The Effect of Increasing the Number of Wind Turbine Generators on Transmission Line Congestion in the Australian National Electricity Market from 2014 to 2025

Abstract

This report investigates the effect of increasing the number of wind turbine generators on transmission line congestion in the Australian National Electricity Market’s (NEM) existing transmission grid from 2014 to 2025. This reports answers urgent questions concerning the capability of the existing transmission grid to cope with significant increases in wind power. The report findings will help develop a coherent government policy to phase in renewable energy in a cost effective manner.

We use a sensitivity analysis to evaluate the effect of five different levels of wind penetration on transmission congestion. The five levels of wind penetration span Scenarios A to E where Scenario A represents ‘no wind’ and Scenario E includes all the existing and planned wind power sufficient to meet Australia’s 20% 2020 41TWh Large Renewable Energy Target (LRET). We also use sensitivity analysis to evaluate the effect on transmission congestion of growth in electricity demand over the projections years 2014 to 2015 and weather over the years 2010 to 2012. The sensitivity analysis uses simulations from the ‘Australian National Electricity Market (ANEM) model version 1.10’ (Wild et al. 2015).

We find congestion on only 14 of the 68 transmission lines in the ANEM Model (Wild et al. 2015). Notably, these 14 congested transmission lines include six of the NEM’s interstate interconnectors and eight of the intrastate transmission lines although only three of the intrastate transmission lines exhibited any significant degree of congestion. The increase in wind power penetration has an uneven effect on congestion. The two Queensland (QLD) to New South Wales (NSW) interconnectors QNI and DirectLink exhibit a complementary pattern. Wind power increases congestion on DirectLink but decreases congestion on QNI. BassLink, the interconnector that links Victoria (VIC) and Tasmania (TAS), and the Tarraleah-Waddamana line in TAS also exhibit a complementary pattern that reverses in the highest wind power penetrations scenario E. In contrast, the congestion on the interconnector Regional VIC-Tumut NSW shows volatility with increasing wind power penetration. Finally, the VIC to South Australia (SA) interconnector MurrayLink shows the greatest percentage increase in congestion with increase in wind power.