Distribution network operator

From Wikipedia, the free encyclopedia

A distribution network operator (DNO), also known as a distribution system operator (DSO), is the operator of the electric power distribution system which delivers electricity to most end users. Each country may have many local distribution network operators, which are separate from the transmission system operator (responsible for transporting power in bulk around the country).


In France, Enedis, a subsidiary of EDF, distributes approximately 95% of electricity, with the remaining 5% distributed by 160 local electricity and gas distribution companies (entreprises locales de distribution d'électricité et de gaz or ELD).[1]

Great Britain[edit]

In Great Britain, distribution network operators are licensed by the Office of Gas and Electricity Markets.

There are fourteen licensed geographically defined areas, based on the former area electricity board boundaries, where the distribution network operator distributes electricity from the transmission grid to homes and businesses. Under the Utilities Act 2000 they are prevented from supplying electricity; this is done by a separate electricity supply company, chosen by the consumer, who makes use of the distribution network.

Distribution network operators are also responsible for allocating the core Meter Point Administration Number used to identify individual supply points in their respective areas, as well as operating and administering a Meter Point Administration System that manages the details relating to each supply point. These systems then populate ECOES (Electricity Central Online Enquiry Service), the central online database of electricity supply points. Their trade association is the Energy Networks Association.


Map of DNO licence areas, coloured by company group (situation as of 2010)

In 1990, the area boards were replaced by regional electricity companies, which were then privatised. The distribution network operators are the successors to the distribution arms of the regional electricity companies. The distribution network operators have a trade association called the Energy Networks Association.

As of October 2022, six company groups hold the fourteen distribution licences:[2]

GSP Group ID Area ID Area DNO company Group Former area electricity board MPAS Operator ID
_A 10 East England Eastern Power Networks plc UK Power Networks Eastern Electricity EELC
_B 11 East Midlands National Grid Electricity Distribution (East Midlands) plc National Grid Electricity Distribution East Midlands Electricity EMEB
_C 12 London London Power Networks plc UK Power Networks London Electricity Board LOND
_D 13 North Wales, Merseyside and Cheshire SP Manweb plc SP Energy Networks MANWEB MANW
_E 14 West Midlands National Grid Electricity Distribution (West Midlands) plc National Grid Electricity Distribution Midlands Electricity MIDE
_F 15 North East England Northern Powergrid (Northeast) plc Northern Powergrid North Eastern Electricity Board NEEB
_G 16 North West England Electricity North West Limited Electricity North West NORWEB NORW
_P 17 North Scotland Scottish Hydro-Electric Power Distribution plc Scottish and Southern Electricity Networks North of Scotland Hydro-Electric Board HYDE
_N 18 South and Central Scotland SP Distribution plc SP Energy Networks South of Scotland Electricity Board SPOW
_J 19 South East England South Eastern Power Networks plc UK Power Networks Seeboard SEEB
_H 20 Southern England Southern Electric Power Distribution plc Scottish and Southern Electricity Networks Southern Electric SOUT
_K 21 South Wales National Grid Electricity Distribution (South Wales) plc National Grid Electricity Distribution SWALEC SWAE
_L 22 South West England National Grid Electricity Distribution (South West) plc National Grid Electricity Distribution SWEB SWEB
_M 23 Yorkshire Northern Powergrid (Yorkshire) plc Northern Powergrid Yorkshire Electricity YELG


In addition to the distribution network operators noted above who are licensed for a specific geographic area there are also independent distribution network operators (IDNO). IDNOs own and operate electricity distribution networks which will predominantly be network extensions connected to the existing distribution network, e.g. to serve new housing developments.

Area ID Name Licensee MPAS Operator ID
24 Envoy Independent Power Networks IPNL
25 ESP Electricity ESP Electricity LENG
26 Last Mile Electricity Last Mile Electricity GUCL
27 GTC The Electricity Network Company Ltd ETCL
28 EDF IDNO UK Power Networks (IDNO) Ltd EDFI
29 Harlaxton Energy Networks Ltd Harlaxton (IDNO) HARL
30 Leep Electricity Networks Ltd Leep Electricity Networks (IDNO) PENL
31 UK Power Distribution Ltd UK Power Distribution Ltd UKPD
32 Energy Assets Networks Ltd Energy Assets Networks Ltd. UDNL
33 Eclipse Power Networks Eclipse Power Networks GGEN
34 mua Electricity Ltd mua Electricity Ltd MPDL
35 Fulcrum Electricity Assets Fulcrum Electricity Assets FEAL
36 Vattenfall Networks Ltd Vattenfall Networks Ltd VATT
37 Optimal Power Networks Optimal Power Networks FORB
38 Indigo Power Limited Indigo Power Limited INDI
39 Squire Energy Metering Ltd Squire Energy Metering Ltd STRK
40 Utility Assets Limited Utility Assets Limited UTAL
42 Advanced Electricity Networks Advanced Electricity Networks AENL

Building network operators[edit]

A further, smaller level of distribution is the building network operator (BNO), usually a company employed by the building owner, in a large building with many meters, such as a block of private flats.

In this case, the DNO may act as BNO and its responsibility may include the sub-mains to the individual flats, or DNO responsibility may end at the first incomer, in which case the independent BNO is responsible for the secure distribution cabling 'laterals' between that point and the individual fuses and meters.

Historically such cabling would have been maintained and sealed by electricity boards that preceded the DNOs, and different DNOs supplying buildings of different sizes and conditions, may choose to adopt the wiring in the building or to insist that an independent BNO is appointed.[3] Unlike a DNO or an IDNO, BNOs may be exempted from any licensing requirement by schedules 2 and 3 of The Electricity (Class Exemptions from the Requirement for a Licence) Order 2001[4] and this allows those responsible for the building network (such as a housing association) to employ any suitable electrical contractor on an ad-hoc basis.


In Canada, the distribution network operators are known as local distribution companies (LDC).

LDCs normally buy their power from larger companies, sometimes ones dedicated solely to wholesale supply. They re-sell it to the smaller customer. Larger customers typically buy their power directly from the wholesaler, and do not use the LDC.

See also[edit]


  1. ^ Jean Proriol, Rapport d'information No. 3307 déposé par la commission des affaires économiques de l'Assemblée nationale, assemblee-nationale.fr du 5 avril 2011, consulté le 30 avril 2020
  2. ^ "Energy network indicators". Ofgem. Retrieved 14 October 2022.
  3. ^ "Engineering Design Standard EDS 08-0118: Multi-Occupied Building Supplies" (PDF). 2016-04-22. Archived from the original (PDF) on 2016-07-06. Retrieved 2016-06-07.
  4. ^ "The Electricity (Class Exemptions from the Requirement for a Licence) Order 2001".

External links[edit]