Ausgrid considers that a fully cost-reflective tariff may involve a localised dynamic peak energy charge. The efficient properties of such a tariff draw from the resulting application of peak prices on only the few days when peak events occur and to only customers using elements of the network that are constrained. The theoretically efficient tariff is discussed in more detail in section 8.1. The illustrative LRMC-based peak energy charge that would arise from the implementation of a dynamic peak charging parameter is presented in Table 7 below. Table 7 – LRMC estimates for dynamic peak charging parameter Tariff LRMC Conversion Parameters Illustrative LRMC DUOS Price $/kW Alpha () No. of peak c/kWh Low Voltage 164 1 72 227 High Voltage 53 1 72 73 Sub-transmission Voltage 8 1 72 11.6 Source: Ausgrid 2015 However, Ausgrid has not introduced localised dynamic peak pricing in the next regulatory control period because the are likely to outweigh the associated economic benefits. Further, the implementation of such a tariff would impose unacceptable bill impacts on our customers, as discussed later in section 8 and in Appendix A. The seasonal peak energy charge Ausgrid is applying seasonal peak energy charges and is reforming the residential winter peak period from 1 July 2018, as discussed in detail in section 6. The resulting definition of the peak periods is summarised in Table 8 below. Table 8 – Time periods for seasonal peak charging parameter Season Proposed Time Period Definition Summer peak period From 2pm to 8 pm on working weekdays during 1 November and 31 March (inclusive) Winter peak period (residential) From 5pm to 9pm on working weekdays during 1 June to 31 August (inclusive) Winter peak period (business) From 2pm to 8pm on working weekdays during 1 June to 31 August (inclusive) For the purpose of guiding its decisions on the peak energy charge for Ausgrid’s TOU tariffs, Ausgrid calculated the illustrative peak energy charge for each tariff class under the seasonal peak period definitions. These illustrative estimates are presented in Table 9 below. 9 – LRMC estimates for seasonal peak charging parameter Tariff LRMC Conversion Parameters Illustrative LRMC DUOS Price $/kW Alpha () No. of peak c/kWh
Table – Ausgrid’s Peak, Shoulder and Off-peak Periods for residential customers – Current Vs Proposed Time Period Existing Definition New Seasonal Peak Period Definition from 1 July 2018 Peak period From 2 pm – 8 pm on working weekdays N/A Summer peak period N/A From 2pm – 8pm on working weekdays during 1 November and 31 March (inclusive) Winter peak period N/A From 5pm – 9pm on working weekdays during 1 June to 31 August (inclusive) Shoulder period From 7 am – 2 pm and 8 pm – 10pm on working weekdays From 7am to 10pm on weekends and public holidays Note: In simple terms, the shoulder period runs from 7am to 10pm every day, except where a peak period applies during that period. In the summer months, from 7am to 2pm and from 8 pm to 10pm on working weekdays In the winter months, from 7am to 5pm and from 9pm to 10pm In the non-summer and non-winter months, from 7am to 10pm on working weekdays. From 7am to 10pm on weekends and public holidays. Off-peak period All other times All other times Source: Ausgrid 2015 Table 12 – Ausgrid’s Peak, Shoulder and Off-peak Periods for small, medium and large business customers – Current Vs Proposed Time Period Existing Definition New Seasonal Peak Period Definition from 1 July 2018 Peak period From 2 pm – 8 pm on working weekdays N/A Summer peak period N/A From 2 pm – 8 pm on working weekdays during 1 November and 31 March (inclusive) Winter peak period N/A From 2 pm – 8 pm on working weekdays during 1 June to 31 August (inclusive) Shoulder period From 7 am – 2 pm and 8 pm – 10pm on working weekdays For business customers only, from 7am to 10pm on weekends In the summer and winter months, from 7 am – 2 pm and 8 pm – 10pm on working weekdays In the non-summer and non-winter months, from 7am – 10 pm on working weekdays Off-peak period All times All other times