ANNUAL REPORT 2021-22

20 Outages and works 21 ANNUAL REPORT 2021-22 ANNUAL REPORT 2021-22 Territory Generation's outage planning program is critical to our business. We forecast and conduct outages and works to maintain our generating units and ensure the delivery of safe, reliable and cost-effective electricity services. Our outage planning scope includes machine replacements, upgrades, maintenance, repairs, and improvements. Darwin-Katherine interconnected system CHANNEL ISLAND AND WEDDELL GAS SUPPLY Gas for Channel Island and Weddell power stations is supplied by Power and Water Corporation from Eni's Blacktip field. In the event Blacktip is unavailable, emergency gas has been supplied by Darwin LNG. However, as production at Darwin LNG is forecast to slow, INPEX has been contracted by PWC as an additional emergency supplier. INPEX gas from the Ichthys field is export quality, which means it has been stripped of inert gases and has approximately 17 per cent more energy content. We carried out crucial trials at Channel Island and Weddell power stations to test if our machinery could handle the transition to higher- energy gas and back again. Both trials were deemed successful. CHANNEL ISLAND C8 is a Siemens aero-derivative turbine which was scheduled for a mid-life overhaul and hot section exchange at 35,000 hours. In 2020, we removed the turbine for transport and repair by Siemens in Abu Dhabi and replaced it with a lease unit. 132 KV CABLE REPLACEMENTS PROGRAM Replacement of the ageing 132 KV cables from the generator set-up at Channel Island Power Station are now 90% complete with only C1 installation remaining. The works were postponed until 2022 to align with Power and Water Corporation switch yard works. WEDDELL The W2 annual outage in May found the engine to be unserviceable. It was replaced with the on-hand spare Weddell engine. A new engine will replace the W3 engine at Weddell Power Station later in 2022 when its service hours have been consumed. Procurement of a new Weddell engine has been completed and delivery is anticipated before 30 June. Southern region OWEN SPRINGS OSO3 is one of three MAN 10.9 mW medium-speed reciprocating dual-fuel engines that provide inertia and improve the security of the Alice Springs power system. Its 16,000-hour service was completed in July 2021. Work included the removal of all cylinder heads and replacement of pilot injector tubes, required because the other two MANS had already been upgraded. Heads were pressure tested and refitted back onto the engine. All pilot injectors and gas valves were then installed. All the work was done. by our own team. KINGS CANYON KCO2 is one of three engines at the Kings Canyon Power Station. KC01 and KCO2 are 400 kW QSX15 Cummins diesel engines and KC03 is a 200 kW QSL9 Cummins diesel engine. KC02 was replaced with the original KC03 after its scheduled overhaul, which was completed in December 2021 by contractors and internal personnel. TENNANT CREEK TC19 is one of three Jenbachers installed at Tennant Creek Power Station in 2017. TC19, TC20 and TC21 are spark-fired engines rated at 1.8 MW. The TC19 head was replaced in September 2021 at the due 10,000 hours by internal personnel and contractors. Graduate Mechanical Engineer, Steven Sawyer, inspects Weddell W2. ial Controls Electrical and maintenance works at Ron Goodin Power Station.

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