Grid stability and renewables integration |
Dealing with the duck curve in Western Australia
How gas turbine based power plants have been modified to act as synchronous condensers, bringing increased stability and reliability to the Western Australia grid
Drew Robb
The Australian grid has been heavily reliant on coal for decades. That is changing rapidly. An abundance of renewable resources is being introduced to the grid as coal plants are steadily retired. According to the Australian Energy Market Operator (AEMO), up to 90% of the coal fired power stations participating in the National Electricity Market (NEM) are projected to retire before 2035, and the entire fleet before 2040. “As coal fired power stations retire, renewable energy connected with transmission and distribution, firmed with storage, and backed up by gas-powered generation is the lowest- cost way to supply electricity to homes and businesses through Australia’s transition to a net zero economy,” said Daniel Westerman Chief Executive Officer, AEMO. “New generation, storage and firming must be in place before coal power stations retire, and to meet Australia’s growing demand for electricity.”
Already this decade, 12.5 GW of new utility- scale generation and 1.3 GW/1.8 GWh of storage has entered the National Electricitry
Market and 490 km of transmission lines have been built. A further 20 GW of generation and storage and 2090 km of transmission lines are progressing from planning to delivery. As more renewables are added, there is a need to support them with sufficient system stability and inertia. Hence, many regions of Australia are adding synchronous condensers to stabilise voltage levels and support the performance and reliability of the grid.
“In recent years, there has been an increased focus on the need for synchronous compensating functions worldwide,” said Jean- Bernard Gross, Technical & Sales Area Manager for Australia at gearbox manufacturer Flender- Graffenstaden. “This is in line with the worldwide push for renewables integration and the need for increased system inertia and system strength.”
The Western Australian picture Western Australia (WA) covers about a third of the Australian landmass. Most of it is empty.
Two million of the 2.6 million people in the state are located in the Perth metro region in the southwest.
WA’s Southwest Integrated System (SWIS) includes Perth but reaches far to the north, south and east to take in a few distant population centres. Western Power owns and operates the transmission and distribution infrastructure within the SWIS. Synergy is a major generator and retailer of electricity in the SWIS, serving over one million residential, business and industrial customers. Western Power and Synergy are owned by the WA government. Due to the enormous distances involved, the NEM grid in the eastern side of Australia is not connected to WA.
The Southwest Integrated System of Western Australia has a network of over 7800 km of transmission lines. Synchronous condensers are needed to add system strength in the face of coal plant retirements as well as to increase the efficiency of the transmission network. Source: Synergy
Electricity in SWIS is generated from a variety of sources. Coal plants, natural gas fired generators, waste-to-energy plants (eg, employing landfill gas), wind farms, and solar farms are all significant contributors. Rooftop solar is now the biggest single source of generation capacity during the middle of the day. More than 30% of homes in SWIS have rooftop photovoltaic systems. The rest of the time, the region relies largely on coal and gas, though wind power is steadily adding to its share of the total. As a result, SWIS now has a duck curve that is similar to the phenomenon first noted on the California grid.
Coral Bay Western Australia Legend
South West Interconnected System (SWIS)
station
Wind farm Gas turbine
Battery
Kalbarri Mungarra
West Kalgoorlie Alkimos PERTH Cockburn Pinjar
Colllie
Muja Bremer Bay
Decarbonising Western Australia The state government has established PoweringWA to co-ordinate the delivery of the new electricity infrastructure needed to decarbonise and strengthen the SWIS grid. As well as embracing renewable energy, the plan includes a more reliable transmission infrastructure that can bring wind and solar power to load centres. For example, the Merredin solar farm is being built about 260 km east of Perth. It comprises 360 000 solar panels and will generate 281 GWh of electricity annually. In addition, PoweringWA is adding more battery energy storage systems (BESS). Synergy has already deployed 100 MW/200 MWh of battery energy storage in the Perth area, known as Kwinana Big Battery, enough to power 160 000 homes for two hours. This is all part of Synergy’s goal to reduce carbon emissions by 80% by 2030, compared to 2020 levels, and achieve net zero by 2050.
The latest forecast calls for 4000 km of new transmission lines and around 50 GW of new
14 | April 2025|
www.modernpowersystems.com
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