The Electricity Information Disclosure Requirements¹

(For 12 months ending 30 June 2012, 2011, 2010 and 2009)

Part 4

Energy Delivery Efficiency Performance Measures and Statistics

Disclosure under Requirement 20

1. Energy delivery efficiency performance measures

   (a) Load factor.(%)

   Electrical energy entering the transmission system as percentage of maximum demand times hours per year

   	2011/12	2010/11	2009/10	2008/09
   	66.51	69.47	68.49	67.02

   (b) Loss ratio.(%)

   Transmission losses as percentage of energy entering the system

   	2011/12	2010/11	2009/10	2008/09
   	3.76	3.79	3.72	4.02

   (c) Capacity utilisation.(%)

   Maximum demand as percentage of total transformer capacity

   	2011/12	2010/11	2009/10	2008/09
   	47.34	45.28	46.27	46.93

2. Statistics

   (a) System length down by voltage (km)

   Total	17,094	17,198	17,348	17,340
   350 kV	611	611	611	614
   270 kV (HVDC)	611	611	611	611
   0 kV (HVDC earth electrode)	31	31	31	31
   220 kV (HVAC)	8,639	8,642	8,642	8,632
   110 kV (HVAC)	6,157	6,152	6,302	6,304
   66/50/33/11 kV (HVAC)ᵃ	1,045	1,151	1,151	1,151

   (b) Circuit length of overhead electric lines, broken down by voltage (km)

   Totalᵃ	17,003	17,108	17,256	17,255
   350 kV (HVDC)	571	571	571	574
   270 kV (HVDC)	571	571	571	571
   0 kV (HVDC earth electrode)	31	31	31	31
   220 kV (HVAC)	8,639	8,642	8,642	8,632
   110 kV (HVAC)	6,146	6,142	6,290	6,294
   66/50/33/11 kV (HVAC)ᵃ	1,045	1,151	1,151	1,151

   NB: HVDC link submarine power cables measure approximately 40 km.

   (c) Total circuit length of underground electric lines (km)

   | (110 kV HVAC) | 11 | 11 | 11 | 4 |

   (d) Transformer capacity (kVA)

   | | 14.61x10⁶ | 14.51x10⁶ | 14.26x10⁶ | 14.09x10⁶ |

   (e) Maximum demand. (kilowatts)ᵇᵒ (kW)

   | | 6.92x10⁶ | 6.57x10⁶ | 6.60x10⁶ | 6.61x10⁶ |

   (f) Total electricity entering the system (before losses).ᵇᵒ (kWh)

   | | 39.70x10⁹ | 39.98x10⁹ | 39.58x10⁹ | 38.82x10⁹ |

   (g) Total amount of electricity (in kilowatt hours) supplied from the system (after losses of electricity) during the financial year on behalf of each person that is an electricity generator or an electricity retailer, or both.ᵈ (kWh)

   | | 38.21x10⁹ | 38.47x10⁹ | 38.10x10⁹ | 37.26x10⁹ |

   (h) Total connected customers

   | | 53 | 53 | 53 | 51 |

Notes

a Excludes 61 km of circuits leased from others and operated by Transpower.
b To 2 decimal places only, higher accuracy used in calculations.
c For all years, figures for maximum demand kW and kWh injected and supplied include loads on circuits leased by Transpower. The effect of these circuits cannot be measured as metering equipment is not installed at the inter-connection points with Transpower-owned assets, but the difference is estimated to be no more than 0.1% of totals. Loads on Transpower assets leased to others are not included, as Transpower does not collect operational data for these assets.
d Including sales to direct connected customers
e Minor corrections to previously disclosed 2010/11 data.

¹ Electricity Information Disclosure Requirements issued 31 March 2004 as amended by the Electricity Information Disclosure Amendment Requirements 2004, 2006, 2007, 2008 (No2), and 2008 (No3).