The South-West of WA will have enough capacity to generate the electricity it needs for the next decade despite the closure of some Collie coal-fired units, helped by rooftop solar and batteries reducing peak demand.

The Australian Energy Market Operator’s 2020 electricity statement of opportunities released today concluded that despite Synergy’s plans to retire its Muja unit 5 in 2022 and Muju unit 6 in 2024 there would be enough generation capacity to meet demand to at least 2030.

Growth in peak demand that determines how much generation capacity is required will slow over the next few years due to increased rooftop solar, the installation of battery storage systems and improved energy efficiency.

Rooftop solar is estimated to have cut 4.4% off-peak demand last summer.

AEMO WA general manager Cameron Parrotte said the world-leading adoption of rooftop solar and the changes in the generation mix presented both operational challenges and exciting opportunities.

AEMO expects the power generated by rooftop solar at times of low demand to push demand for generation below the 700 megawatts that AEMO regards as the system security threshold.

“Below this point, the available synchronous generation and associated inertia and voltage control may not be sufficient to maintain reactive power balance, and the SWIS may be exposed to unacceptable power system risks,” the report said.

Synchronous generation has traditionally provided so-called essential system services, including inertia, frequency control, and voltage control.

An increase in both utility and behind the meter renewable generation means there is less traditional synchronous generation driven by gas turbines and coal-fired steam turbines that rotate with the grid frequency of 50 cycles a second.

“AEMO believes the review of technical standards, regulatory, and market constructs are required, with practical and careful design needed to implement or incentivise new technologies in the SWIS,” Parrotte said.

The AEMO report said other technologies, including batteries and synchronous condensers, can supply these services but the rules of the WA Wholesale Electricity Market will need to change to provide financial incentives for the investment.

In April the WA Government’s Energy Transformation Taskforce produced a distributed energy roadmap of measures to deal with uncontrolled nature rooftop solar generation.

No sunset to renewables growth

The total capacity of rooftop solar is expected to grow by 6.5% a year and reach 2612 MW by 2030, but a high growth 9.5% a year scenario could see behind the meter generation capacity reach 3687 MW.

The capacity of batteries installed on the South West Interconnected System is expected to grow by 30.5% a year over the decade as costs fall.

The combination of rooftop solar and batteries is likely to shift peak demand from between 5 PM and 6 PM to after 6:30 PM.

The number of electric vehicles in the South West of WA is expected to soar from about 1000 now to almost 100,000 in 2030 and account for 2% of total demand.

However, the forecast has an incredibly wide range with a high estimate of 500,000 EVs in 2030 and a low estimate of 11,000.

AEMO noted the influx of utility-scale renewable generation onto the grid.

The 130MW Badgingarra Wind and Solar Farm was commissioned in January 2019.  A further 500MW of renewable generation capacity is expected to connect during 2020, including Yandin Wind Farm (210 MW), the Warradarge Wind Farm (180 MW), and the Merredin Solar Farm (100 MW).


Main image: power lines. Source: Photo by Jan Kaluza on Unsplash