GB Electricity Market

1
GB Electricity Market
See www.nationalgrid.com/uk/library/documents/SYS0
7 for further details
2
Electricity Networks History

• 1904 UK frequency standardised at 50 Hertz
• 1926 to 1937 National 132kV grid constructed.
• 1948 Electricity was nationalised
• Generation transferred to British Electricity
  Authority (later C.E.G.B.)
• local distribution transferred to Area Boards
• 1952 onward CEGB constructed Supergrid
  transmission system at 275kV and 400kV
• 1970s Area Boards took over the 132kV network
• 1990 Electricity Privatisation
• EW - CEGB split into 3 generating companies plus
  National Grid (275400kV)
• EW 12 Regional Electricity Companies (supply
  distribution to132kV)
• Scotland 2 Integrated companies generation,
  transmission, supply and distribution
• 1999 Regional Electricity Companies and Scottish
  Companies forced to separate
• EW into Supply Business and Distribution Network
  Operator (to 132kV)
• Scotland into Generation, Supply, Transmission
  (132-400kV) and Distribution businesses
• 2005 BETTA
• National Grid split into TO and SO SO operates
  Scotland as well as EW

3
Pre-1990 Electricity Supply Organisation
The Electricity Council
CEGB Central Electricity Generating
Board (England Wales)
Generation
Transmission
Distribution
Supply
plus 2 vertically integrated Scottish Boards
4
Todays Electricity Supply Sector
gt30 domestic supply licencees (but 6 big players)
gt 70 generation licencees (but lt10 big players)
Transmission Owners x 3
Transmission Operator x 1
Distribution Owner/Operators x 7
Private Companies
Generation
Transmission
Distribution
Supply
5
Structure of Electricity Industry in early 1990s
Competitive Generation

• Scotland
• Vertical Integration
• two companies

England and Wales National Grid run Pool and
Transmission 12 Regional Electricity Companies
. (Supply distribution network)
6
GB Electricity Distribution Network Owners 2007
7
Characteristics of Distribution/Transmission

• Historically
• Transmission
• Connected major power stations
• for bulk transfer of power
• active control of power and voltage
• Transmission SO has clear independence from
  Generation and Supply
• Distribution
• Very little embedded generation
• single direction flow (400kV to customer)
• essentially passive networks
• Group ownership of generation and distribution
  provides very limited scope for anti-competitive
  behaviour

8
Going forward

• Operational differences between Transmission and
  Distribution beginning to blur
• More Distributed Generation within Distribution
  Networks
• May require extension of Transmission SO
  independence from Generation and Supply to
  Distribution
• But unlikely to change current distribution and
  transmission licence areas / voltages.
• Note New Offshore transmission licences (for
  132kV and above) being developed