences which generating plant are used.

• 4) SHORT TERM FLUCTUATIONS:-

• equipment failures,

• television adverts etc.

– dealt with by use of pumped storage schemes, use of GAS TURBINES etc.

• A reserve of about 0.5 - 1.0% is usually provided by running generators slightly under full load.

6.3. Levels of Forecasting

• FORECASTS FOR SPECIAL OCCASIONS ARE VERY DIFFICULT

• SPECIAL SPORTING EVENTS can cause minor problems

• (e.g. the CUP FINAL going to extra time),

• Electricity cannot be stored except in small quantities so power stations are called into use as needed.

• If a station is cold it may need up to 1 day to come on line. Even when hot most will need at least 20 minutes to come up to full power.

Cheapest marginal plant were run first Then base-load Coal - most efficient coal.

• Above plant are run continuously for several days on end as demand is always above output (at least in short term)

The cost for running a particular plant will depend on how warm the plant is.

6.4. Meeting Demand - former CEGB Method

6.3. Levels of Forecasting