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6. History of Electricity Supply Industry Keith Tovey Н.К.Тови М.А., д-р технических наук Energy Science Director CRed Project ENV-2E02 Energy Resources.

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Presentation on theme: "6. History of Electricity Supply Industry Keith Tovey Н.К.Тови М.А., д-р технических наук Energy Science Director CRed Project ENV-2E02 Energy Resources."— Presentation transcript:

1 6. History of Electricity Supply Industry Keith Tovey Н.К.Тови М.А., д-р технических наук Energy Science Director CRed Project ENV-2E02 Energy Resources 2004 - 2005

2 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

3 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

4 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

5 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

6 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

7 6.1. Change in Demand for Electricity

8 6.1. Change in Efficiency of Generation of Electricity

9 6.1. Installed Capacity

10 6.1. Maximum Demand

11 Typical UK Electricity Demand in Winter 2003 For an up to date indication of actual demand – consult www.bmreports.com

12 Typical UK Electricity Demand in Summer 2002 1st August 2002

13 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

14 Weather affects demand by shifting curve upwards:- *Dominant factors:- EXTERNAL TEMPERATURE (approx. 8% increase in heating demand per 1 o 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

15 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

16 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


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