Transmission overhead and 66kV) 743 km Transmission underground (66kV) 38 km High Voltage overhead (22kV, 11kV and SWER) 3 195 km High Voltage underground 728 km Low Voltage overhead (includes service mains and streetlights) 1 781 km Low Voltage underground (includes service mains and streetlights) 2 177 km Source: Power and Water Corporation Overview of generating plant Appendix A identifies the power stations in the three networks, and the characteristics of the generating units that comprise them. Industry participants Electricity industry participants licensed to operate in the Darwin-Katherine, Alice Springs and Tennant Creek power systems at 30 June 2013 are listed in Table 2.2.
Discussion Historically, drivers for increasing uptake of renewable energy, non-renewable distributed energy and energy efficiency in the Territory have included both federal government initiatives (e.g. the Large Scale Renewable Energy Target (LRET), Small-scale Renewable Energy Scheme (SRES), appliance energy efficiency standards etc.) as well as some specific Territory initiatives (e.g. Alice Solar City (ASC) program and PWC Gross FiT etc.). These factors will continue to encourage the uptake of renewable energy, non-renewable distributed energy and energy efficiency in the Territory. On the one hand, policy support may reduce over time. Notably the federal government has indicated a review of the LRET/SRES schemes and FiT levels have been reducing in most other Australian jurisdictions. On the other hand, the cost of emerging technologies continues to decline. Marsden Jacobs explicitly modelled the contribution of rooftop PV to MD, whereas the impact of other technologies is implicitly accounted for in demand forecasts. PWC Zone Substation Maximum Demand Forecasts The results of the MD projections undertaken by PWC Networks for each of the three systems are presented in turn below. Darwin-Katherine Maximum Demand Forecasts The forecasts of system MD and ZSS MD on a P50 basis for the Darwin-Katherine system are shown in Figures 4.11 and 4.12 respectively. Corresponding tabular results are contained in Appendix D. Figure 4.11: Darwin-Katherine System Maximum Demand Forecasts Figure 4.12: Darwin-Katherine ZSS Maximum Demand Forecasts As described in the methodology review, the ZSS MD forecasts were done first. The ZSS MD forecasts reflect the growth trends and the assumptions of spot loads. On a system wide bass, the Forecast is higher than the historical trend. The Commission also note that excluding the 2007 year would have reduced the historical growth rate by about half. The higher Forecast Trend is considered due to the selection of a 2.7 per cent growth rate that is a combination of historical system MD growth and historical ZSS non-coincident MD growth. However the increasing diversity between the ZSS demands was not accounted for and is likely to be a factor in the overstatement of system MD demand growth. This growth rate is also assumed in some ZSS where there is limited data and this may also result in forecast error.
2 12.9% 3 2.6% >3 0.3 % The future availability quoted by PWC does not seem to be based in any significant science. To demonstrate the high levels of variability actually experienced the actual 201213 availability for Channel Island is compared to the predicted 201314 availability in the following table: Table 5.2: Channel Island Machines Actual vs. Predicted Availability Machine 20122013 Actual Availability 20132014 Predicted availability Unit 1 GE 6 Combustion Turbine (gas or diesel) 31.6 MW capacity 98.1% 92% Unit 2 GE 6 Combustion Turbine (gas or diesel) 31.6 MW capacity 0.0% 92% Unit 3 GE 6 Combustion Turbine (gas or diesel) 31.6 MW capacity 95.6% 92% Unit 4 GE Frame 6 Combustion Turbine (gas or diesel) 31.6 MW capacity 99.4% 92% Unit 5 GE Frame 6 Combustion Turbine (gas or diesel) 31.6 MW capacity 85.4% 92% Unit 6 Mitsubishi Steam Turbine (waste heat) 32 MW capacity 98.8% 92% Unit 7 GE LM6000 Combustion Turbine (gas or diesel) 36 MW capacity 85.1% 92% Unit 8 Trent 60 Combustion Turbine (gas or diesel) 42 MW capacity 87.1% 92% Unit 9 Trent 60 Combustion Turbine (gas or diesel) 42 MW capacity 66.5% 92% The historic availability values for PWC machines are highly volatile, with no discernible pattern. Typically machine availability should follow one of three basic patterns: increasing availability for relatively new plant; constant availability for mid-life plant; or reducing availability for end of life plant. One possible explanation for the PWC machines failing to follow one of these patterns is that the mean time between failures of their machines is following the expected pattern and that the mean time to repair