(1) This paragraph describes the threshold requirements which apply to specified kinds of essential services in the electricity subsector.

(2) For the essential service of electricity supply the threshold requirements are—

• (a)in Great Britain—
  • (i)electricity undertakings that carry out the function of supply to more than 250,000 final customers; or
  • (ii)electricity undertakings that carry out the function of supply, and generation via generators that when cumulated with the generators operated by affiliated undertakings would have a total capacity, in terms of input to a transmission system, greater than or equal to 2 gigawatts;
• (b)in Northern Ireland—
  • (i)the holder of a supply licence under Article 10(1)(c) of the Electricity (Northern Ireland) Order 1992 who supplies electricity to more than 8,000 consumers; and
  • (ii)the holder of a generation licence under Article 10(1)(a) of the Electricity (Northern Ireland) Order 1992 with a generating capacity equal to or greater than 350 megawatts.

(3) For the essential service of the single electricity market in Northern Ireland, the threshold requirement is the holder of a Single Electricity Market operator licence under Article 10(1)(d) of the Electricity (Northern Ireland) Order 1992.

(4) For the essential service of electricity transmission, the threshold requirements are—

• (a)in Great Britain—
  • (i)transmission system operators with a potential to disrupt delivery of electricity to more than 250,000 final customers;
  • (ii)holders of offshore transmission licences where the offshore transmission systems of that licence holder and its affiliated undertakings are directly connected to generators that have a total cumulative capacity, in terms of input to a transmission system, greater than or equal to 2 gigawatts; or
  • (iii)holders of interconnector licences where the electricity interconnector to which the licence relates has a capacity, in terms of input to a transmission system, greater than or equal to 1 gigawatt;
• (b)in Northern Ireland, the holder of a transmission licence under Article 10(1)(b) of the Electricity (Northern Ireland) Order 1992.

(5) For the essential service of electricity distribution, the threshold requirements are—

• (a)in Great Britain, distribution system operators with the potential to disrupt delivery of electricity to more than 250,000 final customers;
• (b)in Northern Ireland, the holder of a distribution licence under Article 10(1)(bb) of the Electricity (Northern Ireland) Order 1992.

(6) Nuclear electricity generators and generators that are not connected to a transmission system are excluded from the threshold described in sub-paragraph (2)(a)(ii).

(7) Transmission systems for which an offshore transmission licence or interconnector licence applies are excluded from the threshold described in sub-paragraph (4)(a)(i).

(8) In this paragraph—

• (a)“affiliated undertaking” has the meaning given by Article 2(12) of Directive 2013/34/EU of the European Parliament and of the Council on the annual financial statements, consolidated financial statements and related reports of certain types of undertakings, amending Directive 2006/43/EC of the European Parliament and of the Council and repealing Council Directives 78/660/EEC and 83/349/EEC;
• (b)“distribution” has the meaning given by Article 2(5) of Directive 2009/72/EC of the European Parliament and of the Council concerning common rules for the internal market in electricity and repealing Directive 2003/54/EC, (“the Electricity Directive”);
• (c)“distribution system operator” has the meaning given by Article 2(6) of the Electricity Directive;
• (d)“electricity undertaking” has the meaning given by Article 2(35) of the Electricity Directive;
• (e)“final customer” has the meaning given by Article 2(9) of the Electricity Directive;
• (f)“generation” has the meaning given by Article 2(1) of the Electricity Directive and includes the generation of electricity from stored energy, and “generator” must be interpreted accordingly;
• (g)“interconnector licence” means a licence granted under section 6(1)(e) of the Electricity Act 1989;
• (h)“offshore transmission licence” and “offshore transmission” have the meaning given by section 6F(8) of the Electricity Act 1989;
• (i)“stored energy” means energy that—
  • (aa)was converted from electricity, and
  • (bb)is stored for the purpose of its future reconversion into electricity;
• (j)“supply” has the meaning given by Article 2(19) of the Electricity Directive;
• (k)“transmission” has the meaning given by Article 2(3) of the Electricity Directive; and
• (l)“transmission system operator” has the meaning given by Article 2(4) of the Electricity Directive.