Over the past couple of years, ‘synchronous condenser’ became a dirty word, when it denoted a last-minute requirement of renewable energy projects seeking to connect to sections of Australia grid suffering system strength issues. The big spinning machines could add unbudgeted millions to the cost of projects already a long way into development. But strategically placed synchronous condensers, installed by network providers to enable greater penetration of renewables into the National Electricity Market, are a whole other language.
The Australian Energy Market Operator (AEMO) gave notice last week that two synchronous condensers, installed by South Australian transmission provider ElectraNet, had been commissioned and completed. A further two syncons at Robertstown will be commissioned this month.
Synchronous condensers were determined by ElectraNet to be the least-cost option for solving system strength (related to managing minor fluctuations in supply and demand on the network) and inertia (which maintains stable system frequency despite such minor fluctuations) problems in the presence of increasing renewable energy generation in South Australia.
That is, they replace the need to call on gas generators to manage gaps in asynchronous generation, delivering an estimated “net saving to customers equivalent to $3 to $5 a year on a typical South Australian residential electricity bill”, says ElectraNet, and at the same time reduce fossil-fuel emissions from gas in the national account.
Nameplate outputs achieved?
The implication for solar and wind farms in South Australia, which are generally restricted in their combined output to a maximum of around 1,300 MW, to keep the current system in balance, is bottom-line changing.
AEMO has said that the four syncons will enable the limit on renewable, aka asynchronous, inverter-based, generation, to be raised to a maximum of 2,500 MW, which should enable the state’s existing solar and wind farms to generate at capacity.
These completed projects, along with renewable generation rippling down the pipeline — such as Iberdrola’s Port Augusta Renewable Energy Park with 107 MW of solar, partnered with 210 MW of wind; and Neoen’s recently DA-approved, massive Goyder South hybrid project (1.8 GW of wind and solar and up to 900 MW of battery storage) — will also find greater purchase when Project Energy Connect, the $2.3 billion, 800 MW capacity transmission link to NSW and Victoria is completed in 2025, and their generation will be able to access interstate demand.
New network recipes to boost capacity for clean energy
The combination of system-strength boosting syncons, batteries to super-soak up peak variable renewable generation and judicious network upgrades is also being deployed in Victoria as a more flexible alternative to massive investment in transmission and distribution networks.
In May, Victorian distribution provider Powercor announced a plan to position 16 syncons, 20 batteries adjacent to substations in its network and selected network augmentation, to support the Victorian state government’s push to a 45-50% decrease in emissions by 2030 and net-zero emissions by 2050.
The combined effect of its investment, Powercor said, would be to unlock more than 1.3 GW of queueing large-scale renewable generation and enable greater distributed rooftop penetration, as well as increasing the reliability of the regional network by an average of 22%.
A renewable triumph in stages
The promise of the Robertstown and Davenport syncons, to enable more renewable generation to feed into the grid will be realised in stages, says AEMO.
Stage 1 of plant commissioning and testing is currently underway.
During Stage 2, AEMO will monitor the syncons’ interaction with the grid and at two weeks of smooth operations will progressively lift constraints currently binding asynchronous generators in South Australia.
Stage 3 comprises an extended monitoring period from 6 to 12 weeks after Stage 1, during which time AEMO will seek to transition the state system to running “a minimum” of two synchronous, gas-fired, generators, the Market Operator says.
Before the renewables industry and investors get too excited about the unleashing of previously curtailed renewable plant, AEMO cautions that during monitoring, if it is “not satisfied with the performance of the synchronous condensers, AEMO may extend this monitoring period and [continue to] limit asynchronous generation in SA”.
The research and modelling of the effects of the syncons, however, are expected to be borne out — allowing old-tech synchronous condensers take a respected, if not heroic place in the energy-transition landscape.
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